Chronic cypermethrin induced toxicity and molecular fate assessment within common carp (Cyprinus carpio) using multiple biomarkers approach and its novel therapeutic detoxification.

Cypermethrin (CYP) is a chemical of emerging concern which has persistent and bioaccumulating impacts as it can be found extensively in freshwater ecosystem and agricultural products. It has exposure risk and toxic effects over human edible fish, as common carp. Four groups were designed for toxicity assessment and detoxification approach: control group (CL), CYP exposure group (CYP), CYP + 10% M. oleifera leaves and 10% M. oleifera seeds (CMO group), 10% M. oleifera leaves and 10% M. oleifera seeds (MO group). Trial period was forty days during which cohort of 240 fish in CYP and CMO group was exposed to 1/5 of 96h LC50 of CYP (0.1612 µg/L). CYP-exposed carp exhibited lower growth parameters, but carp fed with 10% M. oleifera seeds and leaves showed significant improvement in growth rate (SGR, RGR) and weight gain (WG) as compared to the control group. CYP exposure negatively affected haemato-biochemical parameters. Moreover, CYP exposure also led to oxidative stress, damaged immunological parameters, genotoxicity and histopathological damage in liver and intestinal cells. Whereas, M. oleifera supplementation has ameliorated these conditions. Thereby, supplementation with M. oleifera is potential and novel therapeutic detoxication approach for common carp and human health against persistent and bioaccumulating emerging chemicals.

Risk assessment of airborne agricultural pesticide exposure in humans in rural China.

Continuous exposure to airborne pesticides causes their gradual accumulation in the human body, eventually posing a threat to human health. To the best of our knowledge, risk assessment study of pesticide non-occupational exposure to residents in agricultural areas has not been conducted in China. In this study, air samples (gas and dust) were collected from inside and outside residences of seven households and an area near the field in a grain-growing area (wheat and maize rotation) for eight months, and the pesticides present were examined both qualitatively and quantitatively. Using a 95% confidence interval, 9 out of 16 pesticides were detected, namely acetamiprid, acetochlor, atrazine, flucarbazone-sodium, imidacloprid, methyldisulfuron-methyl, nicosulfuron-methyl, pendimethalin, and beta-cyhalothrin, and their safety was subsequently evaluated. The results showed that the inhalation exposure of households to beta-cyhalothrin exceeded the acceptable range in the first residential, and the excess lifetime cancer risk of acetochlor inhalation exposure in six households and area around the field exceeds 1E-6, which highlights the need to strengthen preventive screening for cancer risk.

Time of exposure and assessment influence the mortality induced by insecticides against metabolic resistant mosquitoes.

BACKGROUND: Increasing metabolic resistance in malaria vector mosquitoes resulted in the development of insecticide-treated nets (ITNs) with active ingredients (AI) that target them. Bioassays that accurately measure the mortality induced by these AIs on ITNs are needed. Mosquito metabolic enzyme expression follows a circadian rhythm. Thus, this study assessed (i) influence of the time of day of mosquito exposure and (ii) timing of assessment of mortality post exposure (24 and 72 h) to ITNs against vectors that are susceptible to pyrethroids and those with metabolic and knockdown resistance mechanisms. METHODS: Two cone bioassay experiments were conducted following World Health Organization (WHO) guidelines. Firstly, on ITNs incorporated with 2 g AI/kg of deltamethrin (DM) alone, or combined with 8 g AI/kg piperonyl butoxide (PBO) synergist, during the day (9:00-14:00 h) and repeated in the evening (18:00-20:00 h). This was followed by a confirmatory experiment during the afternoon (12:00-14:00 h) and repeated in the night (22:00-24:00 h) using mosquitoes unexposed or pre-exposed to PBO for 1 h before exposure to DM ITNs. Each net piece was tested with a minimum of eight cones per time (N = 24). The outcome was mortality after 24 h (M24) or 72 h (M72) of holding. RESULTS: The cone bioassays performed using metabolic resistant mosquitoes during the evening showed significantly lower M24 than those performed in the day for DM: odds ratio (OR) 0.14 [95% confidence interval (CI) 0.06-0.30, p < 0.0001] and DM PBO [OR 0.29 (95% CI 0.18-0.49, p < 0.0001). M72 was higher than M24 for metabolic resistant mosquitoes exposed to DM [OR 1.44 (95% CI 1.09-1.88), p = 0.009] and DM PBO [OR 1.82 (95% CI 1.42-2.34), p < 0.0001]. An influence of hour of experiment and time of assessment was not observed for mosquitoes that had knockdown resistance or that were pyrethroid-susceptible. CONCLUSIONS: Time of day of experiment and hour of assessment of delayed mortality after exposure of mosquitoes are important considerations in evaluating insecticides that interact with mosquito metabolism to counter metabolic resistant mosquitoes. This is important when evaluating field-aged ITNs that may have lower concentrations of AI.

