CA Elsinore Valley MWD Riverside Co ( CA 12 LE CB)

San Jacinto river? citrus vegetables olives ( urban; alfalfa) high 47833 Railroad Canyon Reservoir ( Canyon Lake) 11,867 acre ft Small 445,551 1720 ( Oak Ridge)

Corona, CA City of Corona Riverside Co ( CA 16 CO CB)

( actually, Colorado River) citrus vegetables olives high 47833 Lake Mathews ( Colorado River aquaduct) 182,000 acre ft Small 16,350s inter basin transfer watershed is Colorado River upstream from Lake Havasu Lodi, CA Little Potato Slough Mutual San Joachin, Co ( CA 25 ST CB) tree nuts,

stone fruit high 23896 Little Potato Slough  Medium 1,319,214 5341 ( Aventis)

West Sacramento,

CA City of West Sacramento Yolo, Co ( CA 37 WS CB) tree nuts,

stone fruit ( orchard:

2.7% watershed) high 13065 Sacramento River  Medium 14,301,323 57,895 ( Aventis)

Sacramento,

CA ( aka Riverside,

CA CA aquaduct Harvy O Banks Filtration Plant ( State Water Project) multiple counties from Lake Shasta to Sacramento Delta tree nuts,

stone fruit high cannot be estimated Origin in high Sierras, Feather River, Sacramento River and Delta. 2,700,000 acre ft storage in Oroville dam. California aquaduct capacity:

2 billion gallons per day Very large 27,826,575 112,651 ( Aventis)

Bradenton, FL Manatee Co.

Water Treatment Plant Manatee Co.

( FL 2 BR CB) citrus, vegetables medium 3200 Lake Manatee ( impoundment of Little Manattee R) 32,500 acre ft ( est) Small 90,609 300 ( Oak Ridge)

Brockton, MA Brockton Water Treatment Plant Plymouth, MA ( MA 7 BR CB) cranberries medium 8318 Silver Lake 1100 acre ft ( est.) Small 2,620 10.6 ( Aventis) intake location ( city and state) system name watershed location ( SEI #) carbaryl use crop carbaryl sales ( RPAC) carbaryl use ( lbs per county),

based on Doane source water volume of waterbody watershed size Aventis ( acres) EFED ( square km)

90 Deerfield, MI Village of Deerfield Lenawee Co.

( MI 4 DE CB) potatoes,

apples, vegetables,

corn medium 1500 River Raisin  Medium 453,648 1,575 ( Oak Ridge)

Westfield, NY Village of Westfield Chatauqua Co.

( NY 13 WE CB) grapes high 29,901 Minton Reservoir ( 90%) 10.7 acre ft Small 502 0.005 ( Oak Ridge)

Aventis 400 times Oak Ridge Penn Yan, NY Penn Yan Village Yates, Co.

( NY 3 PY CB) grapes,

apples medium 9553 Keuka Lake 1,162,157 acre ft ( 1) Medium:

123,536 438 ( Oak Ridge)

Coweta, OK Wagoner Rural Water District # 5 Wagoner Co.

( OK 11 WR CB) Pecans,

pasture high 1850 Verdigris River oxbow of Verdegris R large ( tributary to Arkansas river) small 31800 medium 5,162,475 129 20,900 ( Aventis)

Jefferson, OR City of Jefferson Marion Co.

( OR 3 JE CB) vegetables high 16718 Santiam River ( Willamette Valley) Medium: 1,140,819 4,620 ( Oak Ridge)

Point Comfort,

TX City of Point Comfort Calhoun Co.

( TX 2 PC CB) rice, pasture,

tree nuts high 900 Lake Texana ( Navidad River impoundment) 165,900 acre ft Medium:

886,462 3,345 ( Oak Ridge)

Beaumont, TX City of Beaumont Water Utility Department Jefferson Co.

( TX 3 BE CB) rice, pasture,

tree nuts ( largely undevelope d) high 4300 Neches River  Medium: 5,819,700 25,178 ( Oak Ridge)

Manson, WA Lake Chelan reclaimation District Chelan Co.

( WA 13 LC CB) apples high 16898 Lake Chelan 15,800,000 acre ft Medium:

558,885 2,384 ( Aventis) intake location ( city and state) system name watershed location ( SEI #) carbaryl use crop carbaryl sales ( RPAC) carbaryl use ( lbs per county),

based on Doane source water volume of waterbody watershed size Aventis ( acres) EFED ( square km)

91 Pasco, WA City of Pasco Franklin, Co ( WA 7 PA CB) apples, potatoes high 13122 Columbia River ( downstream of confluence w/ Snake R) large 65,994,684 267,168 ( Aventis)

( 1) from NY state Depart of Environmental Conservation, 2001, Finger Lakes Synoptic Water Quality Study, http:// www. dec. state. ny. us/ website/ dow/ fingerlakes/ chapter2. pdf, accessed 3/ 13/ 03.

Table 3: Characteristics of Home and Garden Monitoring Sites selected for Carbaryl Monitoring Study.

intake location ( city and state) system name watershed location ( SEI #) source watershed size home and garden sales ( RPAC) county ag sales in pounds ( Doane)

Aventis ( Acres) EFED ( square km)

Birmingham, AL Shades Mt. Filter Plant Jefferson Co.

( AL 1 B1 CB) Cahaba River/

Lake Purdy Small 125,703 509 ( Aventis) N/ A 45 East Point, GA East Point Water Treatment Plant Fulton Co.

( GA 1 EP CB) Sweetwater Creek Small 170,007 682 ( Oak Ridge) N/ A 20 Cary, NC Town of Cary Water Treatment Plant Wake Co.

( NC 3 CA CB) Jordan Lake Reservoir Medium:

188,618 3455 ( Oak Ridge) N/ A 2100 Oak ridge 4 times Aventis Midlothian, TX City of Midlothian, Ellis Co.

( TX 30 MI CB) Joe Pool Lake Small 147,667 313 ( Oak Ridge) N/ A 4600 Aventis 2 times Oak Ridge 92 Table 4. Results of Sampling at all Community Water Supply System Locations ( Agricultural and Home and Garden)

Site type intake location ( city and state) source detection frequesny ( raw only) year months with detections ( 1 = January) Raw Water Results Finished Water Results # detects raw Conc.

( ppt) # detects finished Conc.

( ppt)

A Lake Elsinore,

CA Railroad Canyon Reservoir ( aka Canyon Lake) 3% 123 2   3  6 201 2   3 (?)

 6 (?) NA  ND A Corona, CA Lake Mathews ( Colorado River) not detected 123  ND A Lodi, CA Little Potato Slough 21% 123 5   12 2   9 4  12 6 12 4 2.38   12.48 2.18   30.55 2.3   4.1 240 2.09  3.44 3.63   6.66

A West Sacramento,

CA ( Yolo) Sacramento River 14% 123 6  8 4  12 3  8 284 2.33   3.22 2.54   24.44 2.09   14.4 132 2.86 8.34   9.91 2.19   9.32 A Henry O Banks Filtration Plant,

Sacramento, CA ( aka Riverside CA) State Water Project CA Aquaduct Feather and Sacramento Rivers 1% 123

2

1

8 Not detected A Bradenton, FL Lake Manatee 14% 123 7 10 8 9 7 10 72 13 2.48  8.95 2.15   2.73 2.04   24.58 209 6.12   10.54  2.72   19.04 A Brockton, MA Silver Lake 17% 123 6, 7 8 10 3, 4 572 2.12   31.4 2.2   26.6 2.67   4.64 010  3.37

A Deerfield, MI River Raisin 4% 123 697 111 8.01   12.26 3.7 21.94 201 4.31   180.7  4.43 A Westfield, NY Minton Reservoir 6% 123 6, 8 7 32 2.4   20.58 3.94   5.24

1  8.64

A Penn Yan, NY Keuka Lake 1% 123

1

8  22.82  Not detected A Coweta, OK Verdigris River 4% 123 9   12 2 310 2.09   3.6 2.94  Not detected A Jefferson, OR Santiam River 12  8  1  9.99 Not detected 93 2% 3 9 1 3.58 A Point Comfort,

TX Lake Texana 3% 123  1,12 1

21  4.54   17.51 3.05  Not detected A Beaumont, TX Neches River Not detected 123  Not detected A Manson, WA Lake Chelan Not detected 123 Not detected A Pasco, WA Columbia ( downstream of confluence of Snake River) 3% 123 5,10 6 21 2.19   2.76 2.71  Not detected H& G Birmingham, AL Cahaba River/ Lake Purdy 19% 1234 5 12 1 11 4 11 4 10 8 12 1 2.41 23.25 3.01  35.48 2.85  44.41 3.03 0080  2.85  31.99

H& G East Point, GA Sweetwater Creek 19% 123 5 12 1 12 1 10 10 12 8 2.01  17.56 2.15  17.64 2.96  12.52 110 2.90 7.61

H& G Cary, NC Jordan Lake Reservoir 1% 123 10  2 3.21  3.89  Not detected H& G Midlothian, TX Joe Pool Lake 6% 123 4 6 8 1 9 13.2  14.9  2.94  13.69 Not detected 94 APPENDIX C. SPREADSHEET BASED TERRESTRIAL EXPOSURE VALUES A first order decay assumption is used to determine the concentration at each day after initial application based on the concentration resulting from the initial and additional applications. The decay is calculated from the first order rate equation:

CT = Cie kT or in log transformed form: ln ( CT/ Ci) =  kT Where: CT = concentration at time T Ci = concentration in parts per million ( ppm) present initially ( on day zero) on the surfaces. Ci is calculated based on Kenaga and Fletcher by multiplying the application rate, in pounds active ingredient per acre, by 240 for short grass, 110 for tall grass, and 135 for broad leaf plants/ insects and 15 for seeds. Additional applications are converted from pounds active ingredient per acre to parts per million ( PPM) on the plant surface and the additional mass added to the mass of the chemical still present on the surfaces on the day of application.

k= degradation rate constant determined from studies of hydrolysis, photolysis, microbial degradation, etc. Since degradation rate is generally reported in terms of half life, the rate constant is calculated from the input half life ( k = ln 2/ t ½ ) instead of being input directly. Choosing which process controls the degradation rate and which half life to use in terrestrial exposure calculations is open for debate and should be done by a qualified scientist.

T= time, in days, since the start of the simulation. The initial application is on day 0. The simulation is set to run for 365 days.

The program calculates concentration on each type of surface on a daily interval for one year. The maximum concentration during the year and the average concentration during the first 56 days are calculated. 95 Chemical Name: Carbaryl Use Grasshoppers Formulation Inputs Application Rate 0.25 lbs a. i./ acre Half life 3.708 days Frequency of Application days Maximum # Apps./ Year 1 Outputs Maximum 56 day Average Concentration Concentration ( PPM) ( PPM) Short Grass 60.00 6.28 Tall Grass 27.50 2.88 # days Broadleaf plants/ Insects 33.75 3.53 Exceeded Seeds 3.75 0.39 on short grass ( in first 56) Avian Acute LC50 ( ppm) 5000 0 Chronic NOAEC ( ppm) 300 0 Max Single Application which does NOT exceed Acute RQ Chronic RQ Avian Acute 20.833 ( Max. res. mult. apps.) Avian Chronic 1.250 ( lb a. i.) Short Grass 0.01 0.20 Tall Grass 0.01 0.09 # days Mammalian Acute 8.36 Broadleaf plants/ Insects 0.01 0.11 Exceeded Mammalian Chronic 0.31 Seeds 0.00 0.01 on short grass ( in first 56) Mammalian Acute LD50 ( mg/ kg) 301 0 Rat Calculated LC50 ( ppm) 6020 Chronic NOAEL ( mg/ kg) 75 0 15 g mammal 35 g mammal 1000 g mammal Rat Acute Rat Chronic Acute RQ Acute RQ Acute RQ Dietary Dietary ( mult. apps) ( mult. apps) ( mult. apps) RQ RQ Short Grass 0.19 0.13 0.03 0.01 0.80 Broadleaf plants/ insects 0.09 0.06 0.01 0.00 0.37 Large Insects 0.11 0.07 0.02 0.01 0.45 Seeds ( granivore) 0.00 0.00 0.00 0.00 0.05 Length of Simulation 1 year Level of Concern ( ppm) Terresterial Application Residues 0 10 20 30 40 50 60 70 0 4 8 12 16 20 24 28 32 36 40 44 48 52 Days Concentration ( PPM) Short Grass Tall Grass Broadleaf plants/ Insect s Seeds Terrestrial Exposure Model Output 96 Chemical Name: Carbaryl Use Grasshoppers Formulation Inputs Application Rate 0.5 lbs a. i./ acre Half life 3.708 days Frequency of Application days Maximum # Apps./ Year 1 Outputs Maximum 56 day Average Concentration Concentration ( PPM) ( PPM) Short Grass 120.00 12.57 Tall Grass 55.00 5.76 # days Broadleaf plants/ Insects 67.50 7.07 Exceeded Seeds 7.50 0.79 on short grass ( in first 56) Avian Acute LC50 ( ppm) 5000 0 Chronic NOAEC ( ppm) 300 0 Max Single Application which does NOT exceed Acute RQ Chronic RQ Avian Acute 20.833 ( Max. res. mult. apps.) Avian Chronic 1.250 ( lb a. i.) Short Grass 0.02 0.40 Tall Grass 0.01 0.18 # days Mammalian Acute 8.36 Broadleaf plants/ Insects 0.01 0.23 Exceeded Mammalian Chronic 0.31 Seeds 0.00 0.03 on short grass ( in first 56) Mammalian Acute LD50 ( mg/ kg) 301 0 Rat Calculated LC50 ( ppm) 6020 Chronic NOAEL ( mg/ kg) 75 3 15 g mammal 35 g mammal 1000 g mammal Rat Acute Rat Chronic Acute RQ Acute RQ Acute RQ Dietary Dietary ( mult. apps) ( mult. apps) ( mult. apps) RQ RQ Short Grass 0.38 0.26 0.06 0.02 1.60 Broadleaf plants/ insects 0.17 0.12 0.03 0.01 0.73 Large Insects 0.21 0.15 0.03 0.01 0.90 Seeds ( granivore) 0.01 0.00 0.00 0.00 0.10 Length of Simulation 1 year Terresterial Application Residues 0 20 40 60 80 100 120 140 0 4 8 12 16 20 24 28 32 36 40 44 48 52 Days Concentration ( PPM) Short Grass Tall Grass Broadleaf plants/ Insect s Seeds 97 APPENDIX D1: ECOLOGICAL EFFECTS ASSESSMENT Toxicity testing reported in this section is not representative of the wide diversity of terrestrial and aquatic organisms in the United States. Two surrogate bird species, the bobwhite quail and the mallard duck, are used to represent the 680+ species of birds found in this country. For mammals, acute studies are usually limited to the Norway rat or the house mouse. Reptiles are not tested, as these are assumed to be subject to similar toxicological effects as birds. Of approximately 100,000 species of insects, spiders, and other terrestrial arthropods, toxicity tests are usually required only for the honey bee. Only two surrogate fish species ( rainbow trout and bluegill sunfish) are used to represent the over 2,000 species of freshwater fish found in this country. Amphibians are not tested, as these are assumed to be subject to similar toxicological effects as fish. One crustacean, the water flea, is used to represent all freshwater invertebrates. Estuarine/ marine animal acute toxicity testing is usually limited to a crustacean, a mollusk, and a fish.

