Occurrence and Toxicological Risk Evaluation of Organochlorine Pesticides from Suburban Soils of Kenya

The status of organochlorine pesticide contamination in Greek agricultural soils: the ghost of traditional agricultural history

Inadequate information regarding pesticide contamination in Greek agricultural soils is currently available, while national soil monitoring programs have not been initiated yet. The aim of the present study was to assess the levels, compositions, and distribution of thirty three organochlorine pesticides (OCPs) in Greek agricultural soils, due to the environmental threat posed by these compounds, even after decades from their abrogation from the market. Determination of the organochlorine pesticides was achieved using gas-chromatography-mass spectrometry, following a QuEChERS sample preparation method. A total of 60 soil samples, from two soil horizons (up to 60 cm), were obtained from agricultural lands in Greece throughout 2019-2020. The major findings presented DDTs, γ-HCH, alachlor, and 4,4- DCBP in the examined soil samples, with DDTs being the major compounds with their maximum cumulative concentration (ΣDDTs) reaching 1273.4 μg kg-1 d.w. Compositional profile and diagnostic ratios suggested that the occurrence of DDT residues was due to historical inputs. Most of the samples did not exceed the target values set by the Netherlands and Canadian guidelines for DDTs in soil; however, there was one exception in the case of Aegina Island. Finally, based on the environmental exposure assessment conducted, the vast majority of the analytes presented lower concentrations compared to the predicted environmental concentrations, with an exemption for DDE metabolite where the measured and predicted concentrations were almost equal.

Status, sources, and human health risk assessment of DDT pesticide residues in river sediments in a highly developed agricultural region in the upper Yangtze River in China

The concentrations of DDT and its metabolites in 19 sediment samples from a highly developed agricultural region in the upper reaches of the Yangtze River were measured. Non-carcinogenic hazard quotient for different age groups was evaluated using reference doses provided by the USEPA, and the excess lifetime cancer risk due to eating fish was assessed based on the local eating habits. The results showed that this region had a high level of residual DDT (12.84 ± 8.97 ng/g), which mainly came from the historically used technical DDT in agriculture. The non-carcinogenic risk was just acceptable in the region, but 11 of the 19 sites showed an unacceptable carcinogenic risk. Although DDT has been banned for decades, there were still notable health risks, especially for children. Special attention should be given to the potential health risks in historically developed agricultural regions.

Evaluation of residual level and distribution characteristics of organochlorine pesticides in agricultural soils in South Korea

In this study, we evaluated the residual levels and distribution characteristics of 10 organochlorine pesticides (OCPs) in the soil of agricultural lands (paddy field, vegetable field, and orchard, n = 150) nationwide. As a result of the investigation, 3-10 types of OCPs were detected in combination in 144 locations (96%) of the total 150 locations. Among those OCPs, dichlorodiphenyltrichloroethane (DDT) and endosulfan were detected in high amounts. The geometric mean concentrations of DDT and endosulfan were ∑DDT 0.31 ng g^-1 (ND-2187.18 ng g^-1) and ∑endosulfan 0.33 ng g^-1 (ND-312.68 ng g^-1), respectively. OCP concentrations were generally higher in orchards than in other agricultural fields due to a large amount of pesticides used. DDT in two orchards was detected at 2187.18 ng g^-1 and 1061.78 ng g^-1, exceeding the levels stated in the Canadian DDT Soil Quality Guidance (SQG, 700 ng g^-1). The result of applying the isomer ratio to evaluate the recent or past use of DDT, endosulfan, and hexachlorocyclohexane (HCH), which had a high detection rate, showed that it could be attributable to historical usage. DDT and HCH showed statistically similar residual distribution patterns; however, endosulfan did not show a clear correlation with DDT and HCH due to the effect of its recent use. Thus, the results of evaluation of OCP residual levels and distribution characteristics can be used for the soil management policy of OCPs in agricultural lands in Korea.

Multi-residue screening of pesticides in Panax Ginseng C. A. Meyer by ultra-high-performance liquid chromatography with quadrupole time-of-flight mass spectrometry

In this study, an efficient screening method based on a modified quick, easy, cheap, effective, rugged, and safe extraction method combined with ultra-high-performance liquid chromatography coupled to tandem quadrupole time-of-flight mass spectrometry was established for the determination of 90 pesticides residues in Panax Ginseng. The accuracy of the method was then verified by analyzing the false positive rate and the screening detection limit in Ginseng. The results revealed that the screening detection limit of 33 of 90 pesticide residues were 0.01mg·kg^-1 , 22 species were 0.05 mg·kg^-1 , 11 species were 0.10 mg·kg^-1 , 8 species were 0.20 mg·kg^-1 , and another 16 species were greater than 0.20 mg·kg^-1 . A total of 73 pesticides were ultimately suitable to be practically applied for rapid analysis of pesticide residues in Ginseng. Finally, the established method was used to analyze the pesticide residues in 35 Ginseng samples available on the market. And the residual of Dimethomorph, Azoxystrobin, Tebuconazole, Pyraclostrobin was relatively severe in Ginseng samples. This work expanded the range of pesticides detected and provided a rapid, effective method for pesticides screening in Ginseng. This article is protected by copyright. All rights reserved.

Non-Occupational Exposure to Pesticides: Experimental Approaches and Analytical Techniques (from 2019)

BACKGROUND

Pesticide residues are a threat to the health of the global population, not only to farmers, applicators, and other pesticide professionals. Humans are exposed through various routes such as food, skin, and inhalation. This study summarizes the different methods to assess and/or estimate human exposure to pesticide residues of the global population.

METHODS

A systematic search was carried out on Scopus and web of science databases of studies on human exposure to pesticide residues since 2019.

RESULTS

The methods to estimate human health risk can be categorized as direct (determining the exposure through specific biomarkers in human matrices) or indirect (determining the levels in the environment and food and estimating the occurrence). The role that analytical techniques play was analyzed. In both cases, the application of generic solvent extraction and solid-phase extraction (SPE) clean-up, followed by liquid or gas chromatography coupled to mass spectrometry, is decisive. Advances within the analytical techniques have played an unquestionable role.

CONCLUSIONS

All these studies have contributed to an important advance in the knowledge of analytical techniques for the detection of pesticide levels and the subsequent assessment of nonoccupational human exposure.