Biological monitoring of workers exposed to carbon disulfide.

Urinary 2-thiothiazolidine-4-carboxylic acid (TTCA) concentrations and corresponding personal breathing zone carbon disulfide (CS2) air concentrations were measured for worker populations at a Tennessee rubber product facility and a Virginia viscose rayon plant. At the rubber product facility, all of the 19 workers had urinary TTCA levels less than the limit of detection (LOD) of about 0.03 mg/L, equivalent to less than 0.5 ppm of CS2 in air. At the viscose rayon plant, five of six workers, although wearing half-mask cartridge respirators, showed increased urinary TTCA during the workshift. The cutters and spinners had the largest increases in urinary TTCA concentrations; they also had the highest breathing zone exposures to CS2. The TTCA concentrations for three cutters and spinners did not return to normal preshift levels of < 0.3 mg/g creatinine before the start of the next shift. The arithmetic mean respirator workplace protection factor (WPF) was 7.0 +/- 2.2. Increase in urinary TTCA concentration during the workshift and postshift urinary TTCA concentration reflected CS2 air concentration equally well. In conjunction with air monitoring results, urinary TTCA concentrations allow determination of the WPF afforded workers wearing respirators and identify workers not adhering to safety rules and good work practices. Workers at risk of adverse health effects from overexposure to CS2 for any reason may thus be identified.

1-Hydroxypyrene levels in coal-handling workers at a coke oven.

An environmental and medical survey was conducted at the coal-handling area of a coke oven, where workers came in contact with coal-tar sludge. The purpose of the study was to determine if skin contact with coal-tar sludge was an important route of exposure to pyrene because workers were observed to have substantial contact with the sludge. Environmental monitoring revealed minimal airborne exposure to pyrene, a byproduct of the coke distillation process; only one personal breathing zone sample detected pyrene, and at least of 0.001 mg/m3. However, the mean preshift urinary 1-hydroxypyrene concentration was 1.00 mumol/mol creatinine (range, 0.16 to 2.96 mumol/mol creatinine) and the mean postshift level was 1.7 mumol/mol creatinine (range, 0.24 to 4.85 mumol/mol creatinine) (P < 0.01). These levels probably reflect absorption as a result of skin exposure.

Biological monitoring of commercial pesticide applicators for urine metabolites of the herbicide alachlor.

Alachlor (2-chloro-2',6'-diethyl-N-[methoxymethyl] acetanilide), the active ingredient in several trade name herbicides, is absorbed through the skin and readily excreted in the urine as conjugated metabolites. This paper presents the results of a study to measure alachlor metabolites in the urine of commercial pesticide applicators who were applying alachlor to corn and soybean crops under normal work conditions. Three spot urine samples, collected at the beginning and end of the work shift and the morning after the exposure survey, were collected from 20 applicators, 7 hauler-mixers, and 8 controls. Each sample was analyzed using both a competitive, solid-phase, enzyme-linked immunoassay (ELISA) and a high-performance liquid chromatography (HPLC) technique. Although the urine metabolite concentrations measured by ELISA were consistently higher than the respective HPLC measurements, a high correlation (r = 0.90) was observed between the ELISA and HPLC measurements. The controls, with little exposure to alachlor, had metabolite levels below or near the lower limits of detection for each analysis technique. Similar urine metabolite concentrations were observed for the applicators and hauler-mixers, suggesting similar work exposures. The average postexposure urine concentrations were not correlated with the amount of alachlor handled and applied, suggesting that other factors, such as work practices, are greater determinants of absorbed doses of alachlor.

Efficacy of urinary monitoring for 4,4'-methylenebis (2-chloroaniline).