Toxicity to Terrestrial Animals Birds, Acute and Subacute Toxicity Based on two core studies of Mallard ducks ( Anas platyrhynchos), carbaryl is practically nontoxic ( LD50 > 2000 mg/ Kg) to birds on an acute exposure basis ( Table 1). While less reliable data suggested that carbaryl may be moderately toxic to ring necked pheasants ( LD50 = 707 mg/ Kg) and red winged blackbirds ( LD50 = 56.2 mg/ Kg; Schafer et al., 1983) and highly toxic ( LD50 = 16.2 mg/ Kg) to starlings ( Schafer et al., 1983), these data are based on simple screening tests, and are therefore not reliable for risk assessment purposes. However, these data do suggest that passerine birds may be significantly more sensitive to carbaryl exposure than non passerine birds. The registrant is strongly encouraged to submit acute oral toxicity tests with passerine avian species. The guideline 71 1 is fulfilled ( MRID 00160000; 458206 01). 98 Table 1. Summary of avian acute oral toxicity in mg/ kg ( ppm) of technical grade carbaryl Species % ai LD50 ( mg/ kg) Toxicity Category MRID No. Author/ Year Study Classification1 Mallard Duck ( Anas platyrhynchos) 85 > 2,564 Practically non toxic 00160000 Hudson et al. ( 1984) Core Mallard Duck 99.1% > 2,000 Practically non toxic 458206 01 Ensenbach Core Canada Goose Branta canadensis 50 1,790 Slightly toxic 00160000 Hudson et al. ( 1984) Supplemental Ring necked Pheasant male ( Phasianus colchicus) 95 > 2,000 Practically non toxic 00160000 Hudson et al. ( 1984) Supplemental Ring necked Pheasant female ( Phasianus colchicus) 480g/ L 707 Moderately toxic 00160000 Hudson et al. ( 1984) Supplemental Sharp tailed grouse Tympanuchus phasianellus 85 < 1000 Slightly toxic 00160000 Hudson et al. ( 1984) Supplemental California quail Lophortyx californicus 480 g/ L > 2000 Practically non toxic 00160000 Hudson et al. ( 1984) Supplemental Rock Dove ( Columba livia) 85 1,000  30002 Slightly toxic to Practically non toxic 00160000 Hudson et al. ( 1984) Supplemental 1 Core study satisfies guideline requirements. Supplemental study is scientifically sound, but does not satisfy guidelines.

2 95% confidence interval Two subacute dietary studies using the TGAI are required to establish the toxicity of carbaryl to birds. The preferred test species are mallard duck and bobwhite quail. Results of these tests are summarized in Table 2. The LC50 is higher than 5000 mg/ kg ( ppm) of diet for both species. Therefore, carbaryl is categorized as practically nontoxic to avian species on a subacute dietary exposure basis. An LC50 greater than 10,000 ppm has been reported by Hill and Camardese ( 1986), confirming that carbaryl's low toxicity to birds on a subacute, dietary basis. The guideline 71 2 is fulfilled ( MRID 00028757, 00022923).

Table 2 : Summary of avian subacute dietary toxicity in mg/ Kg of diet ( ppm) for technical grade carbaryl Species % ai 5 Day LC50 ( ppm) Toxicity Category MRID No. Author/ Year Study Classification Ring necked Pheasant ( Phasianus calchicus) 99.8 > 5,000 practically non toxic 00028757 Hill et al. ( 1975) Core Northern bobwhite Quail ( Colinus virginianus) 99.8 > 5,000 Practically non toxic 00028757 Hill et al. ( 1975) Core Japanese Quail ( Coturnix japonica) 99.8. > 5,000 Practically non toxic 00022923 Hill et al. ( 1975) Supplemental Mallard Duck ( Anas platyrhynchos) 99.8 > 5000 Practically non toxic 00022923 Hill et al. ( 1975) Core 99 Incidents Involving Birds According to the Ecological Incident Information System ( EIIS) database summarizing 6( a) 2 incident reports, bird kills have been attributed to carbaryl and have involved " blackbirds", starlings, grackles, Mallard ducks, Canadian geese and a morning dove in New York, South Carolina, Virginia, Michigan and New Jersey (# I002048 001, # I000802 001, # I007720 020, # I004375 004). However, two of the incidents appear to be attributed to the registered use of carbaryl. In incident # I007720 020 involving 10 Mallard ducks both carbaryl and bendiocarb were detected in bird stomach contents; bendiocarb is very highly toxic ( LD50 = 3.1 mg/ Kg) to birds an is more likely the cause of this incident.

In incident # I004375 004, 18 Canadian Geese ( Branta canadensis) were reported killed; necropsy of 4 birds indicated that diazinon was present in the highest concentration in each of the birds with minor amounts of lindane and carbaryl. Diazinon is very highly toxic ( LD50 = 6.16 mg/ kg) to Canadian geese and is therefore the most likely cause of this incident.

In incident I002048 001, one common grackle and five European starlings ( Sturnus vulgaris) were found dead. Pooled stomach contents showed carbaryl at 17 ppm; however, brain cholinesterase levels were normal. In what appears to be a follow up report ( I004169 094), corn kernels were strewn around the base of the incident site suggesting that there was an intentional poisoning of the birds.

Incident I012817 001 involved a single morning dove ( Zenaida macroura) with 2.4 ppm carbaryl in its stomach contents and acetylcholinesterase activity was reduced. The report suggests that the birdseed from a feeder may have been contaminated when carbaryl was applied to the property owner's lawn.

In incident I000802 001, five blackbirds were discovered dead; stomach contents from a single squirrel also found dead on the farm property showed carbaryl residues; however, acetylcholine esterase activity was not reduced.

Based on these incident reports, only two appear to be clearly attributed to carbaryl and not due to misuse or the presence of some other chemical. However, only one incident involving the morning dove is attributed to a particular registered use or carbaryl. Additionally, based on the reported carbaryl residues, it is unclear how the chemical could have inflicted mortality given that carbaryl is practically nontoxic to birds on both an acute and subacute exposure basis. These incidents however underscore the uncertainty whether passerine birds are more sensitive to the effects of carbaryl than current surrogate test species results indicate.

Birds, Chronic Toxicity Exposure to carbaryl at levels equal to or greater than 300 mg/ kg of diet ( ppm) in the mallard duck results in adverse reproductive effects, such as decreased number of eggs produced, increased number 100 of cracked eggs, and decreased fertility ( Table 3). Guideline 71 4 is fulfilled ( ACC263701; MRID 00160044).

Table 3. Summary of avian reproduction toxicity in mg/ Kg of diet ( ppm) for technical grade carbaryl Species % ai NOAEC ( ppm) LOAC Endpoints MRID. No. Author/ Year Study Classification Northern bobwhite Quail ( Colinus virginianus) 99.9 > 3,000 N/ A 00160044 Fletcher ( 1986) Core Mallard Duck ( Anas platyrhynchos) 99.9 300 Number of eggs produced ACC263701 Fletcher ( 1986) Core Mammals, Acute and Chronic As shown in Table 4, carbaryl is categorized as moderately toxic to small mammals on an acute oral basis ( LD50 = 301 mg/ kg). In a two generation rat reproduction study ( MRID 454481 01) the LOAEL for reproductive toxicity could not be established because no effects were observed at any does level; therefore the NOAEL is 1500 ppm; however, the LOAEL for offspring toxicity was 300 ppm based on increased number of second generation offspring with no milk in the stomach and decreased pup survival. The NOAEL is 75 ppm.

Table 4. Summary of mammalian toxicity for technical grade carbaryl Species % ai Test Type Toxicity Value Affected Endpoints MRID No.

Laboratory Rat ( Rattus norvegicus) 99.0% Acute oral LD50 = 301.0 mg/ kg Morbidity 00148500 Laboratory Rat ( Rattus norvegicus) 99.1% 2 generation Rate Reproduction NOAEC/ LOAEC 75 / 300 ppm Decreased pup survival 44732901 Incidents Involving Mammals Incidents involving small mammal kills have been recorded in South Carolina and Virginia. In incident I000802 001, stomach contents from a gray squirrel ( Sciurus carolinensin) were found to have " significant" amount of carbaryl; however, brain acetylcholine activity was not " significantly depressed.".

In the second incident involving carbaryl, a hairytail mole ( Parascalops breweri) was found to have 6 ppm carbaryl in its viscera. No information was provided on how the animal may have come in contact with the pesticide.

Based on these incident reports, it is not possible to determine what use of carbaryl was associated with these deaths. However, carbaryl is moderately toxic to mammals ( LD50 = 301 mg/ Kg) to rodents on an acute exposure basis. 101 Insect Toxicity Technical carbaryl is categorized as highly toxic to bees on an acute contact basis ( Table 5). Guideline 141 1 is fulfilled ( MRID 00036935, 05001991, 05004151). More recent studies with technical grade carbaryl ( purity 99.1%) indicate roughly similar acute oral toxicity ( LC50 = 0.23 : g/ bee). Although a more recent contact toxicity study of technical grade carbaryl was undertaken ( MRID 457854 04), the study was classified as invalid since it relied on dimethylsulfoxide ( DMSO) as a co solvent; EPA recommends against the used of DMSO as a solvent due to the extent to which this solvent can impact cell membranes and hence the uptake and distribution of chemicals. Acute oral toxicity testing with the soluble concentrate ( Carbaryl SC) indicates that the formulated product is roughly an order of magnitude less toxic ( LC50 = 1.57 : g/ bee) than the technical grade. Acute contact toxicity with the soluble concentrate also showed reduced toxicity ( LD50 = 4.02 : g/ bee) compared to the technical grade.

Table 5. Summary of honey bee acute contact ( LD50 in : g/ bee) and acute oral ( LC50 in : g/ bee) toxicity for technical grade carbaryl Species % ai Contact LD50 ( µ g/ bee) Oral LC50 ( µ g/ bee) Toxicity Category MRID No. Author/ Year Study Classification Honey Bee ( Apis mellifera) tech. 1.3 0.14 Highly toxic 05001991 Stevenson ( 1978) Core Honey Bee ( Apis mellifera) tech 2.0  Highly toxic 00036935 Atkins et al. ( 1975) Core Honey Bee ( Apis mellifera) tech 1.1 0.11 Highly toxic 05004151 Stevenson ( 1968) Core Honey Bee ( Apis mellifera) 99.1  0.231  457854 03 Waltersdorfer ( 2002) Supplemental Honey Bee ( Apis mellifera) 479 g/ L  1.57  457854 06 Waltersdorfer ( 2002) Supplemental Honey Bee ( Apis mellifera) 479 g/ L 4.02  moderately toxic 457854 07 Waltersdorfer ( 2002) Supplemental The topical LD50 for alfalfa leaf cutter bee ( Megachile pacifica = M. rotundata) = 262.4 µ g/ g ( 05015678) ( Lee & Brindley 1974). However, exposing leaf cutter bees ( Megachilidae), alkali bees ( Halictidae), and honey bees ( Apidae) to 24 hr residues from 80% WP carbaryl applied at the rate of 1 lb/ acre resulted, respectively, in a 85%, 78%, and 69% mortality rate ( Johansen 1972) ( ID # 05000837). Some carbaryl formulations can be highly toxic to bees exposed to direct application, i. e., when bees are actively visiting blooming crops or weeds. Residual toxicity varies with the crops and weather conditions.

Carbaryl can also range from moderately to highly toxic to predaceous arthropods. These include lace bugs ( Nabidae) ( MRID # 05010807), big eyed bugs ( Geocoridae: Geocoris) ( MRID # 05010807, lady beetles ( Coccinellidae: Coccinella, Cryptolaemus, Hippodamia, Lindorus, Rhodolia, Stethorus) ( MRID # 05013372, 05003978, 05005640), ground beetles ( Carabidae: Scarites, Pterostichus, Bembidion, Harpalus) ( MRID # 05008149), hymenopterous parasitoids ( Aphytis, Metaphycus, 102 Spalangia, Leptomastix) ( MRID # 05003978, 05005640), predaceous mites ( Amblyseius, Typhlodromus) ( MRID # 05004148, 05013359, 05009346), and spiders ( MRID # 05010807).

In a 7 day field study ( MRID 457854 07) designed to examine the effects of carbaryl on bees when the chemical is used to thin fruit, carbaryl SC ( water miscible concentrate) was applied by mist blower at a rate of 0.80 lbs a. i./ Acre to apple orchards in Germany. Bee mortality and behavior was monitored for two days leading up to application and for 7 days following application. Under the conditions tested in Germany, carbaryl SC applications to apple orchards did not have a significant ( P > 0.05) effect on bee mortality and/ or behavior. This nonguideline study is classified as supplemental.

Incidents Involving Bees Bee kill incidents have been reported for carbaryl. In incident I001611 002 Sevin XLR was applied to 200 acres of asparagus in Washington and carbaryl residues were detected in the bees.

In incident I003826 009, a bee keeper in North Carolina reported a bee kill. A variety of pesticides had been used in the vicinity and residues of methyl parathion ( 3.1 ppm), chlorpyrifos ( 0.1 ppm), dimethoate ( 1.7 ppm) and endosulfan ( 0.2 ppm) were detected. Although carbaryl had been used in the vicinity, no residues were detected in the bees. Given that bees are roughly an order of magnitude more sensitive to methyl parathion ( LD50 = 0.11 : g/ bee) and that residues of methyl parathion were detected, the organophosphate is a more likely culprit in this bee incident.

In incident I003826 021, a bee hive owner in North Carolina reported bee mortality. Although a number of pesticides were being used in the vicinity of the apiary, only carbaryl residues ( 0.08 ppm) were detected in the bees. The bee hive owner did not know what served as a source of the carbaryl.

In incident I005855 001, the American Beekeeper Federation, Inc. submitted a report dated August 26, 1997, about the ongoing problem of bees being killed by pesticides in the United States. The report lists several pesticides ( carbofuran, methyl parathion, parathion, carbaryl, naled) associated with bee kills during the period of January 1 through June 16, 1997. No data were provided on chemical residues or on the pesticide uses associated with the kills.

In a related report ( B0000 300 03), the Honey Industry Council of America reported that farmers spraying alfalfa crops with toxaphene, parathion, and Sevin in the middle of the day was resulting in bee kills due to drift. No data were provided to support these concerns though.

Other than the use of carbaryl on asparagus in Washington, none of the other reports on bee kills contain sufficient information to implicate a specific use of carbaryl. Although the bee industry has expressed its concerns regarding the toxicity of carbaryl to bees, it has not provided sufficient data to support its concerns. 103 Earthworms An acute toxicity study of the carbaryl degradate 1 naphthol was conducted using earthworms and is reported in greater detail in the 1 naphthol toxicity section to follow.

Toxicity to Freshwater Aquatic Animals Freshwater Fish, Acute Results of toxicity tests with freshwater fish are tabulated in Table 6. Since the LC50 values for the species tested are in the 0.25  20.0 mg/ L ( ppm) range, carbaryl can therefore range from highly to slightly toxic to freshwater fish on an acute exposure basis. Guidelines 72 1( a) and 72 1( c) are fulfilled ( MRID 40098001, 00043115).

