Associate Professor of Toxicology at Lincoln University, Dr Ravi Gooneratne, describes how the bioavailability of a chemical affects the level of pollution an organism is exposed to.
DR RAVI GOONERATNE
‘Bio’ means life, availability’s… availability of that chemical to life, to be absorbed into the body. So you might have, for example, a pesticide, and it’s very high concentration in the soil – we’ll say a 1000 milligrams per kilogram of soil – but when the earthworm takes in this soil, maybe only 1 milligram per every kilogram of soil enters the body. Why? Because that chemical is probably bound to other substances, which the earthworm’s body cannot take it out from. The test that we do is the effect of the amount of the chemical that is absorbed into the body, and that’s why it has an effect on the nervous system – because it is absorbed into the body.