The Arid West Water Quality Research Project

1997 Conference

April 23-25, 1997

(Selected Conference Materials)

Part One: The Arid West Water Quality Research Project

Introduction of Arid West Issues

Habitats of Concern

An important issue related to chemical criteria development is the identification of habitats to be protected by the standards. Part of the criteria development process involves the identification of sensitive species for which specific pollutants pose acute and chronic hazards when discharged into water bodies. These species are potentially exposed through direct contact with the waters or through ingestion of food sources exposed to waters impacted by discharges.

There is a question whether the species used in criteria development are representative of the species typically found in arid ecosystems. This particularly applies to ephemeral systems which are incapable of supporting perennial aquatic communities and to effluent-dependent streams where there is some question regarding the ability to meet criteria in support of the communities that are created. There is a question whether or not the criteria that have been developed adequately represent the species typically found in these ecosystems (including threatened and endangered species) and whether or not the criteria should take these species into account in the development of acute and chronic criteria which are more applicable to arid West environments.

Biological Criteria

The application of biological criteria is an attempt to identify changes in biological communities that result from point and non-point sources of pollutants to aquatic ecosystems. Specific indicator biological communities are identified and measured for parameters, which may be altered through the introduction of pollutants. These parameters may include diversity, population size, biomass, or some other relevant measurement.

Biological communities may be identified downstream of discharges to be monitored for changes over time that may indicate adverse impacts. Upstream communities may be identified which are similar in composition and other attributes to downstream communities that result from a discharge. It may also be possible to identify representative communities for specific regions, ecosystems, or watersheds that can be considered a standard reference for determining whether discharges have an adverse impact.

The natural variability of biological communities is a concern in that it may "mask" any effects that could result from the introduction of a pollutant. In arid ecosystems, there is a concern with the reliability and applicability of the technique for ephemeral systems due to the extreme variability in flow regime and the potentially erratic nature of biological communities that are dependent on ephemeral flows. With respect to effluent-dependent streams, where the presence of flow causes the nature of the community to be more predictable, it then becomes a question of to what extent the community should be protected such that continued discharge is encouraged.

Chemicals of Concern

EPA's water quality criteria identify physical, chemical and biological characteristics of waters that are necessary to support specific uses of water bodies (e.g., drinking water supply, agriculture, and propagation of fish and wildlife). Water quality criteria have been developed for over 100 parameters to guide states in the development of appropriate water quality standards for lakes and streams within their jurisdiction. States evaluate these criteria relative to the uses of the water bodies, sometimes modifying them (if necessary), and then adopting them as water quality standards.

Important questions have been raised that relate to the relevance, applicability, representativeness and completeness of the pollutants identified for which criteria has been developed. In the arid West, specific chemicals have been identified which pose special challenges in the implementation of the criteria and standards. These typically include chemicals and compounds, which are problematic relative to their control and treatment, and chemicals, and compounds which occur naturally in concentrations which sometimes exceed standards. These chemicals and compounds include ammonia, arsenic, cadmium, copper, lead, mercury, molybdenum, selenium, silver, zinc, phthalates, and diazinon.

Another issues peculiar to the arid West is that, in many cases, the criteria, and resultant in-stream standards are more difficult to attain in ephemeral drainages or effluent-dependent streams. Often in these circumstances, the discharge is subject to end-of-pipe or technology-based standards without the benefit of mixing zones or nutrient waivers that may apply to discharges to perennial streams.

WET Testing

Whole Effluent Toxicity (WET) tests were introduced by EPA in 1984 to help identify whether a discharge has a reasonable potential to release toxics in toxic amounts. The technique is intended to flag toxicity not caused by chemicals for which there are water quality standards or combinations of chemicals.

WET limits and testing requirements are often written into NPDES permits in addition to chemical monitoring efforts. The technique involves exposing specific aquatic species to samples of discharge water and measuring acute and chronic effects based on the response of the species to pollutants in the water sample. Issues that have been raised with respect to the technique include the representativeness of the species involved, the reliability and reproducibility of the test, the significance of episodic events, and the correct interpretation of the results (e.g., the relationship of a negative result and the identification and control of a given pollutant).

In the arid West, there is also concern about the species used in the test. There is concern that the species used for tests in arid regions should simulate those that are found in ephemeral drainages and effluent-dependent streams. Also, given the episodic nature of flow events in ephemeral streams and the lack of any mixing zone for discharges into ephemeral or effluent-dependent streams, there is a question of what exposure assumptions should be applied to make the test results more meaningful.

