Division of Occupational Health and Epidemiology, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Gauteng Province, South Africa.
Epidemiology and Surveillance Section, National Institute for Occupational Health, National Health Laboratory Services, Johannesburg, Gauteng Province, South Africa.
Ann Work Expo Health. 2021 Oct 9;65(8):955-965. doi: 10.1093/annweh/wxab030.
Globally, several strategies for compliance testing and within-group exposure variability have been suggested. This study aimed to evaluate the performance of the South African Mining Industry Code of Practice (SAMI CoP) approach for grouping and compliance testing against international standards.
A total of 28 homogenous exposure groups (HEGs) with 728 underground coal mine workers' eight-hour time-weighted average coal dust concentration data were obtained. Compliance testing was assessed using 10% exceedance above occupational exposure limit (OEL) for SAMI CoP, and the 95th percentile of the lognormal distribution was computed for the European Standardization Committee (CEN) and American Industrial Hygiene Association (AIHA). Comparison of the homogeneity of the HEGs was done between SAMI CoP which mandates that both the arithmetic mean (AM) and 90th percentile must fall in the same exposure band to certify homogeneity and the global geometric standard deviation (GSD) and Rappaport ratio (R-ratio) with specific acceptability criteria. To test the homogeneity of exposure within job titles, eight non-homogenous HEGs that have two or more job titles with three measurements were investigated using GSD and the SAMI CoP criteria.
A total of 21 HEGs out of 28 were non-compliant to the OEL across SAMI CoP, CEN, and AIHA criteria. Compliance to the OEL was observed for seven HEGs according to the SAMI CoP approach, whereas only one HEG was compliant according to both the SAMI CoP and CEN approaches. The GSD criterion and SAMI CoP revealed that 11 and 6 HEGs were homogenous, respectively, and only on 4 occasions, the 2 approaches agreed. The job titles of the majority of non-homogenous HEGs in both SAMI CoP and GSD were actually homogenous. Five out of 10 sub-groups have their AM above that of HEG B. Other HEGs had at least one of their AM and 90th percentile values above that of their respective parent HEGs.
All three approaches mainly confirmed non-compliance of HEGs. SAMI CoP tended to show compliance of HEGs more than CEN. Non-homogenous HEGs had many job titles that were homogenous according to both SAMI CoP and GSD criteria. There was no perfect agreement of homogeneity by all the indicators. For both future constitutions of HEGs as well as a retrospective assessment of high exposure groups, homogeneity can be improved by using job titles.
全球范围内，已经提出了几种用于合规测试和组内暴露变异性的策略。本研究旨在评估南非矿业行业作业规范（SAMI CoP）方法在分组和合规测试方面与国际标准的一致性。
获得了 28 个同质暴露组（HEG）的 728 名地下煤矿工人 8 小时时间加权平均煤尘浓度数据。合规性测试使用 SAMI CoP 规定的职业暴露限值（OEL）的 10%以上超标进行评估，CEN 计算了对数正态分布的第 95 百分位数，AIHA 计算了算术平均值（AM）和第 90 百分位数都必须落在相同暴露带内以证明同质性的 90 百分位数。使用全球几何标准差（GSD）和 Rappaport 比（R-ratio）以及特定可接受标准，对 SAMI CoP 规定的 AM 和 90 百分位数都必须落在相同暴露带内进行同质组认证的方法与同质组进行了比较。为了测试不同职业的暴露是否同质，对 8 个包含两个或更多职业的非同质 HEG 进行了研究，这些 HEG 有三个测量值，使用 GSD 和 SAMI CoP 标准进行了研究。
在 SAMI CoP、CEN 和 AIHA 标准下，28 个 HEG 中有 21 个不符合 OEL。根据 SAMI CoP 方法，有 7 个 HEG 符合 OEL，而根据 SAMI CoP 和 CEN 方法，只有 1 个 HEG 符合。GSD 标准和 SAMI CoP 分别显示，11 个和 6 个 HEG 是同质的，只有 4 次，两种方法是一致的。在 SAMI CoP 和 GSD 中，大多数非同质 HEG 的职业实际上是同质的。在 10 个子组中，有 5 个子组的 AM 高于 HEG B。其他 HEG 至少有一个 AM 和 90 百分位数值高于其各自的母 HEG。
所有三种方法主要都证实了 HEG 的不合规性。与 CEN 相比，SAMI CoP 倾向于显示 HEG 的合规性更高。根据 SAMI CoP 和 GSD 标准，非同质 HEG 有许多职业实际上是同质的。所有指标的一致性都没有达到完美。对于未来的 HEG 构成以及对高暴露组的回顾性评估，可以通过使用职业来提高同质性。
