Understanding how rogue chemicals affect people and marine life

Scientists are just beginning to understand the profound impact that synthetic chemicals are having on humans and other animals in the Puget Sound region.

As a major predator, harbor seals accumulate more than their share of toxic chemicals, including flame retardants. A legal ban on certain chemicals seems to be reducing levels in their tissues. Photo: hj_west, www.flickr.com/photos/hjwest/
As a major predator, harbor seals accumulate more than their share of toxic chemicals, including flame retardants. A legal ban on certain chemicals seems to be reducing average levels in their tissues.
Photo: hj_west

My latest story for the Encyclopedia of Puget Sound addresses so-called chemicals of emerging concern. Please check out “Concerns rise over rogue chemicals in the environment.”

While talking to researchers and investigating a variety of biologically active compounds, I began to realize the complexity of the body’s internal chemistry. I thought I knew something about the endocrine system, but I never fully considered how one hormone can trigger responses in multiple organs, including the release of additional hormones, even creating feedback loops.

Man-made chemicals that mimic hormones or block their function can interfere with this internal chemical-communication system, setting off cascading effects that can disrupt metabolism, growth, development, reproductive cycles, perception and emotions, among other things. See “Not just cancer” at the bottom of the page.

In the main story, I describe chemical flame retardants, invented to reduce death and injury from house fires. It was only after these chemicals were widespread in household products that researchers discovered that they were biologically active, causing problems such as impaired brain development.

While the effects of flame retardants were inadvertent, thousand of drugs have been invented with the sole purpose of causing biological reactions. The problem with pharmaceuticals is that they get into the environment via sewage-treatment plants and septic systems, causing all kinds of trouble for marine organisms. My story describes the effects of synthetic estrogens (birth-control pills) and anti-depressants.

Because hormone levels are ever changing in the body, it becomes difficult for researchers to identify the precise effects that endocrine-disrupting compounds are having on any single organism, let alone the effects on all the animals exposed through the food web.

That may be one reason for the many conflicting studies on endocrine disruptors. Some studies have raised alarms about a specific chemical, while others downplay the effects. I’ve been frustrated, for example, by the research findings on bisphenol-A, or BPA. I covered this chemical extensively for a time starting in 2008 (Water Ways, April 11, 2008), after alarms went off about drinking water from reusable bottles made with the chemical.

Numerous studies on animals have raised concerns about human exposures to BPA, especially for fetuses and children, but the federal Food and Drug Administration maintains that BPA is safe for currently approved uses. The FDA has banned the use in baby bottles. Review FDA’s latest findings, as of November 2014. States have approved various bans on their own. See Washington Department of Ecology, for example.

A new law approved this year by Congress offers hope that the Environmental Protection Agency will sort through the 85,000 man-made compounds to look for the most dangerous ones, providing testing and controls on those with the most harmful effects. Check out the related story “New law will increase testing of chemicals.”

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