Levels of DDTs and other organochlorine pesticides in healthy wild Nile crocodiles (Crocodylus niloticus) from a flagship conservation area

Mass Nile crocodile (Crocodylus niloticus) deaths in Africa's premier conservation area, the Kruger National Park (KNP), prompted numerous studies to determine possible causes of the sudden die-offs. The majority highlighted the involvement of the anthropocene to crocodile mass mortalities. One of the potential causative agents was identified as legacy compounds such as organochlorine pesticides (OCPs) present in the various aquatic ecosystems of the KNP. Thus, this study aimed to quantify OCP levels in wild crocodiles from the aquatic systems associated with the KNP. As part of a larger study, muscle tissue samples were collected from tails of 12 wild crocodiles. Results indicated that eight of the 19 OCPs analysed for were quantifiable. These included DDTs (2130-167968 ng/g lw), chlordanes (BD - 7583 ng/g lw) and cyclodeines (BD - 872 ng/g lw). Measured concentrations indicated spatial- and sex-related differences in accumulation patterns. DDT and its metabolites, paricularly p,p'-DDE accumulated to the highest concentrations of the OCP groups. Levels of the different groups of OCPs were the highest recorded in recent history from any crocodilian tissue. The different measured OCP residues were between 2.5 and 120 times higher than levels reported in literature, depending on the compound. These results are of ecotoxicological significance and have several management implications. In view of individuals being sampled from a conservation area it emphasizes the fact that pollutants know no boundaries and that premier conservation areas such as the world renowned KNP may be some of the most contaminated areas of the world.

Impact of co-exposure of aldrin and titanium dioxide nanoparticles at biochemical and molecular levels in Zebrafish

Aldrin (ALD), a persistent-organic-pollutant (POP), an organochlorine-cyclodiene-pesticide is highly toxic in nature. Titanium dioxide nanoparticles (TNP) are widely used for various industrial applications. Despite the remarkable research on pesticide toxicity, the work with impact of nanoparticles on POP has been dealt with marginally. Chemicals co-exist in the environment and exhibit interactive effects. An investigation was carried out to evaluate the individual and combined effects of ALD (6 ppm) and TNP (60 ppm) exposure at sub-lethal concentration for 24 h in zebrafish. Significant reversal of lipid peroxidation level in liver and brain tissues and restoration in enhanced catalase activity in all examined tissues were observed in combined group. For other parameters, combined exposure of ALD and TNP does not show significant reversal action on ALD toxicity. Further studies are inline to understand combined effects of both to achieve significant reversal of ALD toxicity by TNP nanoparticles with threshold concentration of aldrin.

Degradation of aldrin and endosulfan in rotary drum and windrow composting

Removal efficiencies, kinetics and degradation pathways of aldrin, endosulfan α and endosulfan β in vegetable waste were evaluated during rotary drum and conventional windrow composting. The highest percentage removal of aldrin, endosulfan α and endosulfan β in rotary drum composting was 86.8, 83.3 and 85.3% respectively, whereas in windrow composting, it was 66.6%, 77.7% and 67.2% respectively. The rate constant of degradation of aldrin, endosulfan α and endosulfan β during rotary drum composting ranged from 0.410-0.778, 0.057-0.076 and 0.009-0.061 day(-1) respectively. The pathways of degradation of these pesticides in composting process were proposed. Metabolites dieldrin and 1 hydroxychlorodene formed during composting of aldrin in the vegetable waste indicated the occurrence of epoxidation reaction and oxidation of bridge carbon of aldrin containing the methylene group. Formation of chloroendic acid and chloroendic anhydride during composting of endosulfan containing vegetable waste support the occurrence of endosulfan sulfate and dehydration reaction respectively.

Residential surface soil guidance values applied worldwide to the original 2001 Stockholm Convention POP pesticides

