Risk assessment of dermal exposure of greenhouse workers to pesticides after re-entry

Determinants of Skin and Respiratory Exposure to Lufenuron During Spraying and Re-entry in Italian Ornamental Plants Greenhouses

The aim of this study was to evaluate dermal and respiratory exposure of workers to Lufenuron during spraying and re-entry on ornamental plants (stapling) in greenhouses. Potential and real skin exposure were evaluated using filter paper pads, hand contamination by washing, and respiratory exposure by personal air sampling. Dislodgeable foliar residues (DFRs) during re-entry were determined in order to calculate the dermal transfer factor (DTF). Lufenuron was analysed by liquid chromatography-mass detection. Respiratory dose (ReD) was calculated on the basis of a lung ventilation of 15-20 l min-1 and absorbed doses assuming a skin penetration of 13% and a respiratory retention of 100%. During stapling, from the dependence of exposure of hands from DFRs, the mean DTF was 0.575 cm2 h-1 (geometric mean). The ReD was 68.7-74.6 and 0.022-0.636% of the total real dose during spraying and stapling, respectively. The absorbed doses, 0.144-0.171 and 0.005-0.124 µg kg bw-1 during spraying and stapling, respectively, were less than the acceptable operator exposure level of 10 µg kg bw-1. Proper use of equipment and personal protective equipment and personal hygiene are aspects of fundamental importance on which workers must be trained. Adequate occupational hygiene studies are needed to support and verify working practices.

Occupational exposure to pesticides and associated health effects among greenhouse farm workers

The number and production capacities of greenhouse farms have been increased across the globe, driven by an effort for addressing food security problems related to the rapid population growth and the effects of climate change. As a result, there was a large increase in the number of greenhouse farm workers who are typically involved in chemical preparations and pesticide sprayings, crop harvesting, and greenhouse maintenance activities. Considering the enclosed architecture of the greenhouse farm design and the frequent application of pesticides, the objective of this review was to characterize pesticide exposure levels and resultant health effects among greenhouse farm workers. While most health assessment studies were mainly based on self-reported symptoms, this review showed limited epidemiological and clinical studies on the assessment of the health effects of pesticide exposure on greenhouse workers' health. Reproductive disorders, respiratory symptoms, neurological symptoms, and skin irritations were the most reported health effects among greenhouse farm workers. Additionally, there were limited studies on respirable pesticide-borne fine and ultrafine particulate matters in greenhouse farms. Ventilation systems and indoor environmental conditions of greenhouse farms were not designed according to specifications of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). Among recommendations provided, long-term exposure assessments of pesticide effects on children born by greenhouse farm workers should be considered in future research. Also, compliance with ASHRAE indoor ventilation and environmental standards will be very important in reducing pesticide exposure and health effects among greenhouse farm workers.

The greenhouse work environment: a modifier of occupational pesticide exposure?

Greenhouses are enclosed structures which have various characteristics that enhance crop productivity, but the implications for workers' pesticide exposure and uptake are not well understood. A narrative literature review was conducted to explore the mechanism/s of interactions between greenhouse characteristics and occupational pesticide exposure. Using a "work", "worker" and "workplace" conceptual framework, the greenhouse environment (hot and humid microclimate, limited space and dense crop arrangements) combines with work characteristics (high work and pesticide use intensity, multi-tasking, predominantly manual spraying techniques and quick reentry to treated farms) to potentially increase occupational pesticide exposure, compared with open field farming. Greenhouse environments, are variable but have been shown to influence pesticide availability, route, pathways and frequency of exposure, deposition and distribution on a worker's body as well as use and performance of exposure control methods. Training programs can emphasize the differences in exposure potential between greenhouse and open field farming. Development of tailored guidelines for exposure control strategies to better suit the level of uniqueness of greenhouse agriculture seems warranted.

Risk Assessment of Florists Exposed to Pesticide Residues through Handling of Flowers and Preparing Bouquets

