Biomarker response index in earthworms following chronic exposure to leachate from a closed dumpsite: Behavioral, cytotoxicity and antioxidant system alterations.

Leachate, an effluent produced during solid waste decomposition, interacts directly with soil, mainly in dumpsite areas. Studies on terrestrial animal exposure to leachate are, however, lacking. Plants are the most frequently studied organisms, while animal studies, especially earthworms, are limited. Nevertheless, ecotoxicological assessments involving earthworms are crucial due to their role in soil health and ecosystem maintenance, which are paramount in understanding potential terrestrial ecosystem leachate effects. In this context, this study aimed to evaluate behavioral effects, sublethal cytotoxicity and antioxidant system alterations in Eisenia andrei earthworms chronically exposed to leachate from a closed dumpsite. Cytotoxicity was determined by coelomocyte density, viability and cell typing, while antioxidant system alterations were assessed through superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), reduced glutathione (GSH) and metallothionein (MT) determinations. Malondialdehyde (MDA) and protein carbonylation (PTC) levels were also determined as oxidative effect markers. Finally, the Biomarker Response Index (BRI) was assessed, aiming to quantitatively integrate the results of the investigated endpoints and establish a biological health state (BHS) for each leachate concentration. Leachate exposure led to leak responses at concentrations of up to 50%, but attraction at higher concentrations. Decreased cell density (28%) was observed after 48 days and reduced viability (50%), after 14 days of leachate exposure. The observed cell typing changes indicate anti-inflammatory immune system effects. Leachate exposure led to several antioxidant system alