Reproductive toxicity of micro- and nanoplastics

Large-scale plastic pollution occurs in terrestrial and marine environments and degrades into microparticles (MP) and nanoparticles (NP) of plastic. Micro/nanoplastics (MP/NPs) are found throughout the environment and different kinds of marine organisms and can enter the human body through inhalation or ingestion, particularly through the food chain. MPs/NPs can enter different organisms, and affect different body systems, including the reproductive, digestive, and nervous systems via the induction of different stresses such as oxidative stress and endoplasmic reticulum stress. This paper summarizes the effects of MPs/NPs of different sizes on the reproduction of different organisms including terrestrial and marine invertebrates and vertebrates, the amplification of toxic effects between them through the food chain, the serious threat to biodiversity, and, more importantly, the imminent challenge to human reproductive health. There is a need to strengthen international communication and cooperation on the remediation of plastic pollution and the protection of biodiversity to build a sustainable association between humans and other organisms.

Distribution and accumulation of hexachlorobutadiene in soils and terrestrial organisms from an agricultural area, East China

Hexachlorobutadiene (HCBD) is a potential persistent organic pollutant that has been found in abiotic environments and organisms. However, information on HCBD in soils and its accumulation in terrestrial food chains is scarce. This study investigated the accumulation of HCBD in soils, plants, and terrestrial fauna in a typical agricultural area in Eastern China, and drew comparisons with organochlorine pesticides (OCPs). The HCBD concentrations in soils were <0.02-3.1ng/g dry weight, which were similar to α-endosulfan concentrations but much lower than the concentrations of some other OCPs. The HCBD soil-plant accumulation factors, 8.5-38.1, were similar to those of o,p'-DDT and higher than those of HCHs and p,p'-DDT, indicating that HCBD is strongly bioaccumulated by rice and vegetables. HCBD concentrations of 1.3-8.2ng/g lipid weight were found in herbivorous insects, earthworms, and Chinese toads. The biomagnification factor, the ratio between the lipid-normalized concentrations in the predator and the prey, was found to be 0.16-0.64 for different food chains of Chinese toads, so HCBD was found not to biomagnify, which is in contrast with OCPs. Further research into whether HCBD is biomagnified in high trophic level organisms or through the entire terrestrial food web is required.

Chitinase digestion for the analysis of microplastics in chitinaceous organisms using the terrestrial isopod Oniscus asellus L. as a model organism

Chitinaceous organisms have been found to ingest microplastic; however, a standardised, validated, and time- and cost-efficient method for dissolving these organisms without affecting microplastic particles is still required. This study tested four protocols for dissolving organisms with a chitin exoskeleton: 1) potassium hydroxide (KOH) + chitinase, 2) Creon® + chitinase, 3) hydrogen peroxide (H₂O₂) + chitinase, and, 4) Nitric Acid (HNO₃) + hydrogen peroxide (H₂O₂). The effects on microplastics composed of eight different polymers were also tested. The use of H₂O₂ followed by chitinase was found to be a highly efficient method. The three other protocols either did not digest the chitin sufficiently or negatively affected the tested polymers. A recovery test using microplastic fibres, beads and tyre particles revealed high recovery rates of 0.85, 0.89 and 1 respectively. This further supported the applicability of the H₂O₂ and chitinase (protocol 3) for dissolving chitinaceous organisms. Thus, we recommend that future investigations of microplastic (0.05 μm-5000 μm) in chitinaceous organisms (0.3 cm-5 cm) utilise the here presented methodology. This represents an important component of the ongoing validation and harmonization of methodological approaches that are urgently needed for the advancement of microplastic assessments globally.

Radiological risk assessment in the terrestrial ecosystem: comparative study of two software tools used for dose rate calculations

In this study, two software tools, namely the ERICA Assessment Tool and the RESRAD-BIOTA code, are used for the calculation of the radiological exposure of non-human organisms. For the purposes of the analysis, data retrieved from field studies are used. The site-specific measurements were performed on organisms (mammals-sheep and goats of Bovidae spp.) collected from free-ranged grazing regions in Greece. Plants (grass) of Poaceae spp. and soil samples were also collected from these regions. Natural radionuclides (²²⁶Ra, ²²⁸Ra, and ²²⁸Th) of lithogenic origin and ¹³⁷Cs, resulted from human activities (Chernobyl and Fukushima nuclear power plant accidents and global fallout), were detected in all samples. The measured activity concentrations were used as input to the two software tools, the ERICA Assessment Tool and the RESRAD-BIOTA code. The results of the simulations provided the external, internal, and total dose rates received by the organisms due to the exposure to the radionuclides. The assessments indicated that out of all detected radionuclides, ²²⁸Th is the main contributor to the external dose and ²²⁶Ra and ²²⁸Ra are the main contributors to the internal dose. The comparative analysis of the two tools revealed significant differences in the calculated doses. In fact, external and internal doses calculated by RESRAD-BIOTA are higher than the values calculated by the ERICA Tool, due to the dose conversion coefficients (DCCs) used for the dose calculation. RESRAD-BIOTA provides more conservative values, but ERICA Tool provides lower uncertainty due to the higher flexibility in the design of the phantom organism. On a risk assessment basis, there is no significant impact, due to organisms' exposure to radioactivity. However, further consideration of the exposure levels is required due to the potential effects of protracted low-level ionizing radiation on the various levels of life's organization.