Table 6. Summary of freshwater fish acute toxicity in mg/ L ( ppm) for technical grade carbaryl Species % ai 96 hour LC50 ( mg/ L) ( nominal) Toxicity Category MRID No. Author/ Year Study Classification Rainbow Trout ( Onchorynchus mykiss) 99.5 1.2 Moderately Toxic 40098001 Mayer & Ellersieck ( 1986) Core Chinook Salmon ( Onchorynchus tshawytacha) 99.5 2.4 Moderately Toxic 40098001 Mayer & Ellersieck ( 1986) Supplemental Bluegill Sunfish ( Lepomis macrochirus) 99.9 14.0 Slightly Toxic 00043115 McCann et al ( 1969) Core Bluegill Sunfish ( Lepomis macrochirus) 99.9 5.04 Moderately Toxic 40098001 Mayer & Ellersieck ( 1986) Core Bluegill Sunfish ( Lepomis macrochirus) 99.1 > 7.3* Moderately Toxic 457854 01 Sowig & Gosch ( 2002) Supplemental Channel Catfish ( Ictalurus punctatus) 99.9 7.79 Moderately Toxic 40098001 Mayer & Ellersieck ( 1986) Core Fathead Minnow ( Pimephales promelas) 99.5 7.7 Moderately Toxic 40098001 Mayer & Ellersieck ( 1986) Core Black Crappie ( Pomoxis nigromaculatus) 99.5 2.6 Moderately Toxic 40094602 Johnson & Finley ( 1986) Core Atlantic Salmon ( Salmo salar) 99.5 0.25 Highly Toxic 40098001 Mayer & Ellersieck ( 1986) Core Brown Trout ( Salmo trutta) 99.5 6.3 Moderately Toxic 40098001 Mayer & Ellersieck ( 1986) Core Brook Trout ( Salvelinus fontinalis) 99.5 3.0 Moderately Toxic 40098001 Mayer & Ellersieck ( 1986) Core Lake Trout ( Salvelinus namaycush) 99.5 0.69 Highly Toxic 40098001 Mayer & Ellersieck ( 1986) Core Coho Salmon ( Onchorynchus kisutch) 99.5 2.4 Moderately Toxic 40098001 Mayer & Ellersieck ( 1986) Core Species % ai 96 hour LC50 ( mg/ L) ( nominal) Toxicity Category MRID No. Author/ Year Study Classification 104 Yellow Perch ( Perca flavescens) 99.5 0.35 Highly Toxic 40098001 Mayer & Ellersieck ( 1986) Core Cutthroat Trout ( Onchorynchus clarkii) 99.5 0.97 Highly Toxic 40098001 Mayer & Ellersieck ( 1986) Core Largemouth Bass ( Micropterus salmoides) 99.5 6.4 Moderately Toxic 40094602 Johnson & Finley ( 1980) Core Green Sunfish ( Lepomis cyanellus) 99.5 9.5 Moderately Toxic 40098001 Mayer & Ellersieck ( 1986) Core Black Bullhead ( Ictalurus melas) 99.5 20.0 Slightly Toxic 40098001 Mayer & Ellersieck ( 1986) Core Longnose Killifish ( Fundulus similis) 99.7 1.6 Moderately Toxic 40228401 Mayer ( 1986) Supplemental Carp ( Cyprinus carpio) 99.5 5.3 Moderately Toxic 40098001 Mayer & Ellersieck ( 1986) Core * mean measured concentration over 0  96 hours.

Toxicity was determined for the typical end use product as well, with all LC50 values, except one, ranging from 1.4 to 49 mg/ L ( ppm), which indicates that carbaryl can be classified as slightly to moderately toxic to freshwater fish ( Table 7). Guidelines ( b) and 72 1( d) are fulfilled ( MRID # s 00059202, 00042381, 00151519, 00151417, 42397901, 00124383, 00124391).

Incidents Involving Freshwater Fish A total of three fish kill incidents are recorded in the EIIS database. In incident B0000 501 92 carbaryl was associated with a fish kill in New Jersey ( 1980) following the application of carbaryl to control gypsy moth. No data on residues were provided.

In a second incident ( I000910 001) in Louisiana, a fish kill was reported to have occurred during in early June 1992. A number of pesticides ( carbaryl, MSMA, atrazine, iprodione, dimethylamine, dicamba with 2,4 D, and chlorpyrifos) had been applied to area lawns and golf courses prior to the incident which followed a high rain event. No chemical residues were reported; however, carbaryl had not been applied in the area since late April while chlorpyrifos ( bluegill LC50 = 3 : g/ L) and iprodione ( LC50 = 3.1 mg/ L) had been applied less than a week before the incident. It is unlikely that carbaryl residues would have been sufficiently high to result in a fish kill if the chemical had been applied two months prior. Both chlorpyrifos and iprodione are more likely candidates for being responsible for this fish kill.

In a third incident report ( B0000 246 01) a number of pesticides ( toxaphene, carbaryl, endrin, methyl parathion and DDT) were associated with a fish kill in Oklahoma where approximately 22,000 catfish died. No residue data were provided; however, given that toxaphene and endrin are both classified as very highly toxic to catfish with LC50 values of 2.7 : g/ L and 0.32 : g/ L, 105 respectively, it is likely that they are more credible candidates for having caused the fish kill than carbaryl.

Therefore, based on the incident reports, there appears to be only one credible report where carbaryl use could be directly associated with a fish kill.

Table 7. Summary of freshwater fish acute toxicity in mg/ L ( ppm) for carbaryl ( typical end use product)

Species % ai 96 hr LC50 ( mg/ L) Toxicity Category MRID No. Author/ Year Study Classification Rainbow Trout ( Onchorynchus mykiss) 44 1.4 Moderately Toxic 00151417 Sousa ( 1985) Core Rainbow Trout ( Onchorynchus mykiss) 81.5 3.3 Moderately Toxic 42397901 Lintott ( 1992) Core Rainbow Trout ( Onchorynchus mykiss) 50 3.45 Moderately Toxic 00124383 McCann ( 1971) Core Rainbow Trout ( Onchorynchus mykiss) 50 4.5 Moderately Toxic 00124383 McCann ( 1971) Core Bluegill Sunfish ( Lepomis macrochirus) 30 49.0 Slightly Toxic 00059202 Mc Caan ( 1970) Core Bluegill Sunfish ( Lepomis macrochirus) 5 290.0 Practically Nontoxic 00042381 McCann ( 1968) Core Bluegill Sunfish ( Lepomis macrochirus) 44 9.8 Moderately Toxic 00151519 Sousa ( 1985) Core Bluegill Sunfish ( Lepomis macrochirus) 50 22.0 Slightly Toxic 00124391 McCann ( 1971) Core Freshwater Fish, Chronic Results of the required early life stage with fish are summarized in Table 8. Exposure to 680 : g/ L ( ppb) reduced survival of larvae, reduced number of eggs per female and reduced number of eggs spawned ( TOUCARO5); of the eggs spawned at 680 µ g/ L, none hatched.

Table 8. Summary of freshwater fish life cycle toxicity in mg/ L ( ppm) under flow through conditions for technical grade carbaryl Species % ai NOAEC/ LOAC ( mg/ L) Endpoints Affected MRID No. Author/ Year Study Classification Fathead Minnow ( Pimephales promelas) 99 0.21/ 0.68 Survival and Reproduction TOUCARO5 Carlson ( 1972) Core 106 Amphibians According to a supplemental study with an end use product containing 50% carbaryl ( MRID 00160000), the LD50 for, the bullfrog ( Rana catesbeiana) is greater than 4,000 mg/ kg, or practically nontoxic.

The U. S. Geological Survey Biological Resource Division's Columbia Environmental Research Center has examined the effects of carbaryl on amphibians ( APPENDIX D2). These studies have shown that frogs can exhibit considerable intraspecies ( Boone and Bridges 1998) and interspecies ( Boone and Semlitsch 2002) variability in their response to carbaryl exposure. Genetic factors and stage of development during which exposure took place can impact the vulnerability of frogs. For example, frogs exposed during egg stage had lower weights than corresponding control animals and nearly 18% of leopard frogs exposed to carbaryl during development exhibited some type of developmental deformity ( including visceral and limb malformations). Additionally, environmental conditions such as temperature appear to impact the sensitivity of frogs to carbaryl. In a 96 hr acute toxicity study, green frogs ( Rana climitans) had an LC50 of 22.0 mg/ L at 17oC but at 27 oC the LC50 was roughly half ( 96 hr LC50 = 11.32 mg/ L) ( Boone and Bridges 1998).

Furthermore, in studies comparing the direct toxicity of carbaryl to Southern leopard frogs ( Rana sphenocephala) and fish, tadpoles were relatively tolerant ( 96 hr LC50 = 8.4) to carbaryl compared to bluegill sunfish ( 96 hr LC50 = 6.2 mg/ L, fathead minnow ( 96 hr LC50 = 5.21 mg/ L) and rainbow trout ( LC50 = 1.88 mg/ L). The study also reports the 96 hr LC50 ( 12.31 mg/ L) for the boreal toad ( Bufo boreas); these data suggest that the surrogate fish species used to evaluate the toxicity to carbaryl are protective for amphibians ( Bridges et al. 2002).

Of additional concern is the potential for secondary effects. Several studies have suggested that carbaryl exposure impairs predator avoidance behavior in frogs ( Bridges 1997; Bridges 1999), affects the length of time required for tadpoles to complete metamorphosis into adults ( Boone and Semlitsch 2002), and affected the weight of animals undergoing metamorphosis. Carbaryl concentrations greater than 3.5 mg/ L significantly affected the time tadpoles spent being active where control animals exhibited greater sprint speeds and were able to swim greater distances ( Bridges 1997). Slower swimming speeds, altered activity patterns and prolonged juvenile stages have been suggested as increasing the vulnerability of frogs to predation ( Bridges 1997; Bridges 1999; Relyea and Mills 2001) and/ or that the threat of predation renders the animals more susceptible to the direct toxicity of carbaryl ( Relyea and Mills 2001). While the Relyea and Mills paper indicates that carbaryl was 2 to 4 times more lethal to gray treefrogs ( Hyla versicolor) in the presence of a predator, the study is confounded by the potential effects of water quality on mortality ( APPENDIX D3). Additionally, increased vulnerability to predation assumes that only the prey are incapacitated by carbaryl. The Bridges ( 1999) study indicates however, the predators may also be impacted and that gray treefrogs actually spent less time being active, but that the active times were primarily spent foraging. However, in some cases, it is unclear whether the effects of carbaryl on amphibians has been entirely adverse. For example, Southern leopard frogs exposed to carbaryl at 5 mg/ L exhibited a 20% increase in weight at metamorphosis( Bridges and Boone 2003) and that at concentrations as high as 107 7 mg/ L, Woodhouse's toad ( Bufo woodhousii) survival was roughly 30% higher than controls ( Boone and Semlitsch 2002).

Freshwater Invertebrates, Acute Since the EC50 falls in the range of 1.7  26 : g/ L ( ppb), carbaryl is categorized as very highly toxic to aquatic invertebrates on an acute exposure basis ( Table 9). Toxicity studies with the typical end use product show that carbaryl is very highly toxic to daphnids, with an EC50 in the 4.29  13.0 : g/ L range ( Table 10). Guideline 72 2 is fulfilled ( MRID # s 400980 01, 423979 02, 423979 03).

Acute toxicity studies of the stonefly larvae Chloroperla grammatica with technical grade carbaryl using a 96 hr exposure period ( MRID 458206 02) and a 1 hour ( pulse) exposure period ( MRID 458206 03) resulted in LC50 values of 5.14 : g/ L and 28.1 : g/ L ( ppb), respectively. Following the 1 hour " pulse" exposure, treated Mayflies were transferred to untreated water and monitored for 95 hours. Although 50% of the stonefly larvae were immobilized at 28 : g/ L after a 1 hour exposure period, all of the exposed animals appeared to be completely recovered during the 95 hour post exposure period in untreated waters.

Table 9. Summary of freshwater invertebrate acute toxicity in : g/ L ( ppb) for technical grade carbaryl Species/ Static or Flowthrough % ai 48 hour EC50 (: g/ L) ( nominal) Toxicity Category MRID No. Author/ Year Study Classification Water flea ( Daphnia magna) 99.5 5.6 Very Highly Toxic 400980 01 Mayer & Ellersieck ( 1986) Core Stonefly ( Classenia sabulosa) 99.5 96hr LC50= 5.6 Very Highly Toxic 400980 01 Mayer & Ellersieck ( 1986) Supplemental Stonefly ( Isogenus sp.) 99.5 96hr LC50= 3.6 Very Highly Toxic 400980 01 Mayer & Ellersieck ( 1986) Supplemental Stonefly ( Pteronarcella badia) 99.5 96hr LC50= 1.7 Very Highly Toxic 400980 01 Mayer & Ellersieck ( 1986) Supplemental Stonefly ( Chloroperla grammatica) 99.1 96 hr LC50 = 5.14* Very Highly Toxic 458206 02 Schäfers ( 2002) Supplemental Stonefly ( Chloroperla grammatica) 99.1 1 hr LC50 = 28.1* : g/ L Very Highly Toxic 458206 03 Schäfers ( 2002) Supplemental Scud ( Gammarus fasciatus) 99.5 96hr EC50= 26 Very Highly Toxic 400980 01 Mayer & Ellersieck ( 1986) Core * Mean measured concentrations over study period. 108 Table 10. Acute carbaryl toxicity in : g/ L ( ppb) to freshwater invertebrates using technical end product ( TEP).

Species % ai 48 hour EC50 (: g/ L) Toxicity category MRID No. Author/ Year Study Classification Water flea ( Daphnia magna) 49.0% 7.1 Very highly toxic 00150538 Nicholson and Surprenant ( 1985) Supplemental Water flea ( Daphnia magna) 43.9% 13.0 Very highly toxic 00150540 Nicholson and Surprenant ( 1985) Supplemental Water flea ( Daphnia magna) 47.3% 4.29 Very highly toxic 42432401 Lintott ( 1992) Supplemental Water flea ( Daphnia magna) 43.7% 6.66 Very highly toxic 42397902 Lintott ( 1992) Core Water flea ( Daphnia magna) 81.5% 7.2 Very highly toxic 42397903 Lintott ( 1992) Core In a series of studies ( Table 11) to simulate the presence of sediment, technical grade carbaryl was evaluated for its toxicity to freshwater invertebrates including an amphipod ( Gammarus fossarum), two cladocerans ( Chydorus sphaericus and Daphnia magna), a clam ( Sphaerium corneum), a Mayfly larvae ( Ephemera danica), and a snail ( Planobarius corneus). Exposure was based on mean measured water column concentrations over the length of each study. Carbaryl was moderately toxic to both the clam and the snail ( 96 hr EC50 > 2200 : g/ L) ( ppb) while it was very highly toxic to the remainder of invertebrates studied.( 48 hr EC50 range 5  15 : g/ L).

