Human Health and Ecological Risk / Environmental Investigation Support: Chlor Alkali Superfund Site


EPA Region I


  • Designed, conducted, and managed extensive field investigations and technical tasks in support of a Remedial Investigation
  • Integrated tissue and bioassay data including fish, birds, macroinvertebrates, and bats data, chronic toxicity testing, and fate and transport modeling into comprehensive ecological risk assessments
  • Conducted human health risks assessment for multiple media and exposure areas
Avatar Environmental Chlor Alkali Superfund Site


Avatar was contracted by EPA Region 1 to assess ecological and human health risks at the Chlor Alkali Superfund Site in Berlin, NH and at adjacent and downstream locations along the Androscoggin River. The Chlor Alkali Site was a former chemical plant that produced chlorine and other chemicals to support the pulp and paper industry centered in Berlin NH. Contaminants present in soil and construction debris under an interim cap at the Site are continuing sources of chemicals that are migrating into groundwater, which discharges into the Androscoggin River.

The Project included the estimation of human health risks associated primarily with mercury and dioxin and furan contamination in soils and groundwater at the Site; in sediment and surface water in the Androscoggin River; and in edible fish tissue from fish collected from the Androscoggin River. Notable aspects of the human health risk assessment included:

  • 1) Evaluation of trespasser exposures at three soil contact study areas
  • 2) Evaluation of potential future residential, recreational, day care, and industrial/commercial exposures at three currently vacant soil contact study areas
  • 3) Evaluation of childhood and adult exposures to lead in soils
  • 4) Assessment of fish consumption and direct contact with surface water and sediment in three distinct stretches of the river
  • 5) Evaluation of potential future use of groundwater as a primary drinking water source using a simplified ratio approach
  • 6) A screening evaluation of potential future vapor intrusion should the study areas be developed in the future
  • 7) A qualitative evaluation of dioxin-like polychlorinated naphthalenes (PCNs) using estimates of dioxin Relative Experimental Potencies (REPs) and dioxin toxicity values. In addition to mercury and dioxins and furans, contaminants included PCNs, polycyclic aromatic hydrocarbons (PAHs), several other metals, polychlorinated biphenyls (PCBs), pesticides, and chlorinated solvents.

Avatar designed, conducted and managed numerous technical tasks conducted by Avatar, USEPA, ESAT, US F&WS, USGS and additional contractors in support of a multi-faceted Remedial Investigation of mercury, dioxin, and PCB contamination in sediment of a 20-mile stretch of the Androscoggin River in the White Mountains of New Hampshire. As part of the Remedial Investigation, Avatar and team members collected more than 100 sediment and surface water samples from eight designated reaches of the river. Sediment and surface water samples were collected for a full suite of chemicals with focused interest on inorganic mercury, methyl mercury, PCBs, and dioxins/furans. Because of the unique hydrology of the river in this area, aquatic habitats that were investigated included fast-flowing (lentic) reaches, slow flowing (lotic) impoundments, backwaters, tributary