Analysis of micro- and nanoplastics in wastewater treatment plants: key steps and environmental risk considerations.

The analysis of micro- and nanoplastics (MNPs) in the environment is a critical objective due to their ubiquitous presence in natural habitats, as well as their occurrence in various food, beverage, and organism matrices. MNPs pose significant concerns due to their direct toxicological effects and their potential to serve as carriers for hazardous organic/inorganic contaminants and pathogens, thereby posing risks to both human health and ecosystem integrity. Understanding the fate of MNPs within wastewater treatment plants (WWTPs) holds paramount importance, as these facilities can be significant sources of MNP emissions. Additionally, during wastewater purification processes, MNPs can accumulate contaminants and pathogens, potentially transferring them into receiving water bodies. Hence, establishing a robust analytical framework encompassing sampling, extraction, and instrumental analysis is indispensable for monitoring MNP pollution and assessing associated risks. This comprehensive review critically evaluates the strengths and limitations of commonly employed methods for studying MNPs in wastewater, sludge, and analogous environmental samples. Furthermore, this paper proposes potential solutions to address identified methodological shortcomings. Lastly, a dedicated section investigates the association of plastic particles with chemicals and pathogens, alongside the analytical techniques employed to study such interactions. The insights generated from this work can be valuable reference material for both the scientific research community and environmental monitoring and management authorities.

Nutritional additives dominance in driving the bacterial communities succession and bioremediation of hydrocarbon and heavy metal contaminated soil microcosms.

Soil quality and microbial diversity are essential to the health of ecosystems. However, it is unclear how the use of eco-friendly natural additives can improve the quality and microbial diversity of contaminated soils. Herein, we used high-throughput 16 S rDNA amplicon Illumina sequencing to evaluate the stimulation and development of microbial diversity and concomitant bioremediation in hydrocarbon (HC) and heavy metal (HM)-rich waste disposal site soil when treated with meat and bone meal (MBM), cyclodextrin (Cdx), and MBM and cyclodextrin mixture (Cdx MBM) over a period of 3 months. Results showed that natural additive treatments significantly increased the soil bacterial diversity (higher Shannon index, Simpson index and evenness) in a time-dependent manner, with Cdx eliciting the greatest enhancement. The two additives influenced the bacterial community succession patterns differently. MBM, while it enhanced the enrichment of specific genera Chitinophaga and Terrimonas, did not significantly alter the total bacterial community. In contrast, Cdx or Cdx MBM promoted a profound change of the bacteria community over time, with the enrichment of the genera Parvibaculum, Arenimonas and unclassified Actinobacteria. These results provide evidence on the involvement of the two natural additives in coupling HC and HM bioremediation and bacterial community perturbations, and thus illustrates their potential application in ecologically sound bioremediation technologies for contaminated soils.

Natural additives contribute to hydrocarbon and heavy metal co-contaminated soil remediation.

A biological treatment method was tested in laboratory conditions for the removal of hydrocarbons contained in a waste disposal soil sample consisting of excavated sandy soil from a former fueling station. Two fractions of hydrocarbons were quantified by GC-FID: diesel (C10-C21) and lubricant oil (C22-C40). Meat and bone meal (MBM, 1% w/w) was used as a bio-stimulant agent for soil organisms. Cyclodextrin, an oligosaccharide produced from starch by enzymatic conversion, was also used to assess its ability to improve the bioavailability/biodegradability of hydrocarbons in the soil. Parameters such as temperature, pH, water content and aeration (O2 availability) were monitored and optimized to favor degradation processes. Two different experimental tests were prepared: one to measure the degradation of hydrocarbons; the other to monitor the mobility of some elements in the soil and in the leachate produced by watering with tap water. Soil samples treated with MBM and cyclodextrin showed, over time, a greater removal of the more persistent hydrocarbon fraction (lubricant oil). MBM-treated soils underwent a faster hydrocarbon removal kinetic, especially in the first treatment period. However, the final hydrocarbon concentrations are comparable in all treatments, including control. Over time, the effect of cyclodextrin on hydrocarbon degradation seemed to be relevant. MBM-treated soils sequestered lead in the very first weeks. These results highlight the intrinsic capacity of soil, and its indigenous microbial communities, to degrade petroleum hydrocarbons and suggest that MBM-induced bioremediation is a promising, environmentally friendly technology which should be considered when dealing with hydrocarbon/heavy metal co-contaminated soils.

Dataset on bio-stimulation experiments for the removal of hydrocarbons and the monitoring of certain elements in a contaminated soil.

Meat and Bone Meal (MBM) and ß-cyclodextrin were added to a soil sample co-contaminated by hydrocarbons (diesel fraction C10-C21 and lubricant oil fraction C22-C40) and heavy metals to promote soil remediation. The pilot study was conducted in the laboratory, maintaining optimal conditions (i.e., temperature, pH, water content, soil aeration) to facilitate hydrocarbon biodegradation. Two different experimental tests were prepared: one for the analysis of hydrocarbons in soil, the other to monitor the dynamics of some elements of interest. For the first test, the two hydrocarbon fractions in the soil were quantified separately by GC-FID, following the ISO 16703:2004(E) standard protocol. Sampling and analysis were done every two weeks, for three consecutive months. For the second test (dynamics of certain elements in the soil), soil and leachate samples were analyzed by ICP-MS after appropriate pretreatment steps.