Bioaccumulation of DDT and other organochlorine pesticides in amphibians from two conservation areas within malaria risk regions of South Africa

The threat to wildlife from chemical exposure exists regardless of the presence of conservation boundaries. An issue exacerbated by the use of environmentally persistent insecticides for vector control and long-range transport of legacy persistent organic pollutants. In this comparative study between two important conservation regions in South Africa, Kruger National Park (KNP) and Ndumo Game Reserve (NGR), we assessed organochlorine pesticide (OCP) accumulation in several anuran species collected from within the conservation regions. The two conservation regions differ in size and subsequent proximity of collection sites to OCP input sources. Detectable concentrations of OCPs were present in similar to half the frogs analysed from KNP and similar to all frogs from NGR and total OCP loads were similar between regions, where measured in the same species. The OCP profiles in KNP frogs were representative of legacy pesticides likely introduced via long-range transport, whereas NGR profiles showed influence of current use of DDT consistent with close proximity to sources. This indicates amphibians can accumulate OCPs within conservation regions and that the exposure of non-target organisms inside conservation regions to current use pesticides has a strong association with proximity to sources. These results serve to inform conservation management decision making with regard to the non-target organism effects of chemical interventions such as vector control pesticide use in and around conservation regions. (C) 2020 The Author(s).

Automated summary

The study evaluated OCP accumulation in several anuran species from two conservation regions in South Africa and found that frogs in both regions were contaminated with OCPs. The exposure of non-target organisms to current use pesticides in conservation regions is strongly associated with proximity to sources.