Predicting children's short-term exposure to pesticides: results of a questionnaire screening approach

The ability of questionnaires to predict children's exposure to pesticides was examined as part of the Minnesota Children's Pesticide Exposure Study (MNCPES). The MNCPES focused on a probability sample of 102 children between the ages of 3 and 13 years living in either urban (Minneapolis and St. Paul, MN) or nonurban (Rice and Goodhue Counties in Minnesota) households. Samples were collected in a variety of relevant media (air, food, beverages, tap water, house dust, soil, urine), and chemical analyses emphasized three organophosphate insecticides (chlorpyrifos, diazinon, malathion) and a herbicide (atrazine). Results indicate that the residential pesticide-use questions and overall screening approach used in the MNCPES were ineffective for identifying and oversampling children/households with higher levels of individual target pesticides.     

Measurement of the exposure of workers to pesticides

There is not a single pesticide for which the interrelationships between occupational exposure by different routes, the fate of the compound in the human body, and its clinical effects are all adequately known.     

Organic diets significantly lower children's dietary exposure to organophosphorus pesticides

We used a novel study design to measure dietary organophosphorus pesticide exposure in a group of 23 elementary school-age children through urinary biomonitoring. We substituted most of children's conventional diets with organic food items for 5 consecutive days and collected two spot daily urine samples, first-morning and before-bedtime voids, throughout the 15-day study period. We found that the median urinary concentrations of the specific metabolites for malathion and chlorpyrifos decreased to the nondetect levels immediately after the introduction of organic diets and remained nondetectable until the conventional diets were reintroduced. The median concentrations for other organophosphorus pesticide metabolites were also lower in the organic diet consumption days; however, the detection of those metabolites was not frequent enough to show any statistical significance. In conclusion, we were able to demonstrate that an organic diet provides a dramatic and immediate protective effect against exposures to organophosphorus pesticides that are commonly used in agricultural production. We also concluded that these children were most likely exposed to these organophosphorus pesticides exclusively through their diet. To our knowledge, this is the first study to employ a longitudinal design with a dietary intervention to assess children's exposure to pesticides. It provides new and persuasive evidence of the effectiveness of this intervention.     

Current internal exposure to pesticides in children and adolescents in Germany: urinary levels of metabolites of pyrethroid and organophosphorus insecticides

Aim Pesticides are widely used throughout the world, in agriculture to protect crops and in public health to control diseases transmitted by vectors or intermediate hosts. After the prohibition of organochlorines such as DDT, today, mainly pyrethroids and organophosphorus insecticides are used. Whereas many studies have been published on background exposure of the population to organochlorines, data on internal exposure of the population to pyrethroids and organophosphorus insecticides are scarce. Here, we report on internal exposure of children and young people, in an urban area in Germany, to pyrethroids and organophosphorus acids, assessed by the analysis of urinary levels of their corresponding specific metabolites.Methods Approximately 673 children and adolescents took part in this voluntary investigation, including 331 children <6 years of age. Their parents stated that they and their children had never used pyrethroids or organophosphorus acids in their homes or for medical reasons. We analysed their spot urine samples for six metabolites of organophosphorus insecticides [dimethyl-phosphate (DMP), diethyl-phosphate (DEP), dimethyl-thiophosphate (DMTP), diethyl-thiophosphate (DETP), dimethyl-dithiophosphate (DMDTP) and diethyl-dithiophosphate (DEDTP)] and for four metabolites of pyrethroids [cis-3-(2,2-dibromo-vinyl)-2,2-dimethyl-cyclopropane carboxylic acid (Br2CA), cis-3-(2,2-dichloro-vinyl)-2,2-dimethyl-cyclopropane carboxylic acid (cis-Cl2-CA ), trans-3-(2,2-dichloro-vinyl)-2,2-dimethyl-cyclopropane carboxylic acid (trans-Cl2-CA) and 4-fluoro-3-phenoxy-benzoic acid (F-PBA)] using gas chromatographic methods with mass-selective detection. The limit of detection was 0.1–0.2 g/l for pyrethroid metabolites and 1 g/l for metabolites of organophosphorus acids; in DMP it was 5 g/l.Results The 95th percentiles of the urinary metabolite concentrations were, in microgrammes per litre, DMP 158, DMTP 180, DMDTP 12, DEP 17, DETP 8, DEDTP <1; Br2CA 0.30, cis-Cl2-CA 0.44, trans-Cl2-CA 1.22, F-PBA 0.30. There were no correlations between urinary metabolite levels and the age of the children.Conclusion Current background levels of internal exposure to pyrethroids and organophosphorus insecticides in children and adolescents in Germany are shown. Exposure to these substances in the general population is thought to occur mainly via residues in the diet. The level of background internal pyrethroid exposure in the children is orders of magnitude lower than the corresponding acceptable daily intake (ADI) values published, but the level of internal organophosphate exposure may reach and even exceed ADI values. This observation demands further investigation.     

