XV EPA U.S. Environmental Protection Agency Pacific Southwest, Region 9 Land Division September 2014 Serving Arizona, California, Hawaii, Nevada, the Pacific Island, and 148 Tribes 75 Hawthorne Street, San Francisco, CA 94105 800-EPA-WEST www.epa.gov/region9 Risk Assessment at Evoqua (formerly Siemens) September 2014 Evoqua Water Technologies, formerly known as Siemens Industries, Inc., US Filter and Westates, operates a hazardous waste storage and treatment facility on the Colorado River Indian Tribes' reservation near Parker, Arizona (the "Evoqua Facility"). The Evoqua Facility reactivates spent carbon - carbon which has been previously used to remove pollutants from water and air. The spent carbon is reactivated by heating to very high temperatures under controlled conditions in order to drive off the contaminants. The contaminants are then captured and further processed to ensure that they do not pollute the environment. The newly reactivated carbon product is then ready for reuse. (See Figure 1) Carbon Regeneration Cycle Fffl Carbon filtering site uses activated carbon HI Reactivated carbon, no lor a hazardous waste, is reusi Figure 1 1 ? Spent carbon is fntto Siemens Siemens r«mover£ contaminants from sjk-m carlxm At EPA's request, and as part of the permit process, the Evoqua Facility completed a human health and ecological risk assessment (risk assessment) in July 2007. The purpose of the risk assessment was to estimate the Evoqua Facility's current and possible future impacts on the health of local residents and the surrounding environment. Please note that due to various ownership and name changes to this facility overtime, earlier documents, including on EPA's website, may show older names for this facility. Based on the risk assessment results, EPA concluded that human health impacts (both carcinogenic and non-cancer) and ecological impacts from operations at the Evoqua Facility are low or insignificant. (See page 4 for an explanation of what level of risk EPA considers "insignificant.") Human health risk: the likelihood that an individual's health may be affected by exposure to toxic substances in the environment. Ecological risk: the likelihood that the ecosystem (e.g. plants, wildlife) may be affected by toxic substances in the environment. Carcinogenic vs. non-cancer health impacts: carcinogenic impacts may cause cancer in humans, whereas non-cancer impacts are not believed to cause cancer, but may cause other health effects, such as liver disease. What is a risk assessment? - A scientific study ofthe various ways individuals and/orthe ecosystem might come into contact with toxic substances - A calculation of how likely it is that human health impacts might occur because of hazardous substances at a site - A tool to assist EPA in decision making and in protecting the community' health and the environment 1 ------- How will EPA use the risk assessment results in the permit decision? EPA cannot deny a permit for the Evoqua Facility based on risk, because the risk assessment determined the human health and ecological risk of the operations at the facility to be insignificant. However, if EPA decides to issue the permit, it will not allow the Evoqua Facility to operate under conditions that could have a greater impact than the conditions evaluated by the risk assessment. For example, the permit would prescribe operational conditions such as the temperature to which the carbon is heated and the amount of carbon processed. What categories of impacts did the risk assessment study? Human health impacts from air emissions: Long-term ("chronic") and short-term ("acute") human health impacts, as well as both carcinogenic (cancer) and non-carcinogenic (non-cancer) effects. Water and fish impacts due to waste water discharge from the Evoqua Facility. Ecological impacts from air emissions: Impacts to plants, animals and the environment. How was the risk assessment conducted? EPA provided the Evoqua Facility with guidance and oversight for the risk assessment process, ensured that the report was sufficiently thorough and extensive, and reviewed the results of the risk assessment. The risk assessment followed the steps below: 1) Measured maximum possible concentrations of emissions from the facility by conducting a trial burn (discussed in greater detail below). 2) I dentified exposure routes by which the emissions would reach potential human and ecological receptors. 3) Determined concentrations at which the emissions would reach potential receptors through the identified exposure routes. 