I live in a community which has sent its citizens three letters in the past year notifying us of trihalomethanes in our water supply in excess of the allowable limit (per EPA standards).
I figured I was relatively low-risk for these carcinogens because I don't ingest much of our local water. But now I have learned that bathing in it also puts you at risk. Trihalomethanes are readily absorbed through the skin. And I like my bath very hot, which just increases the uptake of these toxic molecules.
We've got such a long way to go with learning how the disinfection products in our drinking water poison us. It's hard to isolate which particular agents are causing these cancers (most commonly bladder cancer). But we do see that repeated studies show us that exceeding that limit (a mere 80 parts per billion) of of these disinfection by-products, TTHMs (total trihalomethanes), does cause spikes in a variety of cancers.
It's so strange that I never knew growing up that as I splashed around in swimming pools, I was producing and then assimilating toxic by-products. And the really strange thing is that these by-products may have feminizing properties (there is a correlation with reduced testosterone serum levels in adolescent males). So are young male swimmers being feminized by their love of that sport? I suppose one could interpret the results of that study (cited below) to mean that young males with less than average testosterone were drawn to swimming as a sport. In other words, the question of causality is moot without controls. All we know is that there is a correlation.
Wiki:
Trihalomethanes are formed as a by-product predominantly when chlorine is used to disinfect water for drinking. They represent one group of chemicals generally referred to as disinfection by-products. They result from the reaction of chlorine or bromine with organic matter present in the water being treated. The THMs produced have been associated through epidemiological studies with some adverse health effects. Many governments set limits on the amount permissible in drinking water. However, trihalomethanes are only one group of many hundreds of possible disinfection by-products—the vast majority of which are not monitored—and it has not yet been clearly demonstrated which of these are the most plausible candidate for causation of these health effects. In the United States, the EPA limits the total concentration of the four chief constituents (chloroform, bromoform, bromodichloromethane, and dibromochloromethane), referred to as total trihalomethanes (TTHM), to 80 parts per billion in treated water.
Chloroform is also formed in swimming pools which are disinfected with chlorine or hypochlorite in the haloform reaction with organic substances (e.g. urine, sweat, hair and skin particles). Some of the THMs are quite volatile and may easily vaporize into the air. This makes it possible to inhale THMs while showering, for example. The EPA, however, has determined that this exposure is minimal compared to that from consumption. In swimmers, uptake of THMs is greatest via the skin with dermal absorption accounting for 80% of THM uptake. Exercising in a chlorinated pool increases the toxicity of a "safe" chlorinated pool atmosphere with toxic effects of chlorine byproducts greater in young swimmers than older swimmers. Studies in adolescents have shown an inverse relationship between serum testosterone levels and the amount of time spent in public pools. Chlorination by-products have been linked as a probable cause.
I figured I was relatively low-risk for these carcinogens because I don't ingest much of our local water. But now I have learned that bathing in it also puts you at risk. Trihalomethanes are readily absorbed through the skin. And I like my bath very hot, which just increases the uptake of these toxic molecules.
We've got such a long way to go with learning how the disinfection products in our drinking water poison us. It's hard to isolate which particular agents are causing these cancers (most commonly bladder cancer). But we do see that repeated studies show us that exceeding that limit (a mere 80 parts per billion) of of these disinfection by-products, TTHMs (total trihalomethanes), does cause spikes in a variety of cancers.
It's so strange that I never knew growing up that as I splashed around in swimming pools, I was producing and then assimilating toxic by-products. And the really strange thing is that these by-products may have feminizing properties (there is a correlation with reduced testosterone serum levels in adolescent males). So are young male swimmers being feminized by their love of that sport? I suppose one could interpret the results of that study (cited below) to mean that young males with less than average testosterone were drawn to swimming as a sport. In other words, the question of causality is moot without controls. All we know is that there is a correlation.
Wiki:
Trihalomethanes are formed as a by-product predominantly when chlorine is used to disinfect water for drinking. They represent one group of chemicals generally referred to as disinfection by-products. They result from the reaction of chlorine or bromine with organic matter present in the water being treated. The THMs produced have been associated through epidemiological studies with some adverse health effects. Many governments set limits on the amount permissible in drinking water. However, trihalomethanes are only one group of many hundreds of possible disinfection by-products—the vast majority of which are not monitored—and it has not yet been clearly demonstrated which of these are the most plausible candidate for causation of these health effects. In the United States, the EPA limits the total concentration of the four chief constituents (chloroform, bromoform, bromodichloromethane, and dibromochloromethane), referred to as total trihalomethanes (TTHM), to 80 parts per billion in treated water.
Chloroform is also formed in swimming pools which are disinfected with chlorine or hypochlorite in the haloform reaction with organic substances (e.g. urine, sweat, hair and skin particles). Some of the THMs are quite volatile and may easily vaporize into the air. This makes it possible to inhale THMs while showering, for example. The EPA, however, has determined that this exposure is minimal compared to that from consumption. In swimmers, uptake of THMs is greatest via the skin with dermal absorption accounting for 80% of THM uptake. Exercising in a chlorinated pool increases the toxicity of a "safe" chlorinated pool atmosphere with toxic effects of chlorine byproducts greater in young swimmers than older swimmers. Studies in adolescents have shown an inverse relationship between serum testosterone levels and the amount of time spent in public pools. Chlorination by-products have been linked as a probable cause.
No comments:
Post a Comment