Risk assessment of human exposure to cypermethrin during treatment of mandarin fields

Health risks of pest control and disinfection workers after the COVID-19 outbreak in South Korea

The exposure patterns of pest control and disinfection workers have changed after the coronavirus disease 2019 (COVID-19) outbreak, but the health risks of chemical exposure have not been assessed. We identified these workers' chemical exposure patterns and risks before and after the COVID-19 outbreak. We used data conducted between 2018 (pre-pandemic) and 2021 (post-pandemic) from three-year cross-sectional surveys on pest control and disinfection workers. Inhalation and dermal exposure concentrations were estimated using equations based on a biocidal product risk assessment model from the Korean National Institute of Environmental Research. The non-carcinogenic and carcinogenic risks of chemicals were calculated using the United States Environmental Protection Agency risk assessment model. We found that the annual work frequency (50th percentile) of foggers using disinfectants increased the most among all the work types, from 140 uses/year to 176 uses/year after the COVID-19 outbreak. Moreover, all chemicals' non-carcinogenic and carcinogenic risks increased regardless of exposure routes. In the worst scenario (95th percentile), the margin of exposure for citric acid, benzethonium chloride, benzyl-C12-16-alkyldimethyl chlorides, and sodium chlorite of inhalation exposure, and isopropyl alcohol and benzyl-C12-16-alkyldimethyl chlorides of dermal exposure were acceptable (>100) before the COVID-19 outbreak but became unacceptable (<100) after the COVID-19 outbreak. Carcinogenic risks of dichlorvos from inhalation and dermal exposure were above acceptable levels (>10-6) before and after the COVID-19 outbreak but comparatively high after the COVID-19 outbreak. Additionally, significantly more workers experienced health symptoms after the COVID-19 outbreak (p<0.05), with the most common being muscle lethargy (31%), skin/face stinging (28.7%), and breath shortness/neck pain (24.1%).

Exposure and risk assessment for agricultural workers during chlorothalonil and flubendiamide treatments in pepper fields

Pesticides are indispensable tools in modern agriculture for enhancing crop productivity. However, the inherent toxicity of pesticides raises significant concerns regarding human exposure, particularly among agricultural workers. This study investigated the exposure and associated risks of two commonly used pesticides in open-field pepper cultivation, namely, chlorothalonil and flubendiamide, in the Republic of Korea. We used a comprehensive approach, encompassing dermal and inhalation exposure measurements in agricultural workers during two critical scenarios: mixing/loading and application. Results revealed that during mixing/loading, dermal exposure to chlorothalonil was 3.33 mg (0.0002% of the total active ingredient [a.i.]), while flubendiamide exposure amounted to 0.173 mg (0.0001% of the a.i.). Conversely, dermal exposure increased significantly during application to 648 mg (chlorothalonil) and 93.1 mg (flubendiamide), representing 0.037% and 0.065% of the total a.i., respectively. Inhalation exposure was also evident, with chlorothalonil and flubendiamide exposure levels varying across scenarios. Notably, the risk assessment using the Risk Index (RI) indicated acceptable risk of exposure during mixing/loading but raised concerns during application, where all RIs exceeded 1, signifying potential risk. We suggest implementing additional personal protective equipment (PPE) during pesticide application, such as gowns and lower-body PPE, to mitigate these risks.

Potential exposure and risk assessment of agricultural workers to the insecticide chlorantraniliprole in rice paddies

BACKGROUND

Exposure of agricultural workers in rice paddies to the insecticide chlorantraniliprole and its subsequent potential health risks were investigated during two scenarios (mixing/loading and hand-held spraying). The exposure factors, such as the outer dosimeter, inner dosimeter, gauze, and nitrile gloves, were calculated using whole-body dosimetry to measure dermal exposure. The inhalation exposure was determined using a fiberglass filter which is set with an Institute of Occupational Medicine (IOM) sampler. A recovery test was performed to evaluate the accuracy of the analytical method.