Distribution and risk assessment of pesticide pollution in small streams adjoining paddy fields.

The present investigation was planned to bridge the knowledge gap on spatiotemporal variations of pesticide pollution in small streams adjacent to paddy fields, and to visualize the associated risks in the aquatic ecosystems. We screened 106 pesticides using GCMSMS and LCMSMS from 10 small streams (n = 212, surface water samples) adjacent to paddy fields over seven months. Fifty-five pesticides were detected across different streams and months. The highest mean concentration was detected for fenobucarb (272 ng L-1), followed by thiamethoxam (199 ng L-1). The highest maximum concentration was detected for thiamethoxam ( 13,264 ng L-1), followed by triflumezopyrim ( 11,505 ng L-1). The highest detection frequency was recorded for fenobucarb (80.00%), followed by pretilachlor (79.00%). Out of the ten streams, Attabira stream had the highest mean number of pesticides detected in each sample. Maximum number of pesticides were detected in October followed by September. Pesticides namely, hexaconazole, pretilachlor, tricyclazole, fenobucarb and thiamethoxam were consistently detected across all streams. The risk assessment against the fishes, micro-invertebrates and algae were measured by risk quotient index (RQ). Twenty-five pesticides out of the detected pesticides (n = 55) had risk quotient values greater than 1. The highest RQmax values were observed in case of fenpropathrin followed by cyfluthrin-3. The highest RQmean value was observed in case of cyfluthrin, indicating its higher toxicity to fishes. The present study reveals that small streams are polluted with pesticides and there is a need to develop strategies and policy interventions in regularizing the pesticide uses for reducing the pesticide pollution in aquatic systems.

Occurrence, distribution, and health risk assessment of pyrethroid and neonicotinoid insecticides in aquatic products of China.

Synthetic pyrethroid insecticides (SPIs) and neonicotinoid insecticides (NEOs), now dominant in the insecticide market, are increasingly found in aquatic environments. This study focused on six SPIs and five NEOs in aquatic products from four Chinese provinces (Shandong, Hubei, Shanxi and Zhejiang) and the risk assessment of the safety for the residents was conducted. It revealed significantly higher residues of Σ6SPIs (6.27-117.19 µg/kg) compared to Σ5NEOs (0.30-14.05 µg/kg), with SPIs more prevalent in fish and NEOs in shellfish. Carnivorous fish showed higher pesticide levels. Residues of these two types of pesticides were higher in carnivorous fish than in fish with other feeding habits. In the four regions investigated, the hazard quotient and hazard index of SPIs and NEOs were all <1, indicating no immediate health risk to human from single and compound contamination of the two types of pesticides in aquatic products. The present study provides valuable information for aquaculture management, pollution control and safeguarding human health.

Determination, temporal variation and potential health risk assessment of pesticide residues in grapes from South and Southwest China.

Pesticide residues in grapes from South and Southwest China were determined using the QuEChERS procedure and UHPLC-MS/MS and GC-MS/MS methods. The 4-year monitoring and survey showed 94.6% of the 1341 samples of grapes collected from eight main production areas contained one or multiple pesticide residues (above the respective LOQs). Overall, 40 pesticides were detected, including 24 fungicides, 12 insecticides, 2 acaricides and 2 plant growth modulators, of which one pesticide was unauthorised for use in treating grapes. Two or more pesticide residues were discovered in 87.4% of the samples (above the respective LOQs), and pesticide residues in 5.7% of the samples exceeded the MRLs, such as difenoconazole, cyhalothrin, propiconazole, etc. The main risk factors affecting the safety of grape before 2019 were difenoconazole, cyhalothrin and cyazofamid. After 2019, however, the frequency of occurrence of the above pesticides significantly declined, and the banned or restricted pesticides including omethoate were not found, which was credited to the stricter supervision and management policies by local governments. Despite the high detection rates and multi-residue occurrence of pesticides in grapes, about 84% of the samples were compliant with regulatory standards. Moreover, the accumulative chronic diet risk determined from ADI is very low. This study and timely monitoring can ensure that grape growers comply with GAP and minimise the occurrence of residues.

