Occurrence and risk assessment of pharmaceuticals and cocaine around the coastal submarine sewage outfall in Guaruja, Sao Paulo State, Brazil

The aim of this study was to screen and quantify 23 pharmaceutical compounds (including illicit drugs), at two sampling points near the diffusers of the Guaruja submarine outfall, State of Sao Paulo, Brazil. Samples were collected in triplicate during the high (January 2018) and low (April 2018) seasons at two different water column depths (surface and bottom). A total of 10 compounds were detected using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Caffeine (42.3-141.0 ng/L), diclofenac (3.6-85.7 ng/L), valsartan (4.7-14.3 ng/L), benzoylecgonine (0.3-1.7 ng/L), and cocaine (0.3-0.6 ng/L) were frequently detected (75% occurrence). Orphenadrine (0.6-3.0 ng/L) and atenolol (0.1-0.3 ng/L), and acetaminophen (1.2-1.4 ng/L) and losartan (0.7-3.4 ng/L), were detected in 50% and 25% of the samples, respectively. Only one sample (12.5%) detected the presence of carbamazepine (< 0.001-0.1 ng/L). Unexpectedly a lower frequency of occurrence and concentration of these compounds occurred during the summer season, suggesting that other factors, such as the oceanographic and hydrodynamic regimes of the study area, besides the population rise, should be taken into account. Caffeine presented concentrations above the surface water safety limits (0.01 mu g/L). For almost all compounds, the observed concentrations indicate nonenvironmental risk for the aquatic biota, except for caffeine, diclofenac, and acetaminophen that showed low to moderate ecological risk for the three trophic levels tested.

Automated summary

The study aimed to screen and quantify 23 pharmaceutical compounds at two sampling points near the submarine outfall in Guaruja, Brazil. The results showed that most compounds had lower occurrence and concentration in the summer compared to winter, suggesting potential influence of factors such as oceanographic dynamics, hydrodynamics, and population growth.