Effect of variation of exposure to airborne chlorobenzene on internal exposure and concentrations of urinary metabolite.

OBJECTIVES--This study aimed to develop a physiologically based pharmacokinetic model for chlorobenzene and to investigate the effect of variation in exposure to chlorobenzene on the chlorobenzene concentration in blood and the urinary concentration of 4-chlorocatechol. METHODS--A physiologically based pharmacokinetic model was developed and the simulated results of urinary 4-chlorocatechol concentrations were compared with the values found in experiments and field surveys. The area under the chlorobenzene concentration-time curve in blood (CBBauc) was selected as the measure of internal exposure related to the chronic effect of chlorobenzene. The maximum one-hour time weighted average value of chlorobenzene concentration in blood (CBBmax) was chosen as the measure of internal exposure related to the acute effect of chlorobenzene. The total amount of urinary 4-chlorocatechol (TOTCC) and that excreted during the last four hours (CC(4-8)) or two hours (CC(6-8)) of exposure as well as that excreted during two hours on the next morning (CC(22-24)) were used to represent concentrations of urinary metabolites. The effects of variation of the one-hour time weighted averages of airborne chlorobenzene exposure (CBAs) on the internal exposures and the concentrations of urinary metabolites were investigated with the pharmacokinetic model. RESULTS--The comparison of the simulated results with the observed data showed that the pharmacokinetic model can be used to estimate the urinary concentrations of 4-chlorocatechol. The CBBauc and TOTCC were not affected by changes in both the geometric SD (GSD) of CBAs or the variations in CBAs. The CBBmax varied with changes in both the GSD and CBAs. The CC(4-8) and CC(6-8) did not vary with the GSD, but these concentrations were affected by the change in the CBAs. Although there was little effect of the GSD and CBAs on the CC(22-24), this value highly reflected the exposure over the preceding days. CONCLUSION--To protect workers from the chronic effect of chlorobenzene, it may be sufficient to control the daily average exposure. To protect from the acute effect, however, the short term exposure must be controlled as well. The values of CC(4-8) and CC(6-8) were acceptable for estimating daily average exposure, but the CC(22-24) was not.     

Measurement of exposure to mouse urinary proteins in an epidemiological study.

OBJECTIVES: To develop an assay to measure airborne mouse urinary protein (MUP) and to assess the occupational exposure to MUP in the workforce of three establishments as part of an epidemiological study examining the influence of aeroallergen exposure on the development of allergic respiratory disease. METHODS: Personal air samples were collected from nine exposure groups during a workshift. A sensitive and reproducible competitive inhibition assay, which used rabbit antisera specific for MUP, was developed and used to measure the occupational exposure to MUP. RESULTS: The personal measurements of MUP showed that people with direct contact with mice (animal technicians) had the highest exposure followed in decreasing order by those working with anaesthetised animals or their tissue (postmortem workers and scientists) and those with indirect contact with mice (supervisors, office workers, and slide production workers). The only difference in concentrations of MUP between the three establishments were found for cage cleaners, which reflected differences in working practises for this exposure category. Air samples collected during the performance of specific tasks showed that high exposures to MUP were associated with handling mice, indirect contact with mice, and washing floors. CONCLUSIONS: Exposure to mouse urinary proteins has been measured in the occupational environment. This information can be used to determine the relation between exposure to MUP and the development of allergic and respiratory disease.     

