The following are two landmark reports commissioned by CBEP to present information on the levels and impacts of toxic pollution in the watershed:

- Toxic Pollution in Casco Bay: Sources and Impacts, CBEP 2007 (PDF)

- The Dirty History of Portland Harbor, Ed Hawes,  Fact Sheet, 2005 reprint (PDF) | Full 250-Page Report, 1993 (PDF)

CBEP's toxics work includes efforts to monitor and assess the sources, risks, and impacts of toxic pollution in the watershed.  Below is information about some of these efforts:

-    Testing osprey eggs: CBEP funded a study to measure levels of toxic compounds in the eggs of ospreys.  The majority of eggs sampled contained toxic residues — including compounds found in substances like organochloride pesticides, stain repellants, and flame retardants.  More info.

-    Monitoring blue mussels: CBEP supports the Marine Environmental Monitoring Program, a long‐term study to assess the levels and locations of toxic contaminants along the coast, using the common blue mussel as an indicator species. Sampling at several Casco Bay sites suggests that while there was an initial increase in lead levels from 1988 to 2002, there has been a decline in lead levels in more recent samples.  More info.

-    Studying air deposition of toxics: Studies supported by CBEP seek to determine the extent to which toxics are being contributed to the Bay via atmospheric deposition: More info.

-    Assessing levels and impacts of toxics in Casco Bay sediments: Casco Bay's soils contain a legacy of environmental toxics.  CBEP attempts to assess concentrations of these toxics, their potential impacts on marine life, and any changes in levels of sediment toxics over time: More info.

-    Providing guidance on safe disposal of dredged sediments: CBEP funded the production of a guide for property owners on the disposal of dredged material: Guidance for Private Property Owners: Steps and Alternatives for Disposal of Material Dredged from Rivers and Harbors of Casco Bay, Normandeau Associates, 2008 (PDF)

-    Gauging health impacts of dioxins and furans: CBEP helped fund a study to asses the health impacts of two common toxics in fish from Maine rivers: Evaluation of the Health Implications of Levels of Polychlorinated Dibenzo-p-Dioxins (dioxins) and Polychlorinated Dibenzofurans (furans) in Fish from Maine Rivers: 2008 Update,  Maine Center for Disease Control, 2008 (PDF)

-    Watching contaminants of emerging concern: Over the past several years, CBEP has added a new class of contaminants to monitor: “contaminants of emerging concern.” The list includes persistent organic chemicals like polybrominated diphenyl ethers (PDBEs) and perflourinated chemicals (PFCs), as well as pharmaceuticals and personal care products (PPCPs) like drugs, soaps, hairspray, and sunscreen. Monitoring studies are finding contaminants of emerging concern throughout the aquatic environment worldwide, including in Casco Bay.