Occupational/environmental protocols designed for use by poison information specialists.
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Environmental Health↗
Biomedical subjects
C S Clark
Publications and source records attributed to C S Clark.
An occupational/environmental services training program for poison information specialists.
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Environmental Health↗
Poison centers: a resource for occupational health services.
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Education, Continuing↗
Additivity of detector responses of a portable direct-reading 10.2 eV photoionization detector and a flame ionization gas chromatograph for atmospheres of multicomponent organics: use of PID/FID ratios.
The H-Nu PI-101 with a photoionization detector (PID) of 10.2 eV and the Century OVA-128 equipped with a flame ionization detector (FID) were evaluated for the additivity of their responses to a defined mixture of dissimilar organic vapors at a 0 and 90% relative humidity (RH). The responses of both instruments were additive as long as the effect of RH was accounted for with the PID. The PI-101 was not as precise as the Century OVA-128 for 90% RH atmospheres. PID/FID ratios did not change in the presence of 90% RH as long as the effect of RH also was accounted for in the PID reading.
Chemistry Techniques, Analytical↗
Seroepidemiologic study of giardiasis patients and high-risk groups in a midwestern city in the United States.
Serum antibodies to Giardia lamblia were measured in giardiasis patients, in groups at high risk for intestinal parasite infection, and in controls by an indirect fluorescent antibody (IFA) technique. Symptomatic patients had the highest antibody titers, and antibodies remained present for up to 18 months in persons with chronic infection. Indochinese refugees and male homosexuals with the acquired immunodeficiency syndrome (AIDS) and pre-AIDS had higher mean antibody levels than did healthy controls, whereas sewer and highway maintenance workers had levels similar to those of controls. Serum antibodies to Entamoeba histolytica measured by an indirect hemagglutination antibody technique were detected in only a few Indochinese refugees. We conclude that serology is a promising tool in G. lamblia epidemiology and that further population studies would be of interest.
Entamoeba histolytica↗
Simultaneous multi-instrumental monitoring of vapors in sewer headspaces by several direct-reading instruments.
Simultaneous monitoring of the vapors in several sewer headspaces by three direct-reading instruments, the Century OVA flame ionization detector, a 10.2 eV H-Nu Photoionization Detector, and a Hydrogen Sulfide Ecolyzer revealed that the majority of condensable organic vapors in areas of the Metropolitan Sewer District of Cincinnati appeared to be saturated aliphatic organics, except during short, unpredictable episodes. The monitoring was performed in the wet well of a sewage treatment plant, in sewers near two chemical plants, and in three other different sewers. The approach outlined in this paper does not require the use of gas chromatography-mass spectrometry (GC-MS) analysis.
Environmental Monitoring↗
Condition and type of housing as an indicator of potential environmental lead exposure and pediatric blood lead levels.
Environmental evaluations in a prospective behavioral study of children with blood lead levels up to about 50 micrograms/dl were performed by an intensive environmental survey and by exterior visual evaluation of housing quality. Serial blood lead values for infants in the study were compared to exterior housing type and quality, which itself was also compared with results of the intensive environmental evaluation. Five housing condition and type categories were defined: public housing; private housing (satisfactory, deteriorated, and dilapidated); and rehabilitated private housing. In this interim report on the first subset of available data, the housing categories were found to differ in paint and environment dust lead levels, with public and rehabilitated housing having lowest values. Blood lead concentrations of children differed across housing categories as early as 6 months of age, with children residing in public housing having lowest levels, followed by those in rehabilitated housing. The spread in mean blood lead concentrations among the housing quality categories increased with increasing age of the children. Housing category accounted for over one-half of the blood lead variability in 18-month-old children.
Dust↗
Evolution of efficient methods to sample lead sources, such as house dust and hand dust, in the homes of children.
Efficient sampling methods to recover lead-containing house dust and hand dust have been evolved so that sufficient lead is collected for analysis, and to ensure that correlational analyses linking these two parameters to blood lead are not dependent on the efficiency of sampling. Precise collection of loose house dust from a 1-unit area (484 cm2) with a Tygon or stainless steel sampling tube connected to a portable sampling pump (1.2 to 2.5 liters/min) required repetitive sampling (three times). The Tygon tube sampling technique for loose house dust less than 177 microns in diameter was around 72% efficient with respect to dust weight and lead collection. A representative house dust contained 81% of its total weight in this fraction. A single handwipe for applied loose hand dust was not acceptably efficient or precise, and at least three wipes were necessary to achieve recoveries of greater than 80% of the lead applied. House dusts of different particle sizes less than 246 microns adhered equally well to hands. Analysis of lead-containing material usually required at least three digestions/decantations using hot plate or microwave techniques to allow at least 90% of the lead to be recovered. It was recommended that other investigators validate their handwiping, house dust sampling, and digestion techniques to facilitate comparison of results across studies. The final methodology for the Cincinnati longitudinal study was three sampling passes for surface dust using a stainless steel sampling tube; three microwave digestions/decantations for analysis of dust and paint; and three wipes with handwipes with one digestion/decantation for the analysis of six handwipes together.
