Drugs Discharged along Interstate Highway Restroom Facilities in Kentucky: Wastewater Analysis

Polysubstance use and the associated adverse consequences such as the ongoing and exponential increases in drug overdose deaths are major public health threats in the United States. There has been a substantial prevalence of driving under the influence of drugs (4.9% drivers in the United States) and drug-involved collisions (10.2% in Kentucky). In this study, 26 drugs including stimulants, opioids, and antipsychotics were measured in raw wastewater collected from two rest areas and a commercial truck service facility along two interstate highways in Kentucky. Methamphetamine, amphetamine, and cocaine were detected in all wastewater samples (n = 56) at both rest areas (I-24 E and I-24 W) and a commercial truck serving facility (I-75 N/S). Methamphetamine was discharged significantly higher at the rest areas (108 and 239 mg/d/1000 people at I-24 E and I-24 W, respectively); however, prescription opioids including tramadol, hydrocodone, and morphine as well as temazepam (benzodiazepine) and citalopram (antidepressant) were significantly discharged higher at the commercial truck service facility. Xylazine, a veterinary sedative, was also quantified for the first time in greater than 33% of collected wastewater samples. To the authors' knowledge, this is the first quantitative study of drugs discharged at rest area facilities along interstate highways.