Serum hexachlorocyclohexane residues in workers engaged at a HCH manufacturing plant

Summary The accumulation of hexachlorocyclohexane, one of the most commonly used chlorinated insecticides, was studied in a high-risk group of people who are exposed during its manufacturing process. The serum HCH concentration was estimated by quantitating its , , and -isomers with the help of GLC analysis. Exposed workers involved in maintenance work were found to have 3 times higher HCH residues than the controls, while in the plant operators and supervisors the levels were 5 times higher. The most severely exposed were the handlers who are in direct contact with the insecticide. The level of serum HCH residues in them was found to be about 12 times higher than those in the controls. The percentage composition of the insecticide, with respect to the different isomers, varied up to 20% for the -isomer, up to 30% for -isomer and had between 60%–100% of the -isomer in the samples. The serum levels of the insecticides were clearly related to the workers' job-related close contact, intensity, frequency, and the duration of their exposure. The total of HCH residues in the sera studied were in the range of 0.143–1.152 ppm. The importance of these findings and the relevant protective measures are discussed.     

Effect of dietary protein, dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) on hepatic microsomal enzyme activity in rats

1. Albino rats were fed on diets containing 30, 120 or 200 g protein/kg with or without the incorporation of dichlorodiphenyltrichloroethane (DDT) or hexachlorocyclohexane (HCH) at 100 mg/kg diet for 4 weeks. 2. The activities of the liver microsomal enzymes NADPH-cytochrome reductase (EC 1.6.2.4), flavoprotein-linked monooxygenase (EC 1.14.14.1) and O-demethylase were significantly greater in animals fed on 120 and 200 g protein/kg diet compared with those fed on 30 g protein/kg diet. 3. The inclusion of DDT or HCH at all protein intakes led to further significant rises in microsomal enzyme activities but the increases were much greater for animals receiving the 120 and 200 g protein/kg diets than for those receiving the 30 g protein/kg diet. 4. The results imply that detoxification of DDT or HCH was carried out more effectively at the higher protein intakes.     

Peripheral neuropathy after occupational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

Reports of human exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) describe signs and symptoms consistent with exposure-related peripheral neuropathy. In a crosssectional study, prevalence of peripheral neuropathy was measured in 265 workers exposed 15 years earlier to chemicals contaminated with TCDD and in 244 unexposed, age-, race-, gender- and community-matched comparisons. Cases of peripheral neuropathy were defined from examination, electrophysiologic and quantitative sensory tests, and symptoms. Exposure was assessed by measuring lipid-adjusted serum TCDD levels. The mean serum TCDD level for workers (220 parts per trillion (ppt)) was significantly higher than for referents (7 ppt) (p < .0001). Thirty-two percent of both worker and referent groups met the case definition for peripheral neuropathy. In the logistic regression analyses, serum TCDD level was not related to peripheral neuropathy. These data suggest that despite continued high serum TCDD levels, peripheral neuropathy is not a long-term sequela of high exposure to TCDD-contaminated chemicals. However, the study cannot preclude the occurrence and subsequent resolution of acute effects caused by high exposure, as experienced in Seveso and possibly by some workers, while exposed to high levels of TCDD-contaminated substances. © 1993 Wiley-Liss, Inc.     

Changes in juvenile coho salmon electro-olfactogram during and after short-term exposure to current-use pesticides

For anadromous salmonids, olfaction is a critical sense, enabling return migration. In recent years, several pesticides have been identified that interfere with salmonid olfaction at concentrations in the microg/L range; thus, they may pose a risk to species longevity. In the present study, we investigated the acute effects of five agricultural pesticides on juvenile coho salmon (Oncorhynchus kisutch) olfaction using the electro-olfactogram (EOG), a measure of odorant-evoked field potentials. Electro-olfactogram responses to the odorant L-serine were measured during and following a 30-min exposure of the left olfactory rosette to chlorothalonil, endosulfan, glyphosate acid, iodocarb (IPBC), trifluralin, and 2,4-dichlorophenoxyacetic acid. With the relatively insoluble pesticides endosulfan and trifluralin, decreases in EOG amplitude were only apparent at relatively high concentrations (100 and 300 microg/L, respectively) following 20 min of exposure and were absent for chlorothalonil (1 mg/L). With the water-soluble herbicide glyphosate, significant EOG reductions occurred within 10 min of exposure to 1 mg/L and more rapidly with higher concentrations. Recovery of EOG post-glyphosate exposure was concentration-dependent, and complete recovery was not observed with some concentrations at 60 min postexposure. Dichlorophenoxyacetic acid only affected EOG at high concentration (100 mg/L), where it eliminated EOG within 2 min of exposure. With IPBC, EOG was decreased at 25 min of exposure to 1 microg/L; higher concentrations caused decreases to occur more rapidly. Excluding IPBC and glyphosate, all EOG reductions occurred at concentrations greater than the current Canadian water-quality guidelines and reported 96-h lethality values. Our results show that olfactory neurons can be impaired rapidly by some current-use pesticides, even at exposures in the low-microg/L range.     

