Cumulative Risks and Toxicity
Evaluating the cumulative impacts of exposure to multiple chemicals is perhaps the most difficult task
CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.
It’s common to think that in science and technical information lies the answer to the many questions people ask about exposures to toxic chemicals. At CHEJ, we have not found this to be the case. While science and technical information is very important, by itself it cannot answer most of the questions people raise about exposure to toxic chemicals. People want answers and they want action to address the contamination in their community. Science and technical information can play a vital role in helping to achieve community goals, but identifying this role and learning how to use scientific and technical information is critical to the success of a local group.
Many assume that if you hire the best scientists and engineers and make solid technical arguments, the government will do the right thing. It rarely works that way. It’s not because people who work for government don’t care, it’s just that the science is not there for government to justify acting. This is primarily because of the lack of scientific knowledge and understanding of how exposures to toxic chemicals lead to health outcomes in people. Scientists know little about the adverse health effects resulting from exposure to combinations of chemicals at low levels. As a result, when politicians and bureaucrats look for answers, the scientists usually don’t have them.
At first glance, this may not make sense. We know so much about many toxic chemicals, like lead and dioxins, for example. But when it comes right down to it, we know very little about what happens to people when they are exposed to low level mixtures of toxic chemicals, even those that include lead and dioxins.
We can estimate risks and talk about the hazards associated with exposure, but we just don’t know much about the mechanisms of how chemicals damage the human body, especially in low level mixtures over long periods of time. This is because in most cases, there is very little information about what a person is exposed to, the concentration they are exposed to, and for how long. A person’s health conditions and prior exposures to toxic chemicals also play a role. In addition, there is no way to distinguish or fingerprint an exposure with a health outcome.
Most scientists are reluctant to discuss how little is known about the link between health outcomes and exposures. Instead, the tendency is to discuss the “risks” of exposure which eventually leads to a debate over what’s an “acceptable” risk. This process hides the fact that scientists don’t know what happens to people who are exposed to low levels of a mixture of toxic chemicals.
Because of this lack of scientific clarity, bureaucrats and politicians use “science” cloaked in uncertainty, not facts, to justify decisions which are based on the political and economic pressures they face. It is naïve to think that science and the many uncertainties resulting from exposures to toxic chemicals can serve as anything but a tool used by politicians and corporations to do what they want.
In the face of these uncertainties, government sees as its main role and primary responsibility to maintain control of a situation and to assure the public that everything is fine, whether it is or not. The government cannot afford to say what it really knows about a situation, which often, is very little. If they did that, then the public would demand action that they could not scientifically justify taking.
Despite these realities, there is a critically important role for science and information to play in addressing exposures to toxic chemicals. This role is to document the exposures and risks posed by these exposures and to support the arguments of activists and people exposed to toxic chemicals. The role of science and technical information is to be part of a larger strategic plan to help the community and the individuals who have been exposed to toxic chemicals achieve their goal, whether it’s to be relocated, or to achieve cleanup of a contaminated site. It’s important to recognize what science and technical information can tell you and what it can’t.
Evaluating the cumulative impacts of exposure to multiple chemicals is perhaps the most difficult task
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