Elevated urinary phenol levels not related to benzene exposure.

Two common over-the-counter medications may elevate urinary phenol to levels exceeding 75 mg/liter (ppm). This study presents data indicating that it is invalid to correct urinary phenol levels to specific gravity of 1.024. Animal studies indicate that having elevated urinary phenol levels secondary to phenyl salicylate ingestion are not harmful.     

A longitudinal approach to assessing urban and suburban children's exposure to pyrethroid pesticides

We conducted a longitudinal study to assess the exposure of 23 elementary school-age children to pyrethroid pesticides, using urinary pyrethroid metabolites as exposure biomarkers. We substituted most of the children's conventional diets with organic food items for 5 consecutive days and collected two daily spot urine samples, first morning and before bedtime voids, throughout the 15-day study period. We analyzed urine samples for five common pyrethroid metabolites. We found an association between the parents' self-reported pyrethroid use in the residential environment and elevated pyrethroid metabolite levels found in their children's urine. Children were also exposed to pyrethroids through their conventional diets, although the magnitude was smaller than for the residential exposure. Children's ages appear to be significantly associated with pyrethroids exposure, which is likely attributed to the use of pyrethroids around the premises or in the facilities where older children engaged in the outdoor activities. We conclude that residential pesticide use represents the most important risk factor for children's exposure to pyrethroid insecticides. Because of the wide use of pyrethroids in the United States, the findings of this study are important for both children's pesticide exposure assessment and environmental public health.     

Effects of low-level occupational exposure to styrene on color vision: dose relation with a urinary metabolite

To investigate the threshold effects of chronic low-level occupational exposure to styrene on color vision, we examined color discrimination in 105 male workers exposed to styrene (mean age 37.7 years; mean length of exposure 6.2 years; mean urinary concentration of mandelic acid 0.21 g/L) and in 117 referents (mean age 37.7 years). We also assessed the effects of styrene by examination of the nature of the relation between disorders of nervous function and age, alcohol consumption, and other variables. A standardized questionnaire was adopted to collect information about work history, occupational or nonoccupational solvent exposure, alcohol consumption, and drug use. Color vision was evaluated by the Lanthony desaturated panel D-15 test. The results of the test were expressed as the color confusion index (CCI). There was a dose-dependent relationship between the urinary concentration of mandelic acid and color vision loss. The CCIs of the subgroups whose urinary mandelic acid levels were 0.1-0.2 and >0.2 g/L were significantly higher than those of each referent group (P<0.05 and P<0.01, respectively), but not in the subgroup whose urinary mandelic acid level was lower than 0.1 g/L. Our study suggests that a low level of styrene, presumably 0.1-0.2 g/L, involves the risk of inducing adverse effects on color vision. After confounding factors were adjusted for, the urinary mandelic acid level had a significant positive relationship with color vision.     

Use of biomarkers to indicate exposure of children to organophosphate pesticides: implications for a longitudinal study of children's environmental health

Because of their history of widespread use in the United States and unknown long-term health effects, organophosphate pesticides (OPs) are being considered as a chemical class of interest in planning for the National Children's Study, a longitudinal study of children's environmental health. The availability and appropriate use of biomarkers to determine absorbed doses of environmental chemicals such as OPs are critical issues. Biomarkers of OP exposure are typically measured in blood and urine; however, postpartum meconium has been shown to be a promising matrix for assessing cumulative in utero exposure to the fetus, and studies are currently in progress to determine the utility of using saliva and amniotic fluid as matrices. In this article, we discuss the advantages and disadvantages of the currently available OP exposure monitoring methods (cholinesterase inhibition in blood, pesticides in blood, metabolites in urine and alternative matrices); study design issues for a large, long-term study of children's environmental health; and current research and future research needs. Because OPs are rapidly metabolized and excreted, the utility of one-time spot measurements of OP biomarkers is questionable unless background exposure levels are relatively stable over time or a specific time frame of interest for the study is identified and samples are collected accordingly. Biomarkers of OP exposure can be a valuable tool in epidemiology of children's environmental health, as long as they are applied and interpreted appropriately.     

