Detection of human-derived fecal contamination in Puerto Rico using carbamazepine, HF183 Bacteroides, and fecal indicator bacteria

The level of fecal pollution in 17 sites in Puerto Rico was determined by Escherichia coli (E. coli) enumeration using an enzyme substrate medium and Quanti-Tray®/2000. Human fecal pollution was identified using an enzyme-linked immunosorbent assay for the detection of carbamazepine (CBZ) and quantitative polymerase chain reaction (qPCR) detection of the human Bacteroides marker, HF183. Carbamazepine was detected in 16 out of 17 sites, including Condado Lagoon, a popular recreational area. Elevated E. coli levels (> 410 CFU 100 mL− 1) were detected in 13 sites. Average CBZ concentrations ranged from 0.005 μg L− 1 to 0.482 μg L− 1 and 7 sites were positive for HF183. Higher CBZ concentrations were associated with the detection of HF183 (Mann-Whitney test; U = 42.0; df = 7; 1-tailed P value = 0.013). This was the second study to determine surface water concentrations of CBZ in the Caribbean and the first in Puerto Rico.