The occurrence of organochlorine pesticides (OCPs) used decades ago for vector control in urban areas is still reported as a threat to human health. Pyrethroids emerged as a replacement for OCPs in sanitary campaigns and are currently the main insecticides used for vector control worldwide, with prominent use as agricultural and household insecticides, for veterinary and gardening purposes, and as wood preservative. This study aimed to assess the occurrence, seasonal variation, and potential sources of pyrethroids in ambient air of two urban regions of Southeastern Brazil, along with the potential health risks to local populations via inhalation exposure. Pyrethroids were sampled by polyurethane foam passive air samplers and their concentrations were determined by gas chromatography coupled with electron capture negative ionization mass spectrometry (GC/ECNI-MS). Atmospheric pyrethroid concentrations (hereinafter reported in pg m⁻³) were considerably higher than those reported by previous studies worldwide. Cypermethrin (median: 2446; range: 461–15 125) and permethrin (655; 19–10 328) accounted for 95% of the total measured pyrethroids in ambient air. The remaining fraction comprised smaller amounts of bifenthrin (46; <limit of detection (LOD)–5171), deltamethrin (58; <LOD–564), phenothrin (7; <LOD–22) and fenvalerate (0.3; <LOD–3). Bifenthrin, deltamethrin and permethrin were linked to local sources, while cypermethrin, fenvalerate and phenothrin had more prominent regional contributions. In broad terms, most pyrethroids showed no clear seasonal trend. The concentrations and hazard quotients (HQs) showed the following order of occurrence and magnitude: urban > urban-industrial > background areas. HQs increased with decreasing age group, but deterministic and probabilistic estimates did not identify direct health risks for any group. Nevertheless, since only inhalation exposure was considered in this work, other pathways should be investigated to provide a more comprehensive risk assessment of the human exposure to pyrethroids.

This study was designed to assess the gradual increase in the use of insecticides on vegetables and to familiarize the consumers regarding the insecticide residues. The purpose of this research work was to highlight the detrimental effects of pyrethroids (bifenthrin, cyfluthrin, cypermethrin, deltamethrin, fenvalerate, lambda-cyhalothrin, and permethrin) compare with dietary intake assessment of eggplant and okra grown in peri-urban environment. In this manner, a total of 180 (n = 60 × 3) samples of eggplant (Solanum melongena) and okra (Abelmoschus esculentus) were procured from the peri-urban farming system of Faisalabad, Multan, and Gujranwala to assess the pyrethroid residues along with their dietary intake assessment. The procured vegetables were quantified for pyrethroid residues by using gas chromatography (GC) equipped with an electron capture detector (ECD). Outcomes of this study revealed that for okra samples, the highest residues of bifenthrin (1.25 mg kg⁻¹) were found in Gujranwala then Multan (1.5 mg kg⁻¹) and Faisalabad (1.04 mg kg⁻¹), whereas in eggplant, the highest residues were recorded for bifenthrin from Faisalabad (1.33 mg kg⁻¹) and Gujranwala (0.78 mg kg⁻¹). In Multan, the highest residues for cyfluthrin (1.18 mg kg⁻¹) were reported in eggplant. Out of all analyzed samples for pyrethroid residues, 32% samples contained detectable residues and 6% samples exceeded their maximum residual limits (MRLs) established by the European Union (EU). Dietary intake assessment (mg kg⁻¹ day⁻¹) was calculated as per their maximum permissible intake (MPI) values, i.e., bifenthrin (1.28), cyfluthrin (1.28), cypermethrin (3.20), deltamethrin (0.64), fenvalerate (1.28), lambda-cyhalothrin (0.064), and permethrin (3.20) respectively. Conclusively, residues from the Multan region were greater than those from Gujranwala and Faisalabad showing excessive application of pyrethroids. Overall results revealed that although some samples exceeded MRLs in selected areas, their safe consumption limit was found.

Fenvalerate (type II synthetic pyrethroid), widely used in agricultural practices, find its way into aquatic ecosystem through air, by runoff, or by percolation to groundwater. It is an extremely toxic insecticide for aquatic organisms especially fish. In the present study, the fenvalerate (FEN) induced toxicity and the protective efficacy of ascorbic acid (AA) against FEN in Ctenopharyngodon idella was evaluated by studying the structural alterations in scales, erythrocytes and gills. The fishes were exposed to 1.2 μg/L and 2 μg/L of FEN and orally administered with 1000 mg/kg diet of AA. The fishes were scrutinized on 15ᵗʰ, 30ᵗʰ and 60ᵗʰ day of experiment. Scanning electron microscopic studies (SEM) of FEN-treated fish revealed extensive morphological alterations on the microstructure of scales including deformed focus, uprooted lepidonts and tubercles, hole formation and worn out calcareous material from the surface. FEN intoxication induced severe damage on erythrocytes including formation of dacrocytes, serrated spherocytes, echinocytes with oozed out cytoplasmic content, contracted plasma membrane and appearance of lobopodial projections. Ultrastructural studies in gills declared profound lesions in the form of aneurysm, loss of secondary lamellae and destructed microstructures of pavement cells. On the other hand, supplementation of AA in diet mitigated the impairment provoked by FEN on the scales, erythrocytes and gills due to its antioxidant properties.