Correlation of fluorescent tracer measurements of dermal exposure and urinary metabolite excretion during occupational exposure to malathion

Nineteen workers conducting mixing and high-volume airblast applications of the organophosphorus pesticide malathion were monitored simultaneously by biological monitoring and fluorescent tracer evaluation of dermal exposure. Complete 72-hr urine samples were collected and analyzed for dimethylthiophosphate and dimethyldithiophosphate metabolites. Dermal exposure was measured through the addition of a fluorescent tracer to the tank mix, subsequent examination of the skin surface under long-wave ultraviolet light, and fluorescence quantification with a video imaging system. Dermal exposure to applicators was correlated highly with total metabolite excretion (r = 0.91). Mixer exposure was not correlated significantly (r = 0.73) because of wide scatter in the data and the small number of workers monitored. Applicator exposures were more than 3 times higher than mixer exposures, reflecting the high exposure potential inherent in airblast spraying. Exposure to regions protected by gloves or clothing was more than 75% of total exposure for both mixers and applicators. These results provide evidence that the fluorescent tracer technique is a valid methodology for measuring relative levels of dermal exposure during agricultural work activities. The technique also holds promise as a quantitative procedure for evaluating the effectiveness of engineering control strategies and protective clothing performance.     

Occupational exposure to cholinesterase inhibiting pesticides: a Greek case

The determination of plasma or serum cholinesterase is absolute and it is considered as a reliable index of exposure in workers of organophosphorus pesticides industries. In the present study the plasma cholinesterase of 28 persons working in the packaging of an ortho-thio-phosphate was determined, before and after their exposure to this agent. The results of this study showed a plasma cholinesterase depression of 37%, a decrease which was statistically significant (P<0.001).     

Relationship between vapor exposure and urinary metabolite excretion among workers exposed to trichloroethylene

The exposure-excretion relationship was investigated in 140 trichloroethylene (TRI)-exposed workers and 114 nonexposed controls. The time-weighted average intensity of exposure to TRI during the shift as measured by the diffusive sampling method was compared with metabolite levels in the urine collected at the end of the shift in the second half of a working week, when the urinary metabolite levels are expected to reach a maximum. The TRI levels in breathing zone air of the exposed workers were mostly below 50 ppm. The urinary metabolite levels (i.e., total trichloro-compounds, trichloroethanol, and trichloroacetic acid) increased as a linear function of the TRI exposure. The relationship between the two exposure indicators was statistically significant in men, women, and both combined. The cross-sectional balance study at the end of the shift revealed that about 4% of TRI absorbed will be excreted at the end of the shift, in agreement with the long biological half-life of this chlorinated hydrocarbon solvent. A possible ethnic difference in the metabolism of TRI is discussed.     

Prenatal exposure to pesticides: a feasibility study among migrant and seasonal farmworkers.

BACKGROUND: Migrant and seasonal farmworkers have a high potential for pesticide exposures, yet are rarely included in epidemiologic studies. This study examined the feasibility of assessing prenatal exposures to pesticides and other compounds in pregnant Hispanic farmworkers. METHODS: Nine women completed a survey about work experiences during pregnancy. Maternal urine, cord blood, and placenta samples were obtained at delivery for analysis of 51 analytes, including 6 phenoxy acid or triazine herbicides, 21 organochlorine insecticides, 10 PCBs, and 14 volatile organic compounds. RESULTS: Seven of 51 analytes were found in the biological samples. DDE, DDT, dichlorbenzene, toluene, trimethylbenzene, and endosulfan sulfate were detected in cord blood samples, and 2,4-D in urine from one or more women. CONCLUSIONS: We documented the feasibility of following farmworkers to assess in utero exposure to pesticides and other contaminants, and demonstrated exposure to these compounds. Difficulties in measuring pesticides with short half lives were noted.     

Impaired colour discrimination among workers exposed to styrene: relevance of a urinary metabolite.