Surface soil contamination is a worldwide problem. Many regulatory jurisdictions attempt to control human exposures with regulatory guidance values (RGVs) that specify a soil's maximum allowable concentration. Pesticides are important soil contaminants because of their intentional toxicity and widespread surface soil application. Worldwide, at least 174 regulatory jurisdictions from 54 United Nations member states have published more than 19,400 pesticide RGVs for at least 739 chemically unique pesticides. This manuscript examines the variability of the guidance values that are applied worldwide to the original 2001 Stockholm Convention persistent organic pollutants (POP) pesticides (Aldrin, Chlordane, DDT, Dieldrin, Endrin, Heptachlor, Mirex, and Toxaphene) for which at least 1667 RGVs have been promulgated. Results indicate that the spans of the RGVs applied to each of these pesticides vary from 6.1 orders of magnitude for Toxaphene to 10.0 orders of magnitude for Mirex. The distribution of values across these value spans resembles the distribution of lognormal random variables, but also contain non-random value clusters. Approximately 40% of all the POP RGVs fall within uncertainty bounds computed from the U.S. Environmental Protection Agency (USEPA) RGV cancer risk model. Another 22% of the values fall within uncertainty bounds computed from the USEPA's non-cancer risk model, but the cancer risk calculations yield the binding (lowest) value for all POP pesticides except Endrin. The results presented emphasize the continued need to rationalize the RGVs applied worldwide to important soil contaminants.

Study on effects of temperature, moisture and pH in degradation and degradation kinetics of aldrin, endosulfan, lindane pesticides during full-scale continuous rotary drum composting

Study focused on effects of temperature, moisture and pH on degradation and degradation kinetics of aldrin, endosulfan (α), endosulfan (β) and lindane during vegetable waste composting using full-scale continuous rotary drum composter (FSCRDC). Extraction, concentration and quantification of pesticides were made from waste material at different stages by ultra-sonification, silica gel column and GC-MS analysis. Removal efficiency of aldrin, endosulfan α, endosulfan β and lindane was found 85.67%, 84.95%, 83.20% and 81.36% respectively due to optimum temperature, moisture, pH and enhanced microbial activity. Maximum temperature in inlet zone was found 60-65°C which is most suitable for complex microbial population. After feeding and turning in inlet zone, temperature reduced to 38°C from 60 to 65°C and regained it within 7-8h, and pH reduced to 5.3±0.2 from 7.5±0.3 in 4h and regained it in 10h. Heterotrophic bacteria Bacillus sp., Pseudomonas sp. and Lactobacillus sp. also decreased from 4.4×10(3) to 7.80×10(2)CFU g(-1) in 2 h due to gradual variation in temperature and pH. No significant temperature change was found in middle and outlet zones during feeding and turning. Degradation of pesticides was observed as first order kinetics and half-life of aldrin, endosulfan α, endosulfan β and lindane was reduced to 25.54, 18.43, 18.43 and 27.43 d from 1095, 60, 270 and 160 d respectively. Thus, the observations in contrast of removal and degradation kinetics of organochlorine pesticides residues in vegetable waste though full-scale rotary drum composting proved it the best suited technique.

Serum organochlorine pesticide levels in patients with metabolic syndrome

INTRODUCTION

Organochlorine pesticides (OCPs) are endocrinal disruptors that tend to accumulate in adipose tissue and have been found to be associated with Metabolic Syndrome (MS).

AIM AND OBJECTIVES

1. To measure serum OCP levels in patients of MS and control subjects, 2. To identify differences, if any, in serum OCP levels, in patients with MS and control subjects.

MATERIALS AND METHODS

Cross-sectional study was conducted in the Departments of Medicine and Biochemistry at University College of Medical Sciences (UCMS) and Guru Teg Bahadur Hospital (GTBH), Delhi. Nine OCPs [α-HCH (Hexachlorocyclohexane), β-HCH, g-HCH, α-endosulfan, β-endosulfan, aldrin, dieldrin, p, p'-DDT (Dichloro-diphenyl-trichloro-ethane), and p, p'-DDE (Dichloro-diphenyl-dichloro-ethylene)] were studied. Fifty subjects ≥18 years with MS (study group) and 50 age and sex-matched controls were included in the study.

EXCLUSION CRITERIA

(1) Persons having chronic occupational exposure to OCPs such as workers of pesticide factories, (2) Recent exposure to OCPs within 4 weeks.

RESULTS

Levels of all nine OCPs were higher in cases as compared to controls. However, only the mean value of β-HCH in cases (8.40 ± 8.64 ng/ml) was significantly (P < 0.001) higher as compared to controls (2.58 ± 2.34 ng/ml). After adjustment of confounding factors like age, sex, smoking, alcohol, and body mass index (BMI), only β-HCH and aldrin levels were positively and significantly associated with the risk of having MS. Adjusted Odds Ratio (OR) was 1.34 [CI = 1.14-1.57 (P < 0.001)] and 1.23 [CI = 1.01-1.50 (P = 0.045)], respectively.

CONCLUSION

There was a significant association of β- HCH and aldrin levels with MS.