Surface Water Quality
Surface Water Quality Criteria and Standards
Water quality criteria are U.S. Environmental Protection Agency (EPA) recommended maximum concentrations for pollutants in ambient waters. The values are calculated, using primarily laboratory data, to protect most of the species most of the time, on a national basis. State agencies incorporate EPA’s water quality criteria or other state-approved site-specific criteria into legally enforceable water quality standards.
These state standards consist of designated uses for each specific body of water and maximum water quality concentrations for individual chemicals that will be protective of the uses specified. State standards also include a policy concerning anti-degradation, that is, whether standards can ever be revised so as to be less stringent. State agencies use water quality standards in establishing water quality-based permit limits, which are incorporated into permits issued under the National Pollutant Discharge Elimination System (NPDES). This process of setting water quality-based permit limits may be associated with development and allocation of a total maximum daily load (TMDL). The TMDL must be completed for a water body listed by the state as “impaired,” that is, not meeting water quality standards for one or more pollutants.
API groups address issues pertaining to federal water quality criteria and state standards. These issues include setting technically sound and achievable criteria for nutrients such as nitrogen and phosphorus, determining whether mixing (dilution) zones should be allowed in calculating permit limits for pollutants that bioaccumulate, developing appropriate procedures for determining designated uses for individual water bodies and for determining whether those uses are in fact attainable, determining how to implement water quality criteria that are based not on pollutant concentrations in water but in fish tissue, etc. The following API reports pertaining to surface water quality, including criteria and standards, are available for download as PDF files:
Publication 4665 – Mixing Zone Modeling and Dilution Analysis for Water-Quality-Based NPDES Permit Limits
Publication 4656 – Bioaccumulation – How Chemicals Move from the Water into Fish and Other Aquatic Organisms
Publication 4701 – Bioaccumulation: An Evaluation of Federal and State Regulatory Initiatives
Publication 4694 – Laboratory Analysis of Petroleum Industry Wastewaters – Arranging for Analysis and Understanding Laboratory Reports
Publication 4695 – Understanding and Preparing Applications for Petroleum Facility NPDES Discharge Permits
Publication 4721 – Analytical Detection and Quantification Limits: A Survey of State and Federal Approaches
Sediments and the Sediment Quality Guidelines (SQGs)
Sediment quality is one of the important issues presently being addressed by EPA and the oil and natural gas industry. Sediment issues are also rank highly by a number of states, the Army Corps of Engineers, and NOAA, among other organizations.
Several characteristics of sediments dominate the discussion and potential actions taken. Sediments tend to be a “sink” or repository for pollutants that have settled out of the water column. This means that any problems may be based on both historical and recent inputs, and these inputs may be either from point or non-point sources. The chemical nature of the sediment-bound material and their resulting availability to organisms, both aquatic and human, are also not well understood. These aspects create dilemmas in terms of control, responsibility and clean-up.
EPA has been developing draft numeric sediment quality guidelines (SQGs) that are supposed to provide states with guidance in setting sediment standards as part of their water quality programs. SQGs are perceived by EPA to be a key element in extending the reach of water quality-based permits to control inputs to sediments. This, in turn, would make the sediment values important in determining whether or not water bodies are in attainment with state standards, a decision that drives the development of Total Maximum Daily Load (TMDL) analyses.
EPA has decided against the release of draft guidelines and the “Sediment Guidelines Implementation Framework” at this time, indicating that there are a number of issues that need to be addressed before the documents are ready for release, even in draft form. Their decision for delay was influenced by visits from a coalition of concerned industrial representatives, including API, which provided the agency with concerns about the technical development and practical application of the SQGs, as well as possible remedies.
API's involvement in this activity and our participation with broadly based sediment-focused coalitions has allowed us to work constructively with EPA, providing input that should achieve reasonable and protective regulations.
Effluent guidelines are EPA limits on specific constituents in effluents from industries in a number of industrial categories, including Petroleum Refining and Oil and Gas Extraction. Effluent guidelines are based on the performance of treatment technologies available to the industry category. API, through its groups, addresses industry issues associated with effluent guidelines. For example, API participated in a forum to discuss the process by which effluent guidelines are periodically reviewed and revised. API provided effluent data to EPA to demonstrate that discharges from petroleum terminals are sufficiently low that effluent guidelines for terminals are not warranted. API has also provided extensive comments to EPA in support of case-by-case permit limits, that take local conditions into account, rather than uniform effluent guidelines for cooling water intakes at facilities such as petroleum refineries.
Total Maximum Daily Loads (TMDLs)
Total Maximum Daily Loads (TMDLs) are “budgets” setting the amounts of pollutants that waters can receive and be considered by EPA as safe for various designated uses, such as fishing, swimming, drinking, etc. The designated uses are established by the states as part of their process of setting water quality standards for waters that do not meet the use requirements.
The TMDL analysis should examine the chemical and biological condition of the water body, determine all of the inputs to the system, including both point and non-point sources, and ascertain the resilience of the system to those inputs. Based on the scientific data, the TMDL would then determine the maximum acceptable quantities of any chemicals or other materials that could limit the designated use. The total loadings thus determined are allocated among the inputs previously identified. Those allocations are then used in establishing limits for discharge permits.
In response to an EPA proposed rule to impose unduly stringent TMDL requirements nationwide, API conducted studies on the potential impact of the proposed TMDL rule, including an analyses of the costs and benefits of a variety of plausible outcomes, such as the possible loss of mixing zones in setting permit limits and the probable overextension of state resources to complete the TMDLs. Comments received by EPA from API and many other parties moved EPA to not move forward with this onerous rule. In lieu of this rule, EPA moved to revise and clarify its impaired water listing procedures, creating multi-part lists that ensure only truly impaired waters are listed and that TMDLs for these waters are properly identified as a priority.