Exposure to Organic Fraction Extracted from Oil Sands Process-Affected Water Has Negligible Impact on Pregnancy and Lactation of Mice

Abstract

Dissolved organic compounds are major contaminants in oil sands process-affected water (OSPW), of which naphthenic acids (NAs) are one of the main persistent toxicants. In the present study, we explore the toxic effects of the organic fraction extracted from OSPW (OSPW-OF) in mice during pregnancy and lactation. Here, we report that acute oral exposure of female Balb/c mice during gestation, and subchronic exposure throughout gestation and lactation to OSPW-OF (containing naturally occurring levels of NAs found in tailings ponds), had negligible effects on their reproductive performance. Specifically, mating behavior, pregnancy success, embryonic implantation, gestation period, litter size, and offspring viability were not affected by OSPW-OF containing up to 55 mg/L NAs. OSPW-OF exposure also did not affect plasma concentrations of pregnancy-associated hormones or pro- and anti-inflammatory cytokines, and it had minimal effects on liver stress gene expression. This study presents the first comprehensive in vivo analysis of mammalian toxicity associated with OSPW-OF exposure. Overall, our results suggest that the risk of acute and subchronic toxicity to mice exposed to OSPW-OF at environmentally relevant concentrations of NAs in contaminated drinking water is likely negligible.

Naphthenic acid fraction components from oil sands process‐affected water from the Athabasca Oil Sands Region impair murine osteoblast differentiation and function

“…Although few studies have investigated the effects that chronic exposures to NAFCs have on major organ systems in mammals (Clemente & Fedorak, 2005 ; Li et al, 2017 ), there is evidence that OSPW and NAFCs can act as endocrine disrupting compounds. Endocrine effects of NAFCs that have been observed include alterations in sex hormone and glucocorticoid production (Knag et al, 2013 ; Lister et al, 2008 ), impaired development and reproductive success, and reduced secondary sexual characteristics in animals exposed to NAFCs (Kavanagh et al, 2013 ; Li et al, 2019 ; Philibert et al, 2019 ; Rogers et al, 2002 ).…”