Spatial distribution and risk assessment of pyrethroid insecticides in surface waters of East China Sea estuaries.

Pyrethroid insecticides are the most commonly used household insecticides and pose substantial risks to marine aquatic organisms. many studies have detected pyrethroid insecticides in the waters and estuaries of the western United States, but their distributions within western Pacific estuaries have not been reported. Accordingly, we used high-throughput organic analyses combined with high volume solid-phase extraction to comprehensively assess 13 pyrethroid insecticides in East China Sea estuaries and the Huangpu River. The results demonstrated the presence of various ∑13pyrethroid insecticides in East China Sea estuaries (mean and median values of 8.45 ± 5.57 and 7.78 ng L-1, respectively), among which cypermethrin was the primary contaminant. The concentrations of ∑12pyrethroid insecticide detected in the surface waters at the Huangpu River (mean 6.7 ng L-1, outlet 16.4 ng L-1) were higher than those in the Shanghai estuary (4.7 ng L-1), suggesting that runoff from inland areas is a notable source of insecticides. Wetlands reduced the amount of runoff containing pyrethroid insecticides that reached the ocean. Several factors influenced pesticide distributions in East China Sea estuaries, and higher proportions were derived from agricultural sources than from urban sources, with a higher proportion of agricultural sources than urban sources, influenced by anthropogenic use in the region. Permethrin and cypermethrin were the main compounds contributing to the high ecological risk in the estuaries. Consequently, to prevent risks to marine aquatic life, policymakers should aim to reduce insecticide contaminants derived from urban and agricultural sources.

Residue estimation and dietary risk assessment of fenvalerate, novaluron, and profenofos in bell pepper grown under protected and open field conditions.

Residue studies were conducted in bell pepper crops (green and yellow bell pepper) to ensure the safe use of fenvalerate, profenofos, and novaluron (under open field and protected conditions) in randomized block design (RBD) following three applications at a 10-day interval over two consecutive years, 2021 and 2022. A robust analytical method was developed using quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and gas chromatography-tandem mass spectrometry (GC-MS/MS) for the determination of pesticide residues in bell pepper samples. The half-lives for fenvalerate were 2.47-2.87 and 2.50-3.03 days on bell pepper under open field conditions, whereas the corresponding values for bell pepper under protected conditions were 3.84-4.58 and 4.17-4.71 days, during 2021 and 2022, respectively. Profenofos displayed half-lives of 2.03-2.65 and 2.15-2.77 days in open field conditions and 3.05-3.89 and 3.16-3.78 days in protected conditions during 2021 and 2022, respectively. Similarly, novaluron had half-lives of 2.87-3.49 and 3.24-3.75 days under protected conditions in 2021 and 2022, respectively. The maximum residue limits (MRLs) were calculated to be 0.6 mg/kg for fenvalerate, while for profenofos it was 0.7 mg/kg on bell pepper under open field conditions at double doses, at the proposed pre-harvest interval (PHI) of 3 days. Likewise, for bell peppers grown under protected conditions, MRLs at the PHI of 3 days were determined to be 0.8 mg/kg for fenvalerate, 0.3 mg/kg for novaluron, and 1.5 mg/kg for profenofos. A dietary risk assessment study indicated that the percentage of acute hazard index (% aHI) was significantly lower than 100, and hazard quotient (HQ) values were below 1, signifying no acute or chronic risk to consumers. These findings underscore the safety of consuming bell peppers treated with fenvalerate, profenofos, and novaluron under the protected and open field conditions.

Risk of papillary thyroid carcinoma and nodular goiter associated with exposure to semi-volatile organic compounds: A multi-pollutant assessment based on machine learning algorithms.