Table 11. Acute toxicity of carbaryl in : g/ L ( ppb) to freshwater invertebrates using technical grade carbaryl in the presence of sediment Species % ai 48 hour EC50 (: g/ L) Toxicity category MRID No. Author/ Year Study Classification Pulmonate Snail Planobarius corneus 99.1% 96 hr EC50 > 2245 Moderately Toxic 458609 05 Schäfers ( 2002) Supplemental Freshwater clam Sphaerium corneum 99.1% 96 hr EC50 > 2467 Moderately Toxic 458609 06 Schäfers ( 2002) Supplemental Cladoceran Chydorus sphaericus 99.1% 48 hr EC50 = 7.25 Very Highly Toxic 458609 02 Schäfers ( 2002) Supplemental Amphipod Gammarus fossarum 99.1% 96 hr EC50 = 17.5 Very Highly Toxic 458609 04 Schäfers ( 2002) Supplemental Cladoceran Daphnia magna 99.1% 48 hr EC50 = 15 Very Highly Toxic 457848 01 Schäfers ( 2002) Supplemental Cladoceran Daphnia longispina 99.1% 48 hr EC50 = 4.9 Very Highly Toxic 4548609 01 Schäfers ( 2002) Supplemental Mayfly Ephemera danica 99.1% 48 hr EC50 = 4.9 Very Highly Toxic 458609 03 Schäfers ( 2002) Supplemental 109 Field studies that evaluated populations of damselflies ( Xanthocnemis zealandica) after exposure to 0.1 mg/ L carbaryl showed a 90% reduction in emergence success after 10 12 days exposure ( Hardersen and Wratten, 1998). Studying natural plankton communities in enclosed mesocosms, Havens ( 1995) reports a decline in total zooplankton biomass and numbers of individuals up to 0.100 mg/ L. Furthermore, at carbaryl concentrations greater than 0.02 mg/ L Daphnia was no longer found and that at concentrations above 0.050 mg/ L all cladocerans were eliminated, resulting in an increase in algal biomass, representing a repartitioning of biomass from zooplankton to phytoplankton. Hanazato ( 1995) exposed Daphnia ambigua to carbaryl and a kairomone released by the predator Chaoborus ( phantom midge) simultaneously. Daphnia developed helmets in response to the kairomone, but not in response to carbaryl at 0.001 0.003 mg/ L. However, carbaryl enhanced the development of high helmets and prolonged the maintenance period of the helmets in the presence of the kairomone, suggesting that at low concentrations carbaryl can alter predator prey interactions by inducing helmet formation and vulnerability to predation in Daphnia. In related mesocosms studies, exposure to carbaryl at 1 mg/ L killed all plankton species, including Chaoborus larvae ( Hanazato, 1989). However, this concentration is well above the maximum EECs modeled for carbaryl, and is unlikely that such high levels of this chemical would be found under field conditions. Mora et al. ( 2000) studying the relationship between toxicokinetics of carbaryl and effects on acetylcholinesterase ( ACHase) activity in the snail, Pomaca patula, observed increased enzyme inhibition, along with the bioconcentration of carbaryl, after 72 hours of exposure to sublethal levels ( 0.0032 mg/ L). The transfer of snails to carbaryl free water was followed by rapid monophasic elimination with a half life of 1.0 hour, although ACHase activity levels never returned to control values.

Freshwater Invertebrate, Chronic A 21 day toxicity study preformed with the water flea estimated a NOAEC and a LOAEC of 1.5 : g/ L and 3.3 : g/ L ( ppb), respectively, based on affected reproduction ( Table 12). Guideline 72 4( b) for freshwater invertebrates is fulfilled ( MRID 00150901).

In a recent 28 day chronic ( static) toxicity of carbaryl ( technical; 99.1% purity) to the midge larvae Chironomus riparius ( MRID 457848 02 ), organisms were exposed to negative control, solvent ( acetone) control and test chemical at a single dosing of nominal concentration of 0.0625, 0.125, 0.25, 0.50, and 1.0 mg/ L. Reduced emergence and development rates were the most sensitive endpoints ( NOEC = 0.5 mg/ L; LOEC = 1.0 mg/ L) ( ppm). The study is classified as supplemental since it is uncertain whether the use of dechlorinated tap water may have impacted the study's ability to differentiate treatment effects; however, the study provides information on the effects of carbaryl technical ( 99.1% purity) on benthic invertebrates based on a single exposure to carbaryl followed by a 28 day observation period. Analytical analysis of overlying water revealed that carbaryl and its primary degradate, 1 naphthol, had essentially dissipated by day 7. 110 Table 12. Summary of freshwater aquatic invertebrate life cycle toxicity in : g/ L ( ppb) for technical grade carbaryl Species % ai 21 day NOAEC/ LOAEC (: g/ L) Endpoints Affected MRID No. Author/ Year Study Classification Water flea ( Daphnia magna) 99.0% 1.5 / 3.3 Reproduction 00150901 Surprenant ( 1985) Core Midge Chironomous riparius 99.1% 500 / 1000 Emergence / developmental rate 457848 02 Ebeling & Radix ( 2002) Supplemental Toxicity to Estuarine and Marine Animals Estuarine/ Marine Fish, Acute Since the minnow LC50 is 2.6 mg/ L ( ppm) ( Table 13), carbaryl is categorized as moderately toxic to estuarine/ marine fish on an acute basis. The guideline 72 3( a) is fulfilled ( MRID 42372801).

Table 13. Summary of estuarine/ marine fish acute toxicity for technical grade carbaryl Species/ Static % ai 96 hour LC50 mg/ L ( nominal) Toxicity Category MRID No. Author/ Year Study Classificati on Sheepshead Minnow ( Cyprinodon variegatus) 99 2.2 Moderately Toxic 00150539 Sousa and Surprenant ( 1985) Supplemen tal Sheepshead Minnow ( Cyprinodon variegatus) 99.7% 2.6 Moderately Toxic 42372801 Lintott ( 1992) Core Estuarine and Marine Fish, Chronic An estuarine/ marine fish early life stage toxicity test using the TGAI is required for carbaryl because the end use product is expected to be transported to this environment from the intended use site. The pesticide uses ( e. g. turf) are such that its presence in water is likely to be continuous ( multiple applications), and chronic concerns have been noted for freshwater and marine fish. At this point, the guideline 72 4( a) for estuarine/ marine fish is not fulfilled.

Estuarine and Marine Invertebrates, Acute As shown in Table 14, the 96 hour mysid shrimp LC50 for technical carbaryl falls is 5.7 : g/ L ( ppb) ( MRID 42343401). Thus, this chemical is categorized as very highly toxic to estuarine/ marine 111 shrimp species on an acute basis. By contrast, carbaryl is moderately toxicity to the oyster ( LC50 = 2.7 mg/ L ( ppm; MRID 00148221). Guidelines 72 3( b) and 72 3( c) are fulfilled.

Table 14. Summary of estuarine/ marine invertebrate acute toxicity for technical grade carbaryl Species % ai. 48 hour LC50 : g/ L Toxicity Category MRID No. Author/ Year Study Classification Brown Shrimp ( Penaeus aztecus) 99.7 1.5 Very Highly Toxic 40228401 Mayer ( 1986) Supplemental Mysid ( Mysidopsis bahia) 99 96 hr LC50 = 6.7 Very Highly Toxic 00150544 Hoberg and Surprenant ( 1985) Supplemental Mysid ( Mysidopsis bahia) 99.7 96 hr LC50 = 5.7 Very Highly Toxic 42343401 Lintott ( 1992) Core Glass Shrimp ( Palaemonetes kadiakensis) 99.5 5.6 Very Highly Toxic 40098001 Mayer & Ellersieck ( 1986) Supplemental Grass Shrimp ( Palaemonetes pugio) 99.7 28 Very Highly Toxic 40228401 Mayer ( 1986) Supplemental Pink Shrimp ( Penaeus duorarum) 99.7 32 Very Highly Toxic 40228401 Mayer ( 1986) Supplemental Eastern Oyster ( Crassostrea virginica) 99.7 96 hr LC50> 2 Very Highly Toxic 40228401 Mayer ( 1986) Core Eastern Oyster ( Crassostrea virginica) 99 2700 Moderately Toxic 00148221 Surprenant, et al. ( 1985) Core Blue Crab ( Callinectes sapidus) 99.7 320 Highly Toxic 40228401 Mayer ( 1986) Supplemental Fairy Shrimp 95.3% 170 Highly toxic 40094602 Mayer ( 1986) Supplemental Eastern Oyster ( Crassostria virginica) 95.0% > 1,000 Moderately toxic 40228401 Mayer ( 1986) Supplemental Results of toxicity testing using the typical end use product are summarized in Table 15. Carbaryl TEPs are highly toxic to mysids, LC50 values ranging from 9.3 to 20.2 : g/ L ( ppb) ( MRID # s 42397904, 42565601, and 42343402), and slightly toxic to oysters ( LC50 = 23.6 mg/ L ( ppm), MRID 42597301). Guidelines 72 3( e) and 72 3( f) are fulfilled. 112 Table 15. Summary of estuarine/ marine invertebrate acute toxicity for TEP Species % ai. 48 hour LC50 : g/ L Toxicity Category MRID No. Author/ Year Study Classification Mysid ( Mysidopsis bahia) 81.5 9.6 Very Highly Toxic 42397904 Lintott ( 1992) Core Mysid ( Mysidopsis bahia) 81.5 9.3 Very Highly Toxic 42565601 McElwee and Lintott ( 1992) Core Mysid ( Mysidopsis bahia) 43.7% 96 hr LC50 = 20.2 Very Highly Toxic 42343402 Lintott ( 1992) Core Eastern Oyster ( Crassostrea virginica) 43.3% 96 hr LC50 = 23,600 Slightly Toxic 42597301 Lintott ( 1992) Supplemental Estuarine and Marine Invertebrate, Chronic There are no available chronic toxicity data for estuarine/ marine invertebrates. The guideline 72 4( b) for estuarine/ marine invertebrates is no fulfilled.

1 Naphthol Toxicity to Aquatic Organisms Acute Toxicity The major metabolite of carbaryl degradation by abiotic and microbially mediated processes is 1 naphthol. As summarized in Table 16, 1 naphthol is categorized as moderately to highly toxic to aquatic organisms on an acute exposure basis. LC50 values ranged from 0.75 to 1.6 mg/ L for freshwater fish, from 1.2 to 1.8 mg/ L for estuarine/ marine fish, from 0.70 to 3.25 mg/ L for freshwater invertebrates, and from 0.21 to 2.5 mg/ L for estuarine/ marine invertebrates.

Acute toxicity testing of 1 naphthol was also conducted using earthworms ( Eisenia fetida). In a 14 day study, the LC50 was 441 mg/ kg of soil ( MRID 457848 06). Although the study was conducted for 14 days, no additional mortality was observed after day 7 suggesting that naphthol had likely degraded. The study is classified as supplemental since EPA does not currently require earthworm testing.. 113 Table 16 Summary of aquatic organisms acute toxicity in mg/ L ( ppm) for the carbaryl degradate 1 naphthol.

Species 96 hour LC50 ( mg/ L) ( nominal) Toxicity Category MRID No. Author/ Year Study Classification Rainbow Trout ( Onchorynchus mykiss) 1.4 Moderately Toxic 40955204 Surprenant ( 1988) Core Rainbow Trout ( Onchorynchus mykiss) 1.6 Moderately Toxic 00164307 Surprenant ( 1986) Supplemental Bluegill Sunfish ( Lepomis macrochirus) 0.76 Highly Toxic 40955203 Surprenant ( 1988) Core Bluegill Sunfish ( Lepomis macrochirus) 0.75 Highly Toxic 00164305 Surprenant ( 1986) Supplemental Sheepshead Minnow ( Cyprinodon variegatus) 1.2 Moderately Toxic 40955201 Surprenant ( 1988) Core Sheepshead Minnow ( Cyprinodon variegatus) 1.8 Moderately Toxic 00164306 Surprenant ( 1986) Supplemental Waterflea ( Daphnia magna) 48 hr EC50 = 0.73 Highly Toxic 40955205 Surprenant ( 1988) Core Waterflea ( Daphnia magna) 48 hr EC50 = 0.70 Highly Toxic 00164310 Surprenant ( 1986) Supplemental Waterflea ( Daphnia magna) 48 hr EC50 = 3.25 Moderately toxic 457854 05 Ebeling & Nguyen ( 2002) Supplemental Mysid ( Mysidopsis bahia) 0.21 Highly Toxic 40955202 Surprenant ( 1988) Core Mysid ( Mysidopsis bahia) 0.20 Highly Toxic 00164309 Surprenant ( 1986) Supplemental Eastern Oyster ( Crassostrea virginica) 48 hr LC50 = 2.1 Moderately Toxic 00164308 Surprenant ( 1986) Core Chronic Toxicity Chronic ( 32 day) exposure to the 1 naphthol degradate of carbaryl at mean measured concentrations of 200 : g/ L resulted in reduced larval survival and reduced body weight and length Table 17. Approximately 75% of the fish exposed to the 200 µ g/ L exhibited deformed jaw, i. e., mouth appeared abnormally small and the lower jaw appeared extended. The guideline requirement 72 4( a) for freshwater fish using 1 naphthol is fulfilled.

Table 17. Chronic toxicity testing of the carbaryl degradate 1 naphthol.

Species % ai NOEC/ LOEC ( mg/ L) Endpoints Affected MRID No. Author/ Year Study Classification Fathead Minnow ( Pimephales promelas) 99 0.10 / 0.20 Larval survival/ growth 457848 04 Sousa ( 2002) Core 114 Terrestrial Plants Toxicity testing of terrestrial plants is required for non herbicide pesticides when the label warns that nontarget plants could be adversely affected. Carbaryl can be used as a fruit thinning agent on apples and pears. However, the label cautions that the product may result in fruit deformity under certain environmental conditions. The label also cautions that application to wet foliage or during periods of high humidity may cause injury to tender foliage. Label language indicates that carbaryl should not be used on Boston ivy, Virginia creeper, and maidenhair fern due to potential injury. Incidents have also been recorded for vegetable crops ( tomatoes, potatoes, cabbage, broccoli, pumpkin, squash, cucumbers) in New York and Pennsylvania (# 1009262 128; # 1009305 001).

Tier 1 terrestrial plant vegetative vigor testing was conducted for 6 plant species ( 4 dicots and 2 monocots) after application of Sevin ® XLR Plus, soluble concentrate ( Carbaryl, 44.35% w/ w) at a single field application rate of 900 g a. i./ ha ( 0.803 lbs a. i./ acre), equivalent to the TEP of 4.059 g/ L per ha ( 0.014 lbs/ gal per acre). Response at this level was compared to response in a negative control group. Test species included cabbage, cucumber, onion, ryegrass, soybean, and tomato. No species were sensitive to Sevin ® XLR Plus, soluble concentrate ( Carbaryl, 44.35% w/ w) because no reductions exceeded 25%. The study ( MRID 457848 07) is classified as supplemental and does not fulfill the guideline requirements for a Tier I vegetative vigor study ( Subdivision J, § 122 1b) because fewer species than recommended ( 6 dicot and 4 monocot species) were tested and the species tested did not include corn and a dicot root crop species. Furthermore, plant height was ( a recommended endpoint) not evaluated Guideline 122 1 is not fulfilled.

