This paper reports on a study that examined monthly results from expanded wastewater surveillance for xylazine from 11 sites in Kentucky, from January 2019 to February 2023; it discusses wastewater signals, which indicate broad geographic exposure to xylazine in Kentucky while noting contradictory health outcomes data; the authors suggest that findings may inform regional, national, and international efforts to incorporate wastewater-based drug surveillance.
In the U.S., xylazine, the veterinary non-opioid sedative, has emerged as a major threat to people who use illicitly manufactured fentanyl and other drugs. The aim of this study was to compare wastewater detection of xylazine with other public health and safety surveillance data from 2019 to 2023 in Kentucky. Wastewater samples from five rest areas, two truck weigh stations, and four wastewater treatment plants were tested for xylazine. Wastewater xylazine positivity rates were compared with xylazine-positive submission rates from the National Forensic Laboratory Information System and Kentucky's fatal overdoses in 6-month periods (Period 1=January–June; Period 2=July–December). Xylazine was detected in 61.6 percent (424 of 688) of daily wastewater samples from roadway sites/wastewater treatment plants. For roadways, detection increased from 55 percent (Period 1, 2021) to 94 percent (Period 1, 2023), and wastewater treatment plants had an overall detection of 25.8 percent (n=66 samples, Periods 1 and 2, 2022). Increasing roadway positivity corresponded to trends in National Forensic Laboratory Information System xylazine-positive submission rates: from 0.19 per 1,000 submissions (Period 1, 2019) to 2.9 per 1,000 (Period 2, 2022, latest available). No deaths from xylazine were reported publicly in Kentucky, although this study's authors identified 1–4 deaths (true count suppressed) in the overdose surveillance system, which, in back-of-the-envelope comparisons with other states, is far fewer than expected. Wastewater signals indicate broad geographic exposure to xylazine in Kentucky, yet health outcomes data suggest otherwise. These findings may inform regional, national, and international efforts to incorporate wastewater-based drug surveillance. Harm-reduction activities along roadways and other suitable locations may be needed. (Published Abstract Provided)