Contaminação das águas subterrâneas e superficiais por cafeína e compostos nitrogenados no entorno dos cemitérios São Pedro e João XXIII – Londrina / PR

Abstract

The presence of emerging compounds and nutrients in urban environments has become an increasing concern, especially in areas with deficient sanitation infrastructure and intense land occupation. This study evaluated the quality of groundwater and surface water in the vicinity of the São Pedro Cemetery, in Londrina, Paraná, Brazil, focusing on the detection of caffeine and nitrogen compounds (nitrate and ammonium) as indicators of anthropogenic contamination. Four sampling campaigns were conducted thronghout 2024, covering both dry and rainy seasons, with water collected at seven strategic points, including shallow and deep monitoring wells and sections of the Água Fresca and Leme streams. Physical-chemical and emerging contaminant analyses were carried out following the Standard Methods for the Examination of Water and Wastewater, with caffeine quantified using LC-MS/MS and nitrogen compounds analyzed via UV-Vis spectrophotometry. The results indicated caffeine concentrations ranging from 56.4 to 195.2 ng/L in shallow groundwater and up to 112.7 ng/L in surface waters, with higher occurrences near the cemetery and during rainy periods. Nitrate levels exceeded the legal limit of 10 mg/L (as N-NO₃⁻) in three groundwater sampling points, reaching up to 15.8 mg/L. These findings snggest contamination from domestic sewage and potential contributions from necroleachate, exacerbated by local hydrogeological vulnerability, including porous soils, fractured basalt, and lack of protective barriers. The study highlights the need for remediation strategies and the inclusion of emerging contaminants in regular water quality monitoring programs, offering technical and scientific support for sustainable urban cemetery management and the protection of water resources.