4) Calculated potential impacts to human and ecological receptors from coming in contact with the emissions. Which human and ecological receptors did the risk assessment consider? Facility workers exposed to emissions on the job. The community around the Evoqua Facility, particularly the following sensitive receptors: o The elderly, people with health impairments, pregnant women, women of childbearing ages, and children. o Individuals engaging in subsistence fishing, hunting and agriculture, and particularly members of the above mentioned higher risk population engaging in subsistence activities. Plants and wildlife found around the Evoqua Facility. ------- Which routes of exposure did the risk assessment consider? I nhalation (breathing in) of affected air. Ingestion (eating) of affected soil (e.g. through soil particles getting onto food or through cultural practices). Eating food that absorbs and accumulates chemicals from the affected air and soil. This food includes locally-raised produce, beef, chicken and eggs. Exposure routes - ways in which particular substances can reach human and ecological receptors. Emissions All chemical compounds that leave the facility Human receptors - individuals who maybe affected by substances emitted by the facility Ecological receptors - plants, animals and habitats in the area that maybe affected by substances from the facility What specific information about the community and the area did the risk assessment consider? Information about community activities, such as home gardening, raising of livestock and use of local plants. Information about Tribal cultural and spiritual activities that may increase exposure of community members to contaminants. Information about local and regional weather patterns. What are the human health impacts from air emissions? Based on the risk assessment study, the EPA concluded that human health impacts from long-term exposure to stack emissions, fugitive emissions, as well as the combination of the two, were below EPA's acceptable thresholds. Stack emissions: To measure stack emissions, the Evoqua Facility conducted a trial burn under specific operating conditions (e.g. temperature of the furnace, amount of carbon being processed by facility, contaminants present in the spent carbon). The concentrations of contaminants coming out of the stack were 3 Incoming Spent Carbon Siemens Process Diagram Fugitive ^ Emissions Furnace Gases Figure 2 Carbon reactivation furnace Hopper After-Burner Air Pollution Control Devices1 Spent Carbon Storage Tanks \ Stack emissions Stack Regenerated Carbon Product Pre-treated Wastewater to Joint Venture ------- measured during the trial burn. Computers helped model how emitted substances would disperse (spread) throughout the air and soil in a 154 square mile area surrounding the facility. Fugitive emissions: Fugitive emissions are generated during unloading of the spent carbon that comes into the Evoqua Facility (see Figure 2). The risk assessment determined levels of fugitive air emissions from information on amounts of spent carbon that Evoqua handles, as well as the concentrations of contaminants in that spent carbon. What are the impacts to water and fish? The Evoqua Facility sends its waste water (mostly from air pollution control devices) through a pipeline to the Colorado River Sewage System Joint Venture, a treatment plant. The treatment plant processes waste water from the Evoqua Facility along with waste water from the surrounding community. It then releases the treated water to the Main Drain - a channel that flows to the Colorado River. Currently, CRIT does not have EPA-approved surface water quality standards. As any discharge from the treatment plant may eventually flow into the Colorado River, the discharge must meet EPA-approved downstream standards established by the State of Arizona Water Quality Standards. The analysis found that waste water from the Evoqua Facility does not cause the discharge from the treatment plant to exceed the State's most stringent water quality standards. It also found that the discharge from the Joint Venture is not toxic to aquatic organisms. The risk assessment did not evaluate the overall risks of eating fish from the Main Drain, so the EPA cannot claim whether or not the fish are safe to eat. However the EPA supports the risk assessment's conclusion that the Evoqua Facility has no significant effect on how safe the fish are for human consumption. What are the ecological impacts? The ecological risk assessment concluded that the stack emissions from the Evoqua Facility do not pose an unacceptable risk to wildlife that was considered to be the most sensitive in the area. How does EPA decide what level of risk is "insignificant"? To decide on an insignificant risk of cancer in a community from a combustion facility such as the Evoqua Facility, EPA typically uses the threshold of "one in one hundred thousand." The "one in one hundred thousand" threshold indicates that for every one hundred thousand residents exposed to facility emissions, at most one additional case of cancer may develop over the course of a 70-year lifetime. This additional case of cancer wouldbe in addition to cancers in the community caused by factors unrelated to the facility, such as smoking, diet, pesticide use, or naturally occurring radon. When we apply the "one in one hundred thousand" threshold to a community with fewer than one hundred thousand residents (such as Parker with about 3,000 residents), we would expect less than one additional case of cancer to develop in that community due to emissions from the facility. 4 ------- Please contact the following with questions or comments Mr. "Mike" Mahfouz Zabaneh, Project Manager 75 Hawthorne St., LND-4-2 San Francisco, CA 94105 (415) Q72-3348 or zabaneh.mahfouz@epa.gov Mr. Patrick Wilson, Senior Toxicologist 75 Hawthorne St., LND-4-1 San Francisco, CA 94105 (415) Q72-33R4 or wilson.patrick@epa.gov The complete text of the risk assessment is available online at http://www.epa.gov/regionQ/waste/evoqua/risk.html ------- |