Flowers are frequently treated with pesticides and, as a result, florists handling daily a large number of flowers can be exposed to pesticide residues. A study was conducted among twenty volunteer florists located in Namur Province and in the Brussels Capital Region of Belgium in order to assess their potential dermal exposure to dislodgeable pesticide residues transferred from flowers to hands. Two pairs of cotton gloves were worn during two consecutive half days while handling flowers and preparing bouquets (from min 2 h to max 3 h/day). The residual pesticide deposits on the glove samples were extracted with a multi-residue Quick Easy Cheap Effective Rugged Safe (QuEChERS) method and analyzed by a combination of gas and liquid chromatography tandem mass spectrometry (GC-MS/MS and LC-MS/MS) by an accredited laboratory. A total of 111 active substances (mainly insecticides and fungicides) were detected, with an average of 37 active substances per sample and a total concentration per glove sample of 22.22 mg/kg. Several predictive levels of contamination were considered to assess the risk. The potential dermal exposures (PDE) of florists were estimated at the average, for different percentiles, and at the maximum concentration of residues in samples. At the PDE P90 and at the PDEMAX (or worst case) values, three and five active substances respectively exceed the Acceptable Operator Exposure Level (AOEL), indicating risk situations. For the systemic exposure (SE), one active substance (clofentezine) exceeds the AOEL at the P90 predictive level. In the worst case, SEMAX (at the maximum concentrations), four active substances (clofentezine, famoxadone, methiocarb, and pyridaben) exceed their respective AOEL values. Among the 14 most frequently detected active substances, two have SEMAX values exceeding the AOEL. Exposure could be particularly critical for clofentezine with an SEMAX value four times higher than the AOEL (393%). The exposure of florists appeared to be an example of a unique professional situation in which workers are exposed regularly to both a very high number of toxic chemicals and rather high concentration levels. Therefore the priority should be to raise the level of awareness among the florists who must change their habits and practices if they want to minimize their exposure.

High Prevalence of Respiratory and Dermal Symptoms Among Ethiopian Flower Farm Workers

The flower industry is among the most important export industries in Ethiopia, employing more than 50,000 workers. The working conditions and health status among workers in Ethiopian flower industry are not documented. A questionnaire-based interview was conducted among 213 flower industry workers from 3 flower farms and 60 control workers from supermarkets from February to March 2012. A walk-through survey was also performed on the 3 flower farms. Interviewed flower farm workers have high prevalences of respiratory and dermal symptoms, which are rarely reported among controls. Female workers inside the greenhouses on the 3 flower farms have significantly more respiratory and dermal symptoms than workers outside the greenhouse, also when adjusting for age and education. Limited access to personal protection equipment (PPE) and unsafe pesticide routines are documented. This study indicates that working in these flower greenhouses might be associated with adverse health effects.

DFT, FT-Raman, FT-IR, HOMO-LUMO and NBO studies of 4-Methylmorpholine

The experimental FT-IR (4000-400 cm(-1)) and FT-Raman (3500-100 cm(-1)) spectra of 4-Methylmorpholine were recorded. The observed bands were interpreted with the aid of normal coordinate analysis and force field calculations based on density functional theory (DFT) using B3LYP functional theory (DFT) using B3LYP functional with 6-311+G and 6-3++G basis sets. The complete assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. The molecular structure and vibrational frequencies, infrared intensities and Raman scattering actives have been calculated frequency showed the best agreement with experimental results. The formation of the hydrogen bond was investigated using NBO calculations. The calculated HOMO and LUMO energies show that charge transfer occur within the molecule. The dipolemoment (μ) and polarizability (α), anisotropy polarizability (Δα) and first hyperpolarizability (β(total)) of the molecule have been reported.

The risk of cryptorchidism among sons of women working in horticulture in Denmark: a cohort study

BACKGROUND

Androgens are crucial for normal testicular descent. Studies show that some pesticides have estrogenic or antiandrogenic effects, and that female workers exposed to pesticides have increased risk of having a boy with cryptorchidism. The main objective of the present study was to investigate whether pregnant women exposed to pesticides due to their work in horticulture experience excess risk of having sons with cryptorchidism.

METHODS

We conducted a cohort study of pregnant women working in horticulture using four cohorts including one cohort established with data from the departments of occupational medicine in Jutland and Funen and three existing mother-child cohorts (n=1,468). A reference group was established from the entire Danish population of boys born in the period of 1986-2007 (n=783,817). Nationwide Danish health registers provided information on birth outcome, cryptorchidism diagnosis and orchiopexy. The level of occupational exposure to pesticides was assessed by expert judgment blinded towards outcome status. Risk of cryptorchidism among exposed horticulture workers compared to the background population and to unexposed horticulture workers was assessed by Cox regression models.

