Organochlorine Pesticides and Polychlorinated Biphenyls in High Mountain Lakes, Mexico

Pollution levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were investigated in the El Sol and the La Luna alpine lakes. The lakes are located in central Mexico, in the crater of the Nevado de Toluca volcano. The El Sol and the La Luna lakes are extremely relevant in Mexico and in the world because they are recognized as pristine regions and environmental reservoirs. Samples of atmospheric aerosol, sediment, plankton, and Tubifex tubifex were collected at three different sample locations for three years (2017, 2018, and 2019) at three different times of year, meaning that the weather conditions at the time of sampling were different. Pollutants were analysed by gas chromatography–mass spectrometry with negative chemical ionisation (GC-MS/NCI). Endosulfan was the most frequent and abundant pollutant, showing the highest peaks of all. Atmospheric aerosol revealed Σ2 = 45 pg/m3, including α and β, while sediment lakes displayed α, β and endosulfan sulphate as Σ3 = 1963 pg/g, whereas plankton and Tubifex tubifex showed Σ2 = 576 pg/g and 540 pg/g for α and β respectively. Results of endosulfan ratios (α/β) and (α-β/endosulfan sulphate) suggest that both fresh and old discharges continue to arrive at the lakesThis study shows for the first time the pollution levels of OCP and PCB in high mountain lakes in Mexico. These results that must be considered by policy makers to mitigate their use in the various productive activities of the region.

Assessment of systemic and carcinogenic health risks of persistent organochlorine pesticide residues in four fruit vegetables in south-western Nigeria

PurposeThe study assessed the levels of organochlorine pesticides (OCPs) and their potential non-carcinogenic and carcinogenic health risks in four regularly consumed fruit vegetables.Design/methodology/approachThe OCPs’ residues were quantified using a gas chromatograph coupled with an electron capture detector (GC-ECD) and the dietary exposure of children, and adult consumers to the detected OCPs was evaluated using carcinogenic and systemic health risk estimations.FindingsAldrin, endrin, endrin aldehyde, a-endosulfan, β-endosulfan, endosulfan sulphate, heptachlor, heptachlor epoxide and dieldrin were detected in the four fruit vegetables. The predominant OCP residue in carrot, cucumber, tomatoes and watermelon was endosulfan sulphate with mean concentrations of 2.532 mg kg−1, 1.729 mg kg−1, 2.363 mg kg−1 and 1.154 mg kg−1, respectively. The residues levels in some of the fruit vegetables were higher than their respective maximum residue levels (MRLs) of 0.01–0.05 mg kg−1 set by the European Commission with concentrations above MRLs ranging between 25.5% and 100%. The systemic health risk estimations showed that the hazard index (HI) values for carrot (3.20), cucumber (9.25), tomatoes (50.21) and watermelon (16.76) were >1 for children consumers and the respective HI values of 2.87, 15.57 and 5.20 for adult consumers of cucumber, tomatoes and watermelon were >1 which implies potential systemic health risks. Four carcinogens (aldrin, dieldrin, heptachlor and heptachlor epoxide) had cancer risk index values greater than the acceptable risk of 1 in 1 million for both adult and children consumers.Originality/valueThe paper shows that despite the ban on the use of OCPs in Nigeria, they are still being used for agricultural production especially on some locally produced and regularly consumed fruit vegetables as reported in the present study. The non-existence of surveillance programmes on pesticide usage and the lack of proper monitoring of pesticide residues in food products including fruit and vegetables must have contributed to the levels of the detected OCP in the samples analysed. The current daily intake of OCP via contaminated vegetables may pose potential health risks to both the children and adult consumers of the fruit vegetables.

