Pacific EcoRisk services

Resolution of problems that may result from the presence of contaminants in aquatic ecosystems can be complex, due in part to the complexity associated with the fate and effects of various contaminants, but also due to the numerous elements that typically comprise a successful study. These can range from conceptual design and planning of a study, all the way through to reporting and communication of findings to clients, regulators, and the general public.

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.

Water quality criteria are the numeric conditions (e.g., contaminant concentrations) that need to be maintained or attained to protect aquatic ecosystems and human health. To provide for protection of aquatic life, it is necessary to consider both short term “acute” (survival) effects and long-term “chronic” (survival, growth, reproduction) effects. When appropriate information on these effects exists, regulatory agencies are able to develop Ambient Water Quality Criteria using existing protocol.

Application of pesticides is important in several areas, including maintaining agricultural productivity, a variety of urban uses (gardening, household pest control, and even pet grooming), and maintenance of rights-of-way, water conveyances, and boating facilities. And while significant improvements have been achieved in developing newer pesticides and the development of improved application and management practices, these essential chemicals can still pose potential ecological risk under adverse conditions. In addition, the legacy of historical-use environmentally-persistent pesticides (e.g., DDT and other organochlorines) continues to impact aquatic ecosystems as a result of bioaccumulation from sediments.

Historical mining activities have and continue to impact aquatic ecosystems throughout the United States, particularly in the western U.S., where they constitute a significant fraction of “Superfund” sites. And while current mining practices, as well as remediation efforts underway at historical mines, are considerably more “environmentally friendly”, monitoring is still required to ensure protection of the aquatic environment.