Integrated pest management and residue levels of dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) in water samples from rural areas in Gujarat State,India

The authors identified 2 rural areas for study in Gujarat State, India, on the basis of pesticide use in agriculture and vector-control programs. In rural area 1, pesticides were used in both agriculture and vector-control programs, whereas in rural area 2, they were used in agriculture only. Water samples were collected from both areas, and they were analyzed for total dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) residues. The mean residue levels of total DDT in rural areas 1 and 2 were 7.56 ng/l and 4.27 ng/l, respectively. The corresponding values for HCH were 6.96 ng/l and 5.53 ng/l, respectively. Residue levels of both pesticides were significantly lower in rural area 2 than in area 1.     

Reproductive effects of occupational DDT exposure among male malaria control workers

To assess potential effects of human DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] exposure, we evaluated the reproductive history of 2,033 workers in the antimalaria campaign of Mexico. Data on occupational exposure to DDT and reproductive outcomes were gathered through a questionnaire, and workers provided information about 9,187 pregnancies. We estimated paternal exposure to DDT before each pregnancy using three approaches: a) a dichotomous indicator for pregnancies before and after exposure began, b) a qualitative index of four exposure categories, and c) an estimation of the DDT metabolite DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] accumulated in fat. To assess associations, we used logistic regression models that accounted for correlated observations and adjusted for parents' age at each child's birth, exposure to other pesticides, exposure to chemical substances in other employment, smoking, and alcohol consumption. The odds ratio for birth defects comparing pregnancies after and before the first exposure was 3.77 [95% confidence interval (95% CI), 1.19-9.52]. Compared with the lowest quartile of estimated DDE in fat, the ORs were 2.48 (95% CI, 0.75-8.11), 4.15 (95% CI, 1.38-12.46), and 3.76 (95% CI, 1.23-11.44) for quartiles 2, 3, and 4, equivalent to p,p -DDE in fat of 50, 82, and 298 microg/g fat, respectively. No significant association was found for spontaneous abortion or sex ratio. We found an increased risk of birth defects associated with high occupational exposure to DDT in this group of workers. The significance of this association at lower exposure levels found in the general population remains uncertain.     

Propylene glycol monomethyl ether (PGME) occupational exposure

An analytical method was developed for the determination of free and conjugated PGME-α in urine. The method involves a solid-phase extraction on LC-18 columns and a GC/FID analysis after derivatization with trimethysilylimidazole. The assay was linear (least-squares regression coefficient 0.996), specific, reproducible (intraassay variability 10%, interassay variability 10%), and allowed a high level of PGME recovery (more than 90%). The assay was applied to the analysis of urine samples from three workers who were occupationally exposed to PGME to estimate their exposure. The highest value of PGME concentration in urine was 7.78 mg/l. Air concentrations of PGME ranged between 20 and 40 ppm. A statistically significant correlation was found between measurements of external exposure and PGME in urine. An important fraction of PGME in urine was found to be conjugated. Received: 6 July 1999 / Accepted: 27 December 1999     

Changes induced by short-term xylene exposure in human evoked potentials

Summary Nine healthy male volunteers were exposed to m-xylene for 3 h in the morning and 40 min in the afternoon with a 40-min break in between. The atmospheric m-xylene concentrations were either stable at 8.2 mol/l (200 ppm) or they fluctuated (5.2–16.4 mol/1; 135–400 ppm) with peaks of 16.4 mol/1 and duration of 20 min at the beginning of each exposure session. The subjects were either sedentary or exercised at 100 W for 10 min at the beginning of each session during both exposure types. The two control days, with and without exercise, were similar to the exposure days but without exposure. Evoked potentials were recorded in the morning before the exposure and immediately after the morning and afternoon sessions. Visual evoked potentials were studied to a pattern reversal stimulus (pattern VEP) and to a light flash (flash VEP). For pattern VEPs the latencies of P50, N70, P100, N135 and P170 as well as the peak-to-peak amplitude of N70 to P100 were measured. For flash VEPs the latencies of P50, N70, P100, N150 and P200 as well as the peak-to-peak amplitude of P100 to N150 were measured. Short-latency auditory evoked potentials arising in the brainstem (BAEP) were recorded for a click stimulus. The peaks 1, II, III, IV and V were identified from the grand averages. The effect of various exposure paradigms was evaluated by comparing the individual changes on an exposure day to those during the control days. The latency N135 of the pattern VEP decreased in exposure at 400 ppm with exercise, and the latency P210 in the flash VEP decreased both at the stable and fluctuating exposure with exercise. The results might suggest some activation of the arousal level of the subjects after the most intensive exposure situations.     

Xeno-oestrogenic activity in serum as marker of occupational pesticide exposure

Background

An increasing number of currently used pesticides are reported to possess oestrogen‐like properties or to disturb the endocrine system in other ways.