Candidate Research Issues

The four tables on the following pages are from the EPA approved Arid West Water Quality Research Project Work Plan. The tables were contained in the Conference Packet that was distributed to conference participants to be used as the starting point for all the discussion groups.

CRITICAL/CANDIDATE ISSUES for the Arid West Water Quality Research Project (WQRP)

CHEMICAL CRITERIA AND STANDARDS

No.	Project/Issue/Description	Proposed by
1.	Identify chemicals and compounds of specific concern for arid West agencies and regulators in ephemeral and effluent-dependent ecosystems, including ammonia, arsenic, cadmium, copper, lead, diazanon, zinc, mercury, molybdenum, phthalates, silver. All the above plus dissolved oxygen. All the above plus selenium. Dissolved oxygen. Develop data on pollutants and places presenting special compliance problems for dischargers (using existing data to the extent clean chemistry requirements are met).	- PCWMD - State Reg - CO - AZ, Phx, TX - Region IX
2.	Develop criteria for species in ephemeral and effluent-dependent streams in the arid West. Develop criteria for these chemicals not currently included in national criteria documents (especially metals, pesticides and ammonia).	- PCWMD, AZ - CO
3.	Quantify the influence of hardness, alkalinity, and Total Organic Carbon regarding metals toxicity to aquatic and wildlife species in ephemeral and effluent-dependent ecosystems. Develop protocols for implementing hardness-dependent metals criteria in waters above 400 mg/l CaCO3.	- PCWMD - Region IX - CO - Riverside - NV, CO, CA - State Reg
4.	Develop laboratory toxicity data for arid West species for use in expanding the national database to cover currently unrepresented species and to develop site-specific criteria, use designations and toxicity testing protocols.	- Region IX - State Reg
5.	Demonstrate analytical or other rational approach to apply water quality standards to stormwater flows, especially in the arid and semi-arid West. Develop alternative methods for managing and regulating stormwater discharges, which are sensitive to arid Western settings.	- PCWWM,TX - State/Reg - Region IX
6.	Investigate and quantify problems with dechlorination and the effectiveness of specific dechlorination systems to relieve individual agencies of making such determinations at each facility, Including chlorine residual compliance.	- CO - CA - Riverside
7.	Quantify the fate and effects of nitrogen transformations that occur at the soil/water interface as surface waters percolate into ground waters.	- CO - Riverside
8.	Define the strength of metal-organic ligands that render metals non-bioavailable and define the conditions under which tarfield release of bound metals into a bioavailable form are likely to occur.	- CO
9.	Develop data necessary to assess public health risks due to subsistence fishing in drains and canals.	- Region IX - Phx
10.	Develop protocols for evaluating flows of ephemeral and effluent-dependent streams for TMDL, mixing zone, and effluent limit development purposes. Site-specific water quality standards for effluent-dependent streams. Mixing Zones	- Region IX - CO - CO
11.	Review fish consumption designated use in canals and waters where use does not currently exist.	- CO, SRP - AZ, CO, Phx

 

ECOLOGICAL CRITERIA AND STANDARDS

No.	Project/Issue/Description	Proposed by
1.	Develop a list of indicator terrestrial and aquatic species in ephemeral and effluent-dependent streams in the arid West not currently included in national criteria documents. Develop expanded list of species identified in ephemeral streams and EDWs.	- PCWMD - Utah - Region IX
2.	Evaluate food chains representative of important arid West wildlife species, including threatened and endangered (T&E) species. Endangered Species Act (ESA) - impact on water quality standards; bioaccumulation; manmade systems implementation	- Region IX - Phx, CO - CO, CA - Riverside
3.	Investigate the net ecological benefit of reuse and recharge programs in ephemeral and effluent-dependent streams in the arid West.	- PCWMD - Region IX
4.	Develop measurable decision criteria for use attainability questions in ephemeral and effluent-dependent ecosystems: what level of use is attainable, what conditions fully protect a use, what data are needed to set site-specific criteria, etc.	- PCWMD - CO
5.	Investigate the issues involved in applying the biological integrity concept to ephemeral and effluent-dependent ecosystems of the arid West.	- PCWMD
6.	Protection of habitats/uses through minimum discharge requirements.	- Phx
7.	Investigate the toxicity of metals and ammonia to salt-tolerant plant species important in arid West ecosystems.	- PCWMD - CO
8.	Develop an "Effluent-Created Ecosystem" use definition for ephemeral and effluent-dependent ecosystems in terms of the physical, biological, and chemical characteristics found in these environments in the arid West. Develop protocols for developing criteria appropriate for ephemeral and effluent- dependent waters (EDWs). Develop arid West-sensitive protocols for evaluating economic impacts of standards implementation for use in use attainability analyses.	- PCWMD - CO - Region IX - Region IX
9.	Review reuse criteria and standards for arid West ecosystems. Develop data necessary to promote beneficial reuse of treated wastewater to protect and enhance aquatic ecosystems (e.g., to develop protocols for evaluating "net environmental benefits"). Review effluent reuse, water rights/ownership issues. Determine best use of effluent as a water resource.	- PCWMD - Region IX - CA - Riverside - PCWMD
10.	Analyze impact of tribal water quality standards.	- Phx
11.	Evaluate tissue concentrations in aquatic life and wildlife for mercury, selenium and other bioaccumulative pollutants.	- Region IX
12.	Review toxics standards guidelines - numeric/narrative including effluent toxicity.	- CO, NV, AZ
13.	Develop data on actual biological systems needed to assess the feasibility of developing wildlife criteria, and to develop wildlife criteria (e.g., mercury).	- Region IX - Riverside

