Water Quality and the Impact by Contaminants of Emerging Concern: The Case of Verde River in Campos Gerais

Abstract

In this article, we report the results of the work carried out on the Verde River, a predominantly urban river located in the city of Ponta Grossa, Paraná, Brazil. Developed in three stages, it aimed to evaluate the water quality through physical-chemical parameters, the presence of caffeine as a chemical tracer, and the compound Triclosan (TCS), considered a pollutant of emerging concern. An attempt was made to identify possible polluting sources along the river. Samples were collected at 4 points from the spring region, with sampling upstream and downstream of a Sewage Treatment Plant (STP). The physical-chemical parameters were determined in situ, through portable analysers, as well as in the laboratory, in this case, through analyses using molecular absorption spectroscopy. For the determination of TCS and Caffeine, high-performance liquid chromatography (HPLC) was used, preceded by a pre-concentration step in the solid phase (SPE), and the techniques were implemented after validation. The physicochemical evaluations of the surface samples showed a decline in water quality after the STP. Mean total phosphorus concentrations of 1.0 mg·L-1 (±0.4), as well as dissolved oxygen (DO) levels below 5.0 mg·L-1 were verified downstream of the STP. Caffeine concentrations for Verde River were between 49.0 to 299.0 μg·L-1, verified upstream and downstream of the STP. The results demonstrated the relationship between the presence of caffeine and impaction, either by the input of raw sewage or by treated effluent. TCS was detected by chromatographic analysis, downstream of the STP, with an average concentration of 27.6 (±1.7) μg·L-1, noting that its presence was associated with the reactor maintenance procedure, with the STP in the process called bypass. Obtaining quality data from Verde River is important for the protection of the environment and affects the health of the population.