Adult↗
The influence of social and environmental factors on dust lead, hand lead, and blood lead levels in young children.
The roles of environmental and behavioral factors in determining blood levels were studied in a cohort of young children living in an urban environment. The subjects were observed at 3-month intervals from birth to 24 months of age. Repeated measurements were made of the children's blood lead levels, environmental levels of lead in house dust, and in the dust found on the children's hands. A qualitative rating of the residence and of the socioeconomic status of the family was obtained. Interviews and direct observation of parent and child at home were used to evaluate various aspects of caretaker-child interactions. Data analysis consisted of a comparison of results obtained by simple correlational analysis, multiple regression analysis, and structural equations analysis. The results demonstrated that structural equation modeling offers a useful approach to unraveling the complex interactions present in the data set. In this preliminary analysis, the suspected relationship between the levels of lead in house dust and on hands and the blood lead level was clearly demonstrated. Furthermore, the analyses indicated an important interplay between environmental sources and social factors in the determination of hand lead and blood lead levels in very young children.
Child, Preschool↗
An evaluation of the response of some portable, direct-reading 10.2 eV and 11.8 eV photoionization detectors, and a flame ionization gas chromatograph for organic vapors in high humidity atmospheres.
Three portable, direct-reading instruments were tested to evaluate their ability to detect organic vapors in high humidity atmospheres. The instruments included two photoionization detectors (10.2 eV and 11.8 eV), and an organic vapor analyzer with a flame ionization detector. The organic vapors used were hexanes, 1,1-dichloroethane, chloroform, trichloroethylene, perchloroethylene, benzene, toluene and chlorobenzene. Relatively impervious gas bags were used to contain atmospheres of low (zero) and high (90 percent) relative humidities for comparisons. The response of the organic vapor analyzer was practically independent of humidity. The responses of the photoionization detectors were influenced by high humidity even though the 10.2 eV lamp did not detect water vapor itself. The photoionization detectors were adjudged to be unsuitable for quantitative sampling of humid confined spaces since the 11.8 eV lamp was sensitive to water vapor and the 10.2 eV lamp showed unpredictable response factors in high humidity.
Air Pollutants, Occupational↗
Method for detecting the 3-hydroxymyristic acid component of the endotoxins of gram-negative bacteria in compost samples.
An analytical chemical method for the 3- or beta-hydroxymyristic (BHM) acid component of endotoxins has been developed for the lipopolysaccharide (LPS) of E. coli, intact E. coli, and sewage sludge compost. Endotoxins are the pyrogens associated with the outer membranes of many gram-negative bacteria, for example, E. coli and Salmonella. The BHM acid content was used as a chemical marker for endotoxin presence, since BHM acid is present in the molecular subunit (Lipid-A) responsible for the toxicity and is the most abundant saturated fatty acid in that subunit. BHM acid quantification thus complements the Limulus bioassay to detect gram-negative bacteria presence in such samples as cotton and other dusts, blood, water, compost and air samples. BHM acid was isolated after digestion, ether extraction, alkaline hydrolysis, and ether extraction. The free acid was quantitated as the methyl ester using two GC columns as a screening method or by GC/MS for confirmatory purposes. Recoveries were unreliable below 15 ng of BHM acid. By the use of the 2-column screening technique, the amounts of BHM equivalent in E. coli LPS, intact E. coli and compost in micrograms BHM acid/g substrate were (arithmetic mean +/- standard deviation), respectively: 56 120 +/- 2200; 2650 +/- 339; and 14.7 +/- 5.7.
Chromatography, Gas↗
Serologic survey of rotavirus, Norwalk agent and Prototheca wickerhamii in wastewater workers.
Analysis of paired sera from 48 wastewater workers and controls who reported gastrointestinal illness did not reveal any excess of seroconversions to Norwalk agent or to rotavirus. Inexperienced wastewater-exposed workers had higher levels of antibody to Norwalk agent than did experienced and control workers and those with high and medium aerosol exposure had higher titres than those in the low aerosol category. Analysis for Prototheca antibody titres was essentially negative.
Adult↗
Risk of infection associated with a wastewater spray irrigation system used for farming.
The use of wastewater for agricultural purposes involves the potential risk of infection from microorganisms in the wastewater. The application of partially treated wastewater on farms has been reported in one study to be associated with human illness, but this has not been confirmed. In the present study, workers at a land application system involving low-pressure spray irrigation of corn fields with wastewater were followed through a growing season to determine if they had an increased risk of infection as compared with a control population of the same socioeconomic group who had no direct exposure to wastewater. Enteroviruses were recovered from the wastewater used for irrigation, but not from the air during spraying. There was no increase in clinical illness among the workers and there was no evidence of an increased risk of infection. The workers who seemed at greatest risk, those who cleaned the spray nozzles, had higher antibody levels to one enterovirus, coxsackievirus B5, but acute symptomatic infections with viral excretion were not documented. This study indicates that there is very limited risk of infection among workers using partially treated wastewater for agriculture purposes.
Adult↗
Enteric parasites in workers occupationally exposed to sewage.
