The ongoing water crisis in Flint, Michigan is a tragedy. The lead (Pb) issue is well documented, as are the health effects from ingesting lead. No safe blood Pb level in children has been identified, and exposure to elevated levels of Pb can cause intellectual impairment and other health issues.
More recently, concerns have arisen regarding disinfection byproducts (DBPs) in Flint drinking water. Unlike exposure to high levels of Pb, the risk from DBPs is a chronic exposure risk, not an acute poisoning risk. In general, consuming elevated levels of DBPs is thought to cause an increased risk of some cancers over a typical lifetime. For this reason, some representative DBPs are regulated by the Environmental Protection Agency (EPA) under the Clean Water Act.
DBPs are formed in the water distribution system through an oxidation reaction between chlorine and natural organic matter (NOM). This formation of DBPs is an unfortunate negative consequence of adding chlorine for water disinfection, which is very common in the United States and other countries. Water chlorination has been practiced for 112 years, starting in Jersey City.
It is difficult to overstate the importance of water chlorination–perhaps the most important public health breakthrough of modern civilization, leading to eradication of most waterborne disease. However, the chlorine required to inactivate pathogens also reacts with NOM to form halogenated (chlorine is a halogen) organic byproducts including total trihalomethanes (aka TTHMs) and Haloacetic Acids (HAAs). This reaction is well understood, and is known to be a function of NOM concentration and character, pH, chlorine dose, time, temperature and other factors. DBPs are always formed whenever chlorine is added to surface waters, but the concentration and type of DBPs vary somewhat from city to city.
TTHMs in Flint water were shown to be problematic in 2014, with violations noted in the Consumer Confidence Report (CCR) of that year. (A similar violation for HAAs occurred in Amherst, Massachusetts that same year). Recently, DBPs including TTHMs have drawn attention following the discovery of Pb and other issues in the Flint Water system, and the subsequent measurement of some DBPs by non-scientists. However, the methods used in this sampling were unorthodox, relying on proprietary sponges marketed by the group, to collect samples, and the results are not comparable to refined and standard scientific methods. There are proven, peer-reviewed and published methods for collecting and analyzing DBP samples. These methods were refined by researchers at UMass, and trustworthy data that is scientifically rigorous are needed during times of crisis.
The UMass team was recruited by Virginia Tech, to execute the advanced DBP sampling. The team (lead by Dr. David Reckhow) is bringing drinking water quality expertise, to quantify the extent of DBP formation in the drinking water currently delivered to Flint residents, following the switch back to the Detroit Water & Sewerage Department (DWSD). It should be noted that, before the switch to Flint River in 2014, DWSD water was far below regulatory limits for TTHMs and HAAs, and no changes to the system during the water crisis is expected to affect formation of DBPs in the Flint system.
Initial results from samples collected in May 2016 indicate that there is nothing exceptional about DBP levels in Flint. Additional rounds of sampling and analyses are now being conducted to gather more information. Beyond regulated TTHMs and HAAs, the UMass team is also conducting analysis for >60 unregulated byproducts to get a more complete picture of the drinking water quality.Results from analysis will be forthcoming.
Members of the UMass Flint DBP Team include:
Dr. Dave Reckhow (Team Lead)
Dr. Joe Goodwill (DBP sampling, THMs, Iodo-THMs and other volatiles)
Yanjun Jiang (Iodo-THMs and other volatiles)
Xuyen Mai (DBP sampling)
Xian “Max” Ma (DBP sampling, Haloacetamides)
Ran Zhao (Haloacetamides and HAAs)
Soon-Mi Kim (Haloacids)
Yun “Rosa” Yu (N-halo-haloacetamides)
Aarthi Mohan (Halobenzoquinones)
Pranav Mashankar (Aldehydes)
Sherrie Webb-Yagodzinski (Sampling preparation)
Primary Author: Dr. Joseph Goodwill
Acknowledgements: Drs. Dave Reckhow and Marc Edwards
While all the problems of DBP’s were well known in the drinking-water world, it did not prevent EPA from setting coliform bacteria levels for its NPDES permits to implement the CWA in 1972. Since disinfection of treated sewage earlier was not required, many sewage treatment plants installed chlorination equipment, resulting in the formation of DBP’s since treated sewage still contains large amounts of organic matter.
For cities, using the receiving waters as a water supply source, this soon became a problem and when both the CDC and the GAO claimed that this disinfection of treated sewage did not prevent waterborne diseases and was damaging to the environment (DBP’s do not only impact humans) , EPA in 1978 dropped this coliform limit for their national NPDES permits. Unfortunately EPA left it up to individual states to either also drop this requirement or keep it. Most states sadly kept this requirement even after attempts by some states at that time (like Illinois) to get rid of it.
Apparently when you have regulations, even if they are technically wrong, it is impossible to get rid of them or even correct them. A similar case we have with the incorrect application of the BOD5 test, the backbone of EPA’s implementation of the CWA and also the cause of the failure to address nitrogenous, now called a nutrient waste in sewage. Wp.me/p5COh2-2C