Involuntary human exposure to carbamazepine: A cross-sectional study of correlates across the lifespan and dietary spectrum

Treated wastewater (TWW) is increasingly used for agricultural irrigation, especially in arid and semi-arid regions. Carbamazepine is among the most frequently detected pharmaceuticals in TWW. Moreover, its uptake and accumulation have been demonstrated in crops irrigated with TWW. A previous controlled trial found that urine concentrations of carbamazepine were higher in healthy volunteers consuming TWW-irrigated produce as compared to freshwater-irrigated produce. The aim of the current study was to assess whether carbamazepine is quantifiable in urine of Israelis consuming their usual diets and whether concentrations vary according to age, personal characteristics and diet. In this cross-sectional study, we recruited 245 volunteers, including a reference group of omnivorous healthy adults aged 18–66; pregnant women; children aged 3–6 years; adults aged >75 years; and vegetarians/vegans. Participants provided spot urine samples and reported 24-hour and “usual” dietary consumption. Urinary carbamazepine levels were compared according to group, personal characteristics, health behaviors, and reported diet. Carbamazepine was detectable (≥1.66 ng/L) in urine of 84%, 76%, 75.5%, 66%, and 19.6% of the reference group, vegetarians, older adults, pregnant women, and children, respectively. Quantifiable concentrations (≥5.0 ng/L) of carbamazepine were found in 58%, 46%, 36.7%, 14%, and 0% of these groups, respectively (p = 0.001 for comparison of proportions across groups). In adults, higher carbamazepine concentrations were significantly associated (p < 0.05) with self-defined vegetarianism, usual consumption of dairy products and at least five vegetables/day, and no meat or fish consumption in the past 24-hours. This study demonstrates that people living in a water-scarce region with widespread TWW irrigation, are unknowingly exposed to carbamazepine. Individuals adhering to recommended guidelines for daily fresh produce consumption may be at higher risk of exposure to TWW-derived contaminants of emerging concern.