OBJECTIVES--To survey the loss of colour vision among Japanese workers who have been exposed to styrene concentrations currently considered low (about 20 ppm). Also to assess the effects of styrene by examination of the nature of the relation between disorder of colour vision and age, alcohol consumption, and other variables. METHODS--Colour discrimination was examined in 64 male workers exposed to styrene (mean age; 38.0, mean exposed years; 7.0) and in 69 controls (mean age; 38.0). A standardised questionnaire was adopted to collect work history, occupational or non-occupational solvent exposure, alcohol consumption, and drug use. Colour vision was evaluated by the Lanthony desaturated panel D-15 test. The results of the test were expressed as the colour confusion index (CCI). RESULTS--The mean atmospheric styrene concentration was about 20 ppm. The mean urinary concentration of mandelic acid was 0.22 g/l. There was a significant difference in CCI between exposed workers and age matched controls. Colour vision of workers whose concentration of urinary mandelic acid was > or = 0.42 g/l was significantly impaired when compared with workers whose concentration was < 0.42 g/l. Multiple linear regression analysis that controlled confounding variables such as age, alcohol consumption, smoking, and educational attainment showed that the CCI was significantly related to the concentration of urinary mandelic acid. In both exposed workers and controls, the types of defects were mostly blue-yellow loss, although a few subjects showed complex loss. No one showed only red-green loss. CONCLUSIONS--These findings suggest that exposure to moderate styrene concentrations can lead to impairment of colour vision, and that there is a significant correlation with the urinary metabolite of styrene.     

Exposure of flight attendants to pyrethroid insecticides on commercial flights: urinary metabolite levels and implications

Pyrethroid insecticides have been used for disinsection of commercial aircrafts. However, little is known about the pyrethroids exposure of flight attendants. The objective of the study was to assess pyrethroids exposure of flight attendants working on commercial aircrafts through monitoring the urinary pyrethroids metabolite levels. Eighty four urine samples were collected from 28 flight attendants, 18-65 years of age, with seventeen working on planes that were non-disinsected, and eleven working on planes that had been disinsected. Five urinary metabolites of pyrethroids were measured using gas chromatographic-mass spectrometric method: 3-phenoxybenzoic acid (3-PBA), cis-/trans-3-(2,2-Dichlorovinyl)-2,2-dimethylcyclo-propane carboxylic acid (cis-/trans-Cl2CA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclo-propane-1-carboxylic acid (cis-Br2CA) and 4-fluoro-3-phenoxybenzoic acid (4F-3-PBA). Flight attendants working on disinsected planes had significantly higher urinary levels of 3-PBA, cis- and trans-Cl2CA in pre, post- and 24-h-post flight samples than those on planes which did not report having been disinsected. Urinary levels of cis-Br2CA and 4F-3-PBA did not show significant differences between the two groups. Flight attendants working on international flights connected to Australia had higher urinary levels of 3-PBA, cis- and trans-Cl2CA than those on either domestic and other international flights flying among Asia, Europe and North America. Post-disinsection duration (number of days from disinsection date to flight date) was the most significant factor affecting the urinary pyrethroid metabolites levels of 3-PBA, cis- and trans-Cl2CA of the group flying on disinsected aircraft. It was concluded that working on commercial aircraft disinsected by pyrethroids resulted in elevated body burdens of 3-PBA, cis- and trans-Cl2CA.     

Battering victimization among a probability-based sample of men who have sex with men

OBJECTIVES: This study measured the prevalence of battering victimization (i.e., experience of psychological/symbolic, physical, and sexual battering) among men who have sex with men (MSM) and identified characteristics of these men. METHODS: A probability-based sample of 2881 MSM living in 4 cities completed telephone interviews between 1996 and 1998. RESULTS: Prevalence estimates were 34% for psychological/symbolic battering, 22% for physical battering, and 5% for sexual battering. The strongest demographic correlate independently associated with all forms of battering was age 40 or younger, whereas education and HIV serostatus were associated with physical and psychological/symbolic violence. CONCLUSIONS: Rates of battering victimization among urban MSM are substantially higher than among heterosexual men and possibly heterosexual women. Public health efforts directed toward addressing intimate partner battering among these men are needed.