Search

Tire wear particles (TWP) are a major source of microplastics in the aquatic environment and the ecological impacts of their leachates are of major environmental concern. Among marine biota, copepods are the most abundant animals in the ocean and a main link between primary producers and higher trophic levels in the marine food webs. In this study, we determined the acute lethal and sublethal effects of tire particle leachates on different life stages of the cosmopolitan planktonic copepod Acartia tonsa. Median lethal concentration (LC 50 , 48 h) ranged from 0.4 to 0.6 g L−1 depending on the life stages, being nauplii and copepodites more sensitive to tire particle leachates than adults. The median effective concentration (EC 50 , 48 h) for hatching was higher than 1 g L−1, indicating a relatively low sensitivity of hatching to tire particle leachates. However, metamorphosis (from nauplius VI to copepodite I) was notably reduced by tire particle leachates with an EC 50 (48 h) of 0.23 g L−1 and the absence of metamorphosis at 1 g L−1, suggesting a strong developmental delay or endocrine disruption. Leachates also caused a significant decrease (10–22%) in the body length of nauplii and copepodites after exposure to TWP leachates (0.25 and 0.5 g L−1). We tested a battery of enzymatic biomarkers in A. tonsa adult stages, but a sublethal concentration of 50 mg L−1 of tire particle leachates did not cause a statistically significant effect on the measured enzymatic activities. Our results show that tire particle leachates can negatively impact the development, metamorphosis, and survival of planktonic copepods. More field data on concentrations of TWPs and the fate and persistence of their leached additives is needed for a better assessment of the risk of tire particle pollution on marine food webs. [Display omitted] • Acute exposure to tire particle leachates caused lethality in all copepod life stages. • Nauplii and copepodites were the most sensitive stages to tire particle leachates. • Metamorphosis was notably reduced, suggesting endocrine disruption. • Tire particle pollution can decrease recruitment success of marine copepods. [ABSTRACT FROM AUTHOR]

Tire rubber microparticles (TRPs) entering aquatic ecosystems through stormwater runoffs is a significant challenge. TRPs are formed by the abrasion of tires with the road surface and include chemical additives that are an additional cause for concern. Currently, information on the molecular effects of TRPs, or especially its additives, in freshwater organisms is scarce. To address this problem, an array covering different cellular processes has been designed for the freshwater midge Chironomus riparius. Fourth-instar larvae were exposed to two concentrations of TRPs (1 mg L−1, 10 mg L−1) and tire rubber leachates (TRLs) (0,0125 %, 5 %) to evaluate the transcriptional activity by Real-Time PCR. To assess acute toxicity, larvae were exposed for 24 h and genes related to the endocrine system, stress response, DNA repair mechanisms, immune system, oxidative stress, and detoxification mechanisms were evaluated. The activity of the enzymes: glutathione S-transferase (GST) and catalase was also examined. The main pathway affected was the stress response showing overexpression of HSPs (HSC70. 3 , HSC70. 4 , HSC70. 5 , HSP60). Moreover, there was a reduction of the GSTd3 and catalase disrupting the antioxidant system. The upregulation of InR indicates a potential disturbance in the insulin pathway and ABCB6 activation only in TRPs exposure suggests its potential implication in their transport. However, most of these alterations are caused by TRLs, showing higher toxicity than TRPs. The results obtained in this work provide the first approach at the molecular and cellular levels to elucidate the impact of TRLs in freshwater organisms. To perform a realistic evaluation of the TR effects, additional research is required to assess the TR's long-term effects at the molecular level. [Display omitted] • TR disrupts detoxification and stress system in C. riparius after 24 h exposure. • TRLs have shown higher toxicity to C. riparius than TRPs. • Zinc is the main metal present in TRLs producing toxicity. • Analyzing effects at transcriptional level enables assessing real scenarios. [ABSTRACT FROM AUTHOR]

