 Sources include micro-organisms from infected swimmers and body oils including sweat, cosmetics, suntan lotion, urine, saliva and fecal matter; for example, it was estimated by researchers that swimming pools contain, on average, 30 to 80 mL of urine for each person that uses the pool.In addition, the interaction between disinfectants and pool water contaminants can produce a mixture of chloramines and other disinfection by-products.The journal "Environmental Science & Technology" reported that sweat and urine react with chlorine and produce trichloramine and cyanogen chloride, two chemicals dangerous to human health.