title: Dose-Response Relationship between Cumulative Occupational Lead Exposure and the Associated Health Damages: A 20-Year Cohort Study of a Smelter in China.
abstract: Long-term airborne lead exposure, even below official occupational limits, has been found to cause lead poisoning at higher frequencies than expected, which suggests that China's existing occupational exposure limits should be reexamined. A retrospective cohort study was conducted on 1832 smelting workers from 1988 to 2008 in China. These were individuals who entered the plant and came into continuous contact with lead at work for longer than 3 months. The dose-response relationship between occupational cumulative lead exposure and lead poisoning, abnormal blood lead, urinary lead and erythrocyte zinc protoporphyrin (ZPP) were analyzed and the benchmark dose lower bound confidence limits (BMDLs) were calculated. Statistically significant positive correlations were found between cumulative lead dust and lead fumes exposures and workplace seniority, blood lead, urinary lead and ZPP values. A dose-response relationship was observed between cumulative lead dust or lead fumes exposure and lead poisoning (p < 0.01). The BMDLs of the cumulative occupational lead dust and fumes doses were 0.68 mg-year/m³ and 0.30 mg-year/m³ for lead poisoning, respectively. The BMDLs of workplace airborne lead concentrations associated with lead poisoning were 0.02 mg/m³ and 0.01 mg/m³ for occupational exposure lead dust and lead fume, respectively. In conclusion, BMDLs for airborne lead were lower than occupational exposure limits, suggesting that the occupational lead exposure limits need re-examination and adjustment. Occupational cumulative exposure limits (OCELs) should be established to better prevent occupational lead poisoning.
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Central South University, 110# Xiang-ya Rd., Changsha 410078, Hunan, China. wuyue7802@csu.edu.cn.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Central South University, 110# Xiang-ya Rd., Changsha 410078, Hunan, China. 13826391706m@sina.cn.|Worker Hospital, Guangdong Shaoguan Smelter, Shaoguan 512024, Guangdong, China. 13826391706m@sina.cn.
authors.forename: Jun-Ming
authors.initials: JM
authors.lastname: Gu
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Central South University, 110# Xiang-ya Rd., Changsha 410078, Hunan, China. lwhw2010@163.com.
authors.forename: Yun
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Central South University, 110# Xiang-ya Rd., Changsha 410078, Hunan, China. duanyy2010@126.com.
authors.forename: Yan-Ying
authors.initials: YY
authors.lastname: Duan
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Central South University, 110# Xiang-ya Rd., Changsha 410078, Hunan, China. arsenite@163.com.
authors.forename: Rui-Xue
authors.initials: RX
authors.lastname: Huang
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Central South University, 110# Xiang-ya Rd., Changsha 410078, Hunan, China. jiananhu@csu.edu.cn.
authors.forename: Jian-An
authors.initials: JA
authors.lastname: Hu
mesh_terms: D000328:Adult; D000395:Air Pollutants, Occupational / Q000097:blood / Q000633:toxicity* / Q000652:urine; D002681:China; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007854:Lead / Q000097:blood / Q000633:toxicity* / Q000652:urine; D007855:Lead Poisoning / Q000097:blood / Q000175:diagnosis / Q000209:etiology* / Q000652:urine; D008297:Male; D066192:Manufacturing Industry; D008875:Middle Aged; D009784:Occupational Diseases / Q000097:blood / Q000175:diagnosis / Q000209:etiology* / Q000652:urine; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis; D012189:Retrospective Studies
chemical_list: D000395:Air Pollutants, Occupational; D007854:Lead
keywords: benchmark dose; biological effects; cumulative lead exposure; dose-response relationship; lead poisoning; occupational exposure limits