Potential dermal exposure during the painting process in car body repair shops

The object of this study was to assess potential dermal exposure to the non-volatile fractions of paints based on studies assessing potential exposure during the painting process in car body repair shops with water-based paints. The measurements were done during filling of the spray gun, paint spraying and cleaning of the gun. Potential dermal exposure was assessed using patches and gloves as dosimeters and analysing deposits of aluminium, a constituent of the paint mixture, which is used as a chemical tracer for these studies. The total body area used excluding hands was 18 720 cm(2) and the area of each hand was 410 cm(2). Dermal exposure to the paint during filling of the spray gun occurs mainly on the hands and ranged from 0.68 to 589 micro g paint/cm(2)/min, as calculated from the amount of aluminium observed and the concentration of aluminium in the paint. During spraying, the levels of exposure of the hands and body ranged from 0.20 to 4.35 micro g paint/cm(2)/min for the body and 0.40 to 13.4 micro g paint/cm(2)/min for the hands. With cleaning of the spray gun the hands were the principal area exposed, with values ranging from 0.44 to 213 micro g paint/cm(2)/min. Information on and observations of each of the scenarios were recorded in a structured questionnaire.     

Solvent exposure and related work practices amongst apprentice spray painters in automotive body repair workshops.

As part of a multidisciplinary study into the health effects of solvents, workplace assessments and airborne solvent vapour monitoring was conducted in 46 spray painting workshops in the Sydney metropolitan area. Breathing-zone samples were taken from 50 apprentices and 14 experienced spray painters. An interview schedule was developed to obtain information about the use of acrylic or two-pack paint systems, the use of engineering controls, the use of personal protective equipment and the availability of material safety data sheets. Contaminants typical of the chemical products used in this industry were encountered (aromatic hydrocarbons, C5-C7 aliphatic hydrocarbons, ketones, esters). The results of airborne solvent monitoring indicate a total solvent exposure in the range 1-99% of a combined Worksafe Australia exposure standard, with a mean of 19%. Solvent exposure was highest when spraying acrylic paint in the open workshop and lowest when spraying two pack paint in a spray booth. Much the same personal protective equipment was available in all workshops, but wide variation in its use was observed. Material safety data sheets were not observed in any of the workshops.     

Exposures to 1,6-hexamethylene diisocyanate during polyurethane spray painting in the U.S. Air Force

1,6-Hexamethylene diisocyanate (HDI) exposures were measured during polyurethane enamel spray painting at four Air Force bases. Breathing zone samples were collected for HDI monomer and polyisocyanates (oligomers) using three sampling methods: NIOSH Method 5521, the Iso-Chek sampler, and the total aerosol mass method (TAMM). Exposures to HDI monomer are low when compared to current occupational exposure limits; the highest 8-hr time-weighted average (TWA) exposure found was 3.5 micrograms/m3, below the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) of 34 micrograms/m3. HDI oligomer levels were higher; mean task exposures indicated by either the Iso-Chek sampler or TAMM are above the Oregon ceiling limit of 1 mg/m3. Eight-hour TWA exposures, however, were much lower, with only one exceeding the Oregon standard of 0.5 mg/m3. Poor worker practices commonly observed during this study included: standing in downwind positions so paint overspray passed through breathing zones; spraying toward other painters; and using excessive paint spray gun air cap pressures. Workers should stand in upwind orientation relative to the aircraft being painted, causing overspray to move away from the painter's breathing zone; adjust their position to prevent spraying other painters or limit paint application to one worker at a time; and use air cap pressure gauges prior to spraying to limit spray gun air cap pressures and reduce paint overspray generation rates. These improved techniques will result in reduced worker exposures to isocyanates.     

