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Reply to:

Dave Williams, Tri-TAC Chair

East Bay MUD

375 11th Street, MS#702

Oakland, CA  94607

October 22, 2001


Public Information and Records Integrity Branch (PIRIB)

Information Resources and Services Division (7502C)

Office of Pesticide Programs (OPP)

Environmental Protection Agency

1200 Pennsylvania Avenue, NW

Washington, DC  20640


Docket Control Number OPP-34239 – Lindane Preliminary Risk Assessments


The purpose of this letter is to comment on EPA’s Preliminary Risk Assessments for lindane.  These risk assessments were made available for public comment on August 29, 2001 (66 FR 45677).  Tri-TAC’s primary concern with the proposed risk assessments is that they are deficient since they fail to take into account the environmental risks associated with the use of lindane in lice and scabies treatments.  Without inclusion of these risks, the risk assessments are essentially meaningless.  Tri-TAC also has comments on EPA’s interpretation of the potential adverse water quality impacts of lindane usage as a seed treatment.




Tri-TAC is California-based organization comprised of members from public agencies and other professionals responsible for wastewater treatment.  It is a technical advisory committee, consisting of representatives from the California Association of Sanitation Agencies, the California Water Environment Association, and the League of California Cities.  The constituency base for Tri-TAC treats and reclaims more than 2 billion gallons of wastewater each day, and serves most of the sewered population of California.


            Wastewater discharged from publicly owned treatment works (POTWs) in California generally contains 20 to 30 parts per trillion (ppt) of lindane.  While this has been acceptable in the past, water quality standards for California’s inland surface waters and enclosed bays and estuaries were promulgated by the Environmental Protection Agency in May 2000[1].  These standards are known as the California Toxics Rule and establish water quality criteria for the protection of aquatic life and human health.  In the latter case, the criteria are intended to minimize the adverse human health effects due to substances in ambient water.  The California Toxics Rule establishes a criterion of 19 ppt lindane for protection of human health via consumption of water and aquatic organisms. This 19 ppt criterion for lindane was also included in EPA’s 1998 compilation of recommended national water quality criteria.


            Since most receiving waters in California are effluent-dominated, the 19 ppt criterion will be applied directly as an effluent limit for many wastewater treatment plant throughout California. POTWs in California that are experiencing difficulties meeting lindane discharge limitations or expecting to have difficulties include the Sanitation Districts of Los Angeles County, the City of Los Angeles, the City of San Jose, the Sonoma County Water Agency, and the County of Sacramento Regional Sanitation District.  It is also important to note that even though mixing zones are available for some POTWs, the EPA has begun a campaign for nationwide elimination of mixing zones for bioaccumulative toxic pollutants, such as lindane.  Thus most POTWs across the country can expect that, at some future date, water quality criteria for bioaccumulative toxic pollutants such as lindane will be applied as end-of-pipe water quality based effluent limits. 


            Because lindane is a highly regulated pesticide, the routes for it to enter the sewerage system are extremely limited.  The main pathway is from human treatments for lice and scabies with lindane-containing products.  Lice are insects that live on human bodies in hairy areas.  A one percent lindane shampoo is available with a physician’s prescription to control lice.  After use, shampoo is washed into the sewer system.  Similarly, scabies is a mite that lives in the human skin. A one percent lindane lotion available with a physician’s prescription can be applied to the skin to control scabies, with the lotion washed to the sewer system following application.  A typical lice or scabies treatment uses one to two ounces of the one percent lotion, or approximately 0.015 ounces of the lindane active ingredient.  This is enough lindane to pollute six million gallons of wastewater to the 19 ppt standard. In the past 17 years, lindane has been applied more than 24 million times to treat scabies[2]. These treatments contained enough lindane to pollute 144 trillion (144,000,000,000,000) gallons of water.


            In order to reduce lindane loadings to POTWs throughout California, many agencies actively pursued a ban on the sale and use of lindane-containing lice and scabies prescriptions that will take effect January 1, 2002.  However, Tri-TAC is concerned that lindane lice and scabies products will continue to enter California from out-of-state.  As a single lice or scabies treatment contains enough lindane to pollute six million gallons of water to the 19 ppt standard, a single treatment could cause a discharge violation at a smaller POTW.  Therefore, even small amounts of lindane entering California from out-of-state are of concern. 


Specific Comments


            Specific comments on the Preliminary Risk Assessments for lindane follow.  Each comment begins with the specific document, page, and language upon which comments are being made.