RESULTS

The exposure amounts of various matrices were calculated from extraction volume and concentration of the target compound. The dermal exposure to chlorantraniliprole was 0.6 mg [0.001% of the total active ingredient (a.i.)] for mixing and loading, and 28.6 mg (0.066% of the total a.i.) for application. The inhalation exposure to chlorantraniliprole was 7.2 μg (1.3%, 1.2 × 10^-5 % of the total applied a.i.) for mixing and loading, and 1.9 μg (0.006%, 4.4 × 10^-6 % of the total applied a.i.) for application. The most exposed part of the body was the hand (90.4%) during mixing and loading, whereas the primary sites during application were the thighs (32.8%) and shins (22.6%). For mixing and loading, the amount of actual dermal exposure was 5.5 μg day^-1 and that of actual inhalation exposure was 21.9 μg day^-1 . By contrast, in the application, the amounts of actual dermal and actual inhalation exposures were 34 178.7 and 5.9 μg day^-1 , respectively.

CONCLUSIONS

The risk assessment results demonstrated that the risk of chlorantraniliprole exposure in rice paddies was low during application than during mixing and loading. © 2022 Society of Chemical Industry.

Occupational exposure and risk assessment for agricultural workers of thiamethoxam in vineyards

Dermal & inhalation exposure was examined and according to these results, risk assessment of agricultural workers to thiamethoxam was performed during pesticide mixing/loading and hand-held sprayer application (11 replicates, each of about 1000 L of spray suspension) in vineyards. For the whole body dosimetry (WBD), clothing (Outer and inner), gauze, and nitrile gloves were analyzed to determine dermal exposure using whole-body dosimetry exposure protocol. The inhalation exposure was measured using a glass fiber filter with an IOM sampler. Analytical method validation of exposure matrices was evaluated including the field recovery and breakthrough test. The dermal exposure amount during mixing/loading was 0.163 mg (0.0004% of the total mixed/loaded active ingredient [a.i.]), whereas there was no inhalation exposure. The gloves (0.154 mg, 94.5%) were the most exposed body parts followed by the chest and stomach (0.009 mg, 5.5%). During application, the dermal and inhalation exposure amounts were 32.3 mg (0.07% of the total applied a.i.) and 10.8 µg (2.4 × 10^-6% of the total applied a.i), respectively. The shin (35.1%) had the highest exposure to pesticides, followed by the chest & stomach (15.6%) and pelvis (12.6%). In case of mixing/loading, the amounts of actual dermal exposure (ADE) and actual inhalation exposure (AIE) were 0.0 and 0.0 μg/day, while those of ADE and AIE were 4707.6 and 15.8 μg/day for application. In risk assessment of the two different scenarios, the risk index was much lower than 1 (mixing/loading:0.000, application:0.014), indicating that vineyard workers are at low risk of thiamethoxam exposure. To determine the validity of the risk assessment using WBD method, the urinary metabolite was analyzed. Comparison of biomonitoring data and WBD exposure data show a reliable correlation (r = 0.885, p = 0.0003), suggesting that these are suitable methods to estimate exposure.

Cypermethrin induces apoptosis of Sertoli cells through the endoplasmic reticulum pathway

Cypermethrin, an extensively used pyrethroid pesticide, is regarded as one of many endocrine-disrupting chemicals (EDCs) with anti-androgenic activity to damage male reproductive systems. We previously found cypermethrin-induced apoptosis in mouse Sertoli cells TM4. We hypothesized cypermethrin-induced TM4 apoptosis by the endoplasmic reticulum (ER) pathway. This study aimed to explore the roles of the ER pathway in cypermethrin-induced apoptosis in TM4 cells. The cells were treated with cypermethrin for 24 h at various concentrations (0 µM, 10 µM, 20 µM, 40 µM, and 80 µM). Flow cytometry was used to test for apoptosis. Western blot was used to test protein expressions in the ER stress pathway. The results showed that the apoptosis rate of TM4 cells increased with increased concentrations of cypermethrin, and a significant difference was detected in the 80-μM group. The protein expressions of glucose-regulated protein 78 (GRP78), protein kinase R (PKR)-like ER kinase (PERK), p-PERK, α subunit of eukaryotic initiation factor (eIF2α), p-eIF2α, activating transcription factor 4 (ATF4), C/EBP homologous protein (CHOP), caspase-12, caspase-9, and caspase-3 increased with increased concentrations of cypermethrin . The results suggested cypermethrin-induced apoptosis in TM4 cells regulated by the ER pathway involving PERK-eIF2α-ATF4-CHOP. The study provides a new insight into cypermethrin-induced apoptosis in Sertoli cells.

