[Application of Benchmark dose (BMD) in estimating biological exposure limit (BEL)].

OBJECTIVE

Based on two sets of data from occupational epidemiology, Benchmark dose (BMD) was applied to estimate biological exposure limit (BEL).

METHODS

Cadmium exposed workers were selected from a cadmium smelting and a zinc products factory and control group was selected from doctors or nurses and staff from shops living in the same area; Urinary cadmium (UCd) was used as exposure biomarker and urinary beta(2) microglobulin (UBM), NAG (UNAG) and albumin (UALB) were as effect biomarkers. All urine parameters were adjusted by urinary creatinine. Software of BMDS (Version 1.3.2, EPA.U.S) was used to calculate BMD.

RESULTS

Calculated abnormal prevalence was based on the upper limit of 95% of effect biomarkers in control group; There are significant dose response relationship between the prevalence of effect biomarkers (UBM, UNAG and UALB) and exposure biomarker (UCd); BEL was 5 microg/g creatinine for UBM as effect biomarker, It consists with the recommendation of WHO; BEL was 3 microg/g creatinine for UNAG as effect biomarker; BEL can be estimated by using the method of BMD; the more sensitive biomarker would used, the more occupational people would protected.

CONCLUSION

The application of BMD in estimating biological exposure limit (BEL) is proper. UNAG is suggested as most sensitive biomarker to be used to estimate BEL for cadmium exposure.