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Columbia River

Prioritization of Toxics in the Columbia River

The following list of high priority "contaminants of concern" was developed by the Columbia River Toxics Reduction Working Group to support their work to identify and reduce toxics in the Columbia River Basin. A printable version is also available below.

Ranking of Toxics in the Columbia River Basin1
Tier I
(highest priority)

Tier II

Tier III

  • DDT (and metabolites)
  • PCBs
  • Mercury (including methylmercury)
  • PBDEs
  • PAHs
  • Arsenic
  • Dioxins/furans
  • Lead
  • Organophospate Insecticides (azinphos methyl, chlorpyrifos, diazinon)
  • Copper
  • Estrogenic compounds (Bisphenol A, AHTN, natural and synthetic estrogens, Nonylphenol)
  • Organochlorines (including alpha BHC, aldrin, dieldrin, chlordane)
  • Trace elements
  • Current use pesticides (including carbamates, triazine herbicides, fipronil)
  • Pharmaceuticals and Personal Care Products
  • Other wastewater compounds (plasticizers, detergents, surfactants)
  • Hormones
  • Synthetic pyrethroids
  • Phthalates

1This prioritization was written by the Columbia River Toxics Working Group. It does not necessarily represent the priorities of individual agencies participating in the group.

Refer to the document below for information about the factors considered in these rankings, and how these tiers inform the group's work.

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