BACKGROUND: Exposure to semi-volatile organic compounds (SVOCs) may link to thyroid nodule risk, but studies of mixed-SVOCs exposure effects are lacking. Traditional analytical methods are inadequate for dealing with mixed exposures, while machine learning (ML) seems to be a good way to fill the gaps in the field of environmental epidemiology research. OBJECTIVES: Different ML algorithms were used to explore the relationship between mixed-SVOCs exposure and thyroid nodule. METHODS: A 1:1:1 age- and gender-matched case-control study was conducted in which 96 serum SVOCs were measured in 50 papillary thyroid carcinoma (PTC), 50 nodular goiters (NG), and 50 controls. Different ML techniques such as Random Forest, AdaBoost were selected based on their predictive power, and variables were selected based on their weights in the models. Weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were used to assess the mixed effects of the SVOCs exposure on thyroid nodule. RESULTS: Forty-three of 96 SVOCs with detection rate >80 % were included in the analysis. ML algorithms showed a consistent selection of SVOCs associated with thyroid nodule. Fluazifop-butyl and fenpropathrin are positively associated with PTC and NG in single compound models (all P < 0.05). WQS model shows that exposure to mixed-SVOCs was associated with an increased risk of PTC and NG, with the mixture dominated by fenpropathrin, followed by fluazifop-butyl and propham. In the BKMR model, mixtures showed a significant positive association with thyroid nodule risk at high exposure levels, and fluazifop-butyl showed positive effects associated with PTC and NG. CONCLUSION: This study confirms the feasibility of ML methods for variable selection in high-dimensional complex data and showed that mixed exposure to SVOCs was associated with increased risk of PTC and NG. The observed association was primarily driven by fluazifop-butyl and fenpropathrin. The findings warranted further investigation.

Lack of fitness costs associated with resistance to permethrin in Musca domestica.

Resistance to permethrin has been reported in Pakistani strains of Musca domestica. The present study explored the performance of biological traits and analyzed life tables to determine whether there is any detrimental effect of permethrin resistance on the fitness of permethrin-resistant strains [an isogenic resistant strain (Perm-R) and a field strain (Perm-F)] compared to a susceptible strain (Perm-S). Perm-R and Perm-F exhibited 233.93- and 6.87-fold resistance to permethrin, respectively. Life table analyses revealed that the Perm-R strain had a significantly shorter preadult duration, longer longevity, shorter preoviposition period, higher fecundity, finite rate of increase, intrinsic rate of increase, net reproductive rate and a shorter mean generation time, followed by the Perm-F strain when compared to the Perm-S strain. Data of the performance of biological traits reveled that permethrin resistance strains had a better fit than that of the Perm-S strain. The enhanced fitness of resistant strains of M. domestica may accelerate resistance development to permethrin and other pyrethroids in Pakistan. Some possible measures to manage M. domestica and permethrin resistance in situations of fitness advantage are discussed.

Assessment of barrier treatments impacting Aedes albopictus (diptera: culicidae) using lambda-cyhalothrin and pyriproxyfen in a suburban neighborhood in Eastern North Carolina, 2018.

Pyrethroids are commonly used in barrier treatments but less is known about how mosquitoes are affected by the simultaneous application of an insect growth regulator (i.e., pyriproxyfen) used in barrier treatments. This field study, conducted from May 14 - October 16, 2018, evaluated the effect of lambda-cyhalothrin (pyrethroid adulticide) and pyriproxyfen on the reproduction (measured by fecundity and adult emergence) and abundance of Aedes albopictus. Nine properties were treated with Demand®CS 0.06% + Archer® 0.010% (every 60 days) and three control properties received no treatment (N=12 total properties). No significant (P>0.05) differences were observed between abundance of Ae. albopictus in treatment compared to control groups. However, significant differences were observed in abundance of Ae. albopictus adults between weeks at both control (P = 0.003) and treatment (P < 0.0001) properties. Results from our research show that continued studies are needed to determine the efficacy of barrier treatments for this species. .

Fitness costs in the presence and absence of insecticide use explains abundance of two common Aedes aegypti kdr resistance alleles found in the Americas.