A multi-biomarker approach to verify chronic effects on Eisenia andrei earthworms exposed to tailings from one of the world's largest mining disasters

Mining is of great relevance to the global economy, but its activities are challenging due to socio-environmental impacts. In January 2019, an iron ore tailings dam collapsed in Brumadinho (Minas Gerais, Brazil) releasing 12 × 106 m3 of tailings, causing human losses and devastation around 3.13 × 106 m2 of a watershed. In this context, the present study aimed to investigate the potential toxic effects of tailings from the collapsed dam using earthworms Eisenia andrei as a model organism for terrestrial environments. An extensive set of tests was performed, including behavioral (avoidance), acute (mortality and biomass) and chronic tests, such as biomass, reproduction and cytotoxicity (viability and cell density and change in coelomocyte pattern). The physical-chemical characterization revealed a higher density of the tailings in relation to the control soil, which can result in physical changes, such as soil compaction and surface sealing. Aluminum, Ca, Fe, Hg, Mg, Mn, K, Na and P registered higher concentrations in the tailings compared to the control soil, while Total Nitrogen, Total Organic Carbon and Organic Matter were higher in the natural soil. Based on the avoidance test, an EC50 of 27.18 ± 2.83% was estimated. No lethality was observed in the acute exposure, nor variations in biomass in the acute and chronic assays. However, there was a tendency to reduce the number of juveniles in relation to cocoons in the proportions of 3125; 12.5 and 25%. Significant changes in viability, cell density and pattern of amebocytes and eleocytes were observed up to the 35th day of exposure. A multi-biomarker approach (Integrated Biological Response version 2) indicated concentration-dependent effects and attenuation of cellular changes over time. These are the first results of chronic effects on earthworms exposed to tailings from the B1 dam. Despite being conclusive, we highlight the possible heterogeneity of the tailings and the necessary care in extrapolating the results.

Antioxidant system alterations and oxidative stress caused by polyfluoroalkyl substances (PFAS) in exposed biota: a review

Contamination of aquatic and terrestrial organisms by Perfluoroalkyl substances (PFAS), emerging contaminants, is widespread, as these compounds are present in water, soil, air, and food, owing to their environmental persistence. PFAS exposure induces biochemical process alterations associated with the disruption of the antioxidant defense system in several species. This review aims to discuss how PFAS-induced antioxidant system alterations lead to changes in biochemical processes in different organisms exposed to these pollutants. This disruption, then leads to an imbalance in antioxidant defense systems, contributing to the formation of reactive oxidative species (ROS), which, in turn, can be exacerbate oxidative stress, induce cellular damage, enhance lipid peroxidation, destabilize lysosomal membranes, and cause genotoxic effects, ultimately compromising DNA integrity. In acute tests, PFAS have led to mortality, growth inhibition, diminished behavioral and locomotor abilities, and reproductive impairment. PFAS-induced effects differ with varying species or types of substances, and further bioaccumulation through food chains exacerbates environmental contamination, carrying considerable risks. These findings demonstrate the complex and enduring impact of PFAS on environmental health, emphasizing the importance of this review in corroborating studies on sub-lethal toxicity in exposed organisms and how these effects reflect on the environment.

Comparison of the potential toxicity induced by microplastics made of polyethylene terephthalate (PET) and polylactic acid (PLA) on the earthworm Eiseniafoetida

