First record of organochlorine pesticides in blood of wild and captive African leopards, Panthera pardus pardus (Linnaeus, 1758)

Abstract

Compared to aquatic ecosystems, limited information exists on organochlorine accumulation in terrestrial ecosystems, and this is specifically true for terrestrial carnivores that have received limited attention in terms of studies on pollutant bioaccumulation. The African Leopard, Panthera pardus pardus (Linnaeus, 1758), is a popular focal species for research by ethologists and ecologists, but a noticeable knowledge gap exists with regards to toxicological aspects. To address this gap, the aim of this study was to determine baseline organochlorine pesticide (OCP) concentrations in blood of live wild and captive leopards in South Africa, and to explore the relationship between OCP levels and different conservation management strategies. Peripheral blood samples of seven captive and seven wild leopards, representing regular and melanistic individuals within the captive population, were collected while under sedation. The ΣOCP concentrations in blood serum were detected by means of GC-ECD. Statistical relationships among pesticide content in leopards from three geographical areas, different sexes, age groups and conservation status were examined. Captive leopards from this study had a slightly higher mean ΣOCP concentration (901 pg/ml) than wild leopards (768 pg/ml), and captive females had lower mean levels of ΣOCPs (797 pg/ml) than males (1,058 pg/ml). OCPs accumulated in the following order DDTs (27%) > HCHs (21%) > Heptachlors (15%) > CHLs (15%) > Drins (14%) > HCB (8%). Differences in OCP composition profiles of resampled captive individuals were also found. The sources of OCPs in the leopards can be attributed to the historic and current use of, e.g., DDT and HCHs, for malaria vector control and in insecticides/avicides in South Africa. For the captive leopards in this study the main source is possibly contaminated chicken that formed the major portion of their diet. This is the first report on OCP concentrations from leopards in Africa and highlights the need for this parameter to be considered in terms of the conservation management of healthy populations.

Review of scientific literature on available methods of assessing organochlorine pesticides in the environment

“…From Table 4 , very high LOD and LOQ (60–720 ng/g and 30–2400 ng/g) were observed from tea [ 269 ], (10–100 ng/mL and 100–10000 ng/mL) [ 69 ], (12–987 ng/g and 40–3290 ng/g) from fruits and vegetables [ 270 ], and (3700–4800 and 12–16000 ng/mL) [ 271 ], (180–780 ng/g and 62–2380 ng/g) [ 272 ] from human milk ( Table 5 ), respectively. Similarly, Serum of a leopard also showed high LOD (800–34000 ng/mL) [ 25 ], (150–12730 ng/mL) [ 273 ], ( Table 5 ). Furthermore, a very low detection limits (3 × 10 −9 – 7.6 × 10 −5 ng/mL) in aqueous sample [ 243 ], (2.8 × 10 −9 - 5.64 × 10 −8 ng/mL) seawater [ 239 ], and (1 × 10 −7 - 1.4 × 10 −6 ng/m 3 ) air [ 104 ] were observed ( Table 2 ).…”

“…Several factors necessitate a critical evaluation of OCP technique validation and optimization in environmental and clinical samples. Despite banning of OCPs in early 1970s, some of them including DDT, HCH, and HCB are still in use in the global South, with renewed interest in measuring levels in different environments, e.g., marine, freshwater, and terrestrial [ [23] , [24] , [25] ]. Both atmospheric deposition and the adulteration of pesticides that are not prohibited can be attributed to the existence of the above mentioned OCPs.…”