Aedes aegypti is the vector of viruses such as chikungunya, dengue, yellow fever and Zika that have a critical impact on human health. Control of adult mosquitoes is widely done using pyrethroids, but resistance has reduced the effectiveness of this class of insecticides. Resistance to pyrethroids in mosquitoes is commonly due to mutations in the voltage-gated sodium channel (Vgsc) gene (these mutations are known as knockdown resistance, kdr). In the Americas and the Caribbean, the most common kdr alleles are 410L+1016I+1534C and 1534C. In this study, we conducted a population cage experiment to evaluate changes in the allele and genotype frequencies of the 410L+1016I+1534C allele by crossing two congenic strains; one carrying the 410L+1016I+1534C and another with the 1534C allele. Changes in allele frequencies were measured over 10 generations in the absence of insecticide exposure. We also applied one cycle of selection with deltamethrin at F9 to evaluate the changes in allele and genotype frequencies. Our findings indicate that fitness costs were higher with the 410L+1016I+1534C allele, relative to the 1534C allele, in the absence of deltamethrin exposure, but that the 410L+1016I+1534C allele provides a stronger advantage when exposed to deltamethrin relative to the 1534C allele. Changes in genotype frequencies were not in Hardy-Weinberg equilibrium and could not be explained by drift. Our results suggest the diametrically opposed fitness costs in the presence and absence of insecticides is a reason for the variations in frequencies between the 410L+1016I+1534C and 1534C alleles in field populations.

Risk assessment of honeybee larvae exposure to pyrethroid insecticides in beebread and honey.

Honeybee is an essential pollinator to crops, evaluation to the risk assessment of honeybee larvae exposure to pesticides residue in the bee bread and honey is an important strategy to protect the bee colony due to the mixture of these two matrices is main food for 3-day-old honeybee larvae. In this study, a continuous survey to the residue of five pyrethroid insecticides in bee bread and honey between 2018 and 2020 from 17 major cultivation provinces which can be determined as Northeast, Northwest, Eastern, Central, Southwest, and Southern of China, there was at least one type II pyrethroid insecticide was detected in 54.7 % of the bee bread samples and 43.4 % of the honey. Then, we assayed the acute toxicity of type II pyrethroid insecticides based on the detection results, the LD50 value was 0.2201 µg/larva (beta-cyhalothrin), 0.4507 µg/larva (bifenthrin), 2.0840 µg/larva (fenvalerate), 0.0530 µg/larva (deltamethrin), and 0.1640 µg/larva (beta-cypermethrin), respectively. Finally, the hazard quotient was calculated as larval oral ranged from 0.046 × 10-3 to 2.128 × 10-3. Together, these empirical findings provide further insight into the accurate contamination of honey bee colonies caused by chemical pesticides, which can be used as a valuable guidance for the beekeeping industry and pesticide regulation.

Risk assessment of a Brazilian urban population due to the exposure to pyrethroid insecticides during the COVID-19 pandemic using wastewater-based epidemiology.

Pyrethroids are synthetic insecticides commonly used in agriculture and homes due to their low toxicity to mammals and effectiveness at low doses. However, exposure to pyrethroids can cause various symptoms, depending on the route of exposure. To measure human exposure to pyrethroids, researchers used wastewater-based epidemiology (WBE) with polar organic chemical integrative samplers (POCIS) sampling. This approach is a cost-effective and efficient way to assess exposure to pyrethroids. The study aimed to evaluate the exposure of an urban population in Brazil to pyrethroids during the COVID-19 pandemic using WBE with POCIS sampling. Researchers analyzed 3-phenoxybenzoic acid (3-PBA) in wastewater using passive sampling with POCIS, which was extracted with methanol and analyzed using UPLC-MS/MS. The range of CTWA concentrations of 3-PBA in wastewater was 24.3-298.2 ng L-1, with a mean value of 134 ± 76.5 ng L-1. The values were used to estimate the exposure of the population to pyrethroid insecticides. Three different conversion factors were applied to determine the range of exposure to at least 20 different pyrethroid insecticides. The exposure values ranged from 18.08 to 1441.49 mg day-1 per 1000 inhabitants. The toxicological risk posed to the exposed population was evaluated by calculating the WBE toxicological level (WBE-TL). Lambda-cyhalothrin was used as a reference for risk assessment, and the WBE-TL values for lambda-cyhalothrin ranged from 0.5 to 8.29 (considering the high CF). We compared mobility trends to 3-PBA exposure during the COVID-19 pandemic. The study highlighted the effectiveness of POCIS sampling in WBE and provided useful information for policymakers and regulatory agencies. POCIS sampling has practical advantages, including analyte pre-concentration, low operational cost, and ease of use. Overall, the study shows the importance of monitoring and understanding the exposure of the population to pyrethroid insecticides, especially during the pandemic when people may be spending more time at home.

