Compound identifications were performed using both targeted and non-targeted strategies, and each compound was assigned a confidence level. Table shows the full list of identified compounds, their uses, their detection information, and the observed trends over time. Trends in identified compounds are discussed categorically below. In the early days of the pandemic the drug combination of hydroxychloroquine and azithromycin received consideration as a potential treatment for COVID-19. The US FDA issued an emergency use authorization (EUA) on March 28, 2020 (week 2 of our data), which remained in effect until June 15, 2020 (week 13) . As shown in Figure , hydroxychloroquine concentrations increased in daily sludge samples in the third week of our study. While an overall hydroxychloroquine trend was not observed during the time that weekly samples were collected, a clear increase in concentration occurs in week 3 (Figure ). Hydroxychloroquine has an elimination half-life in the human body of approximately 22 days for oral doses and over 40 days for intravenous doses , thus the increase in sludge concentrations is not as immediate or drastic as it would be for a drug with a shorter half-life. Our data indicates that the EUA and the large amount of publicity generated around hydroxychloroquine had significant impact on the amount used in the New Haven area, which includes two major hospitals. Hydroxychloroquine is normally used to treat malaria, lupus and rheumatoid arthritis (20), which are unlikely to have changed during the pandemic.