Infantile Internal and External Exposure to Neonicotinoid Insecticides: A Comparison of Levels across Various Sources

Exposure of pregnant women to neonicotinoids in Wenzhou City, East China: A biomonitoring study

BACKGROUND

China produces and consumes a large amount of neonicotinoids. A non-negligible exposure to neonicotinoids might occur for Chinese pregnant women, but relevant data remain limited.

OBJECTIVE

To investigate the exposure to neonicotinoids by urinary biomonitoring in pregnant women from Wenzhou City, East China.

METHODS

We selected 432 pregnant women in Wenzhou City in 2022. A total of eight parent neonicotinoids and four metabolites were determined in single spot urine by liquid chromatography coupled to mass spectrometry. Basic characteristics, physical activity, pre-pregnant body mass index, and intake of drinking water and food were investigated by the questionnaire. Health risk was assessed by hazard quotient (HQ) and hazard index (HI) based on human safety thresholds derived from different health endpoints.

RESULTS

Neonicotinoids and their metabolites in urine had a detection frequency between 0 % and 80.1 %. At least one neonicotinoid or metabolite was detected in 93.5 % of urine samples. Except for clothianidin (51.2 %) and N-desmethyl-acetamiprid (80.1 %), the detection frequencies of other neonicotinoids and metabolites ranged from 0 % to 43.8 %. The summed concentrations of all neonicotinoids and their metabolites ranged from < LOD to 222.83 μg/g creatinine with the median concentration of 2.58 μg/g creatinine. Maternal age, educational level, occupation, household income, screen time, and pre-pregnant body mass index were associated with detection frequencies or concentrations of neonicotinoids and their metabolites. Pregnant women with higher consumption frequencies of wheat, fresh vegetable, shellfish, fresh milk, and powdered milk had higher detection frequencies of neonicotinoids and their metabolites. Both HQ and HI were less than one.

CONCLUSIONS

Overall, pregnant women in Wenzhou City showed a notable frequency of exposure to at least one neonicotinoid, although the exposure frequency for each specific neonicotinoid was generally low. Several food items derived from plants and animals were potential exposure sources. A low health risk was found based on current safety thresholds.

The fate and transport of neonicotinoid insecticides and their metabolites through municipal wastewater treatment plants in South China

Neonicotinoid insecticides (NEOs) have gained widespread usage as the most prevalent class of insecticides globally and are frequently detected in the environment, posing potential risks to biodiversity and human health. Wastewater discharged from wastewater treatment plants (WWTPs) is a substantial source of environmental NEOs. However, research tracking NEO variations in different treatment units at the WWTPs after being treated by the treatment processes remains limited. Therefore, this study aimed to comprehensively investigate the fate of nine parent NEOs (p-NEOs) and five metabolites in two municipal WWTPs using distinct treatment processes. The mean concentrations of ∑NEOs in influent (effluent) for the UNITANK, anaerobic-anoxic-oxic (A2/O), and cyclic activated sludge system (CASS) processes were 189 ng/L (195 ng/L), 173 ng/L (177 ng/L), and 123 ng/L (138 ng/L), respectively. Dinotefuran, imidacloprid, thiamethoxam, acetamiprid, and clothianidin were the most abundant p-NEOs in the WWTPs. Conventional wastewater treatment processes were ineffective in removing NEOs from wastewater (-4.91% to -12.1%), particularly major p-NEOs. Moreover, the behavior of the NEOs in various treatment units was investigated. The results showed that biodegradation and sludge adsorption were the primary mechanisms responsible for eliminating NEO. An anoxic or anaerobic treatment unit can improve the removal efficiency of NEOs during biological treatment. However, the terminal treatment unit (chlorination disinfection tank) did not facilitate the removal of most of the NEOs. The estimated total amount of NEOs released from WWTPs to receiving waters in the Pearl River of South China totaled approximately 6.90-42.6 g/d. These findings provide new insights into the efficiency of different treatment processes for removing NEOs in current wastewater treatment systems.

Neonicotinoid insecticides and metabolites levels in neonatal first urine from southern China: Exploring links to preterm birth