1.      Overview of Lindane Risk Assessment, p. 6. “ The chronic EECs [estimated environmental concentrations] for Lindane in surface water (0.67 ppb, from GENEEC) and in groundwater (0.011 ppb, from SCI-GROW) are less than the chronic DWLOC [drinking water level of comparison] (14 ppb), indicating that chronic exposure to lindane in food and water only is less than the agency’s level of concern.” The chronic EEC for lindane in surface water of 0.67 ppb is thirty-five times EPA’s allowable criterion of 0.019 ppb for the protection of human health via consumption of water and aquatic organisms. If surface water containing 0.67 ppb of lindane was distributed in California, we would expect a similar amount of lindane to be present in wastewater entering treatment plants in the state.  Many California POTWs facing possible discharge limits of 0.019 ppb under the California Toxics Rule.  Since lindane is not removed well in conventional or tertiary wastewater treatment plants, it would be impossible to meet the 0.019 ppb discharge limitation if water entering the plants had lindane concentrations approaching 0.67 ppb.


2.      Overview of Lindane Risk Assessment, p. 6-7.  “In the USGS NAWQA study, lindane was detected in 2.58% of surface water samples (0.67% at levels greater than 0.05 ppb, maximum concentration reported was 0.13 ppb)… Although these long-term monitoring programs have detected lindane in various water bodies, the Agency determined that these data are not suitable for risk assessment, because there is no correlation of monitoring with actual lindane use.  Therefore, these data are presented here solely for informational purposes.”  2.58% of surface water samples represents one in thirty-eight samples, a significant degree of contamination for the nation’s surface water bodies.  As lindane does not naturally occur in the environment[3], these environmental concentrations are coming from lindane usage in some form.  As lindane is only used a pesticide, the contamination must be coming from lindane pest treatments.  It is not clear why the data should be considered “not suitable for risk assessment.”


3.      Overview of Lindane Risk Assessment, p. 7.  “There are no residential or other non-agricultural FIFRA [Federal Insecticide, Fungicide, and Rodenticide Act] uses of Lindane.”  Lindane is widely used as a pesticide to treat lice and scabies in humans.  Although these uses are not currently subject to regulation under the FIFRA, they were subject to such regulation until 1979. Since lindane lice and scabies products are considered to be drugs, they have also been subject to the Federal Food, Drug and Cosmetic Act (FFDCA).  On November 5, 1979 (44 Federal Register, 63749), EPA decided to exempt lindane lice and scabies products from the requirements of the FIFRA.  The regulation of these products under both the FIFRA and the FFDCA was felt to be duplicative, as stated in the announcement of the exemption, “EPA and FDA concluded that the dual review of pesticide/new drug products offered solely for human use represents an expensive duplication of time and resources for both the Agencies and the sponsors of these products without any significant increase in benefits to public health and/or the environment.  It is further concluded that regulations of these products solely by FDA under the FFDCA would adequately serve the intent of FIFRA.” 


Regulation under the FIFRA and the FFDCA is no longer duplicative.  Since 1979, the degree of regulation under FIFRA has changed considerably, most notably with passage of the Food Quality and Protection Act of 1996 (FQPA).  This statute requires EPA to review all pesticide registrations on at least a fifteen-year cycle (7 U.S.C. §136a(g)(1)(A)).  The goal of this requirement is to ensure that all pesticides continue to meet up-to-date standards for safety, public health, and environmental protection. EPA has the authority to require data and take action if needed between registration cycles (7 U.S.C. §136a(c)(2)(B); §136a-1(d)(3)).  No similar provisions exist under the FFDCA.  Additionally, EPA has emergency suspension authority, which means a pesticide registration can be canceled immediately if there is an emergency, imminent threat to public health or the environment. (7 U.S.C. §136d(c)) This appears to be a much more direct and powerful tool to regulate pesticides when compared to the FDA’s authority to simply require an Environmental Assessment in such circumstances.


It is Tri-TAC’s position that EPA should reassert its control over lice and scabies treatments under the FIFRA.  As such action is beyond the scope of the action EPA is currently considering, EPA should, at minimum, consider the human health and environmental impacts of these treatments in its current risk assessments.  As lindane lice and scabies products dominate the human health and environmental risks of lindane, the risk assessments are essentially meaningless without them.  Under the FIFRA, EPA has a statutory responsibility to ensure that pesticides are safe and effective for their intended uses and to prevent unreasonable adverse effects to man, other animals, and the environment from their usage (7 U.S.C. §136(bb), §136a(a), §136a(d)(2); §136d(b)).  By ignoring the risks posed by lindane lice and scabies treatments, EPA is not fulfilling its statutory responsibility. 


