Organochlorine pesticides, polybrominated diphenyl ethers and polychlorinated biphenyls in surficial sediments of the Awash River Basin, Ethiopia

Dirbaba, Niguse Bekele; Li, Sen; Wu, Hongjuan; Xue, Yan; Wang, Jun

doi:10.1371/journal.pone.0205026

Cited by 35 publications

(16 citation statements)

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“…The confirmation of this thesis may be proportional (p,p'-DDD+p,p'-DDE)/ 3DDT, which in all sampling sites was >0.5 (from 0.93 to 2.46). Previous studies of Wang et al [38] and Dirbaba et al [8] showed that (p,p'DDE + p,p'DDD)/ 3DDT > 0.5 indicate historical application of DDTs products. Moreover, the ratio of (p,p'DDE + p,p'DDD)/ 3DDT > 0.5 indicates that aerobic transformation processes, which are typical for upland soils, are advantageous over anaerobic dechlorination, which is characteristic for sediments or waterlogged territories [8,35].…”

Section: Ocp Soil Concentrationsmentioning

confidence: 94%

“…The extensive use of DDT resulted from the low costs of its manufacturing and high efficacy as an insecticide product. Despite Europe and the US banning the use of DDT, Asian countries and less economically developed countries in other continents [4,8,29,[36][37][38] still use it. Therefore, DDTs can be transported with atmospheric particles to other countries and deposited in soils in temperate climate conditions.…”

Section: Ocp Soil Concentrationsmentioning

confidence: 99%

“…In our studies, the ratio of 3DDT and its isomers indicated the microbial transformation of the mother compound. The ratio of p,p'-DDE/p,p'DDT ranging from 0.10 to 14.83 can be used as an index to identify the fresh and/or aged application of DDT in a research area [8,35]. A value of <20 generally indicates an old deposition of these contaminants in the soil abandoned 15-20 years prior [35,37].…”

Section: Ocp Soil Concentrationsmentioning

confidence: 99%

“…The fate of pesticides in soil depends on many factors related to physical, chemical, and photochemical processes, as well as biological transformation [4,8]. Their behavior and persistence in soils are mainly determined by volatilization, plants uptake, leaching and runoff, sorption and binding by soil components, chemical degradation by hydrolysis, oxidation-reduction, photolysis, and degradation by soil micro-organisms [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…These processes are related to environmental factors, including soil characteristics (texture), chemical properties (pH, organic matter and metal ions content), as well as climatic conditions [4,12,13]. The rate and direction of pesticide transformations ultimately determine their content and relative stability in soil [4,8]. The chemical properties of pesticides, as well as their coexistence with other chemical compounds that are often added to commercial products, i.e.,: surfactants, coagulants, decomposition inhibitors, buffer and synergic substances or adjuvants, may significantly modify the interactions of pesticides with soil components and affect their resistance to degradation [8,14].…”

Section: Introductionmentioning

confidence: 99%

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Assessment of Pesticide Residue Content in Polish Agricultural Soils

2020

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Pesticides belong to a group of xenobiotics harmful to humans and wildlife, whose fate and activity depends on their susceptibility to degradation. Therefore, the monitoring of their residue level in agricultural soils is very important because it provides very valuable information on the actual level of soil contamination and environmental risk resulting from their application. The aim of this study was to evaluate contemporary concentrations of organochlorine (OCPs) and non-chlorinated pesticides (NCPs) in arable soils of Poland as an example of Central and Eastern European countries. The results were assessed in relation to Polish regulations, which are more restrictive compared to those of other European countries. The sampling area covered the territory of arable lands in Poland (216 sampling points). The distribution of sampling points aimed to reflect different geographical districts, conditions of agricultural production, and various soil properties. The collected soil samples were extracted with organic solvents in an accelerated solvent extractor (ASE 2000). The OCPs, including α-HCH, β-HCH, γ-HCH, and p,p’DDT, p,p’DDE, and p,p’DDD, were extracted with a hexane/acetone mixture (70:30 v/v) and determined by gas chromatography with an electron capture detector (GC-μECD). NCPs included atrazine, carbaryl, and carbofuran were extracted with a dichloromethane/acetone mixture (50:50 v/v), while maneb was extracted by intensive shaking the sample with acetone (1:1 v/v) and ethylenediamine-tertraacetic acid. The NCPs were identified by a dual mass- spectrometry (GC-MS/MS). The total content of individual OCPs ranged from 0.61 to 1031.64 µg kg−1, while the NCP concentrations were significantly lower, from 0.01 to 43.92 µg kg−1. DDTs were detected in all soils samples (p,p’DDD (23.60 µg kg−1) > p,p’DDT (18.23 µg kg−1) > p,p’DDE (4.06 µg kg−1), while HCHs were only in 4% of the analyzed samples (β-HCH (339.55 µg kg−1) > α-HCH (96.96 µg kg−1) > γ-HCH (3.04 µg kg−1)), but in higher values than DDTs. Among NCPs, higher concentration was observed for carbaryl (<0.01–28.07 µg kg−1) and atrazine (<0.01–15.85 µg kg−1), while the lower for carbofuran (<0.01–0.54 µg kg−1). Maneb was not detected in analyzed soils. Assessment of the level of soil pollution based on Polish regulations indicated that several percentages of the samples exceeded the criterion for OCPs, such as ∑3DDTs (14 samples; 6.5% of soils) and HCH congeners (α-HCH in one sample; 0.5% of soils), while NCP concentration, such as for atrazine, carbaryl and carbofuran were below the permissible levels or were not detected in the analyzed soils, e.g., maneb. The obtained results indicated that residues of the analyzed pesticides originate from historical agricultural deposition and potentially do not pose a direct threat to human and animal health. The behavior and persistence of pesticides in the soils depend on their properties. Significantly lower NCP concentration in the soils resulted from their lower hydrophobicity and higher susceptibility to leaching into the soil profile. OCPs are characterized by a high half-life time, which affect their significantly higher persistence in soils resulting from affinity to the soil organic phase.

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