High pesticide inhalation exposure from multiple spraying sources amongst applicators in Eswatini, Southern Africa

BACKGROUND

Serious concerns surround the potential risks resulting from inhalation exposure to pesticides amongst agricultural workers when mixing and applying these compounds. In Eswatini (formerly known as Swaziland), Southern Africa, pesticides are widely used to improve the yield and quality of sugar cane production, the largest contributor to the country's economy. We assessed applicators' inhalation exposures from multiple spraying sources to four commonly used herbicides in Eswatini.

RESULTS

Analysis of 76 personal air samples by liquid chromatography with tandem mass spectrometry (LC-MS/MS) revealed four pesticides: ametryn, atrazine, pendimethalin and 2,4-dichlorophenoxyacetic acid, with mean concentrations of 36.91, 21.57, 31.05 and 0.89 μg m^-3 , respectively. These inhalation exposures are much higher than those recorded in previous similar studies.

CONCLUSION

Although all applicators in this study used personal protective equipment (PPE), they nevertheless recorded high levels of inhalation exposure to commonly used pesticides. Our findings suggest that in addition to observing mandated regular changing and cleaning practices with PPE for ultimate personal protection, pesticide applicators should distance themselves from each other when spraying to effectively reduce their exposure to pesticides from multiple spraying sources. Further studies are needed to determine the optimal spraying distance between pesticide applicators. © 2021 Society of Chemical Industry.

Enantioselectivity in endocrine disrupting effects of four cypermethrin enantiomers based on in vitro models

Cypermethrin (CP) is a kind of chiral pesticides that has been defined as endocrine disrupting chemical. The diversity in bioactivity, toxicity, metabolism, bioaccumulation, and degradation behaviors of CP enantiomers as well as the research deficiency had made the risk assessment of CP enantiomers very complicated. Herein, four CP enantiomers were separated as target chemicals to investigate their enantioselective endocrine disrupting effects. Firstly, dual-luciferase reporter gene assays were adopted to investigate their potential endocrine disrupting effects via various receptors. The expression levels of steroid hormones related genes and hormone secretion levels in H295R cell were measured to verify the results. Results from the reporter gene assay showed that 1R-cis-αS-CP (CP11) exhibited glucocorticoid receptor (GR), mineralocorticoid receptor (MR), and thyroid receptor (TR) antagonistic activity with the RIC₂₀ values of 9.22 × 10^-7, 3.33 × 10^-7, and 4.47 × 10^-7 M, respectively; 1R-trans-αS-CP (CP21) also showed androgen receptor (AR) agonist activity and estrogen receptor (ER) antagonistic activity with the REC₂₀ and RIC₂₀ values were 1.07 × 10^-4 M and 4.78 × 10^-6 M, respectively. Results of qRT-PCR and hormone measurement also showed that CP11 and CP21 could disturb the expression of steroid hormones related genes and hormone secretion accordingly. Results provided here can help to understand the enantioselective ecological and health risks of CP enantiomers comprehensively and provide constructive guidance for the safe use of chiral pesticides and the invention of green pesticides.

Whole body dosimetry and risk assessment of agricultural operator exposure to the fungicide kresoxim-methyl in apple orchards

This study examined dermal and inhalation exposure of agricultural operators to kresoxim-methyl during pesticide mixing/loading and speed sprayer application (10 replicates, each of 3000 L of spray suspension) in an apple orchard and performed risk assessment. For the whole body dosimetry (WBD) exposure protocol, outer clothing, inner clothing, gauze, and nitrile gloves were examined to measure dermal exposure. In contrast, an IOM (institute of occupational medicine) sampler with a glass fiber filter was used to measure inhalation exposure. Analytical method accuracy in the exposure matrices was evaluated by a field recovery study. The dermal and inhalation exposure amounts for mixing/loading were 9.7 mg [0.002% of the total mixed/loaded active ingredient (a.i.)] and 1.2 µg (1.7 × 10^-6% of the total mixed/loaded a.i.), respectively. The body parts more exposed were the forearms (35.5%), chest & stomach (30.2%), and hands (17.9%). During application, the dermal and inhalation exposure amounts were 66.5 mg (0.009% of the total applied a.i) and 34.8 µg (4.6 × 10^-5% of the total applied a.i.), respectively. The shins (18.5%) and chest & stomach (16.0%) were exposed to higher proportion of pesticide, followed by the thighs (15.8%) and back (14.7%). Comparing the exposure pattern as assessed by the WBD method in the present study with the patch method as in our previous study, the ADE (actual dermal exposure) as measured by the WBD method was 25 times less than that measured by the patch method. The daily exposure amounts of ADE and AIE (actual inhalation exposure) for mixing/loading were 711.8 µg/day and 4.3 µg/day, respectively, whereas the amounts of ADE and AIE for application were 1825.8 µg/day and 116.1 µg/day. In risk assessment of the mixing/loading and application scenarios, the AOEL (acceptable operator exposure level) of kresoxim-methyl was used as the reference dose to show that the RI (risk index) was much lower than 1, indicating that agricultural operators are at low risk of exposure to kresoxim-methyl.

