In a correspondence article published in September 2024, in The Lancet Planetary Health, Mengjiao Wang from the University of Exeter, UK, and co-authors urge scientists in the field of chemical pollution to consider gender in their research. The authors explain that “the mean Eureopean male, with mean body weight and height” is still used to extrapolate exposure and risk assessment data from animal studies. However, it’s most likely others who are carrying out the chemical-intensive work. Accordingly, Wang and co-authors argue that “our systems of knowledge for understanding, managing, and governing chemicals have systemic gaps that reinforce structural inequalities.”
As a way forward, they call for the intergovernmental science-policy panel on chemicals, waste, and pollution prevention (FPF reported) to integrate gender into its work as should the scientific community in general. By considering gender, “routes of exposure and health effect could be more accurately identified to inform gender-specific policy recommendations and interventions.” At the same time, it allows researchers to consider power dynamics and overcome disciplinary silos to address chemical pollution holistically.
While Wang and co-authors emphasize the need to address gender inequities in chemical exposure assessments, another recent study took a complementary approach by focusing on identifying population groups most at risk from chemical exposure. This research, led by Jeff B. Willey from Health Canada and published in Toxicology Letters on September 27, 2024, expands on how chemical exposure varies across demographics, using new metrics to quantify health risks.
In previous research projects, Willey and co-authors developed a metric they called Exposure load, the number of chemicals detected in an individual based on biomonitoring data. Now, they combined Exposure load with Human biomonitoring health-based guidance values (HB2GVs). HB2GVs reflect the biomarker concentrations that are consistent with a health-protective exposure guidance value. Their new metric – Cumulative Health Risk from Exposure Load (CHREL) – combines Exposure load and HB2GV to create “an indicator of the number of chemicals detected in a person above levels that correspond to health-based exposure guidance levels.”
Using data from the Canadian Health Measures Survey (CHMS) as input and considering 18 chemicals, the metric indicates that more than half of the population has a chemical exposure higher than exposure guidance values, i.e., associated with health risks. Interestingly, females had lower health risk values than males, and younger age groups had lower exposure-based health risks compared to older age groups. Furthermore, the study found that the higher chemical exposure of smokers may indeed result in elevated health risks compared to nonsmokers. Focusing on cancer, the scientists calculated the cancer risk of combined exposure to six chemicals and found that it “may exceed the risk considered negligible by Health Canada”, i.e., lifetime cancer risk of less than 1 person in 100,000 being affected. They further identified the chemicals most often responsible for exposures above guidance values. These were arsenic, mercury, acrylamide, xylenes, benzene, and triclosan.
Willey and co-authors highlighted that the CHREL is not an absolute indicator of potential health risks; two individuals with the same CHREL may still have different health outcomes. In addition, HB2GVs, which are used as an input to the metric, are based on several assumptions and bear uncertainties. However, the authors envision CHREL to “be used to interpret population biomonitoring data in a health risk context and could be used as a risk management tool,” including for the identification of vulnerable population groups.
References
Wang, M. et al. (2024). “Why gender matters for addressing chemical pollution.” The Lancet Planetary Health. DOI: 10.1016/S2542-5196(24)00176-1
Willey, J. B. et al. (2024). “Cumulative Health Risk from Exposure Load (CHREL): Looking at multi-chemical exposures through the lens of biomonitoring guidance values.” Toxicology Letters. DOI: 10.1016/j.ecoenv.2024.117099