Residue dynamics and dietary risk assessment of new formulation of novaluron and lambda cyhalothrin on tomato.

Presence of residues on food commodities is major bottleneck of insecticide use under good agricultural practices (GAPs). The use of less persistent with two different mode of action insecticide is novel approach of getting maximum insect control without developing insecticide resistance. Novaluron, an insect growth disruptor and lambda cyhalothrin, a nerve poison has been used widely for the management of lepidopteran pests. Dissipation and consumer risk analysis studies were carried out on a new combination product of novaluron and lambda cyhalothrin are used for control insects of tomato at recommended standard dose of 71 + 14 g/ha and double dose of 142 + 28 g/ha of active ingredients. Extraction and cleanup of sample residues was done using QuEChERS technique and analyzed in GC-ECD. The residues of novaluron were dissipated within 10 to 15 days, and the residues of lambda cyhalothrin were at 7 to 10 days, both at the standard and double the standard dose, following a first order reaction kinetics. Analysis of risk and hazard quotient revealed that the test insecticides do not pose any dietary risk to consumer as TMDI < MPI and HQ < 1.

In vivo-in vitro correlations (IVIVC) for the assessment of pyrethroid bioavailability in honey.

Bioaccessibility/bioavailability is an important factor in assessing the potential human health risk via oral exposure. However, methods for accurately predicting the bioaccessibility/bioavailability of pesticide residues are still limited, preventing accurate measurements of actual exposure to pesticide residues. In this study, pyrethroid bioavailability in honey were analysed using a mouse bioassay and bioaccessibility via in vitro methods with Tenax extraction. The results demonstrated that the combined liver plus kidney data served as an appropriate biomarker to estimate the relative bioavailability. Notably, significant in vivo-in vitro correlations (IVIVC) were observed between bioavailability and bioaccessibility (R2 = 0.7898-0.9793). Estimation of the bioavailability of honey from different nectar plants using derived IVIVC confirmed that different contents and physicochemical properties might affect its bioavailability. The findings provide insight into assessing human exposure to pesticides based on bioavailability and can decrease the uncertainty about the assessment of the risk of dietary exposure to pesticides.

Characterization and fitness cost of bifenthrin resistance in Rhopalosiphum padi (Hemiptera: Aphididae).

Rhopalosiphum padi is an important global wheat pest. The pyrethroid insecticide bifenthrin is widely used in the control R. padi. We explored the resistance potential, cross-resistance, adaptive costs, and resistance mechanism of R. padi to bifenthrin using a bifenthrin-resistant strain (Rp-BIF) established in laboratory. The Rp-BIF strain developed extremely high resistance against bifenthrin (1033.036-fold). Cross-resistance analyses showed that the Rp-BIF strain had an extremely high level of cross-resistance to deltamethrin (974.483-fold), moderate levels of cross-resistance to chlorfenapyr (34.051-fold), isoprocarb (27.415-fold), imidacloprid (14.819-fold), and thiamethoxam (11.228-fold), whereas negative cross-resistance was observed to chlorpyrifos (0.379-fold). The enzymatic activity results suggested that P450 played an important role in bifenthrin resistance. A super-kdr mutation (M918L) of voltage-gated sodium channel (VGSC) was found in the bifenthrin-resistant individuals. When compared with the susceptible strain (Rp-SS), the Rp-BIF strain was significantly inferior in multiple life table parameters, exhibiting a relative fitness of 0.69. Our toxicological and biochemical studies indicated that multiple mechanisms of resistance might be involved in the resistance trait. Our results provide insight into the bifenthrin resistance of R. padi and can contribute to improve management of bifenthrin-resistant R. padi in the field.