Neonicotinoids (NEOs) have indeed become the most widely used insecticides worldwide. Concerns have been raised about their potential impact on newborns due to maternal exposure and their unique neurotoxic mode of action. However, it is still poorly understood whether in utero exposure of pregnant women to environmental NEOs and their metabolites can cause carryover effects on vulnerable newborns and subsequent health consequences. In this study, we determined the concentrations of 13 NEOs and their metabolites in the first urine collected from 92 newborns, both preterm and full-term, in southern China during 2020 and 2021. NEOs and their metabolites were identified in 91 urine samples, with over 93% of samples containing a cocktail of these compounds, confirming their maternal-fetal transfer. N-desmethyl-acetamiprid, imidaclothiz, clothianidin and flonicamid were the most commonly detected analytes, with detection frequencies of 59-87% and medians of 0.024-0.291 ng/mL in the urine. The relative abundance of imidaclothiz was significantly higher in preterm newborns, those with head circumferences below 33 cm, birth lengths less than 47 cm, and weights below 2500 g (p < 0.05). When comparing newborns in the 2nd quartile of imidaclothiz concentrations with those in the 1st quartile, we observed a significant increase in the odds of preterm outcomes in the unadjusted model (odds ratio = 3.24, 95% confidence interval = 1.02-10.3). These results suggest that exposure to elevated concentrations of imidaclothiz may be associated with preterm birth.

Remarkable Contamination of Short- and Medium-Chain Chlorinated Paraffins in Free-Range Chicken Eggs from Rural Tibetan Plateau

Rapid social-economic development introduces modern lifestyles into rural areas, not only bringing numerous modern products but also new pollutants, such as chlorinated paraffins (CPs). The rural Tibetan Plateau has limited industrial activities and is a unique place to investigate this issue. Herein we collected 90 free-range chicken egg pool samples across the rural Tibetan Plateau to evaluate the pollution status of CPs. Meanwhile, CPs in related soils, free-range chicken eggs from Jiangxi, and farmed eggs from markets were also analyzed. The median concentrations of SCCPs (159 ng g-1 wet weight (ww)) and MCCPs (1390 ng g-1 ww) in Tibetan free-range chicken eggs were comparable to those from Jiangxi (259 and 938 ng g-1 ww) and significantly higher than those in farmed eggs (22.0 and 81.7 ng g-1 ww). In the rural Tibetan Plateau, the median EDI of CPs via egg consumption by adults and children were estimated to be 81.6 and 220.2 ng kg-1 bw day-1 for SCCPs and 483.4 and 1291 ng kg-1 bw day-1 for MCCPs, respectively. MCCPs might pose potential health risks for both adults and children in the worst scenario. Our study demonstrates that new pollutants should not be ignored and need further attention in remote rural areas.

Identification of key factors affecting neonicotinoid residues in crops and risk of dietary exposure

Neonicotinoids, widely used on farmland, are ubiquitous in food; however, their distribution among various crops and associated exposure risks at the provincial level in China remain unclear. We collected 19 types of crop samples (fruits, vegetables, and tea) from farmland in nine prefectural cities in Zhejiang Province, China. We analyzed nine commonly used neonicotinoids in the edible portions of these crops. A notable detection rate (42.1 %-82.9 %) and high residual neonicotinoid concentrations (278 ± 357 ng/g) were observed. Tea exhibited the highest residue, followed by fruits, and vegetables showed the lowest (P < 0.05). Neonicotinoid ratios in crops to soil (R_C/S) and soil to water (R_S/W) were defined to discern insecticide distribution across different environments. Increased water solubility leads to increased migration of neonicotinoids (R_S/W) from agricultural soils to water through runoff, thereby increasing the relative contribution of nitenpyram and dinotefuran in water. In comparison with other studied compounds, all crops demonstrated the strongest soil uptake of thiamethoxam, denoted by the highest R_C/S value. Elevated R_C/S values in tea, pickled cabbage, and celery suggest increased susceptibility of these crops to neonicotinoid absorption from the soil (P < 0.05). Estimated dietary intake for teenagers, adults and elders was 8.9 ± 0.5, 8.9 ± 0.6, and 8.8 ± 0.3 μg/kg/d, respectively, below the reference dose (57 μg/kg/d). Teenagers, compared to adults and elders, exhibited significantly higher neonicotinoid exposure through fruit consumption, emphasizing the need for increased attention to neonicotinoid exposure among vulnerable populations.

Carbon quantum dots assisted BiFeO3@BiOBr S-scheme heterojunction enhanced peroxymonosulfate activation for the photocatalytic degradation of imidacloprid under visible light: Performance, mechanism and biotoxicity

A novel S-scheme heterojunction photocatalyst carbon quantum dots (CQDs)/BiFeO3/BiOBr (CBB) was synthesized via a facile hydrothermal method, which was highly effective in activating peroxymonosulfate (PMS) to photodegrade imidacloprid (IMD) (one of the typical neonicotinoid insecticides (NEOs)) under visible light irradiation. Based on the physicochemical and photoelectrochemical analysis, the super photocatalytic performance of the CBB photocatalyst was contributed to the enhanced separation and transfer of photogenerated electrons (e-) and holes (h+), the activation of PMS by reactive species, and the wider light absorption range induced by CQDs. Moreover, the intermediate products and possible photodegradation pathways of IMD were confirmed through high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS) detection and density functional theory (DFT) calculations. Although the photodegradation of IMD in the CBB/PMS/Vis system can be affected by the water quality parameters (i.e., acid group anions, pH, and the presence of humic acid (HA)), the synthesized CBB photocatalyst showed excellent photocatalytic performance in multiple natural water samples. This study provides a new idea to construct an effective and efficient heterojunction photocatalyst, which may have great advantages in photocatalytic degradation of NEOs and possibly other emerging contaminants in the aquatic environment.