To determine if parasitic infections occur more frequently among workers exposed to wastewater than among controls, parasitologic examinations were performed on stool specimens collected over a 12-month period from sewer and highway maintenance workers. Three of 56 sewer maintenance workers (5.4%) had at least one positive specimen compared with 10 of 69 highway workers (14.5%). The highest rate was found among highway workers engaged in street cleaning. Contrary to studies conducted outside the United States, the present study does not indicate that parasitic infections occur more frequently among sewer workers than among controls in the urban midwestern United States. The results of this study indicate that there may be a risk of parasitic infections among street cleaners.
Adult↗
Hazardous chemical exposure at a municipal wastewater treatment plant.
The use of municipal wastewater treatment plants for the disposal of industrial wastes creates the potential for the exposure of treatment plant workers to hazardous chemical compounds that may be present in these wastes. Urine from workers and air and wastewater samples from a municipal wastewater treatment plant receiving wastes from a pesticide manufacturer were analyzed on several occasions by electron-capture gas chromatography for the presence of the compounds hexachlorocyclopentadiene (HEX) and hexachlorobicycloheptadiene (HEX-BCH) which are present in the waste stream from this industry. HEX-BCH was detected more frequently in urine from these workers than in urine from workers at another municipal wastewater treatment plant in the same city. Urine concentrations of HEX-BCH were found to be higher in specimens collected late in the work shift than in those collected earlier. The primary rate of exposure is thought to be by inhalation. This is the first known report of these compounds being detected in human urine and it demonstrates the potential for wastewater treatment plant worker exposure to industrial wastes.
Air Pollutants, Occupational↗
Worker exposure to chlorinated organic compounds from the activated-sludge wastewater treatment process.
The objective of this research was to investigate some of the potentially controlling factors influencing the atmospheric releases of volatile organic chlorinated compounds from the activated-sludge sewage treatment process. The field study was designed to evaluate the wastewater and airborne concentrations of six chlorinated compounds: hexachlorobicycloheptadiene (hex-BCH), heptachlorobicycloheptene (Hex-VCL), chlordene, chloroform (CHCl3), carbon tetrachloride (CCl4) and tetrachloroethylene (TCE). Analysis of samples consisted of saturating 5 mL aliquots with sodium chloride, extracting with an equal amount of petroleum ether (PE) and subsequent analysis using a gas chromatograph. The air samples collected on Chromsorb 102 were desorbed with 2 mL PE. The study revealed that the highest wastewater concentrations for the water-insoluble hex-BCH, hex-VCL and chlordene were found in the aeration basins, which suggests adsorption of these compounds to the biomass. The plant effluent wastewater concentrations were reduced because of airborne release and suspended solids separation in the clarifiers. In contrast, the wastewater concentrations for the more water-soluble CHCl3, CCl4 and TCE were significantly reduced in the aeration basins. This is because of aerial stripping at the grit-chamber weir. This study suggests that the water-insoluble compounds have prolonged aerial release from the aeration basins. The water-insoluble compounds adhere to the biomass, which is recycled through the plant. The aerial release of these water-insoluble compounds was enhanced by increased aeration rate but depressed by higher suspended solids concentrations.
Air↗
Worker exposure to organic vapors at a liquid chemical waste incinerator.
The extent of employee exposure to organic vapors at a liquid/fluid chemical waste incinerator facility was assessed by means of a preliminary survey. The study was conducted at a facility owned by the Metropolitan Sewer District of Greater Cincinnati, Cincinnati, OH. The incineration unit employs a rotary kiln and a cyclone furnace (liquid injection) with a common combustion chamber. A wide variety of liquid industrial chemical wastes are accepted in tank truck quantities. Low flow air pumps were used to collect breathing zone and general area samples on standard 150-mg charcoal tubes. The samples were analyzed by a gas chromatograph equipped with a flame ionization detector. Benzene, methyl ethyl ketone (MEK), toluene and xylene, solvents common to many of the wastes accepted, were selected for determination. The data indicate that the routine operation of this liquid industrial waste incinerator facility results in worker exposure considerably less than the action level (50% of the health standard) for all compounds tested, except benzene. Some workers were at risk of overexposure to benzene if the NIOSH-recommended criteria are used, but not when the OSHA and ACGIH criteria are used. The highest exposure routine operations were cleaning pump strainers after receiving wastes and benzene distillations conducted in the laboratory. The non-routine operation of storage tank entry, which occurred once during the study, resulted in the highest potential exposure of any operation.
Air Pollutants↗
Levels of gram-negative bacteria, Aspergillus fumigatus, dust, and endotoxin at compost plants.
Airborne gram-negative bacteria, endotoxins, dust, and Aspergillus fumigatus were measured in four compost plants in Sweden. At sites where material was processed, the number of airborne A. fumigatus exceeded 10(6)/m3, whereas the number of gram-negative bacteria was usually lower. Dust levels were moderate, and endotoxin levels were well below 0.5 micrograms/m3. Medical studies to evaluate the effects of this type of microbial exposure are recommended.
Air↗