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IX. Water Discharges

Source: EPA 1994 Toxics Release Inventory
Public Data Release, Appendix A:
Questions and Answers

Q64 What are the water quality impacts and toxicity concerns for the TRI chemicals with the largest surface water releases?

A The six chemicals with the largest releases to surface waters account for 89.5% of all the discharges to surface waters reported to the TRI for 1994. The top six chemicals are:

phosphoric acid
ammonium nitrate (solution)
ammonium sulfate (solution)
zinc compounds

Phosphoric acid affects water quality primarily by introducing phosphates into the water body. Phosphates may cause algae blooms which result in deoxygenation of water and other effects which may lead ultimately to fish kills. Ammonia, ammonium sulfate, and ammonium nitrate primarily affect water quality by introducing ammonia into the water body. EPA has issued water quality criteria for ammonia. EPA also regulates the oxygen demand from ammonia and the nutrient impact of all three ammonia chemicals. Methanol is a semi-volatile chemical that biodegrades readily and is toxic only at moderately high levels. Zinc compounds are toxic to fish and other aquatic life.

EPA continues to examine all chemicals discharged to surface waters to see if their toxicity or the characteristics of the receiving waters require short-term or long-term attention. The environmental impact of these discharges is much more dependent on the toxicity of the chemicals and on the physical, chemical, and biological characteristics of the receiving waters than simply on the weight of these chemicals.

Q65 The discharge of phosphoric acid to surface waters decreased by over 150 million pounds between 1993 and 1994, almost six times more than any other chemical discharged to water. What accounts for this large decrease in the discharge of phosphoric acid to surface water?

A Previous TRI reports indicated that two IMC-Agrico facilities in Louisiana reported discharges of very large quantities of phosphoric acid (110.7 million pounds in 1988). In December of 1991, the company set a voluntary goal of reducing its discharges by 75% (from 1988 levels) by 1994. The 1994 levels were reported at 13.5 million pounds, a reduction of 88%. A large portion of the decrease in phosphoric acid discharges for 1994 is a result of implementation of the pollution prevention initiative at IMC-Agrico's Uncle Sam and Faustina Plants. These reductions were achieved by preventing rainwater from falling on gypsum stacks (a byproduct of fertilizer production). The stacks were covered with an impervious clay layer and piping was installed to convey any rainwater runoff to the company's water treatment plant. This best management practice prevented large quantities of contaminated stormwater from being generated and released to surface waters.

Q66 How does EPA (or the states) regulate EPCRA section 313 chemicals discharged to water?

A Under section 301 of the Clean Water Act (CWA), the discharge of any pollutant by any person is unlawful unless it is in compliance with the provisions of the Act. The provisions are implemented by EPA and the states through the development of effluent guidelines, the adoption of water quality standards, and the issuance of a National Pollutant Discharge Elimination System (NPDES) permit. Pursuant to Congressional directive, these programs have focused on 126 toxic pollutants of greatest concern, known as "priority pollutants." However, regulatory authorities also rely heavily on measurements of whole effluent toxicity as an aggregate measure of toxicity and an indication of the presence of toxic compounds other than the priority pollutants. The list of priority pollutants includes 80 of the TRI chemicals.

States are in the process of adopting water quality standards for those priority pollutants that could reasonably be expected to interfere with water quality. The states and EPA then use standards, together with best available treatment technology guidelines, to set enforceable permit limits on the amounts of these and other toxic pollutants that local governments and industries are allowed to discharge to waters of the United States.

While many of the TRI chemicals with the largest surface water discharges are controlled, a number of the small-volume chemicals with high toxicity levels are not fully regulated. EPA will continue to work with the states to ensure that all appropriate standards and permits are adopted. EPA is also preparing to issue Federal water quality standards if states do not adopt standards as Congress has directed. In addition, states and EPA regulate the overall toxicity of effluents with permit limits that rely upon biological toxicity tests. These limits serve, in part, to control the discharge of those TRI chemicals for which there are no state water quality standards.

Q67 What are EPA's plans to develop water quality criteria for chemicals that are on the EPCRA section 313 list that do not yet have them?

A EPA has published aquatic life and/or human health protective ambient water quality criteria for 134 of the TRI chemicals. There is a current capability to develop four to six aquatic life protective water quality criteria a year. Obviously, at this level of effort, it would take many years to complete criteria for all of the chemicals on the TRI list.

Because criteria and advisory development is a multi-year process, EPA is careful to set priorities before beginning work. First, EPA collects a variety of toxicology and exposure information on chemicals we are considering for criteria or advisories. Then, EPA ranks the pollutants. Finally, the Office of Water meets with other affected offices within EPA to obtain their views before making a final selection of chemicals for criteria and advisory development. TRI data will play a major role in setting these priorities.

Once EPA issues a criteria document for a chemical, the next step is for states to adopt them as water quality standards under state law. Those standards are then used to derive enforceable NPDES permit limits for specific direct discharging facilities.

Q68 What is the process for deciding whether to revise effluent guidelines or to develop new effluent guidelines to reflect the TRI information?

A EPA is required to publish a biennial effluent guidelines plan under section 304(m) of the CWA. The purpose of the plan is to identify those industrial categories for which effluent limitations and standards should be developed or revised. Plans were published in 1990, 1992, and 1994. The 1994 plan did not select any new industries for development because work still continued on industries selected in the 1992 plan. The choice of industries to be regulated is based on a number of factors, including TRI data. The Office of Prevention, Pesticides and Toxic Substances has prepared information on the industrial categories that are responsible for the majority of the discharges of the TRI chemicals. A Task Force is currently advising EPA on how to improve the process for selection of additional industries, and this may lead to a greater reliance on TRI data.

Q69 How will EPA use TRI to implement the Public Water Supply Supervision Program of the Safe Drinking Water Act?

A The Office of Ground Water and Drinking Water will use the TRI data in a variety of ways to identify potential contaminants in specific geographic areas.

In particular, these data could be source data for vulnerability assessments to determine frequency of monitoring by public water systems.

The Office of Ground Water and Drinking Water could review chemicals reported in the TRI database to identify candidates for future maximum contaminant level developments.

The Office of Ground Water and Drinking Water compares hazardous waste injection data with TRI data to identify and match those contaminants released.

Q70 How will EPA use the TRI data to improve the management of the permit program?

A EPA will investigate the feasibility of EPA Headquarters and Regions and the states using TRI data to determine whether permits issued to some or all of these facilities control the release of contaminants listed in TRI reports.

The Office of Wastewater Management (OWM) has used TRI data to begin to identify new undetected significant industrial users discharging to POTWs and to identify illegal unpermitted discharges. The Office of Enforcement and Compliance (OEC) has used data to identify discharges by industrial users to POTWs to determine whether additional NPDES permit limits are needed. OEC, EPA Regional offices, and states will continue to use the data for geographic and national planning, and targeting of activities to high priority areas (i.e., near coastal areas, wetlands) and to target inspections to suspected violators that could lead to permit modification, new or revised limits when the permit is reissued, or an enforcement action.

Source: USEPA 1994 Toxics Release Inventory Public Data Release (EPA 745-R-96-002, June 1996).

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