Research on US rivers points to inconclusive results on cosmetics pollution

By Simon Pitman

- Last updated on GMT

Related tags Toxicology Cosmetics

Analysis of research carried out in the US suggests that incidence of inter sex fish cannot always be blamed on high levels of household pollution, including personal care compounds.

Analysis of the results from the United States Geology Survey (USGS) study, which was carried out during the period 1995 to 2004 on 16 fish species in numerous river basins throughout the country, found that there was a particularly high incidence of intersex condition in smallmouth and largemouth basses.

According to the study findings, published in the peer-reviewed Aquatic Toxicology journal, the intersex condition primarily manifested itself in male fish that tended to have immature female egg cells in their testes.

It was also more prevalent in largemouth bass in the southeastern US region, specifically in the Apalachicola, Savannah and Pee Dee river basins, where between 43 and 91 percent of the fish had the intersect condition.

Causes of intersex in fish difficult to pinpoint

However, although a number of previous studies have made a clear link to a wide range of pollution sources - which, as well as household and personal care compounds, also includes petsticides, PCBs and heavy metals - this study suggests that the causes for the intersex condition in fish species are difficult to pinpoint.

Indeed, on a regional basis the intersex condition in the different types of bass fish was observed to be as low as 9 per cent in some river basins, with the lower incidences not always corresponding to the levels of pollution.

“This study adds a lot to our knowledge of this phenomena, but we still don’t know why certain species seem more prone to this condition or exactly what is causing it,”​ said Jo Ellen Hinck, author of the study report and biologist at the USGS research center.

“In fact, the causes for intersex may vary by location, and we suspect it will be unlikely that a single human activity or kind of contaminant will explain intersex in all species or regions,”​ she added.

Research information still lacking

The study underlines the fact that the science world still lacks clear information on which particular fish species are most sensitive to which particular pollutive compounds and the specific effect it has on the endocrine system.

“Proper diagnosis of this condition in wild fish is essential because if the primary causes are compounds that disrupt the endocrine system, then the widespread occurrence of intersex in fish would be a critical environmental concern,”​ Hinck said.

Earlier this year three separate studies relating to pollution from personal care products were given significant print space in a variety of publications, both trade and consumer related.

Studies carried out by the University of Gothenburg, in Sweden, The Baylor University in the US and a joint study by the Birmingham and Warwick Universities in the UK, point to potential hazards caused by pollution from a range of household products, including personal care.

The studies have highlighted how a range of chemicals have been detected in waterways, the sea and in farm land, detailing the potential hazards associated with these chemicals.

All of these studies suggested that further research would have to be carried out in an effort to identify which specific compounds have what effect on the environment, as well as deducing the exact origin of the pollutive compounds.

Related topics Formulation & Science

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