A growing number of studies have demonstrated that microplastic (MP) contamination is widespread in terrestrial ecosystems. A wide array of MPs made of conventional, fossil-based polymers differing in size and shape has been detected in soils worldwide. Recently, also MPs made of bioplastics have been found in soils, but there is a dearth of information concerning their toxicity on soil organisms. This study aimed at exploring the potential toxicity induced by the exposure for 28 days to irregular shaped and differently sized MPs made of a fossil-based (polyethylene terephthalate - PET) and a bioplastic (polylactic acid - PLA) polymer on the earthworm Eisenia foetida. Two amounts (1 g and 10 g/kg of soil, corresponding to 0.1% and 1% of soil weight) of both MP types were administered to the earthworms. A multi-level approach was used to investigate the MP-induced effects at sub-individual and individual level. Changes in the activity of antioxidant and detoxifying enzymes, as well as in lipid peroxidation levels, were investigated at specific time-points (i.e., 7, 14, 21 and 28 days) as sub-individual responses. Histological analyses were performed to assess effects at tissue level, while the change in digging activity was considered as a proxy of behavioral effects. Earthworms ingested MPs made of both the polymers. MPs made of PET did not induce any adverse effect at none of the biological levels. In contrast, MPs made of PLA caused the modulation of earthworms' oxidative status as showed by a bell-shaped activity of superoxide dismutase coupled with an increase in glutathione peroxidase activity. However, neither oxidative and tissue damage, nor behavioral alteration occurred. These findings suggest that the exposure to bio-based MPs can cause higher toxicity compared to fossil-based MPs.

Nano versus bulk: Evaluating the toxicity of lanthanum, yttrium, and cerium oxides on Enchytraeus crypticus

Considering the increase in demand for rare earth elements (REEs) and their accumulation in soil ecosystems, it is crucial to understand their toxicity. However, the impact of lanthanum, yttrium and cerium oxides (La2O3, Y2O3 and CeO2, respectively) on soil organisms remains insufficiently studied. This study aims to unravel the effects of La2O3, Y2O3 and CeO2 nanoparticles (NPs) and their corresponding bulk forms (0, 156, 313, 625, 1250 and 2500 mg/kg) on the terrestrial species Enchytraeus crypticus. The effects on survival, reproduction (21 days (d)), avoidance behavior (2 d) and DNA integrity (2 and 7 d) of E. crypticus were evaluated. No significant effects on survival were observed. For La2O3, the bulk form affected more endpoints than the NPs, inducing avoidance behavior (1250 mg/kg) and DNA damage (1250 mg/kg - 2 d; 2500 mg/kg - 7 d). The Y2O3 NPs demonstrated higher toxicity than the bulk form: decreased reproduction (≥ 1250 mg/kg); induced avoidance behavior (≥ 625 mg/kg) and DNA damage (≥ 156 mg/kg - 2 d; 2500 mg/kg - 7 d). For CeO2, both forms exhibited similar toxicity, decreasing reproduction (625 mg/kg for bulk and 2500 mg/kg for NPs) and inducing DNA damage at all tested concentrations for both forms. REEs oxides toxicity was influenced by the REEs type and concentration, exposure time and material form, suggesting different modes of action. This study highlights the distinct responses of E. crypticus after exposure to REEs oxides and shows that REEs exposure may differently affect soil organisms, emphasizing the importance of risk assessment.

Microplastic accumulation in a lizard species: Observations from the terrestrial environments

Microplastics are a global environmental problem, polluting both aquatic and terrestrial environments. Terrestrial lizards are suitable model organisms to study human-induced pollution in these areas, as they can live in urbanized areas where microplastics are most abundant. Therefore, we analyzed the prevalence of microplastics (MPs) in a common Lacertid lizard, the snake-eyed lizard, Ophisops elegans. We detected MPs in the gastrointestinal tract (GIT) of 33 of 152 specimens from 18 populations. The detected MPs had six distinct polymer compositions, namely Polyethylene terephthalate, Polyacrylonitrile, Polypropylene, Polyethylene, Poly methyl methacrylate and Polyamide. The majority of these MPs were fiber-type and the dominant color was navy blue. The lengths of MPs varied from 37 to 563 μm, with an average length of 175 μm. MPs were detected in the GITs of 43% of juveniles (n = 7), 30% of males (n = 105), and 18% of females (n = 40), with a mean of 0.27 per specimen. Furthermore, we found that microplastic densities varied with habitat distance from human settlements, supporting the theory that high levels of microplastic contamination are associated with extensive anthropogenic activity.

Microplastics and their environmental effects

Microplastics (MPs) are acknowledged as emerging contaminants that pose a substantial threat to the environment. The adverse impacts of MP pollution extend across marine, freshwater, and terrestrial ecosystems, covering regions from the Tropics to the Poles. Although our comprehension of MP behavior has progressed in recent years, it is still difficult to predict exposure hotspots or exposure scenarios. Despite a noteworthy increase in data concerning MP occurrence in different environmental compartments and species, there is a noticeable scarcity of experimental data on MP uptake, accumulation, and effects. This Virtual Special Issue (VSI) received a total of 19 contributions from 11 countries, with a significant majority originating from Italy, India, Spain, and China. These contributions were categorized into three main themes: the occurrence and effects of MPs on aquatic and terrestrial organisms, the presence of chemical additives in plastics, and review articles summarizing previously published research on MPs.