Disinfection & downstream effects

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Many of the PPCPs detected in the environment are used in different ways, and in vastly different quantities, by men and women. This is true both for pharmaceuticals and for personal care products. Women consume more pharmaceuticals than men, for reasons that are both biological and social. Contraceptives, fertility drugs and menopausal hormones are prescribed exclusively to women, and many women are on some form of hormonal medication throughout their lives, from puberty onwards. Women are also diagnosed with psychiatric problems such as depression and anxiety more often than men and are more likely than men to be prescribed anti-depressants for similar symptoms of emotional distress.

Personal care products (PCPs) are distinct from pharmaceuticals in a number of ways. PCPs are generally meant to be safely used by healthy people. PCPs include such a large and varied range of products that discussing gendered use in relation to particular chemical ingredients is not self-eviden. Some popular products are clearly used predominantly by women, however. For example, the overwhelming majority of users of ultraviolet (UV) filters - the chemicals used in the production of sunscreens - are women; the same is true for many other products (creams, lotions, cosmetics, etc) that now commonly contain UV filtering compounds. Synthetic musks – the chemicals used as fragrance materials in a wide range of consumer products including perfumes, soaps, lotions, shampoos, and laundry detergents - also have distinctly gendered patterns of use.  

Gendered exposures to PPCPs

Assessing gendered exposures to PPCPs in drinking water is difficult given the paucity of data available on PPCPs in the environment broadly, and gender based data specifically. Do women drink more or less water than men? Are women’s places of residence – clearly a factor in determining drinking water quality – distributed differently than men’s? Answers to such questions would provide better insight into gender differences in exposure. The exposure of pregnant women to PPCPs in drinking water is one area where some data are available. For example, the recommendation that pregnant women drink two litres of water of per day, if followed, might expose this group to more contaminants than someone drinking less over an equivalent period. Indeed, one estimate found that following the two litre/day guideline might expose a pregnant woman to five drugs of particular concern during her pregnancy.

Gendered health effects of PPCPs in drinking water

Many PPCPs, including oral contraceptives, hormone therapies, anti-epileptics, anti-inflammatory drugs, some anti-depressants, UV filters, and synthetic musk fragrances, are considered endocrine disruptors. At this stage, evidence of gendered health effects of PPCPs is drawn primarily from research examining the impact of endocrine-disrupting chemicals on aquatic species. A common finding among such studies is the feminization of male fish, which manifests as arrested testicular development and the production of early-stage eggs in their testes. When researchers added low concentrations of ethinylestradiol to a Northern Ontario lake, for instance, male fathead minnows were feminized and egg formation in females was altered, leading to near-extinction of the species in that lake. Intersex fish have attracted attention because reproductive changes observed in fish are comparable to effects, such as testicular dysgenesis syndrome, observed in humans. Clues to possible effects can also be gleaned from research on pesticides and industrial contaminants which suggests that ongoing in utero and early childhood exposures to compounds classified as endocrine disruptors may well have gendered health effects.

Why worry about trace levels?

Compared to the daily therapeutic dosages of a pharmaceutical drug, the concentrations of any particular drug present in the aquatic environment is very low. As a result, some analysts conclude that the risk to human health from the trace amounts detected in Canadian drinking water samples is negligible because “an individual would have to consume thousands of glasses of drinking water a day to reach the maximum acceptable daily intake”. Research on the category of substances known as endocrine disruptors suggests otherwise.

Based on understandings from the new field of epigenetics, endocrine disrupting compounds interact with the body’s endocrine signalling systems in a way that makes not only dosage but also timing critical in determining the effects of exposure. Epigenetic alterations reprogram the regulation of vital cellular functions, allowing the organism’s organ systems to adapt to stresses in the environment, including exposures to hormones, drugs or toxins, and thereby prepare the organism for meeting similar demands in later life. This reprogramming or imprinting takes place at critical periods or “windows” in the development of organ systems. In humans, these periods occur during fetal development, childhood and, for the reproductive and central nervous systems, continue into late adolescence. Synthetic chemicals that mimic internal cues have the capacity to confuse this adaptive system, increasing the risk of diseases later in life. Thus, exposure to chronic low levels of endocrine disruptors in the environment might well have human health effects; stage of development would be highly relevant; and significant interactions among substances might be expected.