The Politics of Regulation: Hexavalent Chromium and Arsenic

Hexavalent chromium, or Cr(VI), is almost constantly in the news lately. California’s Office of Environmental Health Hazard Assessment (OEHHA) has set a hotly contested Public Health Goal (PHG) of 0.020 ug/L, or 20 parts per trillion. Rep. Adam Schiff (D-CA) has introduced legislation into the U.S. House of Representatives to regulate Cr(VI), and Senator Barbara Boxer (D-CA) has introduced the companion legislation into the U.S. Senate. The U.S. Environmental Protection Agency (EPA) is re-reviewing the toxicological data for Cr(VI) after intense political and public pressure to regulate the chemical. But don’t confuse all of this frenzied activity with productivity, or even effective purpose.

The PHG setting process in California is a very rigorous one that takes into account the best available toxicological data in the scientific literature. OEHHA has identified the PHG level of 0.020 ug/L “as protective against all identified toxic effects from both oral and inhalation exposure to hexavalent chromium that may be present in drinking water.”(1) However, there is a great deal of debate among toxicologists that this PHG has been set much too low because of the methodology used in many of the studies OEHHA relied on. In contrast, there is almost no debate that almost any level of arsenic consumption can cause adverse health effects. The PHG in California has been set for arsenic at 0.004 ug/l, which is 4 parts per trillion, or 5 times lower than the PHG for Cr(VI). The EPA has a process similar to OEHHA’s for setting a Maximum Contaminant Level Goal (MCLG) which is analogous to the PHG. The MCLG that EPA has set for arsenic is 0 mg/L. “The International Agency for Research on Cancer (IARC) evaluated arsenic in 1980 and classified ‘arsenic and arsenic compounds’ in Group 1, which includes ‘chemicals and groups of chemicals, which are causally associated with cancer in humans.’ Arsenic is also known to be atherogenic, genotoxic, teratogenic, and may cause other adverse developmental effects in exposed children.’(2)

Setting PHG’s and MCLG’s is the first step in the regulatory process. These goals, along with other considerations such as Best Available Technologies (BAT) for treatment and what that treatment costs, are used to set the Maximum Contaminant Level (MCL), which is the regulatory level. The MCL for arsenic has been set at 10 ug/L, or 2,500 times higher than the PHG. Yet the political and public pressure is being applied to set the MCL for Cr(VI), a less toxic chemical by almost any measure, at or very near the PHG of 0.020 ug/L. The logic here is illusive to say the least.

I don’t think the MCL for arsenic should be lowered. There are too many small systems that can’t meet the MCL now, and many others can only meet it at great expense. That’s an expense that gets passed on to the consumer in a time when complaints about increasing water bills show up in the news a lot more frequently than news about Cr(VI). And I don’t think that the MCL for Cr(VI) should be set at or near the PHG. The same considerations that were used to set the MCL for arsenic 2,500 times higher than the PHG need to be applied to setting the MCL for Cr(VI). Water purity has to be balanced by water expense in providing an acceptable product to the public.

1) PUBLIC HEALTH GOALS FOR CHEMICALS IN DRINKING WATER, HEXAVALENT CHROMIUM (Cr VI), July 2011.  http://oehha.ca.gov/water/phg/pdf/Cr6PHG072911.pdf


2) PUBLIC HEALTH GOALS FOR CHEMICALS IN DRINKING WATER, ARSENIC, April 2004.
http://oehha.ca.gov/water/phg/pdf/asfinal.pdf

Time for Ag to Step Up and Reduce Nitrate Contamination

I find it incredibly disturbing that in California, a State with the 7^th largest economy of any country in the world, we have drinking water issues that we share with countries that are at the bottom of the economic ladder, the so called Third World Countries.  The United Nations even sent a Special Rapporteur, Catarina de Albuquerque, to the United States to report on safe drinking water and sanitation.  The report, available here - http://www2.ohchr.org/english/bodies/hrcouncil/docs/18session/A-HRC-18-33-Add4_en.pdf - was widely reported on in the press (http://newamericamedia.org/2011/09/un-report-california-county-lacks-clean-water.php ; http://articles.latimes.com/2011/apr/25/local/la-me-seville-water-20110425 ; http://www.californiaprogressreport.com/site/comment/reply/9877 ), and documents how terrible water quality conditions are in parts of California’s Central Valley, one of the most productive agricultural areas in the world.  The ground water aquifers in the area, from where most drinking water is drawn, are contaminated with nitrates, arsenic, and pesticides.  While the arsenic is most likely naturally occurring in many if not all of these areas, the nitrates and pesticides are definitely the result of intensive agricultural practices, which include both applications of nitrate fertilizers and the disposal of waste from concentrated animal feeding operations, or CAFO’s.  Currently, several of the Regional Water Quality Control Boards around California, because this is an issue not exclusive to the Central Valley,  are working on adopting new rules that will require agricultural entities to reduce groundwater and surface water pollution from nitrate fertilizers, pesticides and sediment carried from irrigated farm fields.  Needless to say, these regulations are hotly contested by the agricultural lobby as being too expensive and otherwise burdensome for farmers to deal with.  As a regulatory and water quality professional working in the highly regulated field of drinking water, I agree that regulations are burdensome, as well as irksome, but they are also highly necessary to protect public health, and it is more than past time for agriculture to step up and bear the responsibility for the havoc they are reeking on the ground water resources of this State.  Agriculture needs to stop foisting the problem off on to the residents of poverty stricken, politically orphaned, primarily Latino communities who suffer the economic damage and degraded health that is the result of this agricultural pollution.  Instead, they need to do the right thing by working hard and long, something farmers are very good at, to do the monitoring, reporting, and implementation of best management practices that will begin to turn this problem around and clean up California’s precious ground water resources.