Chlorinated, brominated, and fluorinated organic pollutants in Nile crocodile eggs from the Kruger National Park, South Africa

Abstract

a b s t r a c tRepeated annual episodes of Nile crocodile deaths in two isolated areas of the Kruger National Park prompted the investigation of possible organohalogen pollutant involvement. Crocodile eggs were collected close to one of the mortality sites (Gorge) as well as from a crocodile farm (CF) as reference. ∑DDT was significantly higher in Gorge (450 ng/g wm) than in CF eggs (85 ng/g wet mass). Percentage DDT of ∑DDT was significantly higher in CF (14 per cent) than in Gorge eggs (5 per cent). Mean ∑DDT was almost 70 times higher than mean ∑PCB in Gorge eggs. HCB, β-HCH, mirex, brominated flame retardants (BFRs), and perfluorinated compounds (PFCs) occurred at lower concentrations. We believe that the BFR and PFCs data represent the first published results for any crocodile egg. Thickening of the outer eggshell layer of Gorge eggs was significantly associated with higher concentrations of ∑DDT. Concentrations of ∑DDT and other pollutants were in the same range as eggs from elsewhere, where there were no mortalities. Concentrations of ∑DDT in eggs from healthy Australian crocodiles were of the same orders of magnitude as the current study, making it highly unlikely that the concentrations of pollutants measured in the present study would have caused or substantially contributed towards the mortalities observed. Concerns about reproduction and behaviour remain. As large predators, crocodilians are at the apex of the freshwater aquatic food web. More research is needed to guide measures to manage African freshwater systems so that it will also sustainably accommodate these large, long-lived animals.

Perfluorinated alkyl acids in the plasma of South African crocodiles (Crocodylus niloticus)

“…While the Olifants River is known to contain halogenated compounds, few analyses have been performed to examine persistent organic pollutants in this area (Bouwman et al, 2014). The Olifants River runs through KNP and PFAAs seen in the river are likely the result from contaminants upstream and outside of the park (Bouwman et al, 2014).…”

“…While the Olifants River is known to contain halogenated compounds, few analyses have been performed to examine persistent organic pollutants in this area (Bouwman et al, 2014). The Olifants River runs through KNP and PFAAs seen in the river are likely the result from contaminants upstream and outside of the park (Bouwman et al, 2014). Flag Boshielo Dam is located completely outside of KNP and provides a good profile of upstream sources, as it has a significantly denser surrounding human population (Marble Hall) compared to the other sites, extensive agricultural practices, as well as being upstream of KNP along the Olifants River.…”

“…The mortality events of the crocodiles, as well as other aquatic species, were attributed to environmental pansteatitis, a disease hallmarked by inflammation and subsequent hardening of adipose tissue (Osthoff et al, 2010; Huchzermeyer et al, 2013; Lane et al, 2013). To date, no definitive origin of for pansteatitis has yet been determined, though several hypotheses have been noted, which include possible contributions from anthropogenic sources (Larsen et al, 1983; Swanepoel et al, 2000; Ashton, 2010; Masango et al, 2010; Huchzermeyer et al, 2011; Oberholster et al, 2012; Woodborne et al, 2012; Dabrowski et al, 2013; Bouwman et al, 2014; Dabrowski et al, 2014). Of particular interest are those contaminants from anthropogenic sources that have been previously shown to affect lipid pathways and adipose physiology.…”

Biotransformation and Oxidative Stress Responses in Captive Nile Crocodile (Crocodylus niloticus) Exposed to Organic Contaminants from the Natural Environment in South Africa

“…They are mostly aquatic, but travel easily on land. Treated sewage water or other wastewater from cities, towns or villages are linked to the environmental release of chemicals such as PAHs, pharmaceutical agents, POPs and industrial by-products [18,19]. Therefore, the aims of the present study were to (1) evaluate the expression of molecular and biochemical responses in the liver of farmed Nile crocodile exposed to potentially polluted water in the breeding dams, (2) determine potential sex-differences in these molecular and biochemical responses, (3) evaluate these responses in relation to level of contamination in liver, and (4) establish the usefulness of these responses as biomarkers of exposure and effect in this endangered species.…”

Rat Thymocyte Apoptosis and Proliferation Variations in Chronic Exposure to Low-Dose Dichlorodiphenyltrichloroethane

“…In recent decades, endocrinologists and immunologists have been actively studying the effect of low-dose endocrine disruptors on the body. The most wide-spread disruptor is dichlorodiphenyltrichloroethane (DDT), which can be found in all ecosystems of continents and oceans including Arctic and Antarctic regions, and can continue to persist in soil and water for a long time [1][2][3].…”