Cadmium Monitoring at the Workplace: Effectiveness of a Combination of Air- and Biomonitoring

Abstract

Inhalation exposure to cadmium at the workplace has been associated with an increased risk of lung cancer and non-cancer respiratory effects. To ensure levels of cadmium remain below effect levels, air quality is monitored and regulations specifying an air limit value are implemented. The EU Carcinogens and Mutagens Directive of 2019 recommended values for the inhalable fraction and the respirable fraction but the latter only for a transitional period. Cadmium exposure has also been associated with systemic effects, following its storage in the kidneys and due to its long half-life. The accumulation of cadmium occurs via different exposure routes and from different sources, including workplace dust and fumes, food, and smoking. Biomonitoring (in blood, urine) has been identified as the most appropriate method to follow up cumulative exposure and total cadmium body burden, as it conveniently reflects intakes by all routes. However, it is not systematically implemented. This paper has a double objective: first, proposing a possible limit value for the respirable fraction, using an approach integrating epidemiological data. Secondly, demonstrating that the implementation of both air and biological limit values is key to protecting workers' health in occupational settings. The paper summarizes the current knowledge on cadmium health effects and how biomarkers reflect those. It presents an approach to derive a respirable value, using recent human data, and describes how the combination of air monitoring and biomonitoring is applied by the EU industry to protect the workforce. While a respirable fraction value helps protect workers against local respiratory adverse health effects, air monitoring alone is not sufficient to protect workers against systemic effects of cadmium. Therefore, complementary biomonitoring and the implementation of a biological limit value is recommended.

Keywords: air monitoring; biomonitoring; cadmium; dose response; occupational exposure; regulatory decision-making; risk management measures; threshold.

Figure 1

Exposure Risk Relationship (ERR): hockey-stick shape (lung cancer, cadmium), respirable fraction (adapted from BAuA (2021) [2]).

Figure 2

Exposure Risk Relationship (ERR): derivation based on epidemiological data Haney 2016 [48].

Figure 3

Reported urinary cadmium levels as % of exposed employees with Cd-U greater than x µg Cd/g creatinine from the period 2008–2021.