Those of us raised on Paracelsus and "the dose make the poison” may be interested in this Environmental Science & Technology opinion piece by 39 international authors. I’ve included the first two paragraphs below, but there is more at the URL and in the Supplementary Information.

- Ralph

Rethinking Subthreshold Effects in Regulatory Chemical Risk Assessments
https://pubs.acs.org/doi/10.1021/acs.est.2c02896

A great number of dose–response studies indicate that hormesis is a common phenomenon, occurring in numerous organisms exposed to singular or combined environmental stressors, such as pharmaceuticals, heavy metals, micro/nanoplastics, organic flame retardants, pesticides, and rare earths. (1−6) While biological responses to low exposure levels are often beneficial, exposure to doses below the no-observed-adverse-effect-level (NOAEL; hereafter subthreshold doses) does not always translate to beneficial responses. (2,4) For example, subthreshold contaminant doses can enhance the virulence of phytopathogenic microbes and promote the resistance of crop pests with significant implications for crop production. (2,7,8)Subthreshold contaminant exposures can also stimulate infectious animal/human pathogens and promote their resistance to antibiotics and other drugs, threatening long-term sustainability. Importantly, the hormetic function of common pathways that regulate cancer pr!
ogress indicate that current regulatory standards may not protect adequately against cancer risks. (9−11)

Current risk assessment frameworks used around the world to assess exposure and effects are largely based on scientific developments from the mid to late 20th century, which frequently included only very high (often environmentally unrealistic) doses and the broad assumption of linearity in the response in the absence of evidence of alternative dose–response relationships (Figure 1). (12−16) How representative and realistic this approach is increasingly being challenged, in a modern era of analytical advances enabling measurement of low doses and hormetic responses. An expanding scientific literature provides evidence of significant effects of subthreshold contaminant doses on numerous animals, plants, and microbes. (1−6) We opine that regulatory risk assessments on exposure and effects should not be based upon outdated science and biologically unsupported assumptions regarding linearity. Instead, subthreshold effects and dose–response behavior should be included in !
the regulatory risk assessment. We urge for this approach to be adopted as part of a more real-life risk simulation approach, (17) especially in recognition of the growing evidence of genotoxicity of chemicals such as fluoride and arsenic. (18,19)

(more at https://pubs.acs.org/doi/10.1021/acs.est.2c02896

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