Section 303(d) of the federal Clean Water Act requires states to identify those water bodies not attaining water quality standards (i.e., waters whose beneficial uses have been impaired), to identify the pollutant causing the impairment, and to develop remediation plans (known as “total maximum daily loads”, or TMDLs) for each pollutant in each water body that will reduce and eventually eliminate the impairment and restore the beneficial use(s). A TMDL is multi-stage process that ultimately leads to a determination 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.

As experts on the fate and effects of contaminants in aquatic systems, Pacific EcoRisk can provide a wide variety of support services for the TMDL process, ranging from a critical evaluation of technical aspects of existing or proposed TMDLs to review of existing scientific information and/or performance of scientific studies to assist in the preparation of appropriate and technically-supported TMDLs.

Services that we provide in the support of TMDL development include:

	preparation of information (e.g., literature) reviews,
	collection and analyses of water, sediment, and/or biota samples,
	performance of toxicity and/or bioaccumulation testing.
	evaluation of biological communities