Cancer risk assessment from exposure to trihalomethanes in tap water and swimming pool water

We investigated the concentration of trihalomethanes （THMs） in tap water and swimming pool water in the area of the Nakhon Path- om Municipality during the period April 2005-March 2006. The concentrations of total THMs, chloroform, bromodichloromethane, dibromochloromethane and bromoform in tap water were 12.70-41.74, 6.72-29.19, 1.12-11.75, 0.63-3.55 and 0.08-3.40 μg/L, respectively, whereas those in swimming pool water were 26.15-65.09, 9.50-36.97, 8.90-18.01, 5.19-22.78 and ND-6.56 μg/L, respectively. It implied that the concentration of THMs in swimming pool water was higher than those in tap water, particularly, brominated-THMs. Both tap water and swimming pool water contained concentrations of total THMs below the standards of the World Health Organization （WHO）, European Union （EU） and the United States Environmental Protection Agency （USEPA） phase Ⅰ, but 1 out of 60 tap water samples and 60 out of 72 swimming pool water samples contained those over the Standard of the USEPA phase Ⅱ. From the two cases of cancer risk assessment including Case Ⅰ Non-Swimmer and Case Ⅱ Swimmer, assessment of cancer risk of nonswimmers from exposure to THMs at the highest and the average concentrations was 4.43×10^-5 and 2.19×10^-5, respectively, which can be classified as acceptable risk according to the Standard of USEPA. Assessment of cancer risk of swimmers from exposure to THMs at the highest and the average concentrations was 1.47×10^-3 and 7.99×10^-4, respectively, which can be classified as unacceptable risk and needs to be improved. Risk of THMs exposure from swimming was 93.9%-94.2% of the total risk. Cancer risk of THMs concluded from various routes in descending order was： skin exposure while swimming, gastro-intestinal exposure from tap water intake, and skin exposure to tap water and gastro-intestinal exposure while swimming. Cancer risk from skin exposure while swimming was 94.18% of the total cancer risk.

Disinfection byproducts in indoor swimming pool water: Detection and human lifetime health risk assessment

Quantification of regulated and emerging disinfection byproducts (DBPs) in swimming pool water,as well as the assessment of their lifetime health risk are limited in China.In this study,the occurrence of regulated DBPs (e.g.,trihalomethanes,haloacetic acids) and emerging DBPs (e.g.,haloacetonitriles,haloacetaldehydes) in indoor swimming pool water and the corresponding source water at a city in Eastern China were determined.The concentrations of DBPs in swimming pool water were 1-2 orders of magnitude higher than that in source water.Lifetime cancer and non-cancer risks of DBPs stemming from swimming pool water were also estimated.Inhalation and dermal exposure were the most significant exposure routes related to swimming pool DBP cancer and non-cancer risks.For the first time,buccal and aural exposure were considered,and were proven to be important routes of DBP exposure (accounting for 17.9%-38.9%of total risk).The cancer risks of DBPs for all swimmers were higher than 10^(-6)of lifetime exposure risk recommended by United States Environmental Protection Agency,and the competitive adult swimmers experienced the highest cancer risk (7.82×10^(-5)).These findings provide important information and perspectives for future efforts to lower the health risks associated with exposure to DBPs in swimming pool water.

Occurrence and formation of disinfection by-products in the swimming pool environment： A critical review

Disinfection of water for human use is essential to protect against microbial disease;however, disinfection also leads to formation of disinfection by-products（DBPs）, some of which are of health concern. From a chemical perspective, swimming pools are a complex matrix, with continual addition of a wide range of natural and anthropogenic chemicals via filling waters, disinfectant addition, pharmaceuticals and personal care products and human body excretions. Natural organic matter, trace amounts of DBPs and chlorine or chloramines may be introduced by the filling water, which is commonly disinfected distributed drinking water. Chlorine and/or bromine is continually introduced via the addition of chemical disinfectants to the pool. Human body excretions（sweat, urine and saliva） and pharmaceuticals and personal care products（sunscreens, cosmetics, hair products and lotions） are introduced by swimmers. High addition of disinfectant leads to a high formation of DBPs from reaction of some of the chemicals with the disinfectant.Swimming pool air is also of concern as volatile DBPs partition into the air above the pool.The presence of bromine leads to the formation of a wide range of bromo-and bromo/chloro-DBPs, and Br-DBPs are more toxic than their chlorinated analogues. This is particularly important for seawater-filled pools or pools using a bromine-based disinfectant.This review summarises chemical contaminants and DBPs in swimming pool waters, as well as in the air above pools. Factors that have been found to affect DBP formation in pools are discussed. The impact of the swimming pool environment on human health is reviewed.