RESULTS

Pesticide exposed women employed in horticulture had a hazard ratio (HR) of having cryptorchid sons of 1.39 (95% CI 0.84; 2.31) and a HR of orchiopexy of 1.34 (0.72; 2.49) compared to the background population. Analysis divided into separate cohorts revealed a significantly increased risk of cryptorchidism in cohort 2: HR 2.58 (1.07;6.20) and increased risk of orchiopexy in cohort 4: HR 2.76 (1.03;7.35), but no significant associations in the other cohorts. Compared to unexposed women working in horticulture, pesticide exposed women had a risk of having sons with cryptorchidism of 1.34 (0.30; 5.96) and of orchiopexy of 1.93 (0.24;15.4).

CONCLUSIONS

The data are compatible with a slightly increased risk of cryptorchidism in sons of women exposed to pesticides by working in horticulture.

Evaluation of inhaled and cutaneous doses of imidacloprid during stapling ornamental plants in tunnels or greenhouses

The aim of this research was to assess dermal and respiratory exposure of workers to imidacloprid during manual operations with ornamental plants previously treated in greenhouses or tunnels. A total of 10 female workers, 5 in greenhouses and 5 in tunnels, were monitored for 3 or 5 consecutive days. Actual skin contamination, excluding hands, was evaluated using nine filter paper pads placed directly on the skin. To evaluate the efficacy of protective clothing in reducing occupational exposure we also placed four pads on top of the outer clothing. Hand contamination was evaluated by washing with 95% ethanol. Respiratory exposure was evaluated by personal air sampling. Respiratory dose was calculated on the basis of a lung ventilation of 15 l/min. Absorbed doses were calculated assuming a skin penetration of 10% and a respiratory retention of 100%. Dislodgeable foliar residues (DFRs) were determined during the days of re-entry in order to determine the dermal transfer factor. From the dependence of dermal exposure of hands from DFRs, a mean transfer factor was estimated to be 36.4 cm(2)/h. Imidacloprid was determined by liquid chromatography with selective mass detection and electrospray interface in all matrices analysed. Respiratory dose was 4.1+/-4.0 (0.1-14.3)% and 3.0+/-2.0 (0.6-6.9)% (mean+/-SD (range)) of the total real dose during work in tunnels and greenhouses, respectively. The estimated absorbed doses, 0.29+/-0.45 microg/kg (0.06-2.25 microg/kg) body weight and 0.32+/-0.18 microg/kg (0.07-0.66 microg/kg) body weight (mean+/-SD (range)) in tunnels and in greenhouses, respectively, were less than the acceptable operator exposure level of 0.15 mg/kg body weight and than the acceptable daily intake of 0.05 mg/kg body weight. The hands and exposed skin of all workers were found to be contaminated, indicating that greater precautions, such as daily changing of gloves and clothing, are necessary to reduce skin exposure.

Thyroid function in Danish greenhouse workers

BACKGROUND

From animal studies it is known that currently used pesticides can disturb thyroid function.

METHODS

In the present study we investigated the thyroid function in 122 Danish greenhouse workers, to evaluate if greenhouse workers classified as highly exposed to pesticides experiences altered thyroid levels compared to greenhouse workers with lower exposure. Serum samples from the greenhouse workers were sampled both in the spring and the fall to evaluate if differences in pesticide use between seasons resulted in altered thyroid hormone levels.

RESULTS

We found a moderate reduction of free thyroxine (FT4) (10-16%) among the persons working in greenhouses with a high spraying load both in samples collected in the spring and the fall, but none of the other measured thyroid hormones differed significantly between exposure groups in the cross-sectional comparisons. However, in longitudinal analysis of the individual thyroid hormone level between the spring and the fall, more pronounced differences where found with on average 32% higher thyroid stimulating hormone (TSH) level in the spring compared to the fall and at the same time a 5-9% lower total triiodthyroxin (TT3), free triiodthyroxine (FT3) and FT4. The difference between seasons was not consistently more pronounced in the group classified as high exposure compared to the low exposure groups.

CONCLUSION

The present study indicates that pesticide exposure among Danish greenhouse workers results in only minor disturbances of thyroid hormone levels.

Fate of the fungicide dodemorph during anaerobic digestion of biological waste

The aim of this study was to examine the stability and distribution of the fungicide dodemorph during anaerobic digestion of biological waste, including a short subsequent aerobic treatment. Three reactor experiments were conducted. The influences of pH and dissolved organic carbon (DOC) were further studied in batch experiments. The reactor experiments showed no decrease in the concentration of dodemorph, indicating stability of the fungicide. In connection with the results of the batch experiments, a clear pH-dependency of the partitioning of dodemorph between solid and water phase could be shown. At pH values below the pK(a) value of 7.8, protonated dodemorph molecules predominate. However, a release into the water phase was only observed at pH values of 5 and below. It can be assumed that in the pH range between 5 and 7.8 dodemorph forms bonds with carboxyl groups of organic matter. Dodemorph was not completely extractable from the solid waste matrix due to strong bonds with the organic matter. Solubilising effects by water ingredients of the process water were not apparent.