Potential exposure to clothianidin and risk assessment of manual users of treated soil

BACKGROUND

Treated soil is the second most prevalent application technique for all registered pesticides in China. Some developing countries also adopt this method. However, the safety of this scenario has not been reported in the literature. Experiments were therefore conducted to assess exposure using standard whole-body dosimetry and air sampling methodologies.

RESULTS

Dermal deposition was the main route of exposure in this scenario. The total dermal unit exposure (UE) of operators to clothianidin-treated soil was 51.7 mg kg^-1 AI handled (SD = 20.59, n = 16), and hands accounted for 36%. Inhalation UE was 0.04 mg kg^-1 AI handled (SD = 0.02, n = 4), negligible compared with dermal exposure. Using an NOAEL (no observed adverse effect level) of 10 mg kg^-1 day^-1 , the margin of exposure was 773, i.e. greater than 100.

CONCLUSION

For the first time, the scenario of treated soil exposure was assessed and was found to pose less risk than conventional pesticide application. These results can be used as a reference in pesticide management. © 2017 Society of Chemical Industry.

Probabilistic Exposure Assessment for Applicators during Treatment of the Fungicide Kresoxim-methyl on an Apple Orchard by a Speed Sprayer

Probabilistic exposure and risk assessment of kresoxim-methyl were conducted for agricultural applicators during preparation of spray suspension and application with a speed sprayer on an apple orchard. The preparation and application of 1000 L of spray suspension were repeated 30 times. Several exposure matrices, including patches, cotton gloves, socks, masks, and XAD-2 resin, were used to measure the potential exposure for workers. The analytical methods were fully validated to guarantee the precision and accuracy of analysis. The exposure amount on hands for mixer/loader was 0.7 mg [95% confidence interval (CI) from 0.02 to 2.4], taking 0.0005% (95% CI from 1.2 × 10(-5) to 0.001) of total prepared active ingredient. During application of kresoxim-methyl, the amount of dermal exposure was 17.5 mg (95% CI from 9.3 to 28.9), corresponding to 0.010% (95% CI from 0.006 to 0.017) of total applied active ingredient. The major exposure parts of the body were thighs and shins, with correlation coefficients of 0.53 and 0.43, respectively. The inhalation exposure during application were estimated as 6.8 ng (95% CI from 0.4 to 17.0), being 0.04% (95% CI from 0.004 to 0.06) of the dermal exposure. The calculated absorbable quantities of exposures for mixer/loader and applicator were 2.1 × 10(-4) mg/day (95% CI from 5.0 × 10(-6) to 7.2 × 10(-4)) and 2.3 mg/day (95% CI from 1.2 to 3.8), respectively. For risk assessment, the margin of safety of all working activities was much higher than 1, indicating that the possibility of risk to kresoxim-methyl was unlikely.

Identifying the metabolic perturbations in earthworm induced by cypermethrin using gas chromatography-mass spectrometry based metabolomics

Globally, cypermethrin is one of the most widely used synthetic pyrethroid for agricultural and domestic purposes. Most part of the pesticides used in the agriculture ends up as residues in the soil, making soil dwelling organisms, especially earthworms more susceptible to pesticide intoxication. Cypermethrin is known to be a neurotoxicant to many model organisms, including mammals and insects, but such type of toxicity evidence is not available for invertebrate systems like earthworms. In the present work, metabolomics based approach was utilized to identify the toxic mechanism of action of cypermethrin on earthworm (Metaphire posthuma) and these were exposed to sub-lethal concentrations of cypermethrin such as 2.5 mg/kg, 5 mg/kg, 10 mg/kg and 20 mg/kg (1/40^th, 1/20^th, 1/10^th and 1/5^th of LC₅₀, respectively) for fourteen days. The results revealed that 22 metabolites (mainly fatty acids, sugars and amino acids) were shown significant responses in the exposed earthworms and these responses are dose dependent. It is proposed that mainly carbohydrate and fatty acids in neural system metabolism was disturbed. Overall, the results provided that metabolomics can be an effective tool to understand the effects of cypermethrin on the metabolic responses of earthworm Metaphire posthuma.

