Very high concentrations of DDE and toxaphene residues in crocodiles from the Ord River, Western Australia: an investigation into possible endocrine disruption

Abstract

Organochlorine pesticide concentrations, particularly those of the DDT family and of toxaphene, were measured by gas chromatography in samples of liver and body fat taken from Australian freshwater crocodiles Crocodylus johnstoni at three locations along the Ord River in Western Australia. The three sampling sites were the irrigation area, downstream of the irrigation area, and well upstream of the irrigation area; the last site serving as the control. DDT and toxaphene were applied in large and known quantities to cotton grown in the Ord Irrigation Area from 1964 to 1974. Thus the residues in the crocodile tissues are representative of the situation almost thirty years after the use of DDT and toxaphene ceased in the area. Very high concentrations of p,p'-DDE and toxaphene were found in the lipid-rich tissues that were examined. Livers and body fat from estuarine crocodiles Crocodylus porosus from the downstream site were also analysed. As p,p'-DDE and toxaphene are both known to be disruptive of endocrine systems, a range of blood parameters, including estradiol and testesterone concentrations, were also measured for all the animals studied. The ovaries and testes of the freshwater crocodiles were also examined histologically. There were no obvious effects on blood chemistry or gonad histology of the large burden of pesticides and their metabolites carried by exposed animals, although the limited number of samples and the variability of the breeding state of the animals examined may have masked possible effects. The isolation of the area, the accurately known applications of DDT and toxaphene, and the simplicity of the drainage system make the lower Ord River a unique natural laboratory for studying the long term breakdown and effects of pesticides applied in a tropical environment.

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

“…The very high DDE concentrations found in Australian crocodiles (Yoshikane et al, 2006) attest to the improbability of DDE being the cause.…”

“…(Woodword et al, 2011). Yoshikane et al (2006) reported a mean ∑DDT concentration of 252,000 ng/glm (max 671,000 ng/g lm) in Australian Freshwater Crocodile liver from the Ord River irrigation area, Australia (Table 3). They also reported that the crocodiles seemed healthy with normal blood parameters.…”

“…They also reported that the crocodiles seemed healthy with normal blood parameters. Fredericks and Palmer (2008), quoting Yoshikane et al (2006), recalculated the data to wet mass; 500 ng/g DDE in liver (max 3200 ng/g wm). The highest p,p 0 -DDE concentration measured in eggs of the present study was 5300 ng/g wm, the same order of magnitude recorded in Australia (Table 3).…”

The effects of transovarian exposure to <i>p,p’</i>-DDT and <i>p,p’</i>-DDE on avian reproduction using Japanese quails

“…In addition, p,p'-DDE has been detected at very high concentrations even at the places where declines in the populations of wild animals are not currently observed (Yoshikane et al, 2006). Therefore, to confirm or disprove the reproductive toxicity of these two compounds the present study was undertaken and involved injecting the compounds into Japanese quail (Coturnix japonica) eggs.…”

Remediation of DDTr contaminated soil by the combination of solvent extraction and catalytic hydrodechlorination

“…6 Although the use of DDT has declined, DDTr continue to be detected in environmental media and human tissues as they are persistent, lipophilic, and liable to bioaccumulation and biomagnication. [7][8][9][10][11] Even aer decades, the environmental risk of DDTr contaminated soil due to chemical factories has long been a signicant problem in most countries.…”