Organic Contaminants Of Emerging Concern Research Articles

Integrated occurrence of contaminants of emerging concern, including microplastics, in urban and agricultural watersheds in the State of São Paulo, Brazil

Contaminants of emerging concern (CECs), including microplastics, have been the focus of many studies due to their environmental impact, affecting biota and human health. The diverse land uses and occupation of watersheds are important parameters driving the occurrence of these contaminants. CECs such as pesticides, drugs, hormones, and industrial-origin substances were analyzed in urban/industrial (Atibaia) and agricultural (Preto/Turvo) watersheds located in São Paulo state, Brazil. A total of 24 CECs were investigated, and, as a result, only 5 (caffeine, carbendazim, atrazine, ametrine and 2-hydroxytrazine) were responsible for 81.73 % of the statistical difference between watersheds contamination profile. The Atibaia watershed presented considerable concentrations of caffeine (ranging from 75 to 2025 ng L−1), while carbendazim (44 to 1144 ng L−1) and atrazine (3 to 266 ng L−1) presented highest levels in Preto/Turvo watershed. In all sampling points, the cumulative potential aquatic life risk assessed by the NORMAN database indicates some level of environmental concern associated to pesticides and caffeine (risk quotient >1). Microplastics had been analyzed in both watersheds, being the white/transparent fragments in size between 100 and 250 μm the most detected in this study. The estimated abundance in the Atibaia watershed ranged from 349 to 2898 items m−3 presenting some influence of pluviosity, while in Rio Preto/Turvo ranged from 169 to 6370 items m−3, being more abundant in the dam area without a clear influence of pluviosity. In both basins, polyethylene and polypropylene were the most detected polymers, probably due to the intense use of single-use plastics in urban areas. Possibly, due to the distinct physic-chemical properties of microplastics and organic CECs, no correlations were observed between their occurrence, which makes us conclude that they have different transport mechanism, behavior, and fate in the environment.

A pilot-scale study on the removal of binary mixture (ciprofloxacin and norfloxacin) by Scenedesmus obliquus: Optimization, biotransformation, and biofuel profile

Ciprofloxacin (CIP) and norfloxacin (NOR) belong to the organic contaminants of emerging concern (OCECs) that are frequently detected in wastewater matrices at ng/L to mg/L concentrations. This study investigates the potential of Scenedesmus obliquus in the treatment of CIP and NOR as a binary mixture from raw wastewater. Optimization of inoculum was done to find the required cell density concentration that has less inhibition and high removal. The optimum inoculum (cell density: 200 × 105 cells/mL and OD680: 1.0) has shown 75% removal with no inhibition of growth. A pilot scale study was conducted in controlled environment using high-rate algal pond to investigate the contribution of abiotic and biotic removal. Abiotic removal is negligible in comparison with the biotic contribution of removal. The order of removal efficiency is observed as COD (88%) > NOR (84.8%) > CIP (84.6%) > NH4+ (71.7%) with biodegradation as the major removal mechanism. Biotransformed products of CIP + NOR were identified inside the Scenedesmus obliquus. During the pilot-scale study, Biomass (3.70 ± 0.07 g/L) was harvested with carbohydrates (17.85 ± 0.1%), lipids (38.36 ± 0.13%), and proteins (28.18 ± 1.63%). Lipid productivity in binary mixture was 2.6 times higher than the lipid production in control condition. Transesterification of these lipids yielded good biofuel composition of 32.72% of saturated fatty acids and 21.7% of unsaturated fatty acids.

Potential of low-enthalpy geothermal energy to degrade organic contaminants of emerging concern in urban groundwater

Low-enthalpy geothermal energy (LEGE) is a carbon-free and renewable source to provide cooling and heating to infrastructures (e.g. buildings) by exchanging their temperature with that of the ground. The exchange of temperature modifies the groundwater temperature around LEGE installations, which may contribute to enhancing the capacity of aquifers to degrade organic contaminants of emerging concern (OCECs), whose presence is significantly increasing in urban aquifers. Here, we investigate the impact of LEGE on OCECs and their bioremediation potential through numerical modelling of synthetic and real-based cases. Simulation results demonstrate that: (i) LEGE facilities have the potential to noticeably modify the concentrations of OCECs; and (ii) the final impact depends on the design of the facility. This study suggests that optimized LEGE facility designs could contribute to the degradation of OCECs present in urban aquifers, thus improving groundwater quality and increasing its availability in urban areas.