Potential Dermal Exposure to Flonicamid and Risk Assessment of Applicators During Treatment in Apple Orchards

Exposure and risk assessments of flonicamid for applicators were performed in apple orchards in Korea. Fifteen experiments were done with two experienced applicators under typical field conditions using a speed sprayer. In this study, cotton gloves, socks, masks, and dermal patches were used to monitor potential dermal exposure to flonicamid, and personal air samplers with XAD-2 resin and glass fiber filter were used to monitor potential inhalation exposure. The analytical methods were validated for the limit of detection, limit of quantitation, reproducibility, linearity of the calibration curve, and recovery of flonicamid from various exposure matrices. The results were encouraging and acceptable for an exposure study. The applicability of XAD-2 resin was evaluated via a trapping efficiency and breakthrough test. During the mixing/loading, the average total dermal exposure was 22.6 μg of flonicamid, corresponding to 4.5×10(-5)% of the prepared amount. For the spraying, the potential dermal exposure was 9.32 mg, and the ratio to applied amount was 1.9 × 10(-2%). The primary exposed body parts were the thigh (2.90 mg), upper arm (1.75 mg), and lower leg (1.66 mg). By comparison, absorbable quantity of exposure was small, only 1.62 μg (3.2×10(-6)%). The margin of safety (MOS) were calculated for risk assessment, in all sets of trials, MOS > 1, indicating the exposure level of flonicamid was considered to be safe in apple orchards. Although this was a limited study, it provided a good estimate of flonicamid exposure for orchard applicators.

Risk assessment of applicators to chlorpyrifos through dermal contact and inhalation at different maize plant heights in China

Dermal and respiratory exposure assessments and risk assessment for applicators were performed with 48% chlorpyrifos EC. The chlorpyrifos was applied with lever-operated knapsacks under three spraying environments, namely, average maize field heights of 62 cm (A1), 108 cm (A2), and 212 cm (A3). The whole body dosimetry technique was applied to collect dermal exposure samples including cotton protective garments, gloves, socks, and hats. A personal air monitor equipped with an XAD-2 resin was used for respiratory exposure assessment. Without personal protective equipment (PPE) the total potential dermal exposure (PDE) was 27.8, 90.6, and 462.1 mL h(-1) under A1, A2, and A3 spraying environments, respectively. In addition, with the change in the maize plant height, the major exposure parts on the applicators were also different. Under single-layer garment and glove protection circumstances, internal dermal exposure (IDE) was 3.37 mL h(-1) for A1, 4.28 mL h(-1) for A2, and 18.32 mL h(-1) for A3. Potential inhalation exposure (PIE) was detected in A3, but it was not detected in A1 and A2. For risk assessment, the margin of safety (MOS) was calculated from the PDE or IDE and PIE. The MOS values for the three spraying environments were <1 under no PPE and single-layer garment and glove protection circumstances, indicating high possibility of health risk. However, with double protective garments, the MOS values for A1 and A2 cases were all >1, but the MOS was <1 in the A3 case.

Maternal cypermethrin exposure during the perinatal period impairs testicular development in C57BL male offspring

Numerous studies have demonstrated that endocrine-disrupting compounds (EDC) are a possible cause of male reproductive organ malfunction and malformation. Cypermethrin (CYP) is a widely used synthetic pyrethroid and a potential EDC. This study aimed to examine the effects of perinatal exposure to low-dose CYP on the development and function of the offspring testes. Pregnant mice were intragastrically administered 0.12 to 12 mg/kg/day CYP from embryonic day 0.5 (E0.5) to weaning (PD21.5, postnatal day 21.5). Maternal exposure to 0.12, 1.2, and 12 mg/kg/day CYP affected the body and organ weight of the offspring. Exposure of CYP led to a dose-dependent decrease in the male-to-female sex ratio. A histopathological analysis revealed a thinner seminiferous epithelium layer at PD21.5, interstitial hyperplasia at PD45.5, and germ cell vacuolization at PD90.5 in the 12 mg/kg/day CYP group. The TUNEL assay results revealed increased germ cell apoptosis in the 12 mg/kg/day CYP group. The serum testosterone (T) level decreased, whereas the estradiol level increased with age in the 1.2 and 12 mg/kg/day CYP groups. The RT-PCR analysis demonstrated decreased expression of T production-related, mitosis-related, and meiosis-related genes in the 1.2 and 12 mg/kg/day CYP groups. The in vitro experimental results demonstrated reduced expression of steroidogenesis genes and decreased T levels. It is concluded that perinatal exposure to low-dose CYP affects testes development and function in adults.