Objectives

To investigate if xeno‐oestrogenic activity in serum can be used as a biomarker of the combined exposure to pesticides with oestrogen‐like properties in an occupational setting.

Methods

Serum samples were obtained from two separate cohorts representing non‐pregnant and pregnant female greenhouse workers in Denmark. Serum samples from 270 non‐pregnant women and 173 pregnant women were analysed for xeno‐oestrogenic activity. A fraction containing major xeno‐oestrogens but without pharmaceutical and endogenously produced oestrogens was isolated from each serum sample by solid‐phase extraction and tested for oestrogenic response in a MCF‐7 cell proliferation assay. The pesticide exposure for each woman was categorised as low, medium or high based on information collected by detailed interviews of the women and the employers.

Results

In both cohorts, an exposure‐associated increase in the xeno‐oestrogenic activity in serum was demonstrated. Among the pregnant women, the association between pesticide exposure and xeno‐oestrogenic activity in serum was statistically significant for women who had been at work within the last week, while no association was observed for women who had not been at work during the most recent week.

Conclusions

The study illustrates the usefulness of this biomarker for qualitative assessment of the combined exposure to mixtures of oestrogen‐like pesticides. Although the individual pesticides responsible for the xeno‐oestrogenic response were not identified, the study demonstrates that, even within highly‐controlled greenhouse operations, occupational exposure to oestrogen‐like pesticides can result in detectable impacts on hormonal activity in the blood.Exposure situations are often complex and involve several potentially interacting chemicals. Compounds with the same mode of action are likely to be additive.^1,2,3 Development and use of exposure biomarkers is a valuable tool in environmental epidemiology, and a promising approach to complex exposures is to use biomarkers that integrate the response from several substances that affect the same target.Based on strong evidence from studies in wildlife and laboratory animals, there is increasing concern that exposure to endocrine disrupting chemicals may impair reproductive capability, disturb fetal development, and promote carcinogenesis in humans.^4,5,6 A biomarker assessing the total exposure to xeno‐oestrogens in serum samples was initially developed by Soto and Sonnenschein^7,8 and this methodology has since been refined and used for measurement of the xeno‐oestrogenic response in adipose tissue⁹ or in serum samples^10,11,12 from populations with increased exposure to persistent, lipophilic pollutants. The approach used in this biomarker assay includes extraction of oestrogens from serum samples followed by separation of xeno‐oestrogens from endogenous oestrogens, and the oestrogenic activity of the xeno‐oestrogen fraction (XE fraction) is then determined in vitro. The focus so far has been on lipophilic, non‐polar pollutants that are easily separated from the endogenous and pharmaceutical oestrogens. However, several polar substances, including some of the currently used pesticides, are also thought to possess oestrogenic properties in vitro^13,14,15 and in vivo.¹⁶ The aim of this study was to investigate whether the biomarker approach for serum xeno‐oestrogenic activity could be used to assess the mixed exposure to potentially oestrogenic pesticides in an occupational setting. We chose to examine female greenhouse workers in Denmark, where exposures generally are well controlled, although current safety procedures are not specifically aimed at preventing exposures to endocrine disruptors.     

The determination of serum amino-terminal procollagen type-III propeptide (PIIINP) in occupational exposure to rock wool fiber]

Fifty-six males workers exposed to rock wool during production, and 20 referents were examined. Exposure, evaluated by personal sampling, ranged from 0.05 to 0.74 fibres/ml (median 0.15). The subjects underwent a medical examination, chest X-ray according to ILO recommendations and pulmonary function tests. In all subjects the serum levels of type III procollagen N-terminal propeptide (PIIINPs) were determined. No evidence of pulmonary fibrosis, nor work-related lung diseases were observed. PIIINPs mean values in the exposed (9.8 ng/ml; 2.8 S.D.) were slightly higher, but not significantly different when compared to referents (8.5 ng/ml; 2.5 S.D.). No significant correlation between PIIINPs and rock wool exposure (both airborne levels and exposure duration) was observed. Furthermore, peptide levels were not related to pulmonary function test results. Our results suggest that occupational exposure to rock wool fibres lower than 0.75 fibres/ml for less than 20 years does not induce definite cases of pulmonary fibrosis nor an increase of type III collagen synthesis in the lung.     

Unusual complications after occupational exposure to giant hogweed (Heracleum mantegazzianum): A case report

Exposure to giant hogweed brings about the risk of serious skin damage, usually in the form of phytophotodermatitis. Initially, skin changes are signaled by a burning sensation, followed by a vesiculobullous rash and long-term hyperpigmentation. Usually, skin disorders improve after the application of topical and oral corticosteroids. In extremely rare instances, full skin thickness burns or epidermal necrosis occur. The study presents a case of occupational exposure to hogweed, which resulted in extensive skin lesions leading to the disablement of a 27-year-old man. The principles of procedure to be followed when contact with giant hogweed is an occupational hazard are also outlined.