Nowadays, the occurrence of a large volume of plastic litter in oceanic and coastal zones has increased concern about its impacts on marine organisms. The degradation of plastic polymers leads to the formation of smaller fragments at both micro and nano scale (<5 mm and <1 μm respectively). Nanoplastics (NPs), due to their smaller size and high specific surface area can establish colloidal interactions with marine microalgae, therefore potential toxicity can be led. . To assess this hypothesis, the aim of the present study is to examine the behaviour of polystyrene nanoparticles (PS NPs) of different sizes (50 and 100 nm) in marine water and their possible effects at different physiological and cellular levels in the marine diatom Phaeodactylum tricornutum. Different biomarkers and stress responses in P. tricornutum were analysed when organisms were exposed to environmentally relevant PS NPs concentrations between 0.1 and 50 mg L−1. Our results showed significant differences between controls and exposure microalgae, indicating toxicity. After 24 h, an increase in oxidative stress biomarkers, damage to the photosynthetic apparatus, DNA damage and depolarization of mitochondrial and cell membrane from 5 mg L−1 were observed. Further after 72 h the inhibition of population growth and chlorophyll content were observed. Examining effects the effects related to PS NPs size, the smallest (50 nm) induced greater effects at 24 h while bigger PS NPs (100 nm) at72 h. This bigger particles (100 nm) showed more stability (in size distribution and spherical form) in the different culture media assayed, when compared with the rest of particles used. Strong adsorption and/or internalization of PS NPs was confirmed through changes in cell complexity and cell size as well as the fluorescence of 100 nm fluoresbrite PS NPs after washing cell surface.

Contamination of soils by metals and metalloids is an important environmental problem in many residential and industrial sites around the world. Lead is a common contaminant, which enters the soil through mining, industrial activities and waste disposal. A range of technologies can be used to remediate soil lead, however most remediation technologies adversely affect the environment and particularly soil biota. We have assessed the efficacy of vermiremediation (the use of earthworms for remediation) to reduce water extractable lead concentrations in soil. Earthworms were introduced to a sandy soil spiked with the common lead minerals cotunnite (PbCl2), cerussite (PbCO3), massicot (PbO) or galena (PbS) at 1000 mg (Pb) kg−1. Lead concentrations in pore water extracted during the experiment were not significantly different in contaminated soil with and without worms. However, concentrations of lead in water from a deionised water extraction (washing) of contaminated soil were significantly lower in soil with earthworms than in soil without. Earthworms accumulated on average (±1 standard deviation) 276 ± 118, 235 ± 66, 241 ± 58 and 40 ± 30 mg kg−1 (dry weight of earthworms) of lead in their bodies, in PbCl2, PbCO3, PbO and PbS-dosed soils, respectively. During the experiment, earthworms lost weight in all contaminated soils, except those containing PbS.

Sediments nearby harbors are dredged regularly, and the sediments require the stringent treatment to meet the regulations on reuse and mitigate the environmental burdens from toxic pollutants. In this study, FeCl₃ was chosen as an extraction agent to treat marine sediment co-contaminated with Cu, Zn, and total petroleum hydrocarbons (TPH). In chemical extraction process, the extraction efficiency of Cu and Zn by FeCl₃ was compared with the conventional one using inorganic acids (H₂SO₄ and HCl). Despite the satisfactory level for extraction of Cu (78.8%) and Zn (73.3%) by HCl (0.5 M) through proton-enhanced dissolution, one critical demerit, particularly acidified sediment, led to the unwanted loss of Al, Fe, and Mg by dissolution. Moreover, the vast amount of HCl required the huge amounts of neutralizing agents for the post-treatment of the sediment sample via the washing process. Despite a low concentration, extraction of Cu (70.1%) and Zn (69.4%) was done by using FeCl₃ (0.05 M) through proton-enhanced dissolution, ferric-organic matter complexation, and oxidative dissolution of sulfide minerals. Ferric iron (Fe³⁺) was reduced to ferrous iron (Fe²⁺) with sulfide (S²⁻) oxidation during FeCl₃ extraction. In consecutive chemical oxidations using hydrogen peroxide (H₂O₂) and persulfate (S₂O₈²⁻), the resultant ferrous iron was used to activate the oxidants to effectively degrade TPH. S₂O₈²⁻ using FeCl₃ solution (molar ratio of ferrous to S₂O₈²⁻ is 19.8–198.3) removed 42.6% of TPH, which was higher than that by H₂O₂ (molar ratio of ferrous to H₂O₂ is 1.2–6.1). All experimental findings suggest that ferric is effectively accommodated to an acid washing step for co-contaminated marine sediments, which leads to enhanced extraction, cost-effectiveness, and less environmental burden.

