Hazard-based regulation to curb environmental impacts on health

If CEPA was indeed protecting public health, we would expect declining diseases associated with anthropogenic exposures, rather than the opposite.

Yes, today children are exposed to lower levels of tobacco smoke, some old pesticides, and lead in drinking water, gasoline exhaust and paint. Unfortunately, endocrine-related obesity and metabolic syndrome, disorders of early development and sexual differentiation, and cancers in hormone-sensitive tissues (e.g., breast, prostate, thyroid) have not been prevented. This is as groups of chemicals (e.g., phthalates, bisphenols, flame retardants and some pesticides) remain in commerce, in water, food and products, in homes, schools and the workplace, and in the environment, for decades before being restricted or banned.

Endocrine disruption does not follow a classic dose-response, and can be perpetuated under risk-based management. Endocrine disrupting chemicals (EDCs) require actions based on their innate hazard. With many thousands of EDCs, classes of similar chemicals require group actions.

Single-chemical regulation does not work, and Canadian-led research highlights how aggregate effects of low dose mixtures of chemicals can cause cancer.¹ This explains today’s increasing health conditions associated with altered signalling in hormone-driven endocrine systems. Examples include: disorders of sexual development and reproduction; obesity, metabolism and diabetes; neurological development and function; and some cancers. As well, intergenerational effects occur even when the genetic code is not mutated; rather, epigenetic changes that affect expression and suppression of particular genes, can alter susceptibility to dysfunction and disease. Higher prevalence is seen in racialized² and more highly exposed populations.

Examples of adverse trends in public health linked to toxicants include:

• Extensive basic research illuminating interacting mechanisms³ of chemicals in cellular signalling,^4,5 gene expression (epi-genetic effects),⁶ metabolism (including oxidative stress), development and health as a result of environmental exposures and the microbiome,^7,8 from pre-conception and across the life span.⁹ 
• Although historically exceedingly rare in children, prevalence of type 2 diabetes now exceeds that of type 1 diabetes in Canadian youth. In Manitoba, where rates are up to 20-fold higher than in some other areas of Canada, type 2 diabetes increased from 9 to 21 per 100,000 children <18 years of age between 2006 and 2011.¹⁰ Type 2 diabetes is also increasing rapidly in Ontario children.¹¹ Potentially informing aetiology, a prospective nurses’ study report and review describes associations between plasma levels of persistent toxicants and diabetes, as well as interactions with weight changes (Fatty tissue is thought to be protective because it sequesters lipophilic toxicants, that are released into the bloodstream and other tissues during weight loss).¹²
• Storage of toxic chemicals in fat, evident with increased blood levels of toxicants with weight loss, may underlie numerous adverse conditions.^13,14,15 The “obesity paradox” where adipose tissue appears to be protective against disease has been noted for cancer (with cautions regarding analytical complexities),¹⁶ heart failure and mortality in patients with diabetes,¹⁷ and increasing population-adjusted rates of certain cancers, many of which are hormone-related;¹⁸
• Obesity increases risks for about a dozen cancers.^19,20 In Canada, smoking-related cancers are decreasing as smoking rates have fallen, but obesity- and endocrine-related cancers are increasing,¹⁸ although early detection and treatment can help to avert severe disease. Scientists recently found that SARS-CoV-2 can infect fat cells, thus predisposing obese patients to a more severe disease and worse outcomes with COVID-19;²¹
• Male genital birth defects clustered in agricultural regions of Nova Scotia, in contrast with non-endocrine mediated congenital abnormalities that were not clustered;²²
• Lymphoid leukemia incidence rate in Manitoba children increased between 1984 and 2013, with variations by geographic area (suspected to be related to unidentified environmental agents);²³
• Autoimmune disease is increasing rapidly in developed countries.²⁴ Canada ranks globally among the highest rates of inflammatory bowel disease in children, driven by increasing incidence in the youngest children of 6.5% annually;²⁵
• Inflammatory bowel disease predisposes to colorectal cancer, which is increasing 7% annually in Canadian adolescents and young adults²⁶ (the similar rates are thought to be associated);
• Neurological development can be impacted by many toxicants,²⁷ such as metals lead,²⁸ mercury ²⁹ and manganese,³⁰ and endocrine disruptors such as bisphenol-A (BPA),³¹ to name a few. Increases in prevalence and incidence of treated attention-deficit hyperactivity disorder (ADHD) were not uniform across Canadian provinces, suggesting non-uniform contributors to the condition;³²
• Recent research reviews life-changing biological impacts of volatile chemicals and the myriad of scented products in daily use.³³

References

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