Slow curing of aliphatic polyisocyanate paints in automotive refinishing: a potential source for skin exposure

Two-component, polyurethane paints containing aliphatic isocyanates are widely used in autobody spray painting. Such isocyanates can cause asthma, and skin exposure may be an important route of sensitization and may contribute to the development of isocyanate asthma. Autobody workers are frequently in contact with recently painted, dried auto parts. It is not known how fast the newly painted car surfaces are fully cured, that is, for how long unbound, isocyanate species remain on painted surfaces after initial drying. To address this question, scrap sections of auto bodies were painted and dried by autobody shop painters following regular practice. Routinely used paints were sprayed 23 different times on the parts. Drying was accomplished by baking the part in a paint spray booth by heating it with a heat lamp or air drying in the shop. The 23 sprayed surfaces were sampled at regular time intervals after drying to determine the presence of free NCO groups using the semiquantitative SWYPE technique. Quantitative isocyanate analysis was also performed on two sprayed parts using NIOSH method 5525. Geometric mean curing time of 23 painted surfaces was 56.4 hr (range: 0.8 hrs to 32 days). Unbound isocyanate species of similar composition to the original bulk material remained present on the majority of sampled painted surfaces for up to 120 hours for typical paint formulations and for 1 month for others. The actual curing of polyurethane paints in autobody refinishing can be a slow process. Unbound isocyanates may remain on the surface of painted car parts for prolonged periods (days to weeks) after dried. Such surfaces are an under-recognized potential source of skin exposure to autobody workers.     

Use of qualitative and quantitative fluorescence techniques to assess dermal exposure

Fluorescent tracers provide a way of simultaneously assessing the mass of a contaminant hazardous substance on the surface of the skin of a worker and the area of skin exposed. These parameters, along with the duration of exposure and the estimated contaminant concentration in the skin contamination layer, can be used to calculate the likely uptake through the skin. Repeated assessment of the mass of tracer on a surface within a room or on the surface of the skin can also allow the net transfer of contaminant to that compartment to be estimated. Qualitative evaluation of transfer processes using fluorescent tracers can help identify important secondary sources of exposure.     

Transport of a Solvent Mixture Across Two Glove Materials When Applied in a Paint Matrix

The transport of mixed paint solvents through natural rubber latex (4 mil) and nitrile rubber (5 mil) gloves was evaluated after spray application of the paint formulation directly on the glove surface. Glove materials and thicknesses were those selected by the majority of spray painters in the local automobile repair industry. A flat panel containing glove specimens mounted in multiple permeation cells permitted evaporation of solvents from the applied paint and incorporated a solid sorbent receiving medium for measuring glove membrane transport. The panel was sprayed in a paint booth to simulate use conditions. Charcoal cloth under the glove adsorbed transported solvents, which were quantified by gas chromatography. For each solvent component, results were expressed as mass transported through the glove relative to the mass applied, per unit area, during 30 min after spray application. The paint formulation contained ketones, acetates, and aromatics. Natural rubber latex allowed 6-10 times the transport of solvents relative to nitrile rubber for all eight solvent components: methyl ethyl ketone, toluene, styrene, ethyl benzene, xylene isomers, and 2-heptanone. m-Xylene showed the largest difference in transport between the two glove materials. This solvent also had the highest transport for each material. The results indicate that nitrile rubber gloves offer somewhat greater chemical resistance to all eight solvents studied compared with natural rubber latex gloves, regardless of the chemical properties of the individual solvent components. However, it must be emphasized that neither of the glove materials, in the thicknesses used in this study, provide adequate protection when exposed by direct spray painting. Simulation of realistic spray conditions may offer a source of useful information on the performance of chemical protective gloves because it accounts for solvent evaporation and the effect of paint polymerization after application on glove transport.     

Airways symptoms, immunological response and exposure in powder painting

Objectives: Powder painting is an alternative to solvent-based spray painting. Powder paints may contain organic acid anhydrides (OAAs), which are irritants to the airways and may cause sensitisation. The aim of this study was to determine the prevalence of respiratory symptoms and immunological response among powder painters and to describe the exposure to OAAs. Methods: In all, 205 subjects in 32 enterprises participated: 93 exposed and 26 formerly exposed workers in 25 powder paint shops and 86 unexposed workers. They completed a questionnaire about working conditions and symptoms and took part in a medical examination, which included a lung function test. Urine samples, for determination of two OAAs, and blood samples, for analysis of specific antibodies against the OAAs, were taken. In addition, 33 paint samples were analysed for nine OAAs. Results: The powder painters reported more work-related respiratory symptoms than unexposed subjects did. The prevalence of three or more symptoms was 24% in subjects with low exposure, 44% in highly exposed individuals, 46% in formerly exposed subjects and 19% in unexposed workers. Asthma symptoms were frequent, 7%, 40%, 15% and 2%, respectively. Regression analyses of the lung volumes did not show any influence of exposure. IgG, but not IgE, against the OAAs and metabolites of OAAs was found in some subjects, but no associations with the exposure could be observed. OAAs were found in only small amounts in the paint samples. Conclusions: The exposure to organic acid anhydrides was estimated to be low, and yet, IgG antibodies to OAA were observed in some subjects. The prevalence of work-related symptoms from the eyes and the airways was relatively high among the powder painters, and these symptoms, but not the lung volumes, were clearly related to exposure. The symptoms were probably caused by irritative properties of the powder paint dust.     

