Search

A sensitive and reliable method is described for the determination of aromatic and chlorinated hydrocarbons (benzene, toluene, o-, m-, p-xylene, trichloromethane, trichloroethane, trichloroethene and tetrachloroethene) in indoor and outdoor air at environmental concentration levels. The procedure can be easily extended to other VOCs. Using passive samplers the VOCs have been adsorbed onto charcoal during a four-week sampling period and subsequently desorbed with carbon disulfide. After injection with a cold split-splitless multi-injector the VOCs have been separated by capillary gas chromatography. Quantification has been achieved using an electron capture detector (ECD) and a flame ionization detector (FID) switched in series. A limit of about 1 μg/m3 for aromatic hydrocarbons and of about 0.01 μg/m3 for chlorinated hydrocarbons has been obtained. The procedure has been successfully applied in the framework of a field study to measure indoor and outdoor air concentrations in Essen and Borken, two differently polluted areas of Northrhine-Westphalia.

The long-term urinary mercury excretion was determined in 17 28- to 55-year-old persons before and at varying times (up to 14 months) after removal of all (4-24) dental amalgam fillings. Before removal the urinary mercury excretion correlated with the number of amalgam fillings. In the immediate post-removal phase (up to 6 days after removal) a mean increase of 30% was observed. Within 12 months the geometric mean of the mercury excretion was reduced by a factor of 5 from 1.44 micrograms/g (range: 0.57-4.38 micrograms/g) to 0.36 microgram/g (range: 0.13-0.88 microgram/g). After cessation of exposure to dental amalgam the mean half-life was 95 days. These results show that the release of mercury from dental amalgam contributes predominantly to the mercury exposure of non-occupationally exposed persons. The exposure from amalgam fillings thus exceeds the exposure from food, air and beverages. Within 12 months after removal of all amalgam fillings the participants showed substantially lower urinary mercury levels which were comparable to those found in subjects who have never had dental amalgam fillings. A relationship between the urinary mercury excretion and adverse effects was not found. Differences in the frequency of effects between the pre- and the post-removal phase were not observed.

Seventeen persons (2 women and 15 men), who were exposed to glycolethers in a varnish production plant, were examined according to their external and internal solvent exposure. The workers in the production plant (n = 12) were exposed to average concentrations of ethoxyethanol, ethoxyethyl acetate, butoxyethanol, 1-methoxypropanol-2, 2-methoxypropyl-1-acetate and xylene of 2.8; 2.7; 1.1; 7.0; 2.8 and 1.7 ppm. In the air of the store (n = 3) and in the laboratory (n = 2) only minor concentrations of xylene respectively xylene and ethoxyethyl acetate could be measured. Internal exposure was estimated by measuring butoxyethanol (BE) in blood as well as ethoxyacetic acid (EAA) and butoxyacetic acid (BAA) in urine samples. Urine samples were taken pre- and post-shift. As expected, the highest values were found in the varnish production. The average post shift concentrations of BE, EAA and BAA were 121.3 micrograms/l; 167.8 and 10.5 mg/l. The relatively high concentrations of EAA and BAA in pre-shift samples can be explained by the long half-lives of these metabolites. According to our findings most of the glycolethers were taken up through the skin. Comparing our results with those reported in the literature we think that a future tolerable limit value for the concentration of ethoxyacetic acid in urine should be in the order of 100 to 200 mg/l.

A simple, rapid and reliable method is presented for the determination of butoxyacetic acid (BAA), the main metabolite of ethylene glycol monobutyl ether (Butyl Cellosolve). The urine is acidified with hydrochloric acid and passed through a cation-exchange column. BAA which is quantitatively found in the filtrate is subsequently adsorbed on XAD-4 resin. After desorption with diethyl ether an aliquot of the eluate is evaporated in a nitrogen stream and methylated with diazomethane in diethyl ether. A forty-fold enrichment is achieved by this procedure. The gas-chromatographic separation is performed on a 60 m fused silica capillary column DB-1 (100% dimethyl-polysiloxane). Flame ionization is used for detection. Pentoxyacetic acid (PAA) serves as internal standard. The detection limit of BAA in urine is 0.02 mg/l. Linearity has been tested up to 50 mg/l. The losses by the clean-up steps are between 10.0% and 22.7%. The average recovery is 100.9%. Within-series imprecision (n=10) has been determined for three concentrations and ranges between 4.8% and 12.6%.