Measurement of operator exposure to chlorpyrifos

BACKGROUND

To date, no research has been conducted to establish exposure levels for occupational pesticide operators under typical use scenarios in China. Through surrogate skin techniques (the whole-body method), the authors monitored dermal and inhalation exposure of pesticide applicators in China. In addition, the exposure of pesticide mixers was analysed.

RESULTS

The total dermal exposure of inexperienced and experienced applicators was respectively 4037 and 536 mg kg(-1) of active ingredient (AI) handled for application to maize that was <80 cm in height. The exposure level was highest on hands; the closer to the hands, the lower arms and the upper legs, the higher the exposure. The unit exposure of mixers differed according to the formulation; exposure to emulsifiable concentrate (EC) and oil-in-water emulsion (EW) was greater than exposure to wettable powder (WP) or wettable dispersible granules (WG). The unit exposure of mixers via inhalation was significantly greater than that of applicators when chlorpyrifos (48% EC) was used (P < 0.0001).

CONCLUSIONS

The main objectives of this study were to provide an indication of the realistic exposure risk of mixers and applicators, and to contribute useful information for risk mitigation and management and epidemiological studies in China.

A preliminary comparison of three dermal exposure sampling methods: rinses, wipes and cotton gloves

Several methods exist to estimate dermal exposure and it is unclear how comparable they are. These methods fall into three main categories: (i) removal techniques (such as wiping or rinsing); (ii) interception techniques (such as gloves, patches, or coveralls); and (iii) fluorescent tracer techniques. Controlled experiments were conducted to compare two removal methods for exposure to particulate, and a removal method with an interception method for exposure to liquids. Volunteers' hands were exposed to three liquid solutions (glycerol-water solutions of different concentrations) and three particulates (Epsom salts, calcium acetate and zinc oxide) in simulated exposure scenarios. Both hands were exposed and a different sampling method was used on each to allow comparison of methods. Cotton glove samplers and a cotton wipe sampling method were compared for exposure to liquids. For exposure to powders a cotton wipe sampling method was compared to rinsing the hands in deionised water. Wipe and rinse methods generally yielded similar results for Epsom salts and zinc oxide (geometric mean [GM] ratios of wipe-to-rinse measurements of 0.6 and 1.4, respectively) but they did not for calcium acetate (GM wipe-to-rinse ratio of 4.6). For glycerol solutions measurements from the glove samplers were consistently higher than wipe samples. At lower levels of exposure the relative difference between the two methods was greater than at higher levels. At a hand loading level of 24,000 μg cm(-2) (as measured by wiping) the glove-to-wipe ratio was 1.4 and at a hand loading of 0.09 μg cm(-2) the ratio was 42.0. Wipe and rinse methods may be directly comparable but the relationship between glove and wipe sampling methods appears to be complex. Further research is necessary to enable conversion of exposure measurements from one metric to another, so as to facilitate more reliable risk assessment.

Assessment of the exposure of workers to the insecticide imidacloprid during application on various field crops by a hand-held power sprayer

Exposure assessment and risk assessment for imidacloprid were conducted for agricultural workers through mixing/loading and application with a power sprayer in four kinds of crop fields. The spray suspension was prepared with 10% wettable powder (250 g) for 5 min and applied on field crops for 1 h. A patch method and a personal air sampler with XAD-2 resin were used to monitor the dermal and inhalation exposure, respectively. In mixing/loading, the total dermal exposure on the whole body was 0.2 (cucumber) to 2.0 (apple) mg and the most exposed part of body was the hand (48-100% of total exposure). During the application of imidacloprid, whole dermal exposure was in the range of 2.9 (apple) to 9.5 (green pepper) mg. The primary sites exposed to pesticides were legs (51-79% of total exposure) in cucumber, green pepper, and paddy fields, whereas the primary sites were hands (35% of total exposure) in the apple field. The inhalation exposure was determined to be 0.2 (paddy) to 2.8 (cucumber) μg and 0.2 (paddy) to 3.0 (cucumber) μg during mixing/loading and application, respectively. The absorbable quantity of exposure and the margin of safety were determined for risk assessment. Workers were exposed through inhalation as 23-93 and 2-11% of the absorbable quantity of exposure during mixing and application, respectively. The margin of safety of all cases was much higher than 1, indicating the lowest possibility of risk.

