TMDLs

Deposited by countless private citizens, moreover, lawn care toxins have also proven far more difficult to measure and far more resistant to traditional techniques of pollution control. The political momentum for water quality regulation lags far behind this changing land-use reality. The shift in the last few years to decentralized decision-making that allowed for the implementation of the Clean Water Act, for example, has not come to terms with this change. In this case, the Clean Water Act mandates the creation of total maximum daily load (TMDL) criteria, standards for cleaning up nonpoint sources such as farms, suburban developments, and other nonindustrial sites. These standards are drawn up by water quality management committees. 

In 1996, the US Environmental Protection Agency (USEPA) set up a federal advisory committee composed of members with interests ranging from the environmental and agricultural communities to state and local governments. The committee s objective was to recommend ways to improve the effectiveness and efficiency of state, territorial, tribal, and USEPA total maximum daily load (TMDL ) programs. 

TMDL a calculation of the maximum amount of a pollutant that a water body can receive and still meet water quality standards and an allocation of that amount to the pollutant s sources. 

The government s capacity to evaluate TMDLs must be strengthened. 

An iterative approach to TMDL development and implementation is the best way to make progress in uncertain situations. 

USEPA]. US Environmental Protection Agency. 1998. Report of the Federal Advisory Committee on the Total Maximum Daily Load (TMDL) Program. The National Advisory Council for Environmental Policy and Technology (NACEPT). United States Environmental Protection Agency, Office of the Administrator (160IF) EPA 100-R-98-006, July 1998, Washington, DC, USA. 

Total Maximum Daily Load (TMDL) Under Section 303(d) of the 1972 Clean Water Act, states, territories, and authorized tribes were required to develop a list of impaired waters. The impaired waters do not meet water quality standards that states, territories, and authorized tribes have set for them, even after point sources of pollution have installed the minimum required levels of pollution control technology. The law requires that these jurisdictions establish priority rankings for waters on the lists and develop TMDLs for these waters. 

This part of the Clean Water Act was relatively neglected until 1996. A Federal Advisory Committee was convened and produced in 1998 a report and subsequent proposed changes for implementation of the TMDL program and associated changes in the National Pollutant Discharge Elimination System for point sources. A number of court orders were also motivating factors in the implementation and proposed changes to the rule. 

The TMDL specifies the amount of a particular pollutant that may be present in a water body, allocates allowable pollutant loads among sources, and provides the basis for attaining or maintaining water quality standards. 

The TMDL regulations were issued as draft in 1999 and finally published on July 13, 2000. 

U.S. Environmental Protection Agency. http //www. epa.gov/owow/tmdl... 

U.S. Environmental Protection Agency. (1999b). Total maximum daily load (tmdl) program. Office of Water, Washinton, DC (On line). Available at http //www.epa.g0v/OWOW/tmdl (December 20, 1999). 

The daily dietary intakes of BHA and BHT have been estimated in many countries. The daily intakes of BHA and BHT in Japan in 1998 were 0.119 and 0.109 mg/d/person, which reflect 0.5% and 0.7% of the acceptable daily intake (ADI), respectively (35). The estimates of theoretical maximum daily intake (TMDl) of BHA and BHT in Brazil published in 2001 were in the range of... 

Unfortunately, application of TMDL rules does not typically result in achievement of WQS due to the large impact of nonpoint sources (e.g., soil runoff). Nonetheless, TMDLs for such defined pollutants as clean sediments, nutrients (nitrogen and phosphorus), pathogens, acids/bases, heat, metals, cyanide, and synthetic organic chemicals are enforced. 

Caps are established, with margins of safety, and completed facility TDML plans and strategies are provided to the EPA for approval or disapproval. The time defined within a TDML plan does not necessarily have to eqnal 1 day, and a reserve for future polluting activities is typically comprehended. Approved agencies or parties will regularly audit site performance against a facility s TMDL plan. 

The EPA defines waste load allocations (WLA) to point sonrce pollution sources (generally or specifically), which are then regnlated against the defined TMDL (if applicable) established in the NPDES permit site. A nsefnl example of the administration of Waste Load Allocations within the State of California can be fonnd at http //www.swrcb.ca.gov/rwqcb2/Agenda/03-19-03/03-19-... 

For cases where application of BAT to effluent stream discharges will not meet the requirements of a water source s DU, and for which TMDL limits are not established, the permitting agency will apply water quality-based effluent limits (WQBEL). WQBEL includes an analysis of the level of effluent stream dilution required to retain DU levels. Where WQBEL is employed, a high risk has been assigned to the water source, and economics will often be secondary to technology. 

Contrasting the federal position on point sources, the ERA provides grants ( 319 funds ) and other modes of assistance and incentive to such polluting states. The EPA s objective is to curtail pollution from such erosion sources and to define auditable levels of watershed TMDL. For more on nonpoint pollution, see the ERA CWA Web site, http //www.epa.gov/watertrain/cwa/cwa52.htm. 

Special attention is given waters that are directly threatened or do not meet WQS. These receive Section 303(d) or Section 305 (threatened or impaired waters) classification. Section 303(d) includes those surface water sources impacted by pollutants, whereas nonpollutants impair Section 305 waters. Where the source of aquatic life impairment is unclear, the source receives Section 303(d) classification. Waters classified as threatened or impaired require biennial progress reporting, with prioritization of TMDL levels and WQC established accordingly. 

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