Seasonal Changes in Pesticide Residues in Water and Sediments from River Tano, Ghana

Abstract

Pollution due to pesticide residues has been reported in the downstream of the Tano Basin in the rainy season and has been attributed to the anthropogenic activities upstream. However, data on the seasonal variations in pesticide residues in the upstream of Tano Basin are limited. Seasonal variations in 13 organochlorine pesticide residues, 8 organophosphorus pesticide residues, and 5 synthetic pesticide residues in water and sediment samples of River Tano upstream were assessed through extraction and Varian CP-3800 gas chromatography equipped with a CombiPAL Auto sampler set at ionization mode electron impact methods. Significantly higher pesticide residues were detected in water and sediment samples in the rainy season than the dry season. Permethrin (rainy: 0.007 ± 0.01 mg/kg; dry: 0.008 ± 0.02 mg/kg) and profenofos (rainy: 0.021 ± 0.02 mg/kg; dry: 0.026 ± 0.01 mg/kg) showed higher dry season concentrations in the sediment samples. Two isomers of lindane (δ-HCH = 0.059 ± 0.24 μg/L; γ-HCH = 0.002 ± 0.01 μg/L) were detected in the water in the rainy season, but 3 were detected in the sediment samples (δ-HCH = 0.004 ± 0.12 mg/kg; γ-HCH = 0.003 ± 0.01 mg/kg; aldrin = 0.001 ± 0.01 mg/kg) suggesting possible illegal use. The detected pesticide residual levels in both water and sediment samples were lower than the maximum residual levels in water and sediment. The Chemical Control and Management Centre of the Environmental Protection Agency should check possible faking and adulteration of banned organochlorine pesticides.

Occurrence and seasonal variation of organochlorine pesticides in selected vegetable farmlands in Lagos State, Nigeria

“…In addition, it also suggested their intensive use during the dry. This agrees with the study of Nyantaky et al [48].…”

Spatiotemporal Variation and Health Risk Assessment of Selected Polycyclic Aromatic Hydrocarbons and Pesticides in Ogun River, Lagos, Nigeria

“…While some recorded higher mean values in the rainy season (Aldrin, Paraquat dichloride, Glyphosate, Imidachlopride, and λ-Cyhalothrin), others had higher mean values in the dry season. Because of the complex nature of factors that determine the seasonal pattern of pesticides in aquatic environments, different studies have obtained different seasonal trends, while some have reported higher mean values of pesticides during the rainy season (Harnpicharnchai et al, 2013;Stamatis et al, 2013;Jayasiri et al, 2022;Nyantakyi et al, 2022;), others have reported higher levels in dry season (Konstantinou et al, 2006;Cunha et al, 2022;Toth et al, 2022). The major factor is the seasons of pesticide application, which depends on the locality.…”

“…The major source of pesticide to surface water is runoff from agricultural land. Increased application leads to higher levels (Maloschik et al, 2007;Nyantakyi et al, 2022). A study by Pimentel (2003) showed that 99.9% of pesticides applied to agricultural targets end up in the environment.…”

Myricetin Inhibits Photodegradation of Profenofos in Water: Pathways and Mechanisms

“…However, only a small fraction of profenofos can be absorbed by pests, while most of the rest drifts to the environment and is often detected in agricultural water. For example, profenofos contaminations of up to 2.3 mg•L −1 were found in the Bubula River [5], and 0.074 ± 0.04 µg•L −1 and 0.303 ± 0.07 µg•L −1 in water of the Tano River during the rainy and drought seasons [6]. Profenofos has strong toxicity towards non-targeted organisms, including humans.…”