Pharmaceuticals in source waters of 95 First Nations in Canada

Karen Fediuk,Tonio Sadik,Lesya Marushka,Malek Batal,Hing Man Chan,Harold Schwartz,Constantine Tikhonov,Amy Ing

doi:10.17269/s41997-021-00499-3

Abstract

ObjectivesPharmaceuticals are emerging contaminants in the environment. Little has been published about the presence of pharmaceuticals in waterbodies nearby or on reserve land of First Nations in Canada. The objectives of this study were to (1) quantify the level of pharmaceuticals in First Nations’ surface waters, (2) calculate the human health risks of the mixtures found, and (3) measure the exposure to pharmaceuticals in First Nations’ drinking water where source water was highly contaminated.MethodsThis participatory study measured the levels of 43 pharmaceuticals from surface water samples taken at three water sampling sites chosen by the 95 participating First Nations. The sites were in proximity to recreational areas, fishing areas, drinking water sources, and/or wastewater outflows. When elevated levels of pharmaceutical mixtures were found in samples, drinking water samples were obtained and analyzed for potential pharmaceuticals. Human health risks were calculated by an established protocol.ResultsIn total, 432 samples were collected at 302 water sampling sites (285 surface water, 11 drinking water, and 6 wastewater sites). Quantifiable levels of 35 pharmaceuticals were found in 79 of the 95 (83%) participating First Nations at 193 of the 285 surface water sites (68%). Overall, the levels found were comparable to or lower than those found in other studies in Canada and worldwide.ConclusionIn almost all participating First Nations, there is no human health risk from consuming surface water for drinking. However, surface water in the vicinity of major urban centres should not be used as secondary untreated water sources due to the elevated human health risk associated with exposure to the mixtures of multiple pharmaceuticals detected.

Highlights

Pharmaceuticals are synthetic or natural chemicals found in prescription medicines, over-the-counter and veterinary therapeutic drugs used for the diagnosis, cure, treatment, or prevention of diseases in humans and animals (WHO 2012)
Pharmaceuticals were detected in 79 of the 95 (83%) First Nations participating in the pharmaceutical component of the study (Fig. 1)
3 unique pharmaceuticals were found in two First Nations where the source was surface water, and 2 pharmaceuticals were detected in groundwater sites

Summary

Introduction

Pharmaceuticals are synthetic or natural chemicals found in prescription medicines, over-the-counter and veterinary therapeutic drugs used for the diagnosis, cure, treatment, or prevention of diseases in humans and animals (WHO 2012). Since conventional wastewater treatment processes do not entirely eliminate pharmaceuticals, these compounds are frequently detected in surface water at low concentrations (Sui et al 2015). Pharmaceuticals and their metabolites can enter the waterways through run-off from land treated with sludge for agricultural purposes (Topp et al 2008; Sabourin et al 2009). Paracetamol (acetaminophen) and ibuprofen are rapidly degraded in water systems with DT50 (dissipation time of 50% of the amount originally present) ranging between 3.1 and 7 days whereas clofibric acid, diazepam, and carbamazepine are highly persistent with DT50 ranging from 119 to 328 days (Ebele et al 2017)

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