Incidents Involving Terrestrial Plants Of all of the incidents associated with carbaryl, the greatest number ( 11) have affected terrestrial plants. In Minnesota, Sevin XLR Plus damaged all 15 acres of a cucumber crop ( I012089 008). In Florida, Bug B Gon Garden dust killed two tomato plants ( I010017 016). In California, the use of Sevin 80W ( 9.3 lbs/ acre) in conjunction with SunSpray 6E ( petroleum distillate) on olives resulted in pitting, slight burn and leaf drop ( I009846 003). In North Carolina, the use of Sevin XLR Plus was alleged to have damaged an orchard; however, the application rate and crop is not reported ( I009412 001). In Pennsylvania, the use of Garden Tech Ready to Use bug killer to control flea beetles resulted in burning of vegetables ( potatoes, cabbage, broccoli and tomatoes) in a homeowner's garden ( I009305 001). In New York, Bub B Gon Dust killed tomatoes, cucumbers, pumpkins and squash two weeks after application by a home gardener ( I009262 128). In California, application of two different formulations of carbaryl ( Sevin 50W and Sevin 80 WSP) over 4 consecutive months resulted in 50% of a 43 acre quince crop being spotted ( I008034 004 / I008034 003). Also in California, 60% of the fruit from 8 acre quince orchard was spotted following application of Sevin 50W ( I008034 002). In Oregon where two orchards applied Sevin XLR, pear harvest was reduced by low fruit set and malformations in fruit shape ( I002276 002); the certainty factor was classified as " unlikely" since the reviewer felt there was no indication that carbaryl had damaged plants at registered use rates. In California, following the use of Greensweep, a homeowner's lawn was damaged ( I001556 002); the certainty factor however, was classified as unlikely since the reviewer did not believe carbaryl had ever been implicated in causing plant damage. Finally, in Florida use of Greesweep Weed damaged a homeowner's lawn ( I001358 002); the certainty factor was classified 115 as unlikely since the reviewer felt there was insufficient information contained within the incident report to link carbaryl directly to the damage.

Based on the available incident data related to carbaryl use, it appears that many of the reports were generated by homeowner use of the pesticides. Insufficient detail is provided to determine whether the homeowner followed label instructions for the application of carbaryl on plants. The large scale damage inflicted to orchard crops is a greater concern. The limited terrestrial plant data available on carbaryl does not indicate the likelihood of phytotoxic effects; however, the incident data imply that phytotoxic effects are possible.

Aquatic Plants Aquatic plant testing is recommended for all pesticides having outdoor uses ( Keehner. July 1999). The tests are performed on species from a cross section of the nontarget aquatic plant population. The preferred test species are duckweed ( Lemna gibba), marine diatom ( Skeletonema costatum), freshwater blue green algae ( Anabaena flos aquae), freshwater green alga ( Selenastrum capricornutum), and a freshwater diatom. Toxicity testing for aquatic plant species is required for carbaryl because of its registered forestry uses.

To date, the Agency has received data on only one aquatic plant species, i. e., a green algae Pseudokirchneria subcapitata ( formerly Selenastrum capricornutum). I n one study of green algae the LC50 and NOAEC are 1.1 ppm and 0.37 ppm, respectively ( MRID # 42372802); the study is classified as core.

In a recent 96 hour acute toxicity study ( MRID 457848 03), cultures of Pseudokirchneriella subcapitata were exposed to carbaryl at nominal concentrations of 1.0, 1.8, 3.2, 5.6, 10, and 18mg a. i/ L under static. The EC05 and EC50/ IC50 values based on cell density were 0.287 and 1.27 mg a. i/ L, respectively. The percent growth inhibition in the treated algal culture as compared to the control ranged from 27 to 98%. Other than inhibition of cell growth ( in terms of numbers of cells), there were no compound related phytotoxic effects. This toxicity study is classified as supplemental because tap water was used as a source of dilution water and the levels of residual chlorine are not reported; it is uncertain whether this deficiency may have impacted the ability of the study to detect treatment effects.

In a similar 96 hr acute toxicity study ( MRID 457848 08 ), cultures of Pseudokirchneriella subcapitata were exposed to SEVIN XLR PLUS ( carbaryl extra long residue formulated product) at nominal concentrations of 0, 1.0, 1.8, 3.2, 5.6,1 and 10 mg a. i/ L under static conditions. The NOAEC is 1.8 mg a. i./ L and EC50/ IC50 values based on cell count was 3.2 mg a. i/ L. The percent growth inhibition in the treated algal culture as compared to the control ranged from 0 to 97%. No abnormalities in cell morphology were observed at any of the test concentrations. The study is classified as scientifically sound and is suitable for use in estimating the risk of carbaryl formulated end product to aquatic plants. 116 As mentioned earlier, there are data suggesting that amphibians growth has actually increased in carbaryl treated waters ( Bridges and Boone 2003). In this study, chlorophyll a concentrations in ponds treated with carbaryl at 5 mg/ L increased 347% compared to controls. The authors suggest that the increased phytoplankton productivity may have been due to reduced grazing by zooplankton sensitive to carbaryl. It is also possible though that since the carbaryl degradate 1 naphthol is a plant auxin, carbaryl treatment may have stimulated the growth of certain algae. Therefore, EFED is uncertain regarding the potential effects of carbaryl on aquatic plants. Since only one species of aquatic plant has been tested, the Guideline 122 2 is not fulfilled. 117 APPENDIX D2. REVIEW OF LITERATURE ON EFFECTS OF CARBARYL ON AMPHIBIANS Bridges, C. M. 1999. Effects of a Pesticide on Tadpole Activity and Predator Avoidance Behavior. Journal of Herpetology 33 ( 2): 303  306 Gray treefrog ( Hyla versicolor) tadpoles ( 0.025 ± 0.008 g) at stage 25 were housed with redspotted newts ( Notophthalmus viridescens) and exposed to carbaryl at either 1.25 or 2.50 mg/ L, dilution ( well water) water control, or solvent ( 0.06 ml acetone/ L) control. Three replicates of eight 3.78 L glass jars filled with 2 L of well water at 22oC and exposed for 24 hours under static conditions. Testing chambers consisted of 18 L plastic tubs ( 45 x 25 x 15 cm) willed with 10 L well water. A small plastic plant was secured 15 cm from one end. At the other end was a 1 L ( 8 x 8 x 15 cm) plastic container to hold the newt. The containers had plastic mesh sides to facilitate the dissemination of visual, tactile, and chemical cues, but precluded attack by the newt. Following the 24 hr carbaryl exposure, each group of three tadpoles was placed in testing chamber containing the confined newt. After a 5 minute acclimation, tadpole activity ( swimming, resting and feeding) and position within the chamber ( i. e., in refugia, in open, near edge) were recorded every 3 minutes for 1 hour. Activity of all three tadpoles was pooled.

Tadpoles exposed to carbaryl at 2.5 mg/ L were active an average of 45% less of the time than control tadpoles. The responses of tadpoles to carbaryl were not considered adaptive [ to the presence of predators]. Carbaryl exposed tadpoles spent less time in refugia compared to controls when predators were present and also spent more time in refugia when no predator was present.

Both in the presence of predators and carbaryl exposure significantly reduced the amount of time tadpoles spent active. Tadpoles spending too much time resting may not acquire adequate resources to achieve metamorphosis or to outgrow gape limited predators. Although carbaryl exposed tadpoles spent less time active with predators were present, a greater proportion of that active time was spent feeding, thereby minimizing the costs associated with the trade off between time spent foraging and predator avoidance. The author concludes that tadpoles in carbaryl contaminated sites may experience longer larval periods or a smaller size at metamorphosis, both of which can negatively affect adult fitness.

Boone, M. D. and C. M. Bridges. 1998. The Effect of Temperature on the Potency of Carbaryl for Survival of Tadpoles of the Green Frog ( Rana clamitans). Environmental Toxicology and Chemistry 18 ( 7): 1482  1484.

Green frog ( Rana clamitans) tadpoles weighing an average of 80 mg ( ± 15 mg) were exposed to one of nine chemical treatments, i. e., water control, solvent ( acetone 0.5 mL/ L), 3.5, 5.0, 7.2, 10.3, 14.7, 21.0 and 30.0 mg carbaryl/ L, and to one of three temperature treatments, i. e., 17, 22, or 27oC, in a 96 hr static test. The tests were conducted in 3.8 L glass jars containing 2 L of well water ( ph 7.8, hardness 286 mg/ L as CaCO3). Each treatment was replicated three times. Ten tadpoles were randomly assigned to each glass jar and the percent mortality was determined at 12, 24, 48, and 96 hours. Tadpoles were not fed during the exposure. 118 Average survival was significantly different at each temperature treatment. At 24 hours survival was significantly lower at 27oC. Lower concentrations ( 3.5, 5.0, 7.2 and 10.3 mg/ L) were not significantly different from controls ( survival > 96%). The two greatest concentrations ( 21 and 30 mg/ L) were significantly different from controls at all times and had an average survival below 42%, with no tadpoles surviving in the 30 mg/ L group for 96 hours.. Tadpoles at 17 and 22oC had greater survival at higher concentrations than tadpoles at 27oC. At 48 hours, the LC50 at 27oC was 16.17 mg/ L and at 17oC the LC50 was 26.01 mg/ L. By 96 hours, the LC50 at 27oC ( 11.32 mg/ L) was twice as large as at 17oC ( 22.02 mg/ L); that is, a smaller amount of carbaryl was needed to induce mortality at a high temperature.

Bridges, C. M. and R. D. Semlitsch. 2001. Genetic Variation in Insecticide Tolerance in a Population of Southern Leopard Frogs ( Rana sphenocephala): Implications for Amphibian Conservation. Copeia 1: 7  13 In a study investigating the amount of genetic variability in tolerance to carbaryl within a single population of southern leopard frogs ( Rana sphenocephala), time to death was measured in tadpoles exposed to carbaryl at 30 mg/ L. Mortality was determined at 3, 6, 9, 12, 18, 24, 36 and 48 hours among 10 replicates of full and half sibling families. Tadpoles were housed in 250 mL glass beakers containing 200 mL. Control, solvent ( acetone 0.5 mL/ L) and carbaryl treated solutions were prepared using well water ( pH 7.8, hardness 286 mg/ L as CaCO3). The results of the study indicated that significant differences in time to death were attributed to family with some families significantly more sensitive than others. The study found a significant amount of genetic variation for tolerance to carbaryl among half sibling famines suggesting that this population may have the ability to persist in the presence of carbaryl contamination. The data also indicated that smaller tadpoles were more tolerant of carbaryl Boone, M. D. and R. D. Semlitsch. 2002. Interactions of an Insecticide with Competition and Pond Drying in Amphibian Communities. Ecological Applications 12 ( 1): 307  316.

In a 77 day mesocosm study, researchers examined the effects of carbaryl on amphibians in terms of body size, length of larval period, and survival to metamorphosis when exposed to carbaryl early in the larval period. The study units consisted of fifty 1480 L polyethylene ponds ( 1.85 m in diameter) containing 1000 L of well water and 1 kg of leaf litter. The study manipulated initial larval density, i. e., low ( 80) and high ( 240), pond hydroperiod, ( constant or drying), and chemical concentration ( absent, 3.5 mg/ L, 5.0 mg/ L, or 7.0 mg carbaryl / L). Frogs species included: Southern leopard frog ( Rana sphenocephala), plains leopard frog ( R. blairi), and the Woodhouse toad ( Bufo woodhousii). The results suggest that for Woodhouse toads, carbaryl exposure actually increased the survival of the frogs by roughly 30% in the highest treatment. Toads in the high density ponds showed greater survival than those in low density ponds at the highest carbaryl level.

For Southern and plains leopard frogs, carbaryl treatment did not have a significant or profound influence on either species. For green frogs, carbaryl exposure had a significant effect on days to metamorphosis with tadpoles in the chemical treatments generally having longer larval periods. 119 The study concluded that both leopard frog species may be less affected by carbaryl than Woodhouse ` s toad.. Toads show a dramatic increase in survival with carbaryl treatment. The authors speculate that the increase in survival could have resulted from decreased predation by newts exposed to carbaryl, or more likely, a competitive release from zooplankton in the presence of carbaryl. In general, the three species studied showed no direct negative effect when exposed to carbaryl; however, poor survival in the control ponds may have confounded the test's ability to detect carbaryl treatment effects. Additionally, the authors speculate that since the test animals were collected from agricultural areas, the animals may have been more tolerant to carbaryl.

Bridges, C. M. 2000. Long term Effects of Pesticide Exposure at Various Life Stages of the Southern Leopard Frog ( Rana sphenocephala). Arch. Environ. Contam. Toxicol. 39: 91  96.

In a study to determine whether chronic exposure of tadpoles to carbaryl affected responses at metamorphosis and whether the effects are dependent on the life stage at which individuals are exposed, Southern leopard frogs ( Rana sphenocephala) eggs, embryos and tadpoles were exposed to control, solvent control ( 0.25 mL acetone/ L), 0.16, 0.40 and 1.0 mg carbaryl/ L. Each treatment combination was replicated 10 times ( total n = 250 tadpoles) in individual 1.5 L plastic containers filled with 1 L of well water ( pH 7.8, hardness 286 mg/ L as CaCO3; temperature 21 ± 1.5oC). The results indicated that metamorphs exposed throughout the tadpole stage and throughout development ( egg, embryo, tadpole) experienced significant mortality at all chemical levels. Additionally, metamorphs exposed during the egg stage were smaller than their corresponding controls. Nearly 18% of individuals exposed to carbaryl during development exhibited some type of developmental deformity ( including visceral and limb malformations) compared to less than 1% in controls.

Bridges, C. M., F. J. Dwyer, D. K. Hardesty, and D. W. Whites. 2002. Comparative Contaminant Toxicity: Are Amphibian Larvae More Sensitive than Fish? Bull. Enviorn. Contam. Toxicol. 69: 562  569.

In a study designed to determine the LC50 of Southern leopard frog ( Rana sphenocephala) tadpoles and determine whether amphibians are more sensitive to contaminants than fish, three replicates ( containing 10 tadpoles per replicate) for each of six test concentrations were tested. Tadpole ( 0.05 mg ± 0.008 mg) mortality was recorded after 6, 12, 24, 48, 72 and 96 hours. The 96 hr LC50 was then compared to similar values on rainbow trout ( Onchorynchus mykiss), fathead minnow ( Pimephales promelas), bluegill sunfish ( Lepomis macrochirus) and boreal toad tadpoles ( Bufo boreas). In this study, tadpoles ( 96 hr LC50 = 8.4 mg/ L) were relatively tolerant to carbaryl compared to the bluegill sunfish ( 96 hr LC50 = 6.2 mg/ L), fathead minnow (( 96 hr LC50 = 5.21 mg/ L) and rainbow trout ( 96 hr LC50 = 1.88 mg/ L). The only species that was less sensitive than the leopard frog was the Boreal toad ( 96 hr LC50 = 12.31 mg/ L). In fact, of the 5 compounds tested ( 4 nonylphenol, carbaryl, copper, pentachlorophenol and permethrin) only copper exhibited enhanced toxicity to the leopard frog. For the remaining organic compounds, the toxicity estimates obtained for fish proved to be protective for amphibians. The report notes that correlations obtained from surrogate species and leopard frogs suggest that rainbow trout may be the most appropriate surrogate fish species for making reference to anuran tadpoles as their LC50 values for many contaminants are most similar. 120 Bridges, C. M. 1997. Tadpole Swimming Performance and Activity Affected by Acute Exposure to Sublethal Levels of Carbaryl. Environ. Toxicol. and Chem. 16( 9): 1935  1939.

In a study to determine the effects of sublethal concentrations of carbaryl on activity level and swimming performance ( i. e., sprint speed and distance) of plains leopard frog ( Rana blairi) tadpoles, two replicate groups of five 3.8 L glass jars each filled with 2 L of well water were used to test single tadpoles ( approximately 20 mg) to control, solvent ( 0.5 mL acetone/ L), 3.5, 5.0 and 7.5 mg carbaryl/ L. Tadpoles were not fed 24 hours up to study or during study. Well water was characterized at having pH of 7.8, water hardness of 286 mg/ L as CaCO3 and a temperature of 22 ± 1oC. Each tadpole was observed for 5 seconds every 4 minutes to determine swimming activity or resting activity for a total of 20 times per jar initially. Activity was also examined at 24, 48, 72 and 96 hours after which time, the tadpoles were transferred to clean water and their activity monitored for 24 and 48 hr post exposure.

