The increasing presence of plastics in the environment has raised concerns about their potential impact, especially as carriers of heavy metals such as Cd, Ni, and Pb. However, the adsorption mechanism of heavy metals on microplastics remains poorly understood. In this study, we investigated the adsorption behavior of Cd, Ni, and Pb by polystyrene (PS) and polypropylene (PP) microplastics to better comprehend their interaction and potential environmental implications. Our results revealed that equilibrium adsorption of microplastics with different heavy metals was achieved within a 6-h contact time. The FTIR analysis findings, which suggest that physical interactions play a significant role in the adsorption of heavy metals onto microplastics, are further supported by the observed changes in surface morphology after adsorption. We explored the influence of solution pH, contact duration, and initial concentration on the adsorption capacity and found significant effects on the adsorption behavior. To model the adsorption process, we applied Langmuir and Freundlich adsorption isotherm models and observed that the Langmuir model better fit the experimental data. Furthermore, we compared the pseudo-first and pseudo-second-order kinetic models and found that the pseudo-second-order model provided a more accurate description of the adsorption kinetics. Notably, the adsorption percentages varied depending on the type of microplastic and experimental conditions. Overall, this study enhances our understanding of the adsorption mechanism of heavy metals on microplastics and provides valuable insights into their behavior in aquatic environments. These findings have implications for the development of effective strategies for mitigating pollution caused by microplastics and heavy metals in aquatic ecosystems.

The principal objective of the present research involved the achievement of high biodegradation degrees of perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS) using pure individual bacterial strains. The use of such microorganisms can contribute to the improvement of the wastewater treatment process in sewage treatment plants through bioaugmentation or other bioremediation processes. Thus, in this study, we investigated the biodegradation potential of PFOA and PFOS. Bacterial strains tested in this study were from the Pseudomonas genus, namely: Pseudomonas aeruginosa and Pseudomonas putida, due to their known capacity to degrade xenobiotic compounds. The results indicated that Pseudomonas aeruginosa was able to transform 27.9% of PFOA and 47.3% of PFOS in 96 h, while Pseudomonas putida managed to transform 19.0% of PFOA and 46.9% of PFOS in the same time frame. During the biodegradation tests, PFHxA was recognized as the principal biotransformation product of PFOA in the presence of Pseudomonas aeruginosa, and PFPeA, PFPxA and PFHpA were recognized as the biotransformation products in the presence of Pseudomonas putida. For PFOS, only two biotransformation products (PHHxA and PFHpA) were observed as a consequence of biodegradation by both bacterial strains.

This study aimed to evaluate the behavior of Mentha piperita under Cd, Pb, Ni, and As soil contamination and their transfer from soil in plants as well as translocation in the roots/stems/leaves system compared with a control without metal addition. The mint seedlings were exposed for a three-month period using two metal mixtures in the same concentrations such as AsCd and AsCdNiPb (23.7 mg/kg As, 5 mg/kg Cd, 136 mg/kg Ni, and 95 mg/kg Pb). The results of metal concentration in plants showed that Cd, Ni, and Pb were accumulated in different parts of the plant, except for As. In plants organs, the order of metal accumulation was roots > stems > leaves. No significant impact on the growth, development, and chlorophyll content compared to the control was observed in the first month of exposure. After three months of exposure, phytotoxic effects occurred. Generally, the transfer coefficients and translocation factors values were less than 1, indicating that Mentha piperita immobilized the metals in root. The laboratory experiments highlighted that for a short period of time, Mentha piperita has the capacity to stabilize the metals at the root level and was a metal-tolerant plant when using a garden rich-substrate.

