Many amphibian species - frogs, toads and newts - worldwide are in decline, with an estimated one third now either threatened or extinct. It is thought that pollution is playing a role by both affecting reproduction and also the immune response amking them more vulnerable to disease.
Amphibians – frogs, toads and newts – undergo a dramatic metamorphosis from tadpole to adult, involving a radical reorganisation of body and biochemistry. Because various hormones are involved in this change, amphibians are particularly at risk from endocrine disrupting chemicals. During hibernation, amphibians can bury themselves in sediments or soil, which may also bring them into close contact with contaminants.
Atrazine, a highly persistent herbicide and known endocrine disrupter, can no longer be used in the EU from the end of 2007. However, before this it was a relatively frequent contaminant in rivers and in some drinking water supplies. Now, recent research in the US has shown that at least two different species of male frogs (African clawed frogs and leopard frogs) show gonadal abnormalities and hermaphrodism when exposed to environmentally relevant atrazine concentrations.
CHEM Trust’s report Effects of Pollutants on the Reproductive Health of Male Vertebrate Wildlife - Males Under Threat by Gwynne Lyons.
This report shows that male fish, amphibians, reptiles, birds and mammals have been harmed by chemicals in the environment. Widespread feminisation of male vertebrate wildlife is highlighted. These findings add to mounting worries about the role of hormone-disrupting or so-called ‘gender-bending' chemicals in the environment, and the implications for human health.