DescriptionThis dissertation research examined the validity of urinary 1-OHP as a biomarker of PAH for coke production workers and non-coke oven workers in Anshan City, China. It has been examined whether a first morning urine sample can be used to reflect daily average exposure. Results show that intra-individual differences ranged from 40% to 62% between first morning voids and 24-hour urine composite urine samples. Coke workers showed larger intra-individual differences than non-coke oven workers. Creatinine adjustment of 1-OHP in urine reduced intra-individual difference by approximately 10% for both coke and non-coke oven workers. Despite significant intra-individual difference, a high overall correlation (r=0.76) was observed between first morning and 24-hour average 1-OHP concentrations. Significant effect of season on the association between first morning and 24-hour 1-OHP in urine has been observed. Creatinine adjustment did not improve overall correlation between 1-OHP concentrations in first morning voids and 24-hour composite urine samples.
An exposure-biomarker relationship between PAH exposure and urinary 1-OHP concentration has been determined with a wide range of personal inhalation exposure., suggesting a threshold value for this exposure-biomarker relationship at 49 ng/m3 for personal air pyrene and 20 ng/m3 for personal air BaP. The corresponding urinary 1-OHP concentration was 0.46 ?mol/(mol creatinine). However, no significant exposure-biomarker relationship was observed for dietary intake. With inhalation exposure, an increase of 1-OHP concentration by 1 ?mol/(mol creatinine) predicted an increase in personal air concentration of BaP by 0.12 ?g/m3 and 0.13 ?g/m3 in males and females, respectively.
In addition, reproducibility of urinary 1-OHP has been demonstrated over 6 to 9 months. Intra-class correlation coefficient for urinary 1-OHP was similar to those for personal air and dietary intakes of pyrene. Within-person variances were larger than between-person variances in all measured media. Urinary 1-OHP had the highest variance ratio (within- to between-person), suggesting that urinary 1-OHP may be less accurate to estimate PAH exposure than personal air and dietary intake. No significant effects of work type and season were found on intra-class correlation in urinary 1-OHP, personal air concentration of pyrene, and dietary pyrene intake.