Improved Assessment of Soil Nonextractable Residues of the Pyrethroid Insecticide Cyphenothrin.

The metabolic fate of pyrethroid insecticide cyphenothrin (1) [(RS)-α-cyano-3-phenoxybenzyl (1RS)-cis-trans-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate] in soils was investigated using 14C-labeled (1R)-cis/trans isomers at the cyclopropane ring. Both isomers degraded with half-lives of 19.0-47.4 days, and 48.9-56.0% and 27.5-38.7% of the applied radioactivity (AR) were mineralized to CO2 and incorporated into nonextractable residues (NER), respectively, after 120 days at 20 °C. NER analyses revealed 37.5-42.2% (cis-1) and 44.9-54.1% (trans-1) of each residue at 30/120 days were comprised of 14C-amino acids (AAs) as microbial products. Assuming that 50% of microbial biomass is AAs, it was estimated that 11.3-22.9%AR (cis-1, 75.0-84.4% of NER) and 13.9-30.4%AR (trans-1, 89.8-108.2% of NER) were nonhazardous biogenic NER (bio-NER), while type I/II xenobiotic NER (xeno-NER) characterized by silylation was insignificant at 0.9-1.0%/2.8-3.3%AR (cis-1). Detailed 14C-AA quantitation indicated a high relevance of the tricarboxylic acid cycle and pyruvate pathway during bio-NER formation, offering new insights into the microbial assimilation of the chrysanthemic moiety.

Pyrethroid residues in Indonesian river Citarum: A simple analytical method applied for an ecological and human health risk assessment.

Pyrethroid residues in the Citarum River, Indonesia, was first investigated based on their occurrences, water assimilative capacity, and risk assessment. In this paper, first, a relatively simple and efficient method was built and validated for analysis of seven pyrethroids in a river water matrix: bifenthrin, fenpropathrin, permethrin, ß-cyfluthrin, cypermethrin, fenvalerate, and deltamethrin. Next, the validated method was used to analyze pyrethroids in the Citarum River. Three pyrethroids, ß-cyfluthrin, cypermethrin, and deltamethrin, were detected in some sampling points with concentration up to 0.01 mg/L. Water assimilative capacity evaluation shows that ß-cyfluthrin and deltamethrin pollution exceed the Citarum river water capacity. However, due to hydrophobicity properties of pyrethroids, removal through binding to sediments are expected. Ecotoxicity risk assessment shows that ß-cyfluthrin, cypermethrin and deltamethrin pose risks to the aquatic organisms in the Citarum River and its tributaries through bioaccumulation in food chain. Based on bioconcentration factors of the detected pyrethroids, ß-cyfluthrin poses the highest adverse effect to humans while cypermethrin is the safest. Human risk assessment based on hazard index suggests that acute non-carcinogenic risk associated to consuming fish from the study location polluted with ß-cyfluthrin, cypermethrin and deltamethrin is unlikely. However, hazard quotient shows that chronic non-carcinogenic risk associated to consuming fish from the study location polluted with ß-cyfluthrin is likely. However, since the risk assessment was performed separately for each pyrethroid, further assessment on the impact of mixture pyrethroid to aquatic organisms and humans should be performed to explore the real impact of pyrethroids to the river system.

Dietary exposure risk assessment of pyrethroids in fruits and vegetables: a national scale investigation.

The pyrethroids (PYRs) were extensively used to increase agriculture outputs. However, the cumulative exposures of PYRs would bring about potential risks through food intake. It is an urgent requirement to explore the cumulative exposures on the fruits and vegetables. In this study, a total of 1720 samples incorporating eight primary fruits and vegetables collected around China were investigated to assess the health risk for adults and children from eight PYRs. The relative potency factor (RPF) method was employed to reveal both chronic and acute cumulative exposure. As a result, the hazard index (HI) were 0.004 ~ 0.200% and 11.85 ~ 99.19% for chronic and acute cumulative dietary exposure, respectively. The national wide investigation indicated the cumulative assessments were not hazardous. Besides, the acute intake of pear, grape, and lettuce should be paid on more attention, particularly. This study provides compelling evidence to develop relative policy and regulation to improve the food quality and safety.