|Amphibians are in decline worldwide, with an estimated one third now either threatened or extinct. It is thought that pollution is playing a role by affecting reproduction or by affecting their immune response, making them more vulnerable to disease.
Amphibians undergo a dramatic metamorphosis from tadpole to adult, involving a radical re-organisation 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 report Effects of Pollutants on the Reproductive Health of Male Vertebrate Wildlife – Males Under Threat by Gwynne Lyons, 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.
Frogs at risk and possible implications for humans?
Why EU chemicals legislation needs updating to address chemical that damage the immune system highlights serious concerns for the health of frogs (amphibians) in the UK.
Scientific research suggests that exposure to man-made chemicals in our environment may be playing an important role in disease because some chemicals can weaken the immune system and increase susceptibility to infections and disease.
There are likely to be implications for human health too.