The pollution load of urban runoff is boosted due to the washing away of road-deposited sediment (RDS). Therefore, a source-oriented mitigation strategy is essential to integrated stormwater management. This study showcases the influence of land use dependent source apportionment and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in RDS. Samples were collected from areas of different land uses, including commercial city centre, highway, residential rural and campus areas. According to the positive matrix factorisation (PMF) receptor model, different primary sources were identified at different land use areas. Generally, potential sources of gasoline- and diesel-powered engine emissions and other pyrogenic sources of biomass, coal, and wood combustions were identified as main sources of PAH content in RDS. The source specific risks posed by PAHs at different land uses were further estimated by the incremental lifetime cancer risk (ILCR). This shows that the mean ILCRs of the total cancer risk for children and adults at the given land uses were lower than the baseline value of an acceptable risk. However, the potential exposure risk to RDS adsorbed PAHs for children was considerably higher than that for adults. Vehicular emissions and wood combustion were the major contributors to the cancer risk with average contributions of 57 and 29%, respectively.

Ethylenediurea (EDU) is a common research tool for investigating ozone impacts on vegetation, although the role of different application routes (foliar spray vs soil drench) on EDU persistence in the leaves is unknown. We quantified EDU concentrations in leaves of the O3-sensitive Bel-W3 cultivar of tobacco treated with EDU as either foliar spray or soil drench. Foliar EDU concentrations were measured by Q-TOF LC/MS. When EDU was applied as foliar spray, 1 h was enough for reaching a measurable concentration within the leaf. EDU concentration increased over the 21-day period when the leaf was not washed after the application (treatment #1), while it decreased when the leaf was washed after the application (treatment #2). These results suggest that: a) dry deposition of EDU onto the leaf surface was gradually absorbed into the unwashed leaf, although the mechanisms of such uptake were unclear; b) concentration of EDU was decreased quickly (−35%) during the first 24 h from application and more slowly during the following three days (−20%) in the washed leaves. Degradation did not involve enzymatic reactions and was not affected by the presence of ROS. When EDU was applied as soil drench, foliar concentrations increased over time, likely due to adsorption onto soil organic matter and gradual re-solubilization by irrigation water. An analysis of EDU concentration in protoplast and intercellular washing fluid showed that EDU did not enter the cells, but was retained in the apoplast only. Possible implications of EDU in the apoplast and recommendations for EDU application are discussed.

The remediation of a genuinely PAH-contaminated soil was performed, for the first time, through a new and complete investigation, including PAH extraction followed by advanced oxidation treatment of the washing solution and its recirculation, and an analysis of the impact of the PAH extraction on soil respirometry. The study has been performed on the remediation of genuine PAH-contaminated soil, in the following three steps: (i) PAH extraction with soil washing (SW) techniques, (ii) PAH degradation with an electro-Fenton (EF) process, and (iii) recirculation of the partially oxidized effluent for another SW cycle. The following criteria were monitored during the successive washing cycles: PAH extraction efficiency, PAH oxidation rates and yields, extracting agent recovery, soil microbial activity, and pH of soil. Two representative extracting agents were compared: hydroxypropyl-beta-cyclodextrin (HPCD) and a non-ionic surfactant, Tween® 80. Six PAH with different numbers of rings were monitored: acenaphthene (ACE), phenanthrene (PHE), fluoranthene (FLA), pyrene (PYR), benzo(a)pyrene (BaP), and benzo(g,h,i)perylene (BghiP). Tween® 80 showed much better PAH extraction efficiency (after several SW cycles) than HPCD, regardless of the number of washing cycles. Based on successive SW experiments, a new mathematical relation taking into account the soil/water partition coefficient (Kd*) was established, and could predict the amount of each PAH extracted by the surfactant with a good correlation with experimental results (R² > 0.975). More HPCD was recovered (89%) than Tween® 80 (79%), while the monitored pollutants were completely degraded (>99%) after 4 h and 8 h, respectively. Even after being washed with partially oxidized solutions, the Tween® 80 solutions extracted significantly more PAH than HPCD and promoted better soil microbial activity, with higher oxygen consumption rates. Moreover, neither the oxidation by-products nor the acidic media (pH approximately 3) of the partially oxidized solution inhibited the general soil microbial activity during the washing cycle.

