Synthetic organic chemicals (SOCs) are man-made compounds that are used for a variety of industrial and agricultural purposes. Adverse health effects from exposure to synthetic organic chemicals include damage to the nervous system and kidneys, and cancer risks. SOCs are divided into two groups for monitoring purposes, non-volatile SOCs (which include industrial chemicals like pesticides and polychlorinated biphenyls [PCBs]) and volatile SOCs. This section discusses the non-volatile SOCs. Volatile organic chemicals are discussed in a separate section of this Guide. Also see the section on disinfectants and disinfection by-products.

Do the SOC Regulations Apply to Your Community?

Yes. All community and non-transient, non-community public water systems are required to test for non-volatile SOCs unless they have been granted a waiver by the state. Non-transient, non-community public water systems are those that are not community water systems and that regularly serve at least 25 of the same persons over 6 months per year, (e.g., schools, businesses with their own system).

Actions Your Community Should Be Taking

Your community is required to monitor the levels of regulated non-volatile SOCs in your water system. A special timetable was developed for these regulations. It consists of nine-year "compliance cycles" divided into three "compliance periods" of three years each. Each community and non-transient, non-community water system should have sampled quarterly for each of the regulated pesticides and PCBs beginning in the first compliance period (January 1993 - December 1995) of the first compliance cycle (January 1993 - December 2001). If the regulated pesticides and PCBs were not detected during the first compliance period, repeat sampling is as follows: for systems serving more than 3,300 people, two quarterly samples every three years beginning in the second compliance period (January 1996-December 1998); or for systems serving less than 3,300 people, one quarterly sample every three years beginning in the second compliance period.

If, after completing the initial sampling requirements, your public water supply system does not detect any non-volatile SOCs, it may apply to the state for a waiver from the sampling requirements. If a waiver is granted, no monitoring is required for the next compliance period. However, your system must reapply for a waiver for each compliance period. Keep in mind that your public water supply system must be granted a waiver before the year that testing is required.

If your tests indicate levels of pesticides and/or PCBs higher than the maximum contaminant level (averaged over the year), you are in violation. You should:

• Continue quarterly sampling (at times of highest vulnerability, i.e., after fertilizer application and a rain).
• Notify the state agency and complete public notices as required.
• Request an exemption from the state agency to allow the community to continue to use the water supply while solutions to the violation are being explored and any needed financing is being arranged.
• Work with the state agency and/or your engineer to determine how pesticides and PCBs are getting into your water supply. If possible, eliminate the source of contamination.
• If you must treat your water supply to remove the pesticides and/or PCBs, work with your engineer to choose the best available technology for treatment. Filtering through granular activated carbon is suggested for most non-volatile SOCs. Packed tower aeration and polymer addition practices are also viable options.
• Changing water sources may be the most economical solution in situations where alternate sources are available.

  Additional Information

  The synthetic organic chemicals requirements are published in Title 40 Code of Federal Regulations, Parts 141.12, 141.24, 141.61.

  For further information on the federal requirements, contact the EPA Safe Drinking Water Hotline. Telephone: 1/800/426-4791.

  (See Resource Section for drinking water contacts)

  Maximum Contaminant Levels for Non-Volatile Synthetic Organic Chemicals (SOCs)

  

  * A treatment technique is established instead of a maximum contaminant level. See 40 CFR 141.110 - 141.111.