The aromatic amine 4,4'-methylenebis (2-chloroaniline) (MBOCA), an animal carcinogen, is used commercially as a curing agent for isocyanate-containing polymers. It is structurally similar to other aromatic amines that cause bladder cancer in occupationally exposed workers. Since the late 1970s, MBOCA users have relied on urinary monitoring as the primary method of assessing MBOCA exposure in the workplace. This paper (1) outlines uncertainties about MBOCa's metabolism in humans that complicate interpretation of urinary MBOCA results; (2) describes alternative laboratory techniques for measuring MBOCA in urine; and (3) discusses observations from site visits concerning the practical application of urinary monitoring. Recommendations to improve the efficacy of monitoring programs for urinary MBOCA are outlined.

4,4'-methylene-bis-ortho-chloro-aniline (MBOCA): absorption and excretion after skin application and gavage.

4,4'-methylene-bis-ortho-chloro-aniline ( MBOCA ) is an aromatic amine and industrial chemical that has been shown to cause cancer of several different organs in rats and mice and bladder cancer in dogs. The purpose of this study was to determine the efficacy of using urinary concentrations of MBOCA as a means for evaluating extent of exposure. Male Sprague-Dawley rats were given MBOCA and [14C] MBOCA by either gavage or skin application. Concentrations and amounts of 14C were measured in urine, feces, skin and total carcasses, and parent MBOCA in urine at several intervals after application. The percentages of administered doses excreted and retained in the animals were calculated and comparisons made. Within 72 hr after gavage 16.5% of the administered compound was excreted in urine as 14C but only 0.25% as parent MBOCA . In the same interval after skin application a maximum of 2.54% of administered MBOCA was excreted as 14C but only 0.008% as parent MBOCA . Seventy-two hours after gavage 13.7% of the administered dose was retained in the tissues, and after skin absorption 5-13% was retained. With gavage the rate of excretion of 14C in urine and feces was very high in the first 24 hr (68.3%) but fell off rapidly (2.07%) by the third day. After skin absorption the rates of excretion of 14C were fairly constant over a 3-day period. Less MBOCA was absorbed from the skin if the skin was washed within 8 hr after application, as compared to waiting 24 hr or not washing at all. The amount of parent MBOCA detected in urine is a very small amount of that applied or absorbed. The percentage detected and the rates of excretion depend upon the route of administration, and the interval between exposure and sampling. For these reasons urinary analysis for MBOCA can be used only as very imprecise indicators of extent of recent exposure.

Chemical monitoring of urine from workers potentially exposed to benzidine-derived azo dyes.

Benzidine (Bzd) and monoacetylbenzidine (MoAcBzd) were found in the urine of workers exposed to benzidine-based azo dyes. A colorimetric screening method, based on the reaction of extracted free aromatic amines with 2,4,6-trinitrobenzene-sulfonic acid (TNBS), was used with a specific electron-capture gas chromatographic (EC-GC) method. Alkaline hydrolyzable conjugates of Bzd and 2,4-diaminoazobenzene (DiAmAzBz) were found together with free DiAmAzBz and traces of 3,3'-dimethylbenzidine (DiMeBzd) and 3,3'-dimethoxybenzidine (DiMxBzd). The presence of a known human bladder carcinogen (Bzd) and its metabolites in the urine of workers exposed to benzidine-based azo dyes is a cause for concern.

Histamine induction and release following proteolytic enzyme exposure.

The mechanism of biologic response from exposure to a 12% subtilisin Carlsberg preparation is shown to be one of histamine release in the guinea pig. Three groups of guinea pigs were pretreated by intradermal injections withsaline solution of (1) the commercial proteolytic enzyme preparation containing 12% subtilisin Carlsberg, (2) an alkaline protease preparation obtain from Aspergillus oryzae that was isolated from cotton dust, or (3) a nonproteolytic mixture of proteins and lipases obtained from cotton seeds. The histamine content of the ling, liver, and ear tissues of guinea pigs that were pretreated with any one of the three preparations showed an in untreated animals. Following challenge by intratracheal injection of a saline solution containing the subtilisin preparation, the guinea pigs pretreated with the same preparation showed a markedly reduced liver histamine level. Challenge by inhalation exposure to the subtilisin preparation of guinea pigs that were pretreated with any one of the above preparations resulted in a lower histamine concentration in the lungs and livers.