Carbaryl concentration significantly affected the time tadpoles spent being active. At 48 hrs post exposure, activity of tadpoles in the control and 3.5 mg/ L treatments were not significantly difference. Some recovery of tadpoles, although not significant, was noted in all treatments except the 7.2 mg/ L group. Additionally, control tadpoles exhibited greater sprint speed than carbaryltreated tadpoles and the controls swam greater distances than their carbaryl treated counterparts.

Bridges, C. M. and M. D. Boone 2003. The Interactive Effects of UV B and Insecticide Exposure on Tadpole Survival, Growth and Development. Biological Conservation In Press.

In a study of the Southern leopard frog ( Rana sphenocephala), the interaction of three ultraviolet B ( UV B) radiation levels and carbaryl exposure was explored. Artificial ponds ( 1480 L) consisting of polyethylene cattle tanks were willed with 1000 L of well water and 1 kg of leaf litter and inoculated with algae from a local pond. Ponds were allowed to equilibrate for 45 days. One day prior to the start of the study, 45 tadpoles were added to each pond. Dissolved oxygen ( range 2.5  4.9 mg/ L), pH ( range 6.9  7.1) and temperature ( 16.4  16.9oC) were monitored the day of Sevin ( 22.5% carbaryl) application; the nominal carbaryl concentration was 5 mg/ L. Differing pond lids ( plastic wrap, Mylar D and Polycarbonate) served as filters to provide, high ( ambient), medium ( roughly 50%) and low ( roughly10%) UV B exposure intensities. Control ponds were uncovered ( ambient UV B).

UV B intensity significantly increased survival to metamorphosis. The presence of carbaryl significantly increased the mass at metamorphosis; tadpoles in tanks containing carbaryl were 20% larger than those in tanks without carbaryl. Chlorophyll concentrations in ponds with carbaryl was 347% greater than in control ponds. 121 Bridges C. M. and R. D. Semlitsch. 1999. Variation in Pesticide Tolerance of Tadpoles Among and Within Species of Ranidae and Patterns of Amphibian Decline. Conservation Biology14( 5): 1490  1499.

In a series of studies designed to assess the degree of variation in response to carbaryl among and within species of frogs in the family Ranidae, the tolerance to carbaryl was tested among nine species and among Southern leopard frogs. The study was conducted over 3 years by collecting species ( red legged frog ( Rana aurora), yellow legged frog ( R. boylii), spotted frog ( R. pretiosa), wood frog ( R. sylvatica), Pickeral frog ( R. palustris), plains leopard frog ( R. blairi), northern leopard frog ( R. clamitans) , and crayfish frog ( R. areolata) from across the United States. At least three egg masses from each species. To examine variation in response among populations of southern leopard frogs ( R. sphenocephala), 10 populations were sampled. Tadpoles from separate egg masses from each population were tested to determine the within population, i. e., among family, variation on all but two ( Illinois and Texas) collection sites. Time to death assays were conducted by placing individual tadpoles in 250 mL glass beakers containing 200 ml of 30 mg/ L carbaryl in well water with 0.1 ml acetone as a co solvent. All beakers were held at 22 ± 1oC and tadpoles were not fed during exposure. Each family was replicated 10 times except in three cases. Mortality was determined at 3, 6, 9, 12, 18, 24, 36, 48 and 60 hours. Activity changes were also tested using 2.5 mg/ L carbaryl. Each family was replicated 10 times with one tadpole per replicate except in three cases where there were too few animals. Activity ( presence or absence of tail movement) was monitored after 24 hours of exposure. Each observation was made for 5 seconds and a total of 20 observations were recorded per tadpole.

There were significant differences ( p < 0.0001) in time to death among the nine ranid species. From most to least sensitive: Rana sylvatica > R. areolata > R. boyii > R. clamitans > R. blairi > R. sphenocephala > R. palustris > R. pretiosa > R. aurora. Mean time to death varied from 5 to 34 hours. R. sylvatica was significantly more sensitive than all other species.

There were significant differences among species with respect to overall activity ( P < 0.0002); however, there was no significant interaction of treatment and species; the lack of interaction indicated that all species were equally sensitive to carbaryl exposure.

Time to death significantly differed among southern leopard frog populations in each of the 3 years. Populations in Texas, Mississippi, South Carolina, and one from Missouri were most tolerant, whereas populations from Virginia and Illinois and three from Missouri were most sensitive. In two of the years there was a significant population by treatment interaction indicating that populations were differentially sensitive to carbaryl exposure 122 APPENDIX D3. REVIEW OF RELYEA AND MILLS PAPER U. S. ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, DC 20460 OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES MEMORANDUM PC Code No. 129106 DP Barcode : D283014 SUBJECT: EFED Review of Relyea Paper Entitled " Predator induced stress makes the pesticide carbaryl more deadly to gray treefrog tadpoles ( Hyla versicolor) "

TO: Anthony Britten, Chemical Review Manager Betty Shackleford, Product Manager Special Review and Reregistration Division FROM: Thomas M. Steeger, Ph. D., Senior Biologist Environmental Risk Branch IV/ EFED ( 7507C)

Through: Betsy Behl, Branch Chief Environmental Risk Branch IV/ EFED ( 7507C)

The Environmental Fate and Effects Division ( EFED) has completed its review of the research article entitled " Predator induced stress makes the pesticide carbaryl more deadly to gray treefrog tadpoles ( Hyla versicolor)" published in the February 2001 issue of the Proceedings of the National Academy of Science. The paper, authored by Rick Relyea and Nathan Mills ( Department of Biology, University of Pittsburgh) provides data demonstrating that prolonged sub acute exposure of gray treefrog tadpoles to carbaryl at 3 to 4% of the reported LC50 ( 2.5  20.6 mg/ L) killed 10 to 60% of the tadpoles. Furthermore, the paper claims that in the presence of " predatory cues" carbaryl was 2 to 4 times more lethal to tadpoles. The authors conclude that " under more realistic conditions of increased exposure times and predatory stress [ simulated in their study], current application rates for carbaryl can potentially devastate gray treefrog populations" and that given the common mechanism of action, i. e., acetylcholinesterase inhibition, of carbaryl with other widely used pesticides ( carbamates and organophosphates), the " negative impacts may be widespread in nature."

While EFED concurs that biotic and abiotic effects do impact the toxicity of chemicals, we do not concur with the author's contention that their protocol is indicative of " more realistic ecological conditions" than EFED's current battery of acute and chronic toxicity tests; all of these studies are conducted under rigidly controlled laboratory conditions and are not intended to be representative of all of the variables that may affect the toxicity of a compound in the field. Furthermore, the EFED environmental fate and ecological risk assessment chapter on carbaryl 123 submitted in support of the re registration eligibility decision does attempt to account for carbaryl's risk to amphibians and is to some extent protective to amphibians at the concentrations discussed in the Relyea and Mills paper. However, while the authors are correct that a cumulative assessment of the effects of all chemicals acting through a similar mode of action may be more realistic, the logistics of conducting such an evaluation would require additional resources than are currently available in EFED.

The EFED environmental fate and ecological risk assessment chapter on carbaryl contains both acute and chronic amphibian toxicity data ( see Attachment 1 for excerpt on amphibians from chapter). Although bullfrogs ( Rana catesbeiana) are relatively inured ( LD50 > 4,000 mg/ Kg) to carbaryl on an acute oral exposure basis, leopard frog tadpoles ( Rana blairi) exhibited a 90% reduction in swimming activity at carbaryl concentrations in the 3.5  7.2 mg/ L range. The chapter notes that such an impairment would likely render the tadpoles [ prey] vulnerable to predation provided the predators were not similarly impaired. Furthermore, the chapter notes that chronic exposure of southern leopard frogs ( Rana sphenocephala) to carbaryl led to developmental and growth effects and that the long term effects of short term carbaryl exposures to amphibians during critical life stages was uncertain and could potentially lead to population level effects. Therefore, the EFED risk assessment does discuss qualitatively the potential susceptibility of amphibians following both acute and chronic exposure to carbaryl.

EFED does not typically evaluate risk to aquatic animals on a species by species or class byclass basis but rather relies on surrogate species as representatives of broad ranges of aquatic organisms. As with most screening level risk assessments conducted by EFED, the carbaryl chapter used fish toxicity data as a surrogate for amphibians. Toxicity values for freshwater fish ranged from 0.25 to 20 mg/ L; the most sensitive species, i. e., Atlantic salmon ( Salmo salar) with a 96 hour LC50 value of 0.25 mg/ L, was selected for calculating risk quotient ( RQ) values used in EFED's assessment of ecological risk to freshwater vertebrates. The salmon LC50 value represents roughly 10% of the lower LC50 range ( 2.5 to 20.6 mg/ L) for amphibians reported in Relyea and Mills paper. Given that EFED's levels of concern ( LOC), i. e., the ratio of expected environmental concentrations ( EEC) to the LC50 value, for endangered is 0.05, if the EEC was greater than 0.01 mg/ L, it would exceed EFED's LOC. Therefore, the ecological risk assessment for aquatic vertebrates is protective for species with 96 hour LC50 values greater than 0.01 mg/ L. ( 0.04% of the range reported by Relyea and Mills).

EFED concurs with the study authors that biotic and abiotic effects can impact the toxicity of pesticides and that it is difficult to account for these effects on the basis of the limited laboratory tests that are typically available for evaluating the effects of pesticides. EFED also concurs with the authors that chemicals with similar modes of action may have additive toxicities and that commutative assessments may better account for toxicity; however, the practicality of implementing such evaluations is limited for screening level assessments.

EFED is uncertain regarding how representative the Relyea and Mills article is of field effects though or of the direct effects of carbaryl and predatory cues. The experimental design included 10 tadpoles in 10 liter polyethylene tubs containing filtered tapwater. In a 10 day static renewal study, they changed water on days 3 and 7. In 16 day static renewal exposures, they changed water every 124 4 days. Water quality parameters ( dissolved oxygen, temperature, pH and ammonia) were measured midway through the 16 day exposure studies. Predator treatments consisted of a larval salamander ( Ambystoma maculatum) housed within a 250 ml plastic cup, covered with a fiberglass window screening, in each of the exposure tanks; controls consisted of the plastic cup alone. Nominal carbaryl concentrations ranged from 0.045 to 0.54 mg/ L; both negative and solvent ( acetone) controls were run concurrently. The results demonstrate that increased ammonia concentrations were associated ( P< 0.0001, range of means = 0.21  0.99 mg/ L) with carbaryl concentration, an effect attributed to the presence of dead tadpoles and excess unconsumed food. A regression analysis of survival against ammonia was significant ( P < 0.001, but not particularly predictive ( R2 = 0.395). Predators had no effect on ammonia ( P > 0.1) and only had small effects on oxygen and pH ( 9% decrease in oxygen, P < 0.0001; 5% decrease in pH, P = 0.019). Given that water quality parameters were only measured midway through the study and that both tadpoles and thus feeding rates were likely increasing throughout the study, ammonia levels may have been considerably higher toward the end of the studies. Thus it is unclear whether ammonia, pH and dissolved oxygen had an effect on the toxicity of carbaryl to tadpoles. It is noteworthy that the Relyea and Mills data showed precipitous declines in tadpole survival after 5 days of exposure.

Although it is difficult to design a study that can accurately reflect field conditions and particularly predator prey relationships, EFED is not convinced that the Relyea and Mills study could be interpreted as more representative of field conditions. Typically, prey demonstrate predator avoidance behavior in the presence of a perceived threat. In this study, tadpoles were unable to escape their perceived threat; predatory cues, i. e., seeing a predator ( visual cues) may have protracted their response well beyond the chemical cues released following the salamander's consumption of tadpoles. It is questionable whether tadpoles would have remained in view of a potential predator under more realistic conditions.

In refined ecological assessments, EFED oftentimes has mesocosm study data available to assess the risk of pesticides under " field conditions". These studies, while considerably more expensive that the Relyea and Mills protocol, may represent the most accurate reflection of controlled field studies. It is interesting to note though that while mesocosm studies may yield LC50 values similar to laboratory studies, they rarely provide LC50 values showing enhanced toxicity. Test species within these studies are better able to rely on compensatory mechanism to shield themselves from the toxic effects of chemicals.

In addition, the environmental fate of pesticides is often different under field conditions. Under alkaline conditions, i. e., pH > 7, carbaryl undergoes hydrolysis with half lives ranging from 0.15 to 12 days. While Relyea and Mills accurately note carbaryl's susceptibility to hydrolysis, they fail to mention that under aerobic conditions, carbaryl is also microbially degraded in the aquatic environment with a half life of approximately 5 days. It is likely that gray treefrogs in the Relyea and Mills study were exposed to carbaryl concentrations considerably lower than nominal after 3 to 4 days. Thus the actual exposure regime may have been more representative of pulsed exposures to declining concentrations of carbaryl and increasing concentrations of ammonia. While it is clear that predators had an effect on the response of tadpoles to the exposure regime, EFED does not concur that the test results are representative of the effects of predation on carbaryl toxicity alone. 125 EFED concurs with Relyea and Mills that both biotic and abiotic factors impact the toxicity of pesticides and that current screening methods do not account for the full range of these effects nor do screening level assessments take into account aggregate effects from exposure to chemicals with similar modes of action. Screening level assessments attempt to identify where EFED's LOCs are exceeded and where EFED has uncertainties regarding risk. With respect to amphibians, the chapter discusses the likelihood of acute and chronic effects from current uses of carbaryl. 126 Attachment 1. Excerpt on Amphibians from the Initial Draft Environmental Fate and Ecological Risk Assessment for the Reregistration of Carbaryl Chapter According to an available supplemental study with a 50% carbaryl formulation, the LD50 for the bullfrog ( Rana catesbeiana) is greater than 4,000 mg/ kg, or practically nontoxic ( MRID 00160000). A single acute exposure of plains leopard frog tadpoles ( Rana blairi) to carbaryl concentrations in the 3.5  7.2 mg/ L range led to a 90% reduction in swimming activity, including sprint speed and sprint distance, activity ceasing completely at 7.2 mg/ L ( Bridges 1997). This reduction in activity and swimming performance may result in increased predation rates and, because activity is closely associated with feeding, may result in slowed growth that could lead to failure to complete metamorphosis. Acute exposure to low carbaryl levels may not only affect immediate survival of tadpoles but also impact critical life history functions.

On a chronic basis, carbaryl has been shown to have the potential to adversely affect amphibians. In a recent study, nearly 18% of southern leopard frog ( Rana sphenocephala) tadpoles exposed to carbaryl during development exhibited some type of developmental deformity, including both visceral and limb malformations, compared to a single deformed (< 1%) control tadpole demonstrating that carbaryl exposure can result in amphibian deformities ( Bridges, 2000). Although the length of the larval period was the same for all experimental groups, tadpoles exposed throughout the egg stage were smaller than their corresponding controls. Because exposure to nonpersistent chemicals may last for only a short period of time, it is important to examine the long term effects that short term exposure has on larval amphibians and the existence of any sensitive life stage. Any delay in metamorphosis or decrease in size at metamorphosis can impact demographic processes of the population, potentially leading to declines or local extinction. 127 APPENDIX E1. SECTION 24c USE OF CARBARYL TO CONTROL BURROWING SHRIMP Although Texas recently applied for a Section 24c ( Supplemental Label of the Amended Federal Insecticide, Fungicide and Rodenticide Act) for use of carbaryl in shrimp culture ponds which drain into estuaries along the Gulf of Mexico, Washington is currently the only state sanctioning the use of carbaryl in estuarine/ marine waters for control of burrowing shrimp on mud flats used for oyster culture. The use of carbaryl to control burrowing shrimp has generated concern regarding the effects of the chemical in the immediate application area and the movement ( drift) and potential subsequent effects of carbaryl to nontarget sites.