Total and leached Arsenic, Mercury and Antimony were determined in the topsoils developed on the mining waste dumping area of Le Lame (Mt. Amiata, central Italy) where the post-processing Hg-rich ore deposits from the mining area of Abbadia San Salvatore were stored. The concentrations of As, Hg and Sb were up to 610, 1910 and 1610 mg kg−1, respectively, while those in the leachates (carried out with CO2-saturated MilliQ water to simulate the meteoric water conditions) were up to 102, 7 and 661 μg·L−1, respectively. Most aqueous solutions were characterized by Hg content −1. This is likely suggesting that the mine wastes (locally named “rosticci”) were possibly resulting from an efficient roasting process that favored either the removal or inertization of Hg operated by the Gould furnaces and located in the southern sector of Le Lame. The highest values of total and leachate mercury were indeed mostly found in the northern portion where the “rosticci”, derived by the less efficient and older Spirek-Cermak furnaces, was accumulated. The saturation index was positive for the great majority of leachate samples in Fe-oxy-hydroxides, e.g., ferrihydrite, hematite, magnetite, goethite, and Al-hydroxides (boehmite and gibbsite). On the other hand, As- and Hg-compounds were shown to be systematically undersaturated, whereas oversaturation in tripuhyte (FeSbO4) and romeite (Ca2Sb2O7) was evidenced. The Eh-pH diagrams for the three chalcophile elements were also constructed and computed and updated according to the recent literature data.

Considering that electronic wastes (e-wastes) have been recently recognized as a potent environmental and human threat, the present study aimed to assess the potential risk of personal computer motherboards (PCMBs) leaching into aquatic media, following a real-life scenario. Specifically, PCMBs were submerged for 30 days in both distilled water (DW) and artificial seawater (ASW). Afterwards, PCMBs leachates were chemically characterized (i.e., total organic carbon, ions, and trace elements) and finally used (a) for culturing freshwater (Chlorococcum sp. and Scenedesmus rubescens) and saltwater (Dunaliella tertiolecta and Tisochrysis lutea) microalgae for 10 days (240 h), (b) as the exposure medium for mussel Mytilus galloprovincialis (96 h exposure), and (c) for performing the Cytokinesis Block Micronucleus (CBMN) assay in human lymphocytes cultures. According to the results, PCMBs could mediate both fresh- and marine algae growth rates over time, thus enhancing the cytotoxic, oxidative, and genotoxic effects in the hemocytes of mussels (in terms of lysosomal membrane impairment, lipid peroxidation, and NO content and micronuclei formation, respectively), as well as human lymphocytes (in terms of MN formation and CBPI values, respectively). The current findings clearly revealed that PCMBs leaching into the aquatic media could pose detrimental effects on both aquatic organisms and human cells.

Increased permafrost thaw due to climate change in northern high-latitudes has prompted concern over impacts on soil and stream biogeochemistry that affect the fate of dissolved organic carbon (DOC). Few studies to-date have examined the link between molecular composition and biolability of dissolved organic matter (DOM) mobilized from different soil horizons despite its importance in understanding carbon turnover in aquatic systems. Additionally, the effect of mixed DOM sources on microbial metabolism (e.g., priming) is not well understood. No studies to-date have addressed potential priming effects in northern high-latitude or permafrost-influenced aquatic ecosystems, yet these ecosystems may be hot spots of priming where biolabile, ancient permafrost DOC mixes with relatively stable, modern stream DOC. To assess biodegradability and priming of DOC in permafrost-influenced streams, we conducted 28 day bioincubation experiments utilizing a suite of stream samples and leachates of fresh vegetation and different soil horizons, including permafrost, from Interior Alaska. The molecular composition of unamended DOM samples at initial and final time points was determined by ultrahigh resolution mass spectrometry. Initial molecular composition was correlated to DOC biodegradability, particularly the contribution of energy-rich aliphatic compounds, and stream microbial communities utilized 50–56% of aliphatics in permafrost-derived DOM within 28 days. Biodegradability of DOC followed a continuum from relatively stable stream DOC to relatively biolabile DOC derived from permafrost, active layer organic soil, and vegetation leachates. Microbial utilization of DOC was ∼3–11% for stream bioincubations and ranged from 9% (active layer mineral soil-derived) to 66% (vegetation-derived) for leachate bioincubations. To investigate the presence or absence of a priming effect, bioincubation experiments included treatments amended with 1% relative carbon concentrations of simple, biolabile organic carbon substrates (i.e., primers). The amount of DOC consumed in primed treatments was not significantly different from the control in any of the bioincubation experiments after 28 days, making it apparent that the addition of biolabile permafrost-derived DOC to aquatic ecosystems will likely not enhance the biodegradation of relatively modern, stable DOC sources. Thus, future projections of carbon turnover in northern high-latitude region streams may not have to account for a priming effect.