 

WHOLE EFFLUENT TOXICITY (WET) TESTING

No.	Project/Issue/Description	Proposed by
1.	T&E Species: - Develop evaluations of whole effluent toxicity as it relates to T&E species. - Modify protocols for biomonitoring testing to allow ceridaphs/fatheads to be more tolerant of arid Western waters. - WET testing - Endangered Species Act	- Region IX, TX - Utah - TX
2.	Support studies to determine the Method Detection Level (MDL). Support studies to determine the Practical Quantification Level (PQL). Determine WET testing variability compliance.	- PCWMD - PCWMD - Riverside
3.	Investigate the relationship between ammonia toxicity, pH and temperature.	- PCWMD
4.	Determine appropriate use of biomonitoring and WET testing in ephemeral and effluent-dependent ecosystems.	- PCWMD, AZ

 

OUTREACH PROGRAM RESPONSE SUMMARY

RESEARCH IDEAS AND SUGGESTIONS

The table below summarizes significant ideas from responses received to date.

No.	Summary of Interest	Municipality
1	A constructed wetlands pilot project was recently initiated. A portion of abandoned sludge drying beds has been converted to wetlands. The project allows for extremely accurate data collection and control. A study to determine site specific water quality standards for the Rio Grande is being conducted in conjunction with the U.S. EPA.	City of Albuquerque, New Mexico
2	Interested in collecting water quality data on Lake Alan Henry. Presently this lake has impounded only enough water to furnish irrigation to establish a grass cover on the downstream side of the dam. Data collected from Lake Alan Henry may provide valuable information on the habitat and species changes that occur in West Texas from pre-impoundment stage to full lake capacity.	City of Lubbock, Texas
3	Currently in the early stages of a project that will recharge groundwater supplies using sewage effluent. The process will include partial aeration through aerobic-anaerobic lagoons to reduce BOD and suspended solids to secondary standards. Nitrogen reduction will occur through a constructed wetlands. Rapid infiltration basins will be used to recharge and soil aquifer treatment will polish the water quality through the vadose zone. Feasibility studies confirmed project economically feasible and expected that drinking water quality standards can be met before reaching water table.	City of Sierra Vista, Arizona
4	Have a series of RBA studies of intermittent streams underway in the Trinity Basin. Basin is in transition between areas typical of southeast and southwest U.S. Rainfall ranges from 27" to 52". Majority of stream miles go to zero flow some time each year and remaining mileage is effluent-dependent. Latter includes main stem from Ft. Worth/Dallas over 200 miles downstream. Because of problems and large population involved, many studies and data collection have been done.	Trinity River Authority of Texas
5	Interested in possibility of conducting environmental research on Paradise Lake, an effluent-dependent stream.	Arizona City Sanitary District
6	Just beginning water programs with assessment of surface water/groundwater to establish areas of critical concern and for future monitoring.	Salt River Pima-Maricopa Indian, Scottsdale, AZ
7	Abstract submitted for a proposed project in Santa Margarita River in southern California. Need to acquire appropriate water quality effluent limitations in discharge permit.	Eastern Municipal Water District, San Jacinto, CA
8	Summary of a proposal for a study to address ecological/water quality issues raised by EPA. Results used to develop hypotheses that can be tested with more long-term but will provide sufficient data to allow initial interpretation of differences in function of riparian ecosystems located along effluent and non-effluent-dependent Arizona rivers.	Arizona State University, Tempe, AZ
9	Proposal to conduct bioassessment survey studies, chemical specific testing of in-channel stormwater run-off, use attainability study and whole effluent toxicity testing in the arid southwest for stormwater.	Pima County - Dept. of Transportation and Flood Control District & the Dept. of Env. Quality

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