GC-MS fragmentation patterns of sprayed endosulfan and its sulphate metabolite in samples of Theobroma cacao L from a field kinetic study

Most environmental analytical methods for the determination of organochlorine pesticides (OCPs) are multi-residual with other organic compounds co-extracted and co-eluted. This has been observed in GC spectra using classical detectors like electron-capture detector (ECD) even after appropriate clean-up. This limitation could be resolved by using GC-MS methods which are more specific and selective. Thus, a commercial-grade endosulfan treated Theobroma cacao plantation was sampled. Representative samples comprising leaves, stem bark and pulp were obtained between 0.5 h and 60 days after treatment. Samples were analyzed for residual parent endosulfan ( α- and β-isomers) as well as the metabolite endosulfan sulphate using an ion trap GC-MS. The retention times and chromatogram peaks obtained for various endosulfan were identified and compared with reference standards, and confirmed with National Institute of Standards and Technology library. Results showed that the molecular ion at m/z 407 was exhibited by α- and β-endosulfan, representing the parent molecular ion M+• ([C9H6Cl6SO3]+•). The α-isomer was more thermally stable, hence exhibited more relative abundance. Other predominant peaks were 339, 307, 277, 265, 243, 241, 207, 195, 160, 159, 99 and 75 m/z. The peak at m/z 159 was the base molecular ion. For endosulfan sulphate, the peak at m/z 422 corresponded to parent molecular ion (M+•), while m/z 424 was due to isotopic pattern characteristic of the chlorine atom. The peaks at 387, 357, 289, 272, 229, 206, 170, and 120 m/z were characteristic for the sulphate metabolite. The m/z peak at 272 was the base molecular ion, while m/z 143 may be due to metabolite diol and lactone. These results showed that the various endosulfan species can be identified and confirmed simultaneously using a GC-MS.

Determination of multiple organochlorine pesticide residues in shrimp using modified QuEChERS extraction and gas chromatography

Determination of organochlorine pesticide residues in shrimp is very important to ensure the consumer’s safety and to fulfill the importer’s demand. Therefore, a simple and efficient multiple organochlorine pesticide residues analytical method using quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction technique and Gas Chromatography coupled with Electron Capture Detector (ECD) has been developed and validated for the determination of 19 organochlorine pesticides (α- BHC, δ- BHC, β- BHC, γ- BHC, Heptachlor, Aldrin, Heptachlor Epoxide, γ- Chlordane, α- Chlordane, α- Endosulfan, 4,4 DDE, Dieldrin, Endrin, 4,4 DDD, β- Endosulfan, 4,4 DDT, Endosulfan sulphate, Methoxychlor, and Endrin Ketone) in shrimp. The method was validated by evaluating the accuracy, precision, linearity, limit of detection (LOD) and limit of quantification (LOQ). The average recoveries of the selected pesticides ranged from 84% to 106% with RSDr ≤ 14% in four fortification levels of 0.05, 0.1, 0.2 and 0.3 mg kg-1. The linearity was ≥ 0.996 for all of the selected pesticides with matrix matched calibration standards. The LOD ranged from 0.003 to 0.009 mg kg-1 and the LOQ was 0.05 mg kg-1. This method was applied successfully for the residue analysis of 40 shrimp samples collected from different regions in Bangladesh.SAARC J. Agri., 16(1): 81-93 (2018)

MICROBIAL DEGRADATION OF ENDOSULFAN IN AGRICULTURAL SOILS

A study of the degradation of endosulfan (6, 7, 8, 9, 10, 10-hexachloro – 1, 5, 5a, 6, 9, 9a –hexahydro – 6, 9- methano – 2, 4, 3 – benzodioxanthiepin 3 – oxide) in Malaysian sandy loam and clay soils was carried out using a radioisotopic technique under laboratory conditions. It was demonstrated that endosulfan possessed long half-lives of 433, 495 and 462 days in aerobic sandy loam, aerobic clay and anaerobic clay soils respectively. Endosulfan degrades faster in non-sterile than in sterile soils. This study indicates that microorganisms are involved in the degradation of endosulfan. In general, degradation of the pesticide was relatively higher in the clay soil than in the sandy soil. Apart from the parent compounds, α- and β-isomers, the degradation products include endosulfan sulphate and three minor unidentified products.