Risk assessment of the exposure of insecticide operators to fenvalerate during treatment in apple orchards

Dermal and inhalation exposure of the applicator to the insecticide fenavalerate in an apple orchard was measured for risk assessment during treatment. Emulsifiable concentrate (EC) and wettable powder (WP) formulations were sprayed using a speed sprayer (SS) or power sprayer (PS). Dermal patches, gloves, socks, and masks were used to monitor potential dermal exposure to fenavalerate, while personal air samplers with XAD-2 resins were used to monitor potential inhalation exposure. Validation of analytical methods was performed for the instruments' limit of detection, limit of quantitation, reproducibility, linearity of calibration curve, and recovery of fenvelerate from various exposure matrices. The results were encouraging and reasonable for an exposure study. Applicability of XAD-2 resin was evaluated with a trapping efficiency and breakthrough test. During mixing/loading, the amount of dermal exposure ranged from 262.8 μg (EC/SS) to 1652.6 μg (WP/PS) of fenvalerate, corresponding to ~0.0011-0.0066% of the total prepared quantity. In the case of WP, the amount of dermal exposure was 2032.3 μg (0.0081% of the total applied amount) for SS and 1087.9 μg (0.0145%) for PS after application. In the case of EC, the amount of dermal exposure was 3804.6 μg (0.0152%) for SS and 4055.0 μg (0.0541%) for PS after application. The primary body parts subject to exposure were thigh and upper arm for SS, and thigh and hand for PS. The amount of inhalation exposure with WP was 2.2 μg (8.65 × 10⁻⁶% of the total applied amount) for SS and 1.3 g (1.67 × 10⁻⁵%) for PS. The amount of inhalation exposure with EC was 2.5 μg (9.81 × 10⁻⁶%) for SS and 3.7 μg (4.97 × 10⁻⁵%) for PS. The absorbable quantity of exposure and margin of safety (MOS) were calculated for risk assessment. The MOS for all 4 cases was much greater than 1, indicating a low possibility of risk.

A current review of cypermethrin-induced neurotoxicity and nigrostriatal dopaminergic neurodegeneration

Cypermethrin, a class II pyrethroid pesticide, is used to control insects in the household and agricultural fields. Despite beneficial roles, its uncontrolled and repetitive applications lead to unintended effects in non-target organisms. Cypermethrin crosses the blood-brain barrier and induces neurotoxicity and motor deficits. Cypermethrin prolongs the opening of sodium channel, a major site of its action, leading to hyper-excitation of the central nervous system. In addition to sodium channel, cypermethrin modulates chloride, voltage-gated calcium and potassium channels, alters the activity of glutamate and acetylcholine receptors and adenosine triphosphatases and induces DNA damage and oxidative stress in the neuronal cells. Cypermethrin also modulates the level of neurotransmitters, including gamma-aminobutyric acid and dopamine. It is one of the most commonly used pesticides in neurotoxicology research not only because of its variable responses depending upon the doses, time and routes of exposure and strain, age, gender and species of animals used across multiple studies but also owing to its ability to induce the nigrostriatal dopaminergic neurodegeneration. This article describes the effect of acute, chronic, developmental and adulthood exposures to cypermethrin in experimental animals. The article sheds light on cypermethrin-induced changes in the central nervous system, including its contribution in the onset of specific features, which are associated with the nigrostriatal dopaminergic neurodegeneration. Resemblances and dissimilarities of cypermethrin-induced nigrostriatal dopaminergic neurodegeneration with sporadic and chemicals-induced disease models along with its advantages and pitfalls are also discussed.