Three experiments were conducted to optimize the use of ethylenediaminetetraacetic acid (EDTA) for reclaiming urban soils contaminated with trace metals. As compared to Na2EDTA, (NH4)2EDTA extracted 60% more Zn and equivalent amounts of Cd, Cu and Pb from a sandy loam. When successively saturating and draining loamy sand columns during a washing cycle, which submerged it once with a (NH4)2EDTA wash and four times with deionised water, the post-wash rinses largely contributed to the total cumulative extraction of Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn. Both the washing solution and the deionised water rinses were added in a 2:5 liquid to soil (L:S) weight ratio. For equal amounts of EDTA, concentrating the washing solution and applying it and the ensuing rinses in a smaller 1:5 L:S weight ratio, instead of a 2:5 L:S weight ratio, increased the extraction of targeted Cr, Cu, Ni, Pb and Zn. A single EDTA addition is best utilised in a highly concentrated washing solution given in a small liquid to soil weight ratio.

Microfiber is a subgroup of microplastics and accounts for a large proportion of microplastics in aquatic environment, especially in municipal effluents. The purpose of the present study was to quantify microfiber shedding from three most populate synthetic textile fabrics: polyester, polyamide, and acetate fabrics. The results showed that more microfibers were released after washing with a pulsator laundry machine than a platen laundry machine. The greatest number of microfibers was released from acetate fabric, which was up to 74,816 ± 10,656 microfibers/m2 per wash, although microfibers were shed from all materials. Moreover, an increasing trend was found in the number of microfibers shedding from synthetic fabrics with the washing temperature increasing, and greater microfiber release occurred when washing fabrics with detergent rather than with water alone. The lint filter bag equipped with the pulsator laundry machine retained the longer microfibers (>1000 μm), but not the shorter microfibers (<500 μm) instead of releasing into the drainage system. Our data suggested that microfibers released during washing of synthetic fabrics may be an important source of microfibers in aquatic environment due to the increasing production and use of synthetic fabrics globally. Thus, more efficient filtering bags or other technologies in household washing machines should be developed to prevent and reduce the release of microfibers from domestic washing.

Baltic amber, adored for its beauty already in Homer's Odyssey (ca. 800 B.C.E), has its material density close to that of wide-spread plastics like polyamide, polystyrene, or acrylic. Migrations of amber stones in the sea and their massive washing ashore have been monitored by Baltic citizens for ages. Based on the collected information, we present the hypothesis on the behaviour of microplastic particles in sea coastal zone. Fresh-to-strong winds generate surface waves, currents and roll-structures, whose joint effect washes ashore from the underwater slope both amber stones and plastics – and carries them back to the sea in a few days. Analysis of underlying hydrophysical processes suggests that sea coastal zone under stormy winds plays a role of a mill for plastics, and negatively buoyant pieces seem to repeatedly migrate between beaches and underwater slopes until they are broken into small enough fragments that can be transported by currents to deeper areas and deposited out of reach of stormy waves. Direct observations on microplastics migrations are urged to prove the hypothesis.

The ability of Posidonia oceanica spheroids (egagropiles, EG) to incorporate plastics was investigated along the central Italy coast. Plastics were found in the 52.84% of the egagropiles collected (n = 685). The more represented size of plastics has range within 1–1.5 cm, comparable to the size of natural fibres. Comparing plastics occurring both in EG and in surrounding sand, Polyethylene, Polyester and Nylon were the most abundant polymers in EG, while PSE, PE, PP and PET were the most represented in sand. In particular PE and PP were significantly more represented in sand, while PE, Nylon, Polyester and microfibers (as pills) were more represented in EG. Within plastics found in EG, 26.9% were microfibers as small pills (<1 cm), mainly composed of polyamide, polyester, cotton and PET mixing. These microfibers might be produced by discharges from washing machines and currently represents an emerging pollutant with widespread distribution in marine and freshwater ecosystems.