Endocrine disruptors (EDCs), many of them synthetic, are being investigated for their possible harmful effects on the human endocrine system. (Some investigations have already noted negative effects on wildlife.)

The endocrine system includes glands — such as the thyroid, pituitary, pancreas, testes or ovaries — that secrete natural chemicals to regulate growth, behavior, reproduction, metabolism, etc. EDCs may interfere with the amount of natural hormones (such as estrogen or adrenaline) the body makes, block the way they are made, or mimic a hormone and give a “wrong” chemical signal.

Some EDC-containing drugs are given intentionally (such as birth control pills). But these and other EDCs, including common product ingredients and industrial wastes, can also enter water supplies.

What they are:
— EDCs include:

• Ingredients of some pharmaceuticals (like birth control pills).


• Dioxin and dioxin-like compounds


• Polychlorinated biphenyls (PCBs)


• DDT and other pesticides


• Plasticizers

— Many everyday items contain EDCs: some plastics, toys, metal can linings, flame retardants, cosmetics, pesticides.

— Exposure: Exposure to EDCs can occur through ingestion of contaminated water or food, breathing the products of industrial or waste combustion, or even ingestion of some plant foods containing natural EDCs.

Regulation:

• Most EDCs are not regulated, although efforts are under way to determine whether they should be. The major controversy is whether low-level exposure can have adverse health effects.


• A few EDCs are listed as primary drinking water contaminants by the US Environmental Protection Agency (EPA). Two examples, and their EPA maximum contaminant levels, are:
• Dioxin: 0.00000003 mg/L


• PCBs: 0.0005 mg/L


• In 1996, Congress ordered EPA to develop the Endocrine Disruptor Screening Program (EDSP) to screen and test chemicals for possible endocrine disrupting effects. After years of advisory committee recommendations and draft proposals, the EDSP is now at the stage of developing scientific testing protocols, prioritizing chemicals for screening and testing, and setting up testing policies and procedures.

Water treatment:
The Water Quality Association (WQA) has noted that EDCs are among the “emerging contaminants” expected to be regulated in coming years. While no product performance standards have been developed yet, many point-of-use technologies have proven effective for some of these emerging contaminants, according to WQA: nanofiltration, reverse osmosis, activated carbon, distillation, ozonation, and advanced oxidization.

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Sources: US EPA, WQA, National Institute of Environmental Health Sciences, Canadian Centre for Occupational Health and Safety, GreenFacts. From Water Technology Magazine Volume 31, Issue 4 - April 2008