Per- and polyfluoroalkyl substances (PFAS) are a global concern due to their persistence, ubiquity, and accumulation in living organisms. Found in soils, biosolids, water, and the food chain, they pose health risks such as hormone disruption, immune damage, reproductive issues, and cancer. Regulations mainly target older PFAS like PFOA and PFOS, while many newer PFAS, including breakdown products, are poorly understood in terms of distribution, behavior, and toxicity. To address this complex issue, this review offers a detailed overview of human exposure to PFAS and their toxic effects. It highlights biosolids as a key, understudied source of PFAS in the environment. The review also discusses limitations of testing, missing long-term cleanup data, and regulatory issues that neglect total exposure and vulnerable populations. Additionally, it evaluates, in the specific context of biosolids management, the effectiveness, scalability, benefits, and drawbacks of various treatment technologies, such as thermal processes (pyrolysis, incineration, smoldering combustion), advanced oxidation, adsorption, hydrothermal liquefaction, and biological degradation. This work combines environmental science, toxicology, and engineering to outline PFAS management in biosolids and proposes a research and policy plan. Focusing on regulating PFAS as a group, validating real-world results, and employing adaptable treatment strategies underscores the need for a coordinated, science-based effort to reduce PFAS risks worldwide.

Microplastics (MPs) are emerging vectors for hydrophobic organic pollutants, including polycyclic aromatic hydrocarbons (PAHs), in aquatic environments. Due to their high surface area and sorption potential, MPs can enhance the environmental persistence and bioavailability of toxic compounds, posing potential risks to both aquatic organisms and human health. This study investigates the distribution, sorption behavior, and effects on pollutant transport, distribution, and exposure pathways of PAHs-contaminated microplastics in two major Romanian rivers: the Prahova and Ialomita. PAHs concentrations were quantified in surface water, sediments, and microplastic particles collected from both rivers. Results revealed PAHs levels in surface waters ranging from below the limit of quantification (LOQ) to 0.0187 µg/L in the Prahova River and < LOQ to 0.0176 µg/L in the Ialomita River. Sediment concentrations varied from < LOQ to 397 µg/kg dry weight (d.w.) in the Prahova and 449-875 µg/kg d.w. in the Ialomita. Significantly elevated PAHs concentrations were detected on microplastics, with maximum values of 38.9 ng/g d.w. and 49.7 ng/g d.w., respectively. Ecotoxicological risk assessment, based on environmental quality criteria and known toxicological thresholds, indicated low to moderate ecological risks for aquatic organisms. However, health risk modeling revealed that while adult exposure remained within safe margins, children exhibited a higher non-carcinogenic risk due to increased susceptibility and intake rates. These findings highlight the role of microplastics in modifying the toxicokinetics and exposure pathways of PAHs in freshwater systems and underscore the importance of targeted monitoring and mitigation strategies to protect vulnerable populations and maintain aquatic ecosystem health.

Organophosphate ester flame retardants (OPFRs) are ubiquitous organic pollutants in the environment and present an important preoccupation due to their potential toxicity to humans and biota. They can be found in various sources, including consumer products, building materials, transportation industry, electronic devices, textiles and clothing, and recycling and waste management. This paper presents the first survey of its kind in Romania, investigating the composition, distribution, possible sources, and environmental risks of OPFRs in five wastewater treatment plants (WWTPs) and the rivers receiving their effluents. Samples from WWTPs and surface waters were collected and subjected to extraction processes to determine the OPFRs using liquid chromatography with mass spectrometric detection. All the target OPFRs were found in all the matrices, with the average concentrations ranging from 0.6 to 1422 ng/L in wastewater, 0.88 to 1851 ng/g dry weight (d.w.) in sewage sludge, and 0.73 to 1036 ng/L in surface waters. The dominant compound in all the cases was tri(2-chloroisopropyl) phosphate (TCPP). This study observed that the wastewater treatment process was inefficient, with removal efficiencies below 50% for all five WWTPs. The environmental risk assessment indicated that almost all the targeted OPFRs pose a low risk, while TDCPP, TCPP, and TMPP could pose a moderate risk to certain aquatic species. These findings provide valuable information for international pollution research and enable the development of pollution control strategies.