4.      Overview of Lindane Risk Assessment, p. 7.  “The aggregate risk assessment for lindane examines the combined risk from exposure through food and drinking water only since there are no residential or other non-agricultural uses of Lindane.”  As discussed in Comment Five, there is significant usage of lindane in the residential setting, from lice and scabies treatments.  The Cancer Prevention Coalition has reported that there were 2.3 million retail lindane prescriptions filled in 1992.


5.      Overview of Lindane Risk Assessment, p. 7.  “The DWLOC was calculated based only on dietary exposures.  As noted above neither acute nor chronic, surface water or groundwater EECs exceed the DWLOC and therefore do not exceed the Agency’s level of concern.”  The EEC for surface water signficantly exceeds EPA’s 0.019 ppb lindane human health criterion for waterbodies.


6.      Overview of Lindane Risk Assessment, p. 9. “..lindane and its isomers have been detected in areas of non use (e.g., the Arctic), indicating global atmospheric transport may occur.   The source of these lindane detections is unclear but may be the result of a combination of lindane’s past widespread use and its extreme persistence.”  It may also be the result on on-going usage of lindane in lice and scabies treatments, as these treatments are rinsed into sewer systems after use and thus indirectly enter surface water bodies.


7.      Overview of Lindane Risk Assessment, p. 9.  “Currently, U.S. uses of lindane are restricted to (agricultural) seed treatments at relatively low application rates.” This statement misrepresents lindane usage inasmuch as lindane is also used for lice and scabies treatments in the U.S.


8.      Overview of Lindane Risk Assessment, p. 9.  “At current application rates used on major crops, acute high risk and restricted use levels of concern are exceeded for both freshwater and estuarine/marine organisms.”  These levels are likely to be even higher if lice and scabies treatments are considered, particularly as these treatments are released indirectly to water bodies.


9.      Environmental Fate and Ecological Risk Assessment: Seed Treatment, p. 2. “At present, there is only one agricultural use (seed treatment) that might affect the environment.”  This risk assessment should also take into account aggregate ecological risk posed by the use of lindane in lice and scabies treatments.


10.  Environmental Fate and Ecological Risk Assessment: Seed Treatment, p. 11.  “Based on a screening level assessment, both surface and ground water simulations show that lindane concentrations in water resulting from seed treatments may reach levels of environmental concern and may exceed the MCL for drinking water (0.2 ppb).”  This assessment is incomplete.  It fails to acknowledge lindane contributions from lindane prescriptions for lice and scabies treatments.  It also fails to acknowledge that the resulting concentrations in water could exceed recommended water quality criteria and, in California, adopted water quality standards.


11.  Environmental Fate and Ecological Risk Assessment: Seed Treatment, p. 14.  “Agriculture run-off is likely the major contamination route of lindane and other HCH isomers to surface water.”  This assessment is incomplete.  It fails to acknowledge that in urban areas, as agricultural and structural uses of lindane have become more highly restricted, contamination of water bodies is likely to be caused by lice and scabies treatments.


12.  Human Health Risk Assessment Lindane, p. 7.  “No residential exposure scenarios have been identified for pesticide uses of lindane and therefore no risk estimates will be presented in this document for non-occupational exposure to lindane.”  This conclusion is patently incorrect.  Uses of lindane to treat lice and scabies are definitely pesticide uses.  These uses involve direct application of lindane to humans and thus a very high level of human exposure. These exposures must be considered when doing an aggregate risk assessment for lindane.


13.  Human Health Risk Assessment Lindane, p. 8.  “The Agency considered aggregate exposure and risk estimates for residents who might be exposed to lindane from multiple sources, such as residential use, food, and water.  Since no residential exposure is expected, an aggregate risk estimate was not calculated.”  See Comment Fourteen.  Any aggregate exposure assessment must include risks posed by lindane in lice and scabies treatments.


14.  Occupational and Residential Exposure Assessment and Recommendations for the Reregistration Eligibility Decision Document for Lindane, p.4.  “There are no current registered uses for recreational, residential or other public (non-occupational) settings.”  Although not currently registered under FIFRA, lindane usage in lice and scabies treatments must be considered in properly assessing residential risks from lindane.


Contact Information


            Thank-you for your consideration of our comments.  If you have any questions about this letter or would like additional information,  please contact me by phone at (510) 287-1496 or by e-mail at

Very truly yours,


     David Williams

     Chair, Tri-TAC


[1] Water Quality Standards; Establishment of Numeric Criteria for Priority Toxic Pollutants for the State of California; Rule, May 18, 2000 Federal Register; 31682.

[2] Skin &Allergy News (2000)  31(5):31.

[3] U.S. EPA Preliminary Risk Assessments for Lindane. Environmental Fate and Ecological Risk Assessment, p. 14.


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