Ecotoxicological impact of dinotefuran insecticide and its metabolites on non-targets in agroecosystem: Harnessing nanotechnology- and bio-based management strategies to reduce its impact on non-target ecosystems

The class of insecticides known as neonicotinoid insecticides has gained extensive application worldwide. Two characteristics of neonicotinoid pesticides are excellent insecticidal activity and a wide insecticidal spectrum for problematic insects. Neonicotinoid pesticides can also successfully manage pest insects that have developed resistance to other insecticide classes. Due to its powerful insecticidal properties and rapid plant absorption and translocation, dinotefuran, the most recent generation of neonicotinoid insecticides, has been widely used against biting and sucking insects. Dinotefuran has a wide range of potential applications and is often used globally. However, there is growing evidence that they negatively impact the biodiversity of organisms in agricultural settings as well as non-target organisms. The objective of this review is to present an updated summary of current understanding regarding the non-target effects of dinotefuran; we also enumerated nano- and bio-based mitigation and management strategies to reduce the impact of dinotefuran on non-target organisms and to pinpoint knowledge gaps. Finally, future study directions are suggested based on the limitations of the existing studies, with the goal of providing a scientific basis for risk assessment and the prudent use of these insecticides.

Exposure levels and health implications of fungicides, neonicotinoid insecticides, triazine herbicides and their associated metabolites in pregnant women and men

Exposure to pesticides can pose a series of advance effects on human health. However, the exposure levels and health implications of the current use pesticides and their metabolites in both men and pregnant women remain unclear. In this study, an analytical method was developed to quantify fungicides, neonicotinoid insecticides, triazine herbicides, and their metabolites in the human serum. Fifty of the 73 target pesticides and metabolites were detected in the human serum of men and pregnant women from Wuxi, China, which included 11 triazine herbicides and metabolites, 17 neonicotinoid insecticides and metabolites, and 22 fungicides. Fungicides had the highest cumulative concentration (49.5 ng/mL), followed by neonicotinoid insecticides and metabolites (6.38 ng/mL), and triazine herbicides and metabolites (5.10 ng/mL). Moreover, the estimated daily intake (EDI) of fungicides was 10.4 and 12.7 times higher than that of triazine herbicides (included their metabolites) and neonicotinoid insecticides (included their metabolites), respectively. Of the three categories of pesticides, exposure to fungicides contributed to the highest exposure risk within the hazard quotient in the range of 5.1 × 10-3-0.17. Correlation analysis revealed that the pesticide exposure levels in human serum were correlated with their maximum residue levels in vegetables and fruits. Pesticide exposure has also been correlated with the weight and Body Mass Index (BMI) of humans based on structural equation modeling. This study provides new insights into the exposure of men and pregnant women to a cocktail of fungicides, neonicotinoid insecticides, triazine herbicides and their metabolites.

Proteomic responses in the human dopaminergic LUHMES cell line to imidacloprid and its metabolites imidacloprid-olefin and desnitro-imidacloprid

Neonicotinoids (neonics) are amongst the most commonly used class of pesticides globally. In the United States, imidacloprid (IMI) is extensively used for agriculture and in other common applications such as house-hold pest control. Regular exposure to IMI, and several of its known metabolites including IMI-olefin and desnitro-imidacloprid (DN-IMI), has been shown to be harmful to many organisms including mammals, birds, and fish. Studies show that neonics bind human nicotinicacetylcholine receptors (nAChRs) and cause cellular toxicity. In the dopaminergic Lund human mesencephalic (LUHMES) cell line, IMI and other neonics (10-100 μM) have been recently shown to activate intracellular calcium signaling through nAChRs. Thus, we examined proteomic responses of LUHMES cells to a 48-h treatment with 50 μM IMI, IMI-olefin, or DN-IMI. Our findings show differential effects of these neonics on cellular protein expression. Bioinformatic analysis of significantly altered proteins indicates an effect of IMI, IMI-olefin, and DN-IMI on protein synthesis and ribosomal function. These findings suggest a role for protein synthesis and transcriptional regulation in neonic-mediated dopaminergic neurotoxicity.