Factors associated with self-reported symptoms of acute pesticide poisoning among farmers in northwestern Jamaica

Pesticide poisoning is a major public health concern in developing countries. The authors conducted a population survey among farmers in 3 parishes of northwestern Jamaica to determine the occurrence of acute pesticide poisoning and to identify factors associated with pesticide poisoning. Approximately 16% of 359 farmers who participated in the study reported 1 or more incidents of acute pesticide poisoning within the last 2 years. Only 25% of the farmers reported ever receiving training in pesticide handling or safety. The majority (68%) of farmers who reported pesticide poisoning never sought medical attention for poisoning. The factors found to be associated with pesticide poisoning in this study indicate that implementation of specific intervention strategies and education of farmers is needed in order to improve safe handling, use, and disposal of pesticides and reduce incidents of acute pesticide poisoning.

Long term exposure to cypermethrin induces nigrostriatal dopaminergic neurodegeneration in adult rats: postnatal exposure enhances the susceptibility during adulthood

The study aimed to investigate the effects of cypermethrin on biochemical, histopathological, and motor behavioral indices of the nigrostriatal dopaminergic system in adult rats treated with or without cypermethrin (1/10 adult dose) during postnatal days 5-19. Spontaneous locomotor activity (SLA) and rotarod tests were performed to assess motor behavior. Levels of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the striatum, and tyrosine hydroxylase (TH) immunoreactivity and 4',6-diamidino-2-phenylindole (DAPI)/Fluoro-Jade B staining in the substantia nigra were measured to assess dopaminergic neurodegeneration. Postnatal treated animals did not exhibit significant changes in any measured parameters. The significant reduction in the time of stay on rotarod, spontaneous locomotor activity, dopamine, 3,4-dihydroxyphenylacetic acid, and tyrosine hydroxylase immunoreactivity while an increase in homovanillic acid level and Fluoro-Jade B-positive cells were observed in cypermethrin treated adult rats. These changes were more pronounced in the animals treated with cypermethrin during postnatal days followed by adulthood compared with adulthood alone. The results obtained thus demonstrate that exposure to cypermethrin during adulthood induces dopaminergic neurodegeneration in rats and postnatal exposure enhances the susceptibility of animals to dopaminergic neurodegeneration if rechallenged during adulthood.

Effect of spray application technique on spray deposition in greenhouse strawberries and tomatoes

BACKGROUND

Increasingly, Flemish greenhouse growers are using spray booms instead of spray guns to apply plant protection products. Although the advantages of spray booms are well known, growers still have many questions concerning nozzle choice and settings. Spray deposition using a vertical spray boom in tomatoes and strawberries was compared with reference spray equipment. Five different settings of nozzle type, size and pressure were tested with the spray boom.

RESULTS

In general, the standard vertical spray boom performed better than the reference spray equipment in strawberries (spray gun) and in tomatoes (air-assisted sprayer). Nozzle type and settings significantly affected spray deposition and crop penetration. Highest overall deposits in strawberries were achieved using air-inclusion or extended-range nozzles. In tomatoes, the extended-range nozzles and the twin air-inclusion nozzles performed best. Using smaller-size extended-range nozzles above the recommended pressure range resulted in lower deposits, especially inside the crop canopy.

CONCLUSIONS

The use of a vertical spray boom is a promising technique for applying plant protection products in a safe and efficient way in tomatoes and strawberries, and nozzle choice and setting should be carefully considered.

Potential dermal pesticide exposure affected by greenhouse spray application technique

BACKGROUND

Operator safety is still one of the main problems concerning greenhouse spray applications in South European horticulture. The main objective of this study was to compare potential dermal exposure (PDE) between traditional handheld spray application techniques (i.e. a standard spray gun walking forwards, a spray lance walking forwards and backwards) and novel spray application techniques with spray booms (i.e. a trolley, the Fumimatic and the Fumicar).

RESULTS

PDE varied from 19.7 mL h(-1) for the Fumimatic to 460 mL h(-1) for the spray lance walking forwards. Walking backwards reduced PDE by a factor 7. With the trolley, Fumimatic and Fumicar, PDE was respectively 20, 60 and 8 times lower than with the standard spray gun. With the spray lance, PDE was about 2.5 times higher than with the spray gun. Pesticide distribution over the operator's body was non-uniform and correlated strongly with the application technique. With the traditional techniques, exposure to the legs and feet represents 60-80% of the total exposure.

CONCLUSIONS

Novel spray application techniques using spray booms greatly decrease operator exposure because the operator is not walking directly into the spray cloud and the sprayed crop, and because of their higher capacity. Depending on the type of spray application, different parts of the body need to be protected most.