SPATTER! SPATTER! SPATTER! Workers' health and the spray machine debate

A conflict between industrialization and worker health developed in the painting industry during the early 1900s with the introduction of the spray machine. This technological innovation allowed the application of paint at greater speed and lower cost than hand painting and increased the rate at which painters were exposed to lead and other toxins contained in paint. From roughly 1919 to 1931, the painters' trade union clashed with employers, paint manufacturers, and legislatures over the impact of the spray machine on the health of workers and the need to enact legislation to regulate its use. While painters made gains on local, state, and national levels during the 1920s to prevent the use of the spray machine, their efforts ultimately failed.     

Exposure of the ground dwelling spiderOedothorax apicatus (Blackwall) (Erigonidae) to spray and residues of deltamethrin

Experiments were carried out with deltamethrin using the epigeal erigonid spiderOedothorax apicatus. The spiders were exposed to spray, residues and contaminated food. Exposure in the field, of spiders and their major prey items (collembolans) to the spray, was measured by means of a fluorescent tracer. The quantities of spray fluid recovered from these organisms was lower than the quantity measured on surfaces exposed to the spray on the soil. The availability of residues on soil was assessed by exposing individuals to sprayed soils of varying moisture content, to a soil showered after spraying and by exposing topically treated spiders to unsprayed soils. The effects of the residues were strongly related to the water content of the soil. On sprayed soils at field capacity, the toxic effects were highest. A shower shortly after spraying reduced the effect of residues considerably. On very dry soils (12.5% of field capacity) high effects were also observed both on sprayed and unsprayed soils. This effect could be attributed to unfavorable air humidity conditions near the soil surface. The relative contribution of the three routes of uptake, i.e. exposure to spray and to residues and consumption of contaminated prey, was studied with radio-labelled deltamethrin. Spiders were exposed to sprayed soil surfaces (moisture content 75% of field capacity), topically treated and fed with topically treated fruit flies. The latter route contributed little to the body burden. The amount of deltamethrin absorbed from the soil was twice the amount absorbed after topical treatment.     

Inhalation exposure to isocyanates of car body repair shop workers and industrial spray painters

As part of a large-scale epidemiological study, occupational isocyanate exposure was assessed in spray-painting environments. The aim was to assess which compounds contribute to isocyanate exposure in car body repair shops and industrial painting companies, and to identify tasks with high risk of isocyanate exposure. Mainly personal task-based samples (n = 566) were collected from 24 car body repair shops and five industrial painting companies using impingers with DBA in toluene. Samples were analysed by LC-MS for isocyanate monomers, oligomers and products of thermal degradation. From the 23 analysed compounds, 20 were detected. Exploratory factor analysis resulted in a HDI, TDI and MDI factor with the thermal degradation products divided over the TDI and MDI factors. The HDI factor mainly consisted of HDI oligomers and was dominant in frequency and exposure levels in both industries. Spray painting of PU lacquers resulted in the highest exposures for the HDI factor (相似文献   

Comparison of fluorescence and rinsing methods for assessing dermal exposure

There are a number of methods of estimating dermal contamination. "Potential exposure" methods, such as patch and whole-body oversuit sampling, intercept the contaminant before it reaches the skin. "Actual exposure" measurements recover the contaminant from the skin by wiping, stripping, or rinsing, or, in the case of fluorescent tracer dye monitoring, assess it in-situ on the skin. These different methods can give rise to very different results. Comparison of methods is difficult, because they usually interfere within-subject. This presentation is a comparison of two compatible 'actual dermal contamination' measurement techniques. They are: (1) fluorescence monitoring of a tracer dye in-situ on the skin, using ultraviolet light and a video camera linked to an image processor; (2) rinsing of the skin to recover a metal tracer salt for later assay in solution. Several painting and spraying application tasks were carried out by a panel of volunteers who wore T-shirts, shorts, and open sandals. The exercises simulated domestic or nonoccupational tasks. Results showed excellent agreement, with discrepancies identified and explained. The good agreement of the two completely different, independent tracer methods for measuring skin contamination contributes to their mutual validation.     