The commercial oyster fishery in Willapa Bay has been in existence since the 1800' s. Originally sustained by the indigenous Olympia oyster, Ostrea lurida, the fishery now relies on the Pacific oyster ( Crassostrea gigas). Over the years, increasing numbers of indigenous burrowing shrimp ( ghost shrimp, Callianassa sp., and mud shrimp Upogebia pugettensis) have rendered tidal mud flats in the bay less amenable to traditional oyster culture methods. The activity of burrowing shrimp results in mud too soft to support oysters and as a consequence oysters settle into the mud and suffocate. Since 1963 Washington has issued permits to oyster growers to apply carbaryl to sheltered tidal areas and since 1994 carbaryl has been sprayed annually on 600 acres in Willapa Bay and 200 acres in Grays Harbor at a rate of 7.5  8 lbs/ acre. Although lower application rates have been attempted, they were not effective at penetrating tidal muds to a sufficient depth to kill burrowing shrimp and thus retreatment was required in subsequent years. Carbaryl is applied as a wettable powder to tidelands at low low [ Spring] tide primarily by helicopter; however, hand spraying is used in some instances. The label restricts aerial applications within 200 feet of a channel or slough; hand spraying is prohibited within 50 feet of a channel or slough.

Willapa Bay is located on the Pacific coast of Washington State and encompasses 79,000 acres at mean high tide representing a volume of 56.6 million ft3 of water. The tidal range in Willapa Bay is from 14 to 16 feet and roughly 45% ( 25.4 million ft3) of the water in the bay is exchanged into the Pacific Ocean during a complete tidal cycle. The relatively shallow bay has more than 50% its acreage exposed at low tide with much of the remaining surface area, except for channels, covered by 1 to 6 feet of water. Channel depths range from 30 to 50 feet with maximum depths 75 to 77 ft below mean low water. Willapa Bay opens to the Pacific Ocean at its northwestern corner through a broad shallow pass about 6 miles wide between Cape Shoalwater and Leadbetter Point. Major tributaries to the bay include the Willapa River to the north and the Naselle River to the south, together draining an area of 461,280 acres in Pacific County, Washington . Rainfall in the Willapa Bay area ranges from 85  100 inches per year resulting in mean annual runoff for the entire basin of 3.4 million acre feet; mean maximum discharge at the mouth of Willapa Bay is estimated at 1.6 million ft3/ second. Mean daily runoff is estimated to be about 0.004% of the total volume of the bay ( Hedgpeth, J. W. and S. Obrebski 1981. Willapa Bay: A Historical Perspective and a Rationale for Research. Coastal Ecosystems Project, Office of Biological Services, U. S. Fish and Wildlife Service FWS/ OBS 81/ 03).

The entrance of Willapa Bay is approximately 28 miles north of the mouth of the Columbia River and approximately 11 miles south of the entrance to Grays Harbor. Flushing rates ( tidal prism) 128 in Willapa Bay are influenced by conditions in the ocean. During the summer, strong northwesterly winds bring upwelled water from the ocean into the bay and promotes rapid turnover. Strong Pacific storms also promote mixing. At other times though, freshwater outflow from the Columbia River acts as a discrete water mass moving northward along the Pacific coast and may prevent mixing from occurring in the bay ( Hedgpeth and Obrebski 1981).

To address concerns regarding the mobility/ persistence of carbaryl and it effects on nontarget animals, a series of studies were undertaken as a requirement of the permitting process. These studies have been reviewed by EFED ( APPENDIX E1). Except for more recent studies conducted by Washington State University and the Washington Department of Ecology, much of the older ( pre 1996) data had procedural problems that limited the utility of the data. The more recent data indicate that carbaryl residues in the water column were generally at or below Washington state's projected effect threshold of 0.1 µ g/ L Although large carbaryl applications can affect water quality in areas distant from spray sites, the Washington Department of Ecology concluded that " no widespread effects from carbaryl would be expected in Willapa Bay after the end of the [ carbaryl] application period.".

Additional studies have also been submitted examining potential drift and long term effects of carbaryl in Willapa Bay ( APPENDIX E2). Studies have been undertaken to examine recovery of treated sediments ( Mazzone and McNamara); however, the data underscore the difficulty in conducting well designed field studies that account for the many sources of variability that can affect a study's ability to establish causality. Insufficient detail is provided in the Mazzone and McNamare study to suggest though that carbaryl applications to control burrowing shrimp in selected sites in the bay are likely to exhaust aquatic life within the bay. Given that the reapplication interval is roughly six years and the current study at best demonstrates that after two years a similar range of species exist in treated and untreated sites ( that may or may not be comparable), there is no conclusive evidence to support concerns that carbaryl treatments are reducing the overall " natural productivity" of Willapa Bay. Although a report by Felsot and Ruppert ( 2002) suggests that carbaryl residues may partition to sediment, persist there for extended periods of time, and serve as a sink for carbaryl reentering the water column for as much as year post application, these data are not consistent with previous studies in Willapa Bay nor the environmental fate data reported in this document. Therefore, the source of preapplication carbaryl residues as high as 0.7 µ g/ L is uncertain. In 2002, a total of 810.5 acres and 186 acres were treated in Willapa Bay and Grays Harbor, respectively. As part of the National Pollutant Discharge Elimination System ( NPDES) permit program, established under Section 402 of the Clean Water Act prohibiting unauthorized discharge of pollutants from point sources, monitoring was conducted to document acute and chronic exposure potential. Acute samples were collected at the first falling tide at least 24 hours following the final treatment within a sample area and samples for chronic analysis were taken at the first falling tide at least 30 days after final treatments. Acute monitoring data revealed carbaryl concentration as high as 5.3 µ g/ L while 3 out of 22 ( 14%) of the chronic monitoring samples had carbaryl levels ( range 0.58  1.25 µ g/ L) exceeding detection limits ( Booth et al. 2002). Based on 2002 monitoring data collected by the Shoalwater Bay Environmental Research Laboratory ( docket number OPP 2002 0138 052), carbaryl residues outside of application areas peaked at 1.4 µ g/ L on July 26 and again at 1.6 µ g/ L three days later following carbaryl applications on July 25 and July 27. These data are consistent with a Washington Department of Ecology study showing that carbaryl is frequently 129 0 20 40 60 80 100 0 500 1000 1500 2000 2500 3000 Carbaryl ( ug/ L) Percent of Total Species Brown shrimp Glass shrimp Pink shrimp Fairy shrimp Blue crab Eastern oyster Sheepshead Minnow 24 hour acute exposure level Figure 11. Cumulative percent distribution of acute LC50 values in µ g/ L ( ppb) for estuarine marine fish and invertebrate exposed to carbaryl. The red arrow shows point along curve for an exposure of 5 ug/ L.

0 200000 400000 600000 800000 1000000 1200000 1400000 1600000 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year Total Landings ( Pounds)

Figure 12. Total landings of crab in pounds harvested by year from Willapa Bay, Washington. Source: Washington Department of Fish and Wildlife 2003. detected up to 4 days after application to oyster beds and that carbaryl is transported several miles from the site of application.

Based on a cumulative effects distribution of acute L C 5 0 v a l u e s f o r estuarine/ marine species ( Figure 11), at maximum reported peak values ( 5.3 µ g/ L) after 24 hours, less than 28% of the total species would likely be affected in terms of acute mortality. Although 24 hr post application mortality is expected to be low in treatments sites, aquatic a n i m a l s ( f i s h a n d invertebrates) entrapped in shallow pools by the outgoing tide and in the immediate treatment area are likely to experience 100% mortality the day of treatment. Observations by members of the Shoalwater Bay Indian Tribe ( personal communication Gary Burns, Environmental Programs Director, Shoalwater Bay Environmental Research Laboratory 2003) on the day of treatment report extensive mortality of crustaceans and in particular crabs, which constitute a subsistence level fishery for the Shoalwater Bay Indian reservation members. These observations are consistent with data ( Stonic 1999) indicating that Dungeness crab ( Cancer magister) larvae would be particularly sensitive to carbaryl exposure and that the number of crabs killed by carbaryl in treated areas has increased as the number of acres treated each year has increased ( Washington Department of Ecology 1987). Total crab landings per year from Willapa Bay ( Figure 12) appear to fluctuate on a 10 to 15 year cycle and have ranged from 169 thousand pounds to 1.4 million pounds; on average, 515 thousand pounds are harvested annually. Since a precipitous ( 83%) decline in harvest in 1997, subsequent years have yielded a steady increase in annual harvest. Harvest in 2002 ( 976,870 lbs) was roughly double the annual 130 average. Given that carbaryl application to the bay have been relatively consistent over the years, the information on crab harvest suggests that crab recruitment is not well correlated with carbaryl applications.

Furthermore, age 0+ crabs placed on mud flats 24 hrs after application of carbaryl and monitored for 14 days did not differ in mortality rate from controls ( Feldman et al. 2000); the study indicated that young crabs were capable of recolonizing oyster grounds shortly after treatment. The risks to crabs age 1+ and 2+ foraging on animals immobilized by carbaryl treatments appeared to be greatest during the first 24 hours then declined rapidly; this is consistent with data showing carbaryl residues in tissues of burrowing shrimp treated with carbaryl declined by 90% after 24 hours.

In general, although some species are adversely affected by carbaryl treatments on a shortterm basis, re colonization by bedload transport and rapid reproduction is viewed as largely offsetting impacts resulting from carbaryl application ( Feldman et al. 2002). Ironically, the productive oyster culture in the bay is viewed by some as actually improving environmental conditions through the filter feeding activity of these animals, the refuge that the oyster shells provide for attachment of epibionts and protection for juvenile fish and invertebrates. Juvenile crab densities have been shown to be significantly higher in these habitats compared to areas occupied by large populations of burrowing shrimp ( Dumbauld et al. 1998).

With an application rate of 8 lbs to the acre and assuming that the tidal flats are eventually covered by 6 feet of water at high tide, carbaryl would be theoretically diluted in 1.96 x 106 gallons of water corresponding to a carbaryl concentration of approximately 0.5 parts per million ( 0.5 mg/ L). Based on the environmental fate properties of carbaryl, the chemical is expected to undergo relatively rapid hydrolysis ( t ½ = 10 hrs at pH 8.4) in an estuarine/ marine environment while undergoing considerable dilution from successive tides. The fact that on site monitoring 24 hours postapplication indicates carbaryl concentrations were detected at a maximum of 5 parts per billion ( 0.005 mg/ L) suggests that carbaryl is rapidly dissipating from application sites and that its potential to exert ecological effects is diminished. While EFED recognizes that acute mortality in the immediate application site may be near 100% for aquatic animals trapped in tide pools and/ or living in benthic sediments, the potential for off site effects and overall impact to Willapa Bay as a whole appears limited. This is based on the fact that roughly 1% of the total acres ( 79,000 acres) of the bay are treated during any given year, the treatments are dispersed over several months depending on low low tide schedules and that during a complete tidal cycle ( low low tide to high high tide), as much as 25.4 million ft3 of water ( up to 45% of the bay's total volume) may be exchanged. Thus, the opportunity for dilution alone is significant. Although this discussion has focused primarily on Willapa Bay, it is believed that the same potential for dissipation exists for Grays Harbor where less than 1% of the total acreage is treated.

Although preliminary research ( personal communication Nat Scholz, National Marine Fisheries Service 2002) suggests that salmonid fish exposed to carbaryl in olfactory perfusion assays are not able to detect the chemical, i. e., the chemical does not elicit an electrical response from olfactory cells, the relevancy of these data is uncertain. Concern has been raised though that the animal's inability to detect carbaryl would render the fish incapable of avoiding a chemical plume; however, no evidence has been provided that for fish other than those trapped in tide pools and 131 directly in a chemical treatment site, that the Section 24c use of carbaryl has resulted in fish kills. Studies have been proposed though ( personal communication Christian Grue, University of Washington Cooperative Fish and Wildlife Unit, 2003) that are designed to answer whether salmonids frequent active carbaryl application sites, the extent to which they consume prey containing carbaryl residues and whether the residues have any impact on brain acetylcholinesterase activity in the fish.

Concern has also been raised over the potential effects of carbaryl on birds feeding opportunistically on immobilized aquatic animals in treated areas; however, based on the available information, carbaryl is practically nontoxic to birds on an acute exposure basis ( LD50 > 2,000 mg/ Kg) and a subacute dietary basis ( LC50 > 5,000 mg/ kg of diet). No data are available to suggest that birds are adversely affected on an acute exposure basis from the use of carbaryl to control burrowing shrimp. Furthermore, the data suggest that the likelihood of chronic exposure to birds is low.

As part of a memorandum of agreement ( APPENDIX E2) between the oyster growers and the state of Washington, an integrated pest management plan has been developed in Willapa Bay. The agreement acknowledges that additional data on the environmental fate and effects of carbaryl are necessary and that alternative methods of control should be explored to mitigate adverse effects. As part of these efforts, the shellfish growers are actively engaged in exploring both chemical, biological ( e. g., parasites, predation), and mechanical ( e. g., surface/ vertical barriers, compaction, harrowing/ discing) alternatives along with different methods of oyster culture ( e. g., long lining). Although both chemical and mechanical methods of controlling burrowing shrimp have been had mixed results, an effort is underway to reduce the potential for adverse effects from carbaryl. It is clear from the data that considerable variability exists in estimates on the extent to which carbaryl / naphthol residues persist in both the water column and treated sediments and EFED encourages more refined studies to address this issue. Proposals have been submitted to study the fate and transport of carbaryl in Willapa Bay and to better define the sediment impact zone. Based on the available data, acute mortality is likely for animals in the immediate application area; however, off site acute mortality is not expected to be significant. Additionally, the potential for adverse chronic effects is not expected to be significant due to a combination of relatively rapid degradation and dilution in this tidal environment.

EFED acknowledges that there are uncertainties regarding the use of carbaryl in Willapa Bay/ Grays Harbor and its potential effect on nontarget animals. Maintaining a constructive dialog between shellfish growers, Washington state representatives and other stakeholders within the Willapa Bay/ Grays Harbor communities can only serve to promote the necessary research to address various concerns and uncertainties. 132 APPENDIX E2. REVIEW OF DATA SUBMITTED ON SECTION 24c USE OF CARBARYL TO CONTROL BURROWING SHRIMP U. S. ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, DC 20460 OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES MEMORANDUM PC Code No. 129106 DP Barcode: D279109 SUBJECT: EFED Review of Documents Relative to Section 24c Special Local Needs Registration of Carbaryl for Use on Oyster Beds.