Removing pesticides from the hands with a simple washing procedure using soap and water

Crop activities lead to dermal exposure of workers to pesticides. The efficacy of hand washing as a control measure is unknown. The efficacy of water and soap was studied for some pesticides and exposure situations. Pre-washing contamination levels in field studies were calculated from foliar residues by models using transfer factors. Between 24.5% and 50.7% of the calculated prewashing contamination was removed in two field studies with three pesticides, with coefficients of variation between 43% and 72%. In a human volunteer study, on average 45.8% and 85.7% was removed for two pesticides (coefficients of variation 6% and 7%). No influence of 'washing vigour' was found and efficacy did not depend on pre-washing contamination levels. The combination of field studies and laboratory experiments was successful, partly compensating for weaknesses in both approaches.

Methods of assessing dermal absorption with emphasis on uptake from contaminated vegetation

Dermal absorption may be an important route of exposure in several exposure scenarios for workers and the general public. Because criteria (e.g. RfDs or MRLs) for chemical exposures are usually expressed in units of mg/kg/day, risk assessments often attempt to convert dermal exposure data to units of mg/kg/day absorbed dose. For some types of dermal exposure involving direct and continuous contact with liquids, Fick's first law may be used. In other cases, such as those involving spills onto the skin surface or dermal exposure to contaminated vegetation, the applicability of Fick's first law is limited. This analysis focuses on a method for estimating absorbed dose from dermal contact with contaminated vegetation or other surfaces. The method involves two steps: estimating the transfer rate from contaminated vegetation to the skin surface, and estimating the extent of absorption from the skin surface into the body. A generic equation can be derived for estimating the transfer rate (TR) from dislodgeable foliar residues (DFR): logTR = 1.09 logDFR + 0.05. Given the surface area of the exposed skin and the duration of contact, this equation can be used to estimate the amount of chemical deposited on the surface of the skin. This equation is based on data from eight different studies using 16 different pesticides. Excluding one outlier (Vinclozolin), the squared correlation coefficient for this equation is 0.78, and the model is significant at p < 0.00001. Data from a series of studies by Feldmann and Maibach (1969, 1970, 1974) are used to estimate dermal absorption. These studies were selected as the most relevant for risk assessment because most of the experimental subjects are human and because of the nature of dermal exposures was closely related to many exposure scenarios used in risk assessments. For all 47 compounds included in this series of studies, there were no significant correlations between commonly available physical or chemical properties and dermal absorption. For those compounds with a K0/w > 1.85, however, the average daily absorption rate (AR) over a five-day postexposure period can be estimated from the molecular weight: logAR = -0.04MW + 1.5. The squared correlation coefficient for this equation is 0.68, and the model is significant at p < 0.00001. The usefulness of this approach is evaluated using a study by Harris and Solomon (1992) in which the absorption of 2,4-D from contaminated turf was measured in a group of volunteers. The estimated absorbed dose using the equations above is very close to the measured values.

Skin contamination, airborne concentrations, and urinary metabolite excretion of propoxur during harvesting of flowers in greenhouses

In eight greenhouses used for carnation culture, workers engaged in harvesting (n = 16), were monitored for dermal and respiratory exposure and urinary excretion of propoxur. Dermal exposure of hands and forearms was estimated from dislodgable foliar residue, using a transfer factor (a measure of transfer of pesticides from leaves to the skin) and the total number of working hours. Total estimated dermal and respiratory exposure during harvesting ranged from 0.2 to 46 mg and from 3 to 278 micrograms, respectively. To study the relationship between external and internal exposure to propoxur, respiratory and dermal exposure levels were compared with the total amount of 2-isopropoxyphenol (IPP), the major metabolite of propoxur, excreted in urine in 24 hr. The Pearson correlation coefficient between dermal exposure and the total amount of excreted IPP was 0.95. A correlation coefficient of 0.84 was found between respiratory exposure and the amount of IPP excreted. The latter association was probably caused by the covariation of respiratory and dermal exposure levels (r = 0.85). Assuming negligible oral absorption, calculations indicated that dermal exposure could account for > 80% of the amount of excreted IPP. On the basis of the amount of IPP excreted, there was no reason to suspect increased health risks for workers from exposure to propoxur during harvesting.