To investigate the effect of chiral pesticide fenvalerate (FV) on the micro-ecological environment of aquaculture pond sediment, we used an indoor static experiment to observe the effects of FV added at different concentrations with different chiral isomers on the changes in the sediment bacterial community. The 16S rDNA high-throughput sequencing technique was used to conduct sequencing and analysis of the bacterial community structure as well as changes in aquaculture pond sediments after 4 weeks of cultivation. The results showed that the microbial alpha diversity indices (Sobs and Shannon indices) of the treated groups were significantly lower than those of the control group after 4 weeks (P < 0.05), and the values in the high-concentration group were significantly lower than those of the low-concentration group (P < 0.05). In terms of bacterial group composition, the proportion of abundance of Proteobacteria and Acidobacteria in the treated groups were greater than in the control group after 4 weeks, while the proportion of abundance of Bacteroidetes and Verrucomicrobia were lower. In the high-concentration FV treatment group, the proportion of abundance of Bacteroidetes, Acidobacteria, Chloroflexi, Nitrospinae, unclassified_k_norank, Ignavibacteriae, and Nitrospirae were significantly different from those of the other groups (P < 0.05). Principal coordinate analysis (PCoA) and ANONISIM/Adonis analysis showed that the cis-enantiomer had a stronger effect on the bacterial community as the concentration of FV increased. In addition, the linear discriminant analysis effect size (LEfSe) and linear discriminant analysis (LDA) results revealed differences in the level of enrichment of bacterial groups caused by FV at different concentrations and isomer levels. Collectively, this study showed that FV residue has a pronounced effect on bacterial communities in sediment, which becomes more significant with increasing exposure concentration. The effects of the cis- and trans-enantiomers of FV on the sediment environment are different; the cis-enantiomer has a stronger effect on the bacterial community.

Monitoring of pesticide residues in food commodities of plant origin is part of the regular controls on food to safeguard consumer’s health. This study reports for the first time in Ghana a 3-year (2010–2012) monitoring of pesticide contamination of fruits and vegetables and their health implications. A total of 3483 samples were purchased in notable markets within Accra Metropolis and analysed for pesticide residues, employing the modified quick, easy, cheap, effective, rugged and safe analytical procedure. The results indicated that almost all the fruits and vegetables studied had residues above maximum residue limits (MRLs). The commodities with the greatest concentrations exceeding the European Union (EU) MRLs were long green beans (60.6%) and lettuce (57.1%) with watermelon (10%) and green pepper (8.6%) having the least. The relative occurrence of the pesticides was fenvalerate 11.3%, fenitrothion 5.6%, lambda-cyhalothrin 3.6%, dimethoate 3.2%, permethrin 2.7% and deltamethrin 2.2%. These results will serve as a baseline on which annual or other long-term studies could be compared with, thus emphasizing the need for continuous monitoring programmes to regulate trends of pesticide residues in fruits and vegetables to safeguard the consumers’ health.

Pseudomonas aeruginosa strain GF31, isolated from a contaminated soil, can effectively degrade β-cypermethrin (β-CP), as well as fenpropathrin, fenvalerate, and cyhalothrin. The highest level of degradation (81.2 %) was achieved with the addition of peptone. Surprisingly, the enzyme responsible for degradation was mainly localized to the extracellular areas of the bacteria, in contrast to the other known pyrethroid-degrading enzymes, which are intracellular. Although intact bacterial cells function at about 30 °C for biodegradation, similar to other degrading strains, the crude extracellular extract of strain GF31 remained biologically active at 60 °C. Moreover, the extract fraction showed good storage stability, maintaining >50 % of its initial activity following storage at 25 °C for at least 20 days. Significant differences in the characteristics of the crude GF31 extracellular extract compared with the known pyrethroid-degrading enzymes indicate the presence of a novel pyrethroid-degrading enzyme. Furthermore, the identification of 3-phenoxybenzoic acid and 2,2-dimethylcyclopropanecarboxylate from the degradation products suggests the possibility that β-CP degradation by both the strain and the crude extracellular fraction is achieved through a hydrolysis pathway. Further degradation of these two metabolites may lead to the development of an efficient method for the mineralization of these types of pollutants.

