The new research, led by Jeffery Foran from the Midwest Center for Environmental Science and Public Policy but also aided by the Instititue for Health and the Environment's David Carpenter, looks at cancer and non-cancer health risks associated with exposure to dioxins in wild and farmed salmon, based on further analysis of their previous research under World Health Organization and U.S. Environmental Protection Agency tolerable intake levels.

Under the new research's risk assessment, farmed salmon consumption must be reduced in general to less than 10 meals per month to be at the lower end of WHO tolerable daily intake of dioxins, though for salmon from Northern European farms, it should be reduced to less than four meals per month.

However, to achieve a cancer risk in "the middle of the U.S. EPA's acceptable risk range," the study authors say, consumption of farmed salmon "must be effectively eliminated and consumption of wild salmon must be restricted generally to less than one meal per month."

The Jan. 2004 Science study, which reported that both farmed and wild salmon had high concentrations of dioxins and PCBs but that the level in farmed salmon was in general much higher, was led by Carpenter.

The study sparked outrage among many in the seafood community for its small sample size and methodology (including its use of EPA guidelines for acceptable dioxin intake and not U.S. Food and Drug Administration guidelines), though the researchers defended their work as sound.

Among the criticisms was that the research did not take into consideration that many of the compounds were fat-soluble and ran out of the salmon during cooking. Foran and his team address this criticism in the latest study, saying that the research on the effect of cooking on reducing contaminant levels is not conclusive enough, and so was not incorporated into the preparation of the latest risk assessments.

Consumption of farmed salmon in several countries took a nosedive after the Science study, but have since largely recovered.

To read the new research article in PDF format, click here.

Science study authors publish new research, say lower salmon consumption reduces cancer risk