Nasal, eye, and skin irritation in dockyard painters

OBJECTIVES—To determine whether the risk of irritant symptoms in painters is related to their exposure to paint.
METHODS—The prevalences of skin, eye and nasal symptoms were compared in 260 United Kingdom and 109 Chinese dockyard painters, 539 British community controls, and 255 Chinese dockyard controls, relative to their exposure to paints.
RESULTS—Painters showed an excess of irritant symptoms compared with controls. Adjusted relative risks (RRs) (95% confidence interval (95% CI) were: for skin irritation 1.58 (1.19 to 2.08) in British painters and 2.68 (1.73 to 4.09) in Chinese painters; for eye irritation, 1.41 (0.98 to 2.05) and 3.01 (1.90 to 4.76); and for nasal irritation, 1.53 (1.10 to 2.14) and 6.73 (3.53 to 12.82), respectively. Exposure duration-response relations were found for these symptoms; the risks decreased with time after exposure ended.
CONCLUSIONS—Irritant symptoms occur more often in dockyard painters than in controls, and this is likely to be a response to exposure to paint.


Keywords: paint exposures; dockyard painting; health effect; irritant symptoms     

Skin exposure to aliphatic polyisocyanates in the auto body repair and refinishing industry: a qualitative assessment

OBJECTIVES: Although respiratory exposures have been the primary concern with isocyanates, skin exposure also can occur and may contribute to sensitization and asthma. Methodologies to assess isocyanate skin exposure in the workplace are limited and skin exposure data scarce. The goals of this study were (i) to evaluate and validate the isocyanate colorimetric indicators against a quantitative assay, (ii) to evaluate the extent of isocyanate surface contamination and skin exposure among auto body shop workers and (iii) to evaluate isocyanate skin exposure determinants. METHODS: The colorimetric indicators were compared with a high-performance liquid chromatography (HPLC) quantitative assay based on the National Institute for Occupational Safety and Health Method 5525 using paired laboratory sampling. The colorimetric indicators were then used to assess surface contamination and skin exposure to aliphatic isocyanates in 35 auto body shops and 124 workers as part of an epidemiologic study. The positive sample rate was calculated for various surfaces, body parts and tasks. The color intensity of the colorimetric indicators was rated on a scale 0 (yellow color) to 5 (deep red). Side-by-side comparisons of the qualitative method with the quantitative HPLC assay were also performed in the field using paired samples. RESULTS: Laboratory and field evaluation validated use of the colorimetric indicators. The rate of positive surface samples for isocyanates was 46% (n = 145/313). Thirty-four percent (73/216) of samples were positive for unprotected skin and 20% (n = 22/111) for skin under latex gloves. The highest positive rate observed on skin samples was obtained after paint mixing and spraying tasks. The colorimetric indicators were highly specific for isocyanates, but false negatives occurred when compared with the more sensitive HPLC quantitative assay. The presence of surface contamination and the performance of paint-related tasks were the major determinants of isocyanate skin exposure. CONCLUSIONS: This study documents extensive surface contamination and skin exposure, including under gloves, to aliphatic polyisocyanates during painting and paint mixing tasks in auto body shop workers. Contaminated surfaces and aerosol deposition during spray painting may both contribute to skin exposure. The colorimetric indicator is a quick, practical and low-cost, but not highly sensitive, industrial hygiene tool to detect isocyanate surface contamination and skin exposures following the use of isocyanate-containing products.     

