Background

Selenium and Nitrogen Background
Selenium is a naturally occurring element that is necessary for life, but it is toxic at high levels and is unusual in that the difference between essential and toxic levels is relatively small. Selenium is a bioaccumulative pollutant, meaning that it accumulates in the food chain through uptake and consumption by plants and wildlife, and can cause adverse effects on fish and birds. Addressing bioaccumulative pollutants to protect fish and birds is complex, because pollutant levels in water or soil don't necessarily reflect what is happening in the ecosystem. Selenium occurs in many forms in the environment, and can convert between different forms depending on chemical and biological conditions. Also, some forms of selenium are more harmful than others. Similar to selenium, nitrogen is an essential nutrient, but it can cause harmful algal blooms when nitrogen levels are excessive. Excessive algal blooms decrease dissolved oxygen in surface waters (referred to as eutrophication) and can result in fish kills.

The Problem with Selenium and Nitrogen in the Newport Bay watershed
In the Newport Bay watershed, selenium derived from ancient marine sediments in local foothills accumulated over the last several thousand years in an area known as the Swamp of the Frogs. This ancient swamp, though now drained and filled, has become an almost limitless source of selenium because of the high water table in the area. Virtually any activity that mobilizes groundwater to the surface has the potential to increase selenium contamination of surface waters in the Newport Bay watershed. Activities associated with increased urbanization of the watershed result in passive and active discharges of selenium-laden groundwater into surface waters (e.g. drainage ditches, flood control channels with weep holes, and development and maintenance dewatering activities). Selenium levels in the watershed widely exceed the California Toxics Rule (CTR) criterion, but the actual impacts to fish and birds in the watershed, and the Newport Bay ecosystem in general, are unknown at this time.

During the 1980's and 1990's, large mats of algae were common in Lower and Upper Newport Bay. These extensive mats threatened beneficial uses by lowering dissolved oxygen levels and impeding recreational boating. The peak bloom of 1985-1986 resulted in a fish kill in the Newport Island area. Historically the major source of nitrogen in the watershed was runoff from commercial nurseries. Improvements in nursery operations have reduced this source, and the current primary source is most likely groundwater, which has received nitrogen from agricultural land uses.

There currently are no feasible treatment technologies to remove selenium and nitrogen from groundwater-related discharges in an urbanized watershed, such as the Newport Bay watershed, especially for short-term discharges. This then presents the challenge of how to deal with elevated levels of selenium and nitrogen in groundwater levels to meet regulatory requirements (discussed below) when no feasible treatment options exist.

Regulatory Background

TMDLS
To address nutrient issues in the watershed, the Santa Ana Regional Water Quality Control Board adopted an amendment to the Basin Plan in 1998 in to establish a Total Maximum Daily Load (TMDL) for nutrients. A TMDL is a regulatory process that sets an allowable limit for a particular pollutant in a waterbody at a level, or load, from all sources that won't adversely impact beneficial uses of the designated waterbody. One of the special studies needed under the Nutrient TMDL is an effort to better understand the extent and magnitude of groundwater as a nitrate source. In 2002, the EPA issued a Toxics TMDL for the watershed, which is now being broken down into 5 separate TMDLs by the State (including a TMDL for selenium), expected to be adopted in 2007.

NPDES Permits
In 1998, the Santa Ana Regional Water Quality Control Board (Regional Board) adopted a general National Pollutant Discharge Elimination System (NPDES) permit (Order No. 98-67) prescribing general waste discharge requirements for short-term (i.e. one year or less) discharges to surface waters that pose an insignificant (de minimus) threat to water quality within the Santa Ana Region. This permit was issued prior to the adoption and promulgation of the Nutrient and Toxics TMDLs, therefore groundwater-related discharges were still considered an insignificant threat to water quality in the Newport Bay watershed at that time.

However, when this permit was renewed in 2003 by Order No. R8-2003-0061, the Newport Bay watershed was specifically excluded from its terms and conditions due to concerns that elevated levels of selenium and nitrogen in short-term groundwater-related discharges have the potential to adversely affect surface waters and would not comply with the existing TMDLs in the watershed. Therefore, the Regional Board developed and issued a separate general NPDES permit specific to the Newport Bay watershed - Order No. R8-2004-0021 (Order). The Order acknowledges that while current groundwater levels exceed the California Toxics Rule (CTR) limit of 5 ug/L selenium, a feasible treatment technology does not exist to lower the levels in the discharges to the CTR standard. Therefore, the Order incorporates an alternative compliance approach by authorizing the formation of a Working Group and the implementation of a Work Plan to develop a comprehensive understanding of and management plan for selenium and nitrogen groundwater-related inflows in the watershed. Specifically, the Work Plan will investigate the extent of ecosystem impacts, examine Best Management Practices (BMPs) and treatment technologies that can reasonably be applied throughout the watershed to reduce the inputs of selenium and nitrates, develop a management program (i.e. a trading, offset, or mitigation program) for selenium and nutrients in the watershed, evaluate the Nutrient TMDL, and, if necessary, develop a site specific objective for selenium for the Newport Bay watershed.

To comply with the terms and conditions of the Order, including the development and implementation of the comprehensive Work Plan, certain watershed stakeholders have formed a Working Group and have launched the Nitrogen and Selenium Management Program.

Participation in the Working Group constitutes performance based effluent limits for the five year term of the permit (through December 20, 2009). Additionally, all dischargers must demonstrate to the Regional Board that each discharge has been reduced, eliminated, or avoided to the extent feasible before proceeding with the discharge.

The regulatory approach incorporated into the Order differs from the usual command-and-control regulatory strategy. However, the alternative approach being used in this case will result in broader benefits for the watershed as a whole. Instead of addressing just short-term discharges, the efforts of the Working Group will address all groundwater-related inflows as well as developing watershed-wide management strategies. Additionally, where successful and feasible BMPs are identified, other urban watersheds struggling with the management of selenium and nitrogen may gain from the efforts of the Working Group.