Frequent and widespread pesticide use is a major concern for both human and environmental health. The aim of this study was to screen for 19 pesticides in rural rivers in Guangzhou, China, evaluating the potential impact of detected pesticides on the local ecosystem. Sampling was performed in rural rivers in three environment types: agricultural, industrial, and unpolluted, with sampling of water and sediments in both wet and dry seasons. A total of 11 pesticides were detected overall and their spatiotemporal distribution in water and ecological risk were assessed. Five pesticides were detected at concentrations above 100 ng L⁻¹, with the highest concentration pesticides being dimethoate (1318 ng L⁻¹) in surface water and quinalphos (328 ng g⁻¹ dry weight (dw)) in sediments. The most commonly detected pesticides were chlorpyrifos, acetochlor, and butachlor with detection frequencies of 50–57% and 29–43%, in water and sediments, respectively. Samples from the agricultural rural river contained the most pesticides and at higher concentrations, as compared to industrial and unpolluted areas, especially during the wet season. Ecotoxicological risk assessment through Risk Quotients (RQs) showed that chlorpyrifos and fenvalerate pose high ecological risks in water and therefore, reduction of the source input of these pesticides is essential.

In this study, the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was applied for the analysis of the multiclass pesticide residues of 12 organochlorines (OCs), 9 organophosphates (OPs), 11 synthetic pyrethroids (SPs), 4 herbicides, 6 phthalates in raw tea (loose tea, branded tea and herbal tea), and tea infusion in 4 different containers (glass cup, earthen cup, plastic bag and disposal cup). In loose tea and branded tea residues, malathion (0.257 and 0.118 mg kg⁻¹), cypermethrin (0.065 and 0.030 mg kg⁻¹), and fenvalerate (0.032 and 0.030 mg kg⁻¹) were detected, respectively. In herbal tea, residues of only cypermethrin (0.053 mg kg⁻¹) and fenvalerate (0.045 mg kg⁻¹) were detected. Tea infusion samples contained in a plastic bag were found to be contaminated with only dibutyl phthalate (DBP) (0.038 mg kg⁻¹). Disposable cup was found to be contaminated with DBP (0.026 mg kg⁻¹) and diethyl phthalate (DEP) (0.004 mg kg⁻¹). Further, to know the processing behavior of pesticides, the spiked raw tea was subjected to tea infusion at different brewing times (2, 5, 10 min). The analysis demonstrated that dimethoate, dichlorvos, and malathion had shown more than 10 % of translocation at 5 min of brewing time. Further brewing for 10 min revealed the reduction in concentration of pesticides. Leaching of phthalate residues from different plastic containers was also studied at 10, 30, and 60 min. DBP, benzyl butyl phthalate (BzBP), and di-2-(ethylhexyl) phthalate (DEHP) were leached in the tea infusion samples packed in plastic bags. On the other hand, in disposable cups, leaching of DBP, DEP, and dimethyl phthalate were found. The concentration of phthalate residues increased with retention time. Pesticide and phthalate contaminants were recorded at low quantities in few samples only.

Surface sediment-associated synthetic pyrethroid insecticides (SPs) are known to pose high risks to the benthic organisms in Chaohu Lake, a shallow lake of Eastern China. However, the pollution status of the lake’s tributaries and estuaries is still unknown. The present study was conducted to investigate the occurrence, compositional distribution, and toxicity of 12 currently used SPs in the surface sediments from four important tributaries, as well as in the sediment cores at their estuaries, using GC-MS for quantification. All SPs selected were detectable, with cypermethrin, es/fenvalerate, and permethrin dominant in both surface and core sediments, suggesting that these compounds were extensively applied. Urban samples contained the highest summed concentrations of the 12 SPs analyzed (Σ₁₂SP) in both surface and core sediments compared with rural samples, suggesting that urban areas near aquatic environments posed high risks for SPs. The mean concentration of Σ₁₂SP in surface sediments of each river was generally higher than that found in core sediments from its corresponding estuary, perhaps implying recent increases in SP usage. Surface sediments were significantly dominated by cypermethrin and permethrin, whereas core sediments were dominated by permethrin and es/fenvalerate. The compositional distributions demonstrated a spatial variation for surface sediments because urban sediments generally contained greater percentages of permethrin and cypermethrin, but rural sediments had significant levels of es/fenvalerate and cypermethrin. In all sediment cores, the percentage of permethrin gradually increased, whereas es/fenvalerate tended to decrease, from the bottom sediments to the top, indicating that the former represented fresh input, whereas the latter represented historical residue. Most urban samples would be expected to be highly toxic to benthic organisms due to the residue of SPs based on a calculation of toxic units (TUs) using toxicity data of the amphipod Hyalella azteca. However, low TU values were found for the samples from rural areas. These results indicate that the bottom sediments were exposed to high risk largely by the residual SPs from urban areas. The summed TUs were mostly attributable to cypermethrin, followed by λ-cyhalothrin and es/fenvalerate. Despite permethrin contributing ∼28.7 % of the Σ₁₂SP concentration, it only represented 6.34 % of the summed TUs. Therefore, our results suggest that high levels of urbanization can increase the accumulation of SPs in aquatic environments.