Qualitative assessment of isocyanate skin exposure in auto body shops: a pilot study

BACKGROUND: Little is known about the extent of human isocyanate skin exposure in auto body shops and the effectiveness of personal protective equipment. Animal studies have suggested that skin exposure to isocyanates may be an important risk factor for respiratory sensitization leading to asthma. This study provides initial data on hexamethylene diisocyanate skin exposure in three auto body shops. METHODS: Three auto body shops of different size which use different paint systems were examined for the presence of aliphatic isocyanates on environmental surfaces and workers' skin and for breakthrough of personal protective equipment. Qualitative detection of contamination by isocyanates was conducted using a wipe-sampling technique. Assessment focused on the painters and their tasks, although other auto body repairers were also evaluated. RESULTS: Environmental surfaces such as painters' workbenches, spray equipment, and cleaning tools were found contaminated with isocyanates. Painters had frequent contact with contaminated surfaces, often without wearing gloves. Moderate to heavy contamination of some skin surfaces was found with painters from two of the three auto body shops. Latex gloves used for skin protection showed significant penetrations by isocyanates even after a single painting session. CONCLUSIONS: Contaminated environmental surfaces and skin exposure to isocyanates were documented in several auto body shops. Latex gloves were not adequate protection for workers using isocyanate paints. Further research which would better quantify skin exposure, and its potential relationship to respiratory sensitization and asthma is warranted.     

A video imaging technique for assessing dermal exposure. II. Fluorescent tracer testing

Laboratory and field evaluations were conducted to determine the suitability of employing a fluorescent tracer in conjunction with video imaging analysis to measure dermal exposure during pesticide applications. The Fluorescent Whitening Agent 4-methyl-7-diethylaminocoumarin and the organophosphate malathion were highly correlated (r = .985) when sprayed under controlled conditions. Deposition levels during field studies were correlated similarly (r = .942); however, variability in deposition ratios requires that field sampling be conducted to determine the ratio for a particular application. Penetration of the two compounds through cotton/polyester workshirt material demonstrated a high correlation (r = .979), whereas penetration of cotton/polyester coverall material was more variable (r = .834). The slopes of the regression lines for the two materials were not significantly different. The ratio of pesticide and tracer recovered from targets was consistently higher than the initial tank ratio due to differences in solubility and mixing.     

Occupational exposure to organic solvents during paint stripping and painting operations in the aeronautical industry

Summary The exposure of workers to methylene chloride and phenol in an aeronautical workshop was measured during stripping of paint from a Boeing B 747. Methylene chloride exposure was measured during two work days by personal air sampling, while area sampling was used for phenol. During paint stripping operations, methylene chloride air concentrations ranged from 299.2 mg/m³ (83.1 ppm) to 1888.9 mg/m³ (524.7 ppm). The exposures to methylene chloride calculated for an 8-h work day ranged from 86 mg/m³ (23.9 ppm) to 1239.5 mg/m³ (344.3 ppm). In another aeronautical workshop, exposure to organic solvents, especially ethylene glycol monoethyl-ether acetate (EGEEA), was controlled during the painting of an Airbus A 320. The external exposure to solvents and EGEEA was measured by means of individual air sampling. The estimation of internal exposure to EGEEA was made by measuring its urinary metabolite, ethoxyacetic acid (EAA). Both measurements were made during the course of 3 days. The biological samples were taken pre-and post-shift. During painting operations, methyl ethyl ketone, ethyl acetate, n-butyl alcohol, methyl isobutyl ketone, toluene, n-butyl acetate, ethylbenzene, xylenes and EGEEA were detected in working atmospheres. For these solvents, air concentrations ranged from 0.1 ppm to 69.1 ppm. EGEEA concentrations ranged from 29.2 mg/m³ (5.4 ppm) to 150.1 mg/m³ (27.8 ppm). For biological samples, the average concentrations of EAA were 108.4 mg/g creatinine in pre-shift and 139.4 mg/g creatinine in post-shift samples. Despite the fact that workers wore protective respiratory equipment during paint spraying operations, EEA urinary concentrations are high and suggest that percutaneous uptake is the main route of exposure for EGEEA. The introduction of new paint stripping processes in the aeronautical industry could help to reduce future exposure to methylene chloride.     