Microplastics (MPs) are found in aquatic environments all over the world. Among MPs, tire wear particles (TWPs) are a major contributor to microplastic pollution, and their effects on marine ecosystems are of emerging concern. The blue mussel (Mytilus edulis) is a keystone species in coastal ecosystems with a high risk of exposure to microplastic pollution as the microplastics often overlap in size with the plankton consumed by mussels. In the present study, we investigated the effect of tire particles and their leachates on the filtration rates of M. edulis after short (72 h) and long-term (3 weeks) exposure. Acute exposure to leachates alone causes a significant decrease in the filtration rates of M. edulis with a low observed effect concentration (LOEC) of 1.25 g L -1 and a median effect concentration (EC 50 ) = 3 g L -1 . At a concentration of 1.25 g L -1 , the filtration rate was reduced compared to the control on average by 38% when mussels were exposed to either TWP or leachates for 72 h. Similarly, mussels exposed to tire particles or their leachates for 3 weeks showed a 46% reduction in filtration rates, compared to the control group. A non-significant difference in filtration rate decrease was found between leachates alone or TWP, which indicates that leachates are the main responsible for the observed toxicity. Our findings indicate that elevated levels of TWP pollution can cause an adverse impact on M. edulis. This could disrupt the natural grazing pressure exerted by M. edulis on phytoplankton, potentially leading to an increased likelihood of algal blooms and hypoxia occurrence in coastal ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Municipal solid waste (MSW) dumpsite constitutes a major anthropogenic point source of leachate contamination to the ambient groundwater and poses a significant threat to the geo-ecosystem. This study investigated the pollution of groundwater by leachate emanating from Aba-Eku MSW dumpsite in Ibadan, Nigeria, using bacteriological, hydrochemical, and geophysical techniques. There is a diversity of bacteria in the leachate and the dominant phyla being proteobacteria (83%) and firmicutes (17%). The mean concentrations (mg/L) of Mn, Fe, Al, Cu, Mo, and Cr in the leachate samples were above the World Health Organization wastewater discharge limits. The hydrochemical parameters of the groundwater samples around the dumpsite were generally within the permissible limits, except for K and Cl−; which invariably indicate major inputs from water-rock interaction and minor contributions from the dumpsite. Three geoelectrical layers were indicated from the vertical electrical sounding data, which are the topsoil, the lateritic clay layer, and the weathered basement. Low resistivity values of 5–33 Ωm and 3–24 Ωm were obtained within 2 m and 5.5 m depths for the topsoil and the lateritic layer, respectively; while the 2-D subsurface model reveals leachate plume beyond 5 m. Although the MSW leachate is heterogeneous, the hydrochemical data show that the aquifer around the dumpsite has not been seriously polluted with the leachate, but there is a continuous percolation of leachate into the soil subsurface, based on the geophysical findings. Discontinuing waste dumping and groundwater extraction, which would over time reduce the leachate plume, are measures to enhance the groundwater quality in the area. [ABSTRACT FROM AUTHOR]

