Missing links in our understanding of estrogenic compounds; chemical quantitation vs. biological assessment – where do we go from here?

Authors: Shappell, Nancy

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/6/2016
Publication Date: 11/6/2016
Citation: Shappell, N.W. 2016. Missing links in our understanding of estrogenic compounds; chemical quantitation vs. biological assessment – where do we go from here? [abstract]. 7th Society of Environmental Toxicology and Chemistry [SETAC World Congress/SETAC North America 37th Annual Meeting, Nov. 6-10th, 2016, Orlando, Florida. Abstract #342. p. 97.

Interpretive Summary: .

Technical Abstract: The literature has become replete with reports quantifying estrogenic chemicals in the environment ranging from natural hormones to plasticizers. Laboratories have developed in vitro assays to assess estrogenic activity of both environmental samples and pure chemicals. Information pertaining to the in vivo effects of the chemicals is much less exhaustive and the correlation to in vitro results is often ignored. Estrogenic potency of chemicals can vary significantly depending on the source of transfected estrogen receptor. One lab found trout versus human receptors were 62 fold more sensitive to one compound, while for another compound trout receptors were only 0.04% as responsive as human receptors. The same lab found the in vivo response to a chemical was 1/10,000th as estrogenic as estradiol, while by in vitro assay (transfected estradiol receptors from fish) the chemical was 1/600th as estrogenic. Chemical additivity has been reported from both in vitro and in vivo laboratory exposures, though similar additivity has not been reported for humans “dosed” with multiple estrogenic chemicals. While agriculture and wastewater treatment plants have been implicated as point source contributors of estrogenic contaminants in surface waters, studies of many water bodies have failed to detect these contaminants at biologically relevant concentrations. Further consideration is needed relative to the specific conditions of area of release relative to the impact of various estrogenic agricultural inputs. Surface water release of these compounds in arid regions could result in significant environmental impacts, while posing no problem in less arid regions. Unfortunately, several recent reports have resorted to quantifying estrogen concentration as a sum of all estrogens, ignoring relative estrogenic potential of the specific estrogen. A simple modification of concentration vs. prevalence data would allow for improved risk assessment. The relevance of these findings will be discussed and suggestions for future research directions made.