The presence of pharmaceuticals and personal care products (PPCPs) in the environment has aroused considerable interest in the last few years. However, the occurrence and fate of parent compounds and their metabolites and/or transformation products in soils have been scarcely evaluated to date. In this work, the dissipation kinetics of PPCPs, which are most frequently detected in the environment, and their main metabolites, is evaluated in soil amended with digested and composted sludge. The studied compounds were monitored for 60 days after digested or compost application to the soil. Several kinetic models were used to evaluate the dissipation kinetics of the processes. Parabens and their metabolites were the compounds with the fastest dissipation rates, while the antiepileptic carbamazepine and its metabolites were the poorest degraded compounds studied. Most of the compounds showed a single first-order dissipation kinetics. The application of biphasic kinetic models can improve the knowledge about the dissipation behavior of some of them. For instance, whereas compounds such as carbamazepine showed a high persistence showing a lag phase in its dissipation, resulting in an approximately constant concentration for the first days of batch experiments, others, such as sulfamethoxazole and diclofenac, followed a dissipation kinetics in two phases: a fast dissipation attributed to the amount of compound associated to the soil-water solution and a slow dissipation that could be due to the amount of the compound adsorbed onto the soil particle. For most of the compounds, the dissipation was faster in sludge-amended soil than in soil without organic amendment. This fact could be due to the influence of microbial activity and organic matter on their dissipation.

Discarded plastic wastes are slowly degrading into smaller parts, namely microplastics, that can be easily transported to oceans by water streams. In vast, salty, and sunny environments, they degrade even faster and are subject to come back in the water network used for drinking or industrial water in the form of nearly indetectable objects: nanoplastics. Once in busy buffers such as wastewaters, nanoplastics will tend to aggregate to form tertiary microplastics formed of single or multiple types of plastics and potentially host other materials ranging from organics and metals to bacteria and viruses. Their nature, random shape, and various size are at the origin of nuclei merging together or with other objects. Two particles at a close distance from each other can either attract or repulse themselves depending on their nature and constitution. At very short distances, Van der Waals forces are predominant and a measure of them is given by the so-called Hamaker constant. We propose to predict this aggregation by estimating the Hamaker’s constant.

Concerns about pollution in Arroyo Seco, an important natural water body in the Monterrey Metropolitan Area, have been reported due to possible wastewater discharges and solid waste mismanagement, turning the river into a potential public health hazard in the context of the COVID-19 pandemic. As a result, a volunteer clean-up campaign denominated “Arroyo Vivo” has been promoted by Distrito Tec and the Campana-Altamira initiative. To aid in the efforts, ammonium, nitrates, nitrites, and sulfate concentrations, total solids, and total organic matter were measured in parallel with SARS-CoV-2 detection and quantification in river water samples. Compared with applicable regulations (NOM-001-SEMARNAT-2021, NOM-127-SSA1-2021), total suspended solid levels (55-365 mg/L) were found above the maximum limit (84 mg/L), while ammonium (0.0175-0.198 mg/L), nitrite (0.0585-0.169 mg/L), nitrate (1.065-3.285 mg/L), sulfate (91.2-111 mg/L), and chemical oxygen demand (16.95-43.1 mg/L) were consistently below the maximum limits (0.50, 0.90, 11.00, 84.00, 400.00, and 100.00 mg/L, respectively), showing that no large-scale wastewater discharges had taken place in Arroyo Seco. However, SARS-CoV-2 genetic material was detected at three sampling sites, indicating some degree of sewage leakage and inadequate management of solid waste containing respiratory fluids of infected patients. While reports indicate that water bodies are not sources of SARS-CoV-2 infection in surrounding populations, it proves that waste disposal policies must be enforced more strictly to ensure water quality and environmental protection towards sustainable development. Nonetheless, continued efforts to screen concerning contaminants are still needed to fully assess the environmental status of the stream and propose relevant public policy.

The presence of the two main non-steroidal anti-inflammatory drugs (NSAIDs), diclofenac (DCF) and ibuprofen (IBU), in marine and estuarine systems has been reported. Although the available information about the toxicity of these compounds in aquatic organisms has increased in recent years, the database about marine organisms, specifically invertebrates, is limited. Consequently, the assessment of potential risks posed by these compounds to aquatic species should be improved, given their relevance for aquatic life and the trophic chain. To fill this gap, we analyze the potential risk of IBU and DCF in marine invertebrates. To assess the risk, the database was built with available information from the scientific literature about the occurrence, bioaccumulation, and toxicity of both compounds in the estuaries and marine environments. Risk assessment of both compounds in these environments is scarce and based essentially on their acute toxicity. Data compiled in this review, including environmental concentrations and toxicity thresholds, were used to calculate risk quotients and classify the risk for invertebrate communities in coastal areas with different contamination levels. The results indicated a higher risk for DCF than IBU. Additionally, the simultaneous presence of the two NSAIDs in the aquatic environment increases the risk for exposed organisms. The use of classical methods (e.g., biochemical markers, gene expression), new approaches (e.g., adverse outcome pathway, AOP), and omic techniques has contributed to understanding the underlying toxicity mechanisms and improving the risk assessment. However, in a global change scenario involving multiple drivers and pressures such as ocean acidification, heat waves, climate change, etc., the risk assessment for these emerging pollutants needs improvement. This can be achieved by increasing our knowledge about the metabolic pathway and biotransformation routes of these compounds in marine species and understanding how these changes can affect the bioaccumulation, toxicity, fate, and behavior of both NSAIDs.

2,4-Dichlorophenoxyacetic acid (2,4-D) is a widely used herbicide possessing high herbicidal activity; however, it is potentially toxic to humans and quite persistent in the environment. We investigated the adsorption of 2,4-D in two pasture soils amended with pine sawdust (PSD), paunch grass (PG) and sewage sludge (SS) biochars using batch studies. The results showed that PSD biochar produced at 700 ^oC exhibited the highest adsorption capacity for 2,4-D among the waste-derived biochars tested, which is 200-fold greater than the control and other biochar-amended soils. In general, the sorption affinity of 2,4-D for biochar amended soils followed an order: PSD > > PG > SS. The high adsorption capacity of the PSD may be attributed to its significantly higher specific surface area of 795 m²·g^-1 as compared to other soils and biochars. Moreover, the results of the physicochemical characterization showed no difference in surface oxygen functional groups among the PSD, PG and SS. These findings indicate that oxygen-containing surface functional groups have a negligible role in 2,4-D adsorption, as evident from the spectroscopic investigation, thus emphasizing the role of surface area in the 2,4-D adsorption. Lastly, pore intrusion/filling, hydrogen bonding and π-π EDA interactions are postulated to be the plausible adsorption mechanisms for 2,4-D onto biochar amended soils.