Soil Sorption and Degradation Studies of Pharmaceutical Compounds Present in Recycled Wastewaters Based on Enantiomeric Fractionation

Current scenario of emerging pollutants in farmlands and water reservoirs: Prospects and challenges

Globally, roughly more than 400 million metric tons of plastics are produced annually. Similarly, the pharmaceuticals business is rising exponentially yearly, 5.8 %. It is expected to increase from USD 714 billion to USD 1454 billion by 2029. Beyond their intended uses, these substances are released into the environment as contaminants due to improper usage and management practices. Therefore, pharmaceuticals and microplastics (MPs) are classified as emerging pollutants (EPs), and their existence in agricultural ecosystems adversely affects soil and environmental health, ultimately impacting both ecological and human well-being. Pharmaceuticals and MP-loaded organic amendments (especially manure) are a primary cause of emerging soil pollutants. The increasing application of treated wastewater or biosolids as irrigation water or soil conditioners, mainly when derived from untreated sewage sludge, can introduce pharmaceuticals and MPs into the farmlands, merging these pollutants within the soil medium. The co-occurrence of MPs and pharmaceuticals leads to prolonged environmental presence and gradual bioaccumulation in organisms over time, contributing to persistent contamination and long-lasting effects on ecosystems. Moreover, these EPs have the potential to alter the composition of soil biogeochemistry and disrupt overall soil health and productivity. Numerous methods have been developed to address this emerging issue, including electrochemical degradation, advanced oxidation processes, photocatalytic degradation, biosurfactants, micro- and nano-bubble systems, ultrasonic cavitation, nanotechnology, constructed wetlands, and many hybrid approaches. This review explores the extent of EPs, their interactions, and management strategies in EPs-contaminated environments.

Ecotoxicological risk assessment of wastewater irrigation on soil microorganisms: Fate and impact of wastewater-borne micropollutants in lettuce-soil system

The implementation of the new Water Reuse regulation in the European Union brings to the forefront the need to evaluate the risks of using wastewater for crop irrigation. Here, a two-tier ecotoxicological risk assessment was performed to evaluate the fate of wastewater-borne micropollutants in soil and their ecotoxicological impact on plants and soil microorganisms. To this end, two successive cultivation campaigns of lettuces were irrigated with wastewater (at agronomical dose (not spiked) and spiked with a mixture of 14 pharmaceuticals at 10 and 100 µg/L each) in a controlled greenhouse experiment. Over the two cultivation campaigns, an accumulation of PPCPs was observed in soil microcosms irrigated with wastewater spiked with 100 μg/L of PPCPs with the highest concentrations detected for clarithromycin, hydrochlorothiazide, citalopram, climbazole and carbamazepine. The abundance of bacterial and fungal communities remained stable over the two cultivation campaigns and was not affected by any of the irrigation regimes applied. Similarly, no changes were observed in the abundance of ammonium oxidizing archaea (AOA) and bacteria (AOB), nor in clade A of commamox no matter the cultivation campaign or the irrigation regime considered. Only a slight increase was detected in clade B of commamox bacteria after the second cultivation campaign. Sulfamethoxazole-resistant and -degrading bacteria were not impacted either. The irrigation regimes had only a limited effect on the bacterial evenness. However, in response to wastewater irrigation the structure of soil bacterial community significantly changed the relative abundance of Acidobacteria, Chloroflexi, Verrucomicrobia, Beta-, Gamma- and Deltaprotebacteria. Twenty-eight operational taxonomic units (OTUs) were identified as responsible for the changes observed within the bacterial communities of soils irrigated with wastewater or with water. Interestingly, the relative abundance of these OTUs was similar in soils irrigated with either spiked or non-spiked irrigation solutions. This indicates that under both agronomical and worst-case scenario the mixture of fourteen PPCPs had no effect on soil bacterial community.