Exposure, lung function, and symptoms in car painters exposed to hexamethylendiisocyanate and biuret modified hexamethylendiisocyanate

Individuals who paint cars often complain to doctors about respiratory problems. Car painters are exposed to isocyanates, especially hexamethylendiisocyanate (HDI), and biuret modified HDI (HDI-BT). The mean exposure to HDI-BT was 115 micrograms/m3 in the air (range 10-385 micrograms/m3), which exceeds the time-weighted Swedish threshold level of 90 micrograms/m3. Exposure to HDI was about 1.0 microgram/m3 with brief peaks. This study investigated the effect of HDI and HDI-BT on lung function and included two control groups: (1) car platers, exposed to the same solvents and grinding dust as car painters, but not to isocyanates, and (2) car mechanics (controls), not exposed to the mentioned agents. Car painters and car platers were compared to car mechanics on Monday before work. Acute effects of car painting were tested by comparing the lung function values on Monday morning with those on Friday afternoon. Pulmonary function was evaluated by means of spirometry and a single breath nitrogen washout. Spirometry in painters and platers did not differ from that in controls, i.e., car mechanics. Closing volume in relation to vital capacity (CV%) was increased in car painters, suggestive of a "small airways disease" on Monday before work and tended to increase during a work week. Car platers did not differ from controls.     

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.     

Trends in inhalation exposure to hydrocarbons among commercial painters in The Netherlands

OBJECTIVES: An attempt was made to develop a database for measurements of exposure to solvents that could be used as a tool in the historical exposure assessment of commercial painters participating in a health surveillance program. METHODS: The measurement data on personal exposure from six studies still available for Dutch commercial painters were collected into a database. The database was analyzed to identify time trends for the inhalation exposure levels of hydrocarbons and the production conditions that influence exposure levels among commercial painters in The Netherlands. RESULTS: Altogether 304 measurements of solvent exposure were collected between 1980 and 1999, providing data for 137 workers. Toluene was selected as a marker for solvent exposure, since hydrocarbon exposures appeared to be strongly correlated. Exposure to toluene measured during the application of solvent-based paints has declined by 12% per year. The use of solvent-based paints, painting in small rooms, house (versus shipyard) painting, and spray-painting were associated with increased exposures. Water-based paint was also associated with increased exposure to toluene, relative to tasks in which no paint was used. The exposure model for toluene explained 86% of the between-worker variance. In a subset of the data, we observed that a single cell model did not adequately describe total solvent exposure among painters, because of the stronger-than-expected positive effect of source strength and the lack of the protective effect of general ventilation. CONCLUSIONS: An exposure model was developed that can be used to predict the intensity of inhalation exposure to aromatic solvents among commercial painters in The Netherlands.     

Biomarker response and biomass change of earthworms exposed to chlorpyrifos in microcosms

Background levels of chlorpyrifos and earthworm abundance were determined in an orchard and adjacent areas on a farm in the Western Cape, South Africa before these areas were again sprayed with this organophosphate. The background concentrations ranged from 0.2 microg/kg dm in the spray drift area adjacent to the orchard to 10.18 microg/kg dm on the slope in the run off area. In the target area the chlorpyrifos concentrations varied from a mean of 15.25 +/- 10.0 microg/kg directly after spraying to a mean of 7.0 +/- 0.9 microg/kg 6 months later and in the nontarget area they varied from a mean of 55.0 +/- 35 microg/kg to 12.0 +/- 5 microg/kg after 6 months. Chlorpyrifos was therefore still present in the field soils, but at lower concentrations, up to 6 months after the last spraying event. Earthworm abundance and population densities were very low. Only Aporrectodea caliginosa was found and the densities were much lower in the orchards (22 per m(2)) than in the nontarget areas (98.3 per m(2)). Microcosm studies were undertaken to relate biomarker responses to chlorpyrifos with biomass changes. Microcosms were filled with soil from the same areas and earthworms of the species A. caliginosa were introduced. The microcosms were treated with a series of concentrations of chlorpyrifos in the laboratory under controlled conditions. These concentrations were chosen to fall within the background ranges found in the soils. The biomass of the worms was determined regularly for a period of 5 weeks and worms in a state of estivation were noted. Earthworms were removed from the microcosms for biomarker tests: for cholinesterase (ChE) inhibition assays every week and for a neutral red retention determination 2 weeks after the exposures started. The most prominent biomass loss was noted in earthworms exposed to the highest pesticide concentration of 8.0 microg/kg. Estivation was higher among earthworms exposed to higher exposure concentrations. Inhibition of ChE increased with higher exposure concentrations and with time but there was no clear dose-related response. A clear dose-related response with exposure concentration was established for the neutral red retention assay. A correlation between ChE inhibition and biomass change existed directly after the second application of chlorpyrifos.