The size and chemical composition of leachates migrating into the aquifer are dependent on the parameters of the waste and the storage conditions. Lysimeter studies allow us to determine the size and chemical composition of leachates as well as the leachate water balance. Lysimeter studies were conducted on a 230-L municipal waste sample for 6 months. During the tests, the specific electrolyte conductivity, pH, Eh, and temperature, as well as the chemical composition, microbiological analysis, and profiling of physiological population level using EcoPlate™ microarrays were measured in collected leachate samples. During the entire experiment, the amounts of inflow and outflow from lysimeters were measured. To assess the existence of significant differences in the chemical component concentrations in leachates, use of Principal Component Analysis was taken into account. The maximum EC value from leachate from the lysimeter was 33 mS/cm. High concentrations of ammonium ion (up to approx. 1400 mg dm−3), chlorides (up to approx. 6800 mg dm−3), and iron (up to approx. 31 mg dm−3) were observed in the effluents. The number of enterococci in May reached 53,000 cells/100 ml. By contrast, the number of these microorganisms was about 15,000 and 16,000 CFU/100 ml in January and April, respectively. Community-level physiological profiling indicates that the activity and functional diversity of microorganisms were higher in the leachate samples obtained in winter compared to effluents collected from lysimeters in spring. [ABSTRACT FROM AUTHOR]

The aim of this work was to evaluate the effects of different fertigation treatments: T0 (control treatment), T1 (raw leachates from C. melo) and T2 (raw leachates from C. melo blended with tap water (50/50% v/v)) on plant growth, nutrient concentration in leachate and water and nutrient use efficiencies of rosemary. At the end of experiment, rosemary plants fertigated with leachates decreased the total dry weight and the water use efficiency compared to the control treatment. The fertigation with leachates from C. melo affected the values of the nutrient concentrations in leachates from rosemary plants during the experimental period and improved the nitrogen (NUE) and phosphorus (PUE) use efficiencies compared to the control treatment. Our results indicate that reuse of horticultural leachates for the fertigation of rosemary plant in containers assumes a water and nutrient savings, but from an environmental point of view, there is a risk of pollution. [ABSTRACT FROM AUTHOR]

• Review of fungal treatment of real wastewaters with humic substances. • Effects of type of leachate, fungus, immobilization, medium, temperature and pH. • Fungal biodegradation is a complex function of the experimental conditions. • Bioadsorption and biodegradation should be measured separately. • Fungal processes provide higher purification and lower fouling than bacterial ones. Leachates have different concentrations of organic matter and levels of biodegradability, depending on the age of the landfill and they must be treated using appropriate techniques, such as fungal degradation, in order to protect the environment and water resources. Natural organic matter contains the same type of organic species as old and medium age leachates, but at lower concentrations. The present study compiles and assesses all the available literature on the biotreatment of these compounds, mainly humic acids, by fungi. It was found that the efficiency of the fungal biodegradation of these wastewaters depends on the characteristics and concentration of the organic matter in the leachate, the microorganisms selected and whether they were immobilized or not, the nutrients present in the medium and their concentrations, the experimentation time, the temperature and the pH. The influence of the mode of inoculation has only been studied in natural organic matter, but similar effects are expected in the treatment of the leachates. The interactions between these parameters are complex and the optimal conditions have to be determined by laboratory and pilot testing, employing multivariate statistical techniques and experimental design. [ABSTRACT FROM AUTHOR]

The incorporation of waste materials in asphalt mixtures has driven several studies mainly focused on improving their mechanical performance while minimizing the use of virgin materials. However, these could only be considered cleaner solutions for road paving works if their production and application do not present additional risks for human health and the environment. Therefore, this study aims at assessing the carbon dioxide emissions and possible leachates of stone mastic asphalt mixtures produced with high rates of different waste materials for binder modification or material recycling. Thus, a chemical analysis of eluates that were in contact with those mixtures and an estimation of the carbon dioxide emissions associated with their production and transportation were carried out under different scenarios. In conclusion, these mixtures comply with the established specifications for hazardous leachates. The addition of waste materials to these mixtures decreases carbon dioxide emissions, especially for recycled stone mastic asphalt mixtures with 50% reclaimed asphalt pavement material and bitumens modified with waste materials. Thus, the studied mixtures are innovative solutions for future use in pavement maintenance and rehabilitation operations, in line with the circular economy concept. • GHG emissions were quantified for SMA mixtures incorporating different waste rates. • Studied mixtures comply with the established specifications for hazardous leachates. • The addition of waste materials to SMA mixtures decreases carbon dioxide emissions. • RAP incorporation reduces more CO 2 emissions than binder modification with wastes. • Emissions associated with material transportation distance should not be neglected. [ABSTRACT FROM AUTHOR]