TO: Anthony Britten, Chemical Review Manager Betty Shackleford, Product Manager Special Review and Reregistration Division FROM: Thomas M. Steeger, Ph. D., Senior Biologist Environmental Risk Branch IV/ EFED ( 7507C)

Through: Betsy Behl, Branch Chief Environmental Risk Branch IV/ EFED ( 7507C)

The Environmental Fate and Effects Division ( EFED) has completed its review of the materials submitted relative to the Section 24c Special Local Needs registration of carbaryl for use on oyster beds in Willapa Bay and Grays Harbor, Washington, to control ghost shrimp ( Callianassa californiensis) and mud shrimp ( Upogebia pugettensis). The documents included 1) a report on concentrations of carbaryl and its degradate ( 1 naphthol) in marine sediments from sites treated with or adjacent areas treated with Sevin ( Stonic 1999); 2) a fact sheet on chemicals of special concern in Washington State; 3) a memo from the State of Washington's Department of Ecology's review of data relevant to the environmental effects of applying Sevin   to control burrowing shrimp in Willapa Bay and Grays Harbor oyster beds; 4) a copy of the memorandum of agreement between the Washington State Department of Ecology, the Willapa/ Grays Harbor Oyster Growers' Association and other state government and private organizations; and 5) a Washington State Department of Ecology publication entitled Carbaryl Concentrations in Willapa Bay and Recommendations for Water Quality Guidelines ( Johnson 2001). Except for more recent studies conducted by Washington State University and the Washington Department of Ecology, much of the older ( pre 1996) data had procedural problems that limited the utility of the data. The more recent data indicate that carbaryl residues in the water column were generally at or below an effect threshold of 0.1 ug/ L Although large carbaryl applications can affect water quality in areas distant from spray sites, the Washington Department of Ecology concluded that " no widespread effects from carbaryl would be expected in Willapa Bay after the end of the [ carbaryl] application period." 133 Carbaryl has been used on approximately 600 acres of Willapa Bay and 200 acres of Grays Harbor at a rate of 7.5 to 10 lbs/ acre/ year since the 1960' s. Carbaryl is applied as a wettable powder to tidelands at low low [ Spring] tide primarily by helicopter; however, hand spraying is used in some instances. The label restricts aerial applications within 200 feet of a channel or slough; hand spraying is prohibited within 50 feet of a channel or slough.

The data collected and/ or reviewed by the Washington Department of Ecology indicate that carbaryl residues drop below the level of quantitation (< 0.004 ug/ L) approximately 6 weeks after application. While concentrations in nontarget areas immediately following the carbaryl application period are likely to inflict mortality to aquatic organisms, no data are provided to demonstrate that threatened and/ or endangered species ( e. g. salmonids) are adversely affected by the treatments to oyster beds.

While these documents provide additional information on the environmental fate and effects of carbaryl in estuarine/ marine environments, EFED's review of Washington's Section 24c petition was based on the required guideline fate and effects data provided by the registrant in support of the reregistration of carbaryl. Although the EFED reregistration eligibility document ( RED) for carbaryl does not estimate environmental concentrations for applications directly to tidelands for control of burrowing shrimp in oyster culture, it does discuss the use. Data submitted in support of reregistration ( MRID 419826 06) indicate that estuarine/ marine invertebrates will likely be impacted by this route of exposure and that certain species, e. g., Dungeness crab ( Cancer magister), may experience 100% mortality in the application area. However, the assessment goes on to note that effects on aquatic invertebrates will likely be temporary as most populations show signs of recovery within 2 months. Additionally, the chapter suggests that carbaryl applications that reduce the potential for drift to nontarget sites, such as direct injection of carbaryl into the sediment, may help mitigate nontarget effects.

Review of Submitted Literature 1) Screening Survey of Carbaryl ( Sevin) and 1 naphthol Concentrations in Willapa Bay Sediments The study was undertaken to determine the long term persistence of carbaryl and 1 naphthol; more specifically, the study objectives were to:

° Determine if there are residues of carbaryl and its degradate 1 naphthol in the marine sediments at historically sprayed sites and unsprayed adjacent sites ° Monitor the depletion of these compounds in sediments following applications of Seven   . ° Measure concentrations of carbaryl in centrifuged sediment pore water. ° Determine drift potential.

The study was divided into two phases, pre spray and post spray. Sampling was conducted in Willapa Bay in areas deemed to be conducive to carbaryl persistence. Thus, areas with muddy and/ or fine sediments were selected since they were believed to be more likely to retain both carbaryl 134 0 500 1000 1500 2000 2500 3000 3500 0 10 20 30 40 50 60 Days after Treatment Carbaryl ( ppb)

Figure 1 Average carbaryl concentrations in sediment collected from Willapa Bay at 2, 30 and 60 days after treatment. and 1 naphthol. Sandy sediments were not believed to provide sufficient clay or organic material with which carbaryl and/ or its degradate could sorb.

Pre spray samples were collected from areas that had been sprayed in previous years or were adjacent to areas that had been sprayed in previously. A reference site, Nemah Oyster Reserve, was sampled as an area that had never been sprayed.

Post spray samples were collected immediately following carbaryl treatment and also included areas adjacent to spray sites. Treated sites included areas that had been sprayed in years past in addition to the recent treatment. Sampling was typically conducted 2, 30 and 60 days after treatment ( DAT). Sediment samples were collected using a stainless steel 17 cm diameter device that allowed sediment samples to be stratified into 0  2 cm, 2  7.5 cm, and 7.5  15 cm depths. Total organic carbon ( TOC) and sediment size were also analyzed. Carbaryl and 1 naphthol residues were measured both in whole sediment and in centrifuged pore water. Quality assurance spiked sediment samples suggest considerable amount of variability in recovery of standards. The results may be negatively biased.

Based on the pre spray study results, all of the historically sprayed sites, adjacent unsprayed sites and the reference site showed no carbaryl or 1 naphthol residues above the detection limit range of 21 to 58 ppb. One sample representing the shallowest area adjacent to historically sprayed beds had trace ( 29 ppb) residues of carbaryl.

Post spray study results indicate that carbaryl concentrations at sprayed sites ranged from 2,000 to 3,400 ppb by 2 DAT, 180 to 220 ppb by 30 DAT, and 86  120 ppb by 60 DAT ( Figure 1). Although, adjacent sites contained as much as 2,000 ppb 2 DAT, residues in sediment at all adjacent sites at 60 DAT were close to detection limits and ranged from 27 to 32 ppb.

Residues for the 1 naphthol ranged from detection limits to as high as 170 ppb at 2 DAT and by 30 DAT all samples had dropped to detection limits ( 22 to 33 ppb); one sample at 60 DAT contained naphthol at 34 ppb. The report concluded that once carbaryl degrades to 1 naphthol, the degradate appears to readily leave the sediment. It did not however, allow for the fact that the degradate could have been present in deeper reaches of the sediment. At adjacent sites, 1 naphthol ranged as high as 120 ppb 2 DAT and then dropped to below detection limits for the remaining sample periods.

Carbaryl residues in pore water were only detected 60 DAT and ranged from 0.57 to 1.15 ppb. It is difficult to understand though how the limit of detection for pore water was so much lower than 135 that for sediment. Carbaryl was only detected in one sediment pore water sample collected from an adjacent site; the residue was close to the limit of detection at 0.05 ppb.

Analyses of sediment grain size and total organic carbon revealed that the clay silt fraction of the post spray sites ranged from 25% to 73% while TOC ranged from 0.58% to 2.07%. Grain size and TOC were strongly correlated ( Pearson R2 range 0.89  0.96); however, there was no correlation between carbaryl residues and TOC.

The study concludes that carbaryl is clearly persistent in treatment areas with residues being detected up to 60 DAT. Additionally, residues in sites adjacent to treated areas indicate that drift does occur. Drift to nontarget sites was attributed to wind, depth of water sampled, and both surface and bottom water currents. Additionally, sediment pore water concentrations exceeded the National Academy of Sciences and Engineering water quality recommendation for carbaryl of 0.06 ppb. Additionally, historic sampling revealed that water column concentrations prior to application ranged as high as 9.2 ppb. The report notes that QA/ QC standards suggested that actual pore water concentrations may be higher than those reported. It is uncertain how much naphthol was present in the water column; however, given that naphthol is more toxic than the parent, the potential affect of the residues on aquatic animals is a legitimate concern.

Finally the report compares the sediment residue data to available toxicity data on carbaryl and concludes that Dungeness crab larvae exposed to carbaryl at concentrations ranging from 0.1 to 10 ppb for 25 days exhibited both molting effects and mortality. Although no formal data were provided on the numbers of organisms affected; the author reports that marine fish and invertebrate mortality was observed 2 DAT. The author proposes that the incidental kills could serve as forage for other fish and foraging birds that would then bioaccumulate carbaryl in their tissues. The report further suggests that indirect effects, such as endocrine disruption and mutagenicity, are not sufficiently characterized and that coupled with direct effects and the potential for bioaccumulation in the food chain, carbaryl and 1 naphthol have the potential to impact threatened and/ or endangered salmon stocks.

The study would have been more thorough had water column concentrations of carbaryl been measured. Given that the compound was applied using both aerial and hand held sprayers, it is difficult to assess the affect of drift relative to application method. It would have also been helpful to know how representative the areas sampled were of the total areas treated in terms of TOC and grain size. Additionally, the limit of detection ( 25  35 ppb) was not sufficiently low to document residues in sediment and pore water that may have been sufficiently high to effect benthic invertebrates.

2) Chemicals of Special Concern in Washington State Report published by the Washington Department of Ecology provides a brief overview of the environmental fate and effects of carbaryl. Although the overview has footnote numbers, no references were provided; therefore, data supporting carbaryl's characterization could not be verified. The report implies that carbaryl is relatively persistent and that recoveries of aquatic systems exposed 136 to carbaryl have taken as long as 3 years. According to the overview, carbaryl is teratogenic, immunosuppressive, and degrades to carcinogenic compounds.

3) Washington Department of Ecology Review of Data Relevant to the Environmental Effects of Applying Carbaryl to Control Burrowing Shrimp in Willapa Bay and Grays Harbor Oyster Beds ( 1987).

The object of the Washington Department of Ecology review was to answer the following questions:

° How long do carbaryl and its primary hydrolysis product 1 naphthol persist in the water column? ° What concentrations of carbaryl and 1 naphthol in water are toxic to marine organisms? ° How long do carbaryl and 1 naphthol persist in the sediments? ° What concentrations of carbaryl and 1 naphthol in sediment are toxic to marine organisms? ° What are the effects on abundance and diversity of infauna? ° What are the effects on abundance and diversity of epifauna? ° What mortality is experienced by Dungeness crab and how does this affect the fishery? ° What mortality is experienced by fish? ° Are birds adversely affected? ° What are the potential ecological impacts of Sevin applications?

While the environmental fate studies on water column and sediment concentrations during and after application of carbaryl showed a decline in carbaryl and 1 naphthol concentrations, much of the data were discounted due to poor detection limits and procedural deficiencies. Open literature reviews of ecological effects revealed that carbaryl is more toxic to crustaceans than to molluscs or fish; however, the degradate 1 naphthol is less toxic to crustaceans than carbaryl but more toxic than the parent to molluscs and fish. Subacute effects of carbaryl were reported at concentrations below the detection limit ( 1 mg/ L) of most of the monitoring studies reported; the report states that circumstantial evidence suggests the potential for toxic effects at or below 0.1 mg/ L in sediment. Sublethal effects included reduced development of oysters and delayed molting of crab larvae, malformations in fish eggs and adults. Toxicity of carbaryl is reported to increase with temperature.

Although the report fails to conclusively resolve whether carbaryl and its 1 naphthol degradate are sufficiently persistent to effect aquatic life, it notes that the target population of burrowing shrimp take a number of years to recover. However, failure of a treated area to recover may be due to a number of factors and may not result exclusively on the toxicity of carbaryl or its degradate. 137 0 100 200 300 400 500 600 1976 1978 1980 1982 1984 1986 1988 Year Acres Treated Figure 2. Number of acres treated with carbaryl in Willapa Bay over years.

0 10000 20000 30000 40000 50000 60000 70000 0 100 200 300 400 500 600 Number of Acres Treated Number of Crabs Killed Figure 3. Number of crabs killed versus number of acres treated with carbaryl in Willapa Bay. Fisheries data collected on Willapa Bay from 1977 to 1986 show ( Figure 2) that the number of acres treated with carbaryl increased each year. And that the number of crabs killed by carbaryl treatment also increased ( Figure 3) as the number of acres treated increased. The number of crabs killed was significantly correlated ( Pearson Correlation coefficient = 0.72; p > rho = 0.0187) with the number of acres treated. Over the observation period an average of 53 crabs ( standard error = 13) were killed per acre. Followup studies by the University of Washington that [ Dungeness] crab in treated areas are impacted but that further studies are required to establish population level effects in Willapa Bay.

Mortalities to fish were limited to small specimens which were entrapped in shallow pools by the outgoing tide and directly exposed to carbaryl during treatment; however, the reviewed literature did not address the potential for indirect mortality.

Although no studies were conducted, the report concluded that likelihood of acute or chronic effects of carbaryl on birds was remote.

Whether there are broad ecological impacts associated with the use of carbaryl to control burrowing shrimp in Willapa Bay remains an uncertainty. The Environmental Impact Statement concluded that the use of carbaryl by the commercial oyster industry was not expected to cause significant impacts on the estuarine ecosystem when applied at current levels. It based this conclusion on the fact that:

° Carbaryl is not accumulated by any food chain component or transmitted to higher levels in the food chain. ° No chemically active radical group remains to contaminate the estuarine environment. ° Only a small percentage of the total intertidal lands are treated annually; 0.8% in Willapa Bay and 0.3% in Grays Harbor.

The report recommends though that further work be conducted to evaluate the persistence of carbaryl and 1 naphthol in sediment and to better document the effects of nontarget mortality. 138 4) Burrowing Shrimp Integrated Pest Management Memorandum of Agreement The memorandum of agreement ( MOA) was established between the Washington State Department of Ecology, Washington State Department of Agriculture, the Washington State Commission on Pesticide Registration, the Washington Department of Fish and Wildlife, the Willapa/ Grays Harbor Oyster Growers Association, the Pacific Coast Shellfish Growers Association and the Pacific Shellfish Institute. The agreement acknowledges that while carbaryl and its 1 naphthol degradate affect nontarget species, are likely transported several hundred yards offsite by tidal action, and may persist for several weeks in the water column and sediments within Willapa Bay/ Grays Harbor, treatment for burrowing shrimp is necessary if economic losses due to diminished oyster harvests are to be avoided. The agreement acknowledges that additional data on the environmental fate and effects of carbaryl are necessary and that alternative methods of control should be explored to mitigate adverse effects especially on threatened/ endangered salmonids. The MOA establishes a process and time for the development of a " sustainable site specific, environmentally sound and ecologically based [ integrated] pest management plan for the control of burrowing." The MOA outlines criteria to be met, i. e., demonstration that burrowing shrimp populations have reached a size sufficient to inflict economic losses, before which carbaryl can be applied.

5) Carbaryl Concentrations in Willapa Bay and Recommendations for Water Quality Guidelines.

In the summer of 2000, the Washington State Department of Ecology initiated a study of Willapa Bay. The study was a follow up on the Stonic ( 1999) study from 1996 to 1997 and concern that carbaryl persisted at a level of 0.7 ug/ L. The objectives of the study were to:

° determine if there is a carbaryl background that persists in Willapa Bay water outside the July to August spray period; ° analyze carbaryl in other potential sources to Willapa Bay; ° achieve quantitation limits for carbaryl sufficiently low to evaluate the potential for causing toxicity to sensitive marine organisms; ° review the literature on carbaryl's effects on marine organisms and evaluate appropriate water quality guidelines for carbaryl in Willapa Bay.