Occurrence and ecological risk assessment of pharmaceuticals and cocaine in the urban drainage channels of Santos beaches (São Paulo, Brazil): a neglected, but sensitive issue

Abstract

In some Brazilian coastal cities, it is common to observe ‘black tongues’ in beaches, i.e. a mixture of urban runoff and untreated domestic sewage containing pollutants of emerging concern, namely pharmaceutical and personal care products (PPCPs), flowing into the South Atlantic Ocean. Such diffuse loads of pollutants might expose nontarget aquatic organisms to harmful compounds. In this work, the occurrence and preliminary ecological risk of 27 PPCPs of various therapeutic classes (including cocaine and its primary metabolite, benzoylecgonine) were investigated, for the first time, in seven urban drainage channels whose diffuse loads flow continuously to the beaches of Santos Bay, São Paulo, Brazil. Of these, 21 compounds were detected using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), and nine of them were consistently quantified in all urban channels of Santos, suggesting that those pollutants are ubiquitous in this region: caffeine (143.4–516.0 ng/L), losartan (4.2–21.8 ng/L), atenolol (1.1–18.2 ng/L), acetaminophen (1.5–13.8 ng/L), benzoylecgonine (1.0–4.8 ng/L), carbamazepine (1.1–4.0 ng/L), diclofenac (1.9–3.5 ng/L), cocaine (0.5–1.7 ng/L), and orphenadrine (0.1–0.8 ng/L). Moreover, twelve compounds were found below the limit of quantification ( <LOQ): citalopram, propranolol, diazepam, rosuvastatin, atorvastatin, midazolam, ranitidine, chlortalidone, clopidogrel, chlorpheniramine, enalapril and valsartan. According to our knowledge, this is the first report on the occurrence of midazolam, ranitidine and chlorpheniramine in surface waters in Latin America and, therefore, these compounds should be considered environmental warning signs. A preliminary ecological risk assessment revealed that caffeine, acetaminophen and losartan presented a moderate risk, and carbamazepine a low risk to sensitive aquatic organisms at maximum measured concentrations. This study provides valuable information to reinforce the importance of a continuous monitoring of the diffuse loads (containing PPCPs and illicit drugs) flowing to the coastal zones in developing countries.