Biological monitoring of triethylamine among cold-box core makers in foundries.

Abstract

The objectives of the study were to assess triethylamine (TEA) exposure in cold-box core making and to study the applicability of urinary TEA measurement in exposure evaluation. Air samples were collected by pumping of air through activated-charcoal-filled glass tubes, and pre- and postshift urine samples were collected. The TEA concentrations were determined by gas chromatography. Tea was measured in air and urine samples from the same shift. Breathing-zone measurements of 19 workers in 3 foundries were included in the study, and stationary and continuous air measurements were also made in the same foundries. Pre- and postshift urine samples were analyzed for their TEA and triethylamine-N-oxide (TEAO) concentrations. The TEA concentration range was 0.3-23 mg/m3 in the breathing zone of the core makers. The mean 8-h time-weighted average exposure levels were 1.3, 4.0, and 13 mg/m3 for the three foundries. Most of the preshift urinary TEA concentrations were under the detection limit, whereas the postshift urinary TEA concentrations ranged between 5.6 and 171 mmol/mol creatinine. The TEAO concentrations were 4-34% (mean 19%) of the summed TEA + TEAO concentrations. The correlation between air and urine measurements was high (r = 0.96, P < 0.001). A TEA air concentration of 4.1 mg/m3 (the current ACGIH 8-h time-weighted average threshold limit value) corresponded to a urinary concentration of 36 mmol/mol creatinine. The TEA exposure levels of foundries and their core makers vary greatly. Stationary air measurements in factories are not sufficient to assess TEA exposure; instead, personal sampling is needed. The biological monitoring of TEA in postshift urine samples provides a practical and accurate method for assessing exposure.