US doctors call for action as EPA revises dioxin toxicity estimate

The draft report is the result of the Agency’s reassessment of the health risks from dioxins, one of 12 persistent organic pollutants (POPs) which are created by waste incineration and other industrial processes.

Based on a more complete understanding of dioxin toxicity, the reassessment shows that the risks to people from dioxin exposure may be higher than previously believed, even though actual exposure seems to be declining among the general population. The report is expected to have implications for national waste strategies around the world (see related story).

Dioxin is especially dangerous to children. Developing foetuses, nursing infants and young children are at greatest risk from current levels of dioxin exposure. EPA’s draft risk characterisation warns that young children consume more than three times, and nursing infants 100 times, the amount of dioxins as adults, on a body weight basis.

Animal and human data shows that current exposures to dioxin are enough to contribute substantially to cancer risks in the general population.

According to the report, most dioxins enter ecological food chains by being deposited from the atmosphere. Once they reach the environment, dioxins are highly persistent and can accumulate in the tissues of animals. The EPA estimates that most dioxin exposure occurs through the diet, with over 95% of intake coming through dietary intake of animal fats.

“The industries flooding our environment with dioxin have denied its dangers while this report has been held up for nine years,” said Robert Musil, CEO and executive director of Physicians for Social Responsibility (PSR). “This reassessment tells the truth they don’t want you to hear: dioxin is a dangerous cancer-causing chemical that must be phased out.

“Industry will undoubtedly try to undermine this news as they have in the past, but this report and its endorsement by leading public health professionals should allow us to put to rest the debate,” said Musil. The physicians’ letter to also recommends that the US State Department pursue virtual elimination of dioxin through international treaty negotiations on POPs (see related story).

The report also shows that levels of dioxins in the atmosphere have declined substantially over the past two decades. Following a series of regulatory actions and other activities that have reduced dioxin emissions, the EPA estimates that, between 1987 and 1995, dioxin emissions decreased by about 80% in the US, primarily due to reduced waste incinerator use.

The reassessment is the product of an exhaustive review by EPA scientists and other government and non-government scientists begun in 1991. It reflects comments received since release of an earlier draft in 1994, recommendations received from EPA’s Scientific Advisory Board in 1995 and extensive additional data on dioxin obtained by the Agency.

The next stage is the invitation of comments on two chapters of the reassessment: the summary and a comparison of toxicity among different dioxins. The draft chapters were released as part of a process designed to complete the reassessment by the end of the year. Following completion of scientific and public review, EPA will issue the final dioxin reassessment document and at the same time will publish a draft dioxin Risk Management Strategy for public comment. The strategy will propose EPA policy and programmes for dioxin using the reassessment as its scientific basis.