Concentrations of pharmaceuticals and other micropollutants in groundwater downgradient from large on-site wastewater discharges

Abstract

Large subsurface treatment systems (LSTS) and rapid infiltration basins (RIB) are preferred onsite wastewater treatments compared to direct discharge of treated wastewater to streams and adjacent facilities. Discharge of these wastewater treatments may result in contaminant loading to aquifers that also serve as drinking water sources downgradient from the discharge site. Until recently, few studies have characterized the contribution of micropollutants (e.g. pharmaceuticals, fragrances, flame retardants, etc.) to receiving aquifers. We conducted a pilot project to characterize the occurrence of micropollutants in groundwater downgradient from 7 on-site treatment systems in Minnesota, USA: 5 community LSTS and 2 municipal RIB. One downgradient monitoring well was sampled three times at each facility over one year. Of 223 micropollutants analyzed, 35 were detected. Total sample concentrations ranged from 90 to 4,039 ng/L. Sulfamethoxazole (antibiotic) was detected in all samples at concentrations from 7 to 965 ng/L. Other pharmaceuticals (0.12–1,000 ng/L), organophosphorus flame retardants (10–500 ng/L), and other anthropogenic chemicals (4–775 ng/L) were also detected. The numbers and concentrations of micropollutants detected were inversely related to dissolved oxygen and depth to water. Ratios of pharmaceutical concentrations to human-health screening values were <0.10 for most samples. However, concentrations of carbamazepine and sulfamethoxazole exceeded screening values at two sites. Study results illustrate that large on-site wastewater systems designed to discharge to permeable soil or shallow groundwater effectively deliver pharmaceuticals and other micropollutants to groundwater aquifers and could contribute micropollutants to drinking water via water supply wells.

Hydrophilic trace organic contaminants in urban stormwater: occurrence, toxicological relevance, and the need to enhance green stormwater infrastructure

“…[1][2][3] Therefore, hyphil-TrOCs are ubiquitous in surface waters and groundwater and have been also detected in finished drinking water. 1,[3][4][5][6][7][8] Numerous hyphil-TrOCs cause biological effects such as endocrine disruption at trace concentrations, which pose risks to ecosystem and human health. 9,10 One major point source of hyphil-TrOCs are effluents from conventional wastewater treatment plants.…”

Avaliação geoquímica da influência de fossas rudimentares na água subterrânea da região rural de Paulínia/SP

“…Entretanto, diversos trabalhos recentes têm demonstrado a aplicabilidade de traçadores para diagnosticar inequivocamente a contaminação por fossas sépticas. Destacandose adoçantes como (van STEMPVOORT et al 2011;KHAZAEI e MILNE-HOME, 2017;SPOELSTRA et al 2017) ou fármacos diversos (SCHAIDER et al 2016;ELLIOTT et al 2018, DODGEN et al 2017LEE et al 2019). Por esta razão, o emprego destes traçadores pode representar uma importante alternativa para avaliar as transformações hidroquímicas que podem ser associadas à contaminação por fossas sépticas em áreas carentes de saneamento básico.…”

Groundwater quality

“…Many researchers investigated the source of the PPCPs, and it is shown that the discharge from wastewater treatment facilities and septic systems contribute as the major portion of these contaminations. In a study conducted by Elliott, Erickson, Krall, and Adams (2018) on water quality of downgradient wells from five large subsurface treatment systems (LSTS) and two rapid infiltration basins (RIB), a total of 18 pharmaceuticals out of 223 micropollutants were detected with concentrations ranging between 90 and 4,039 ng/L. Three primary pharmaceuticals, including fluconazole as antifungal, carbamazepine as anticonvulsant, and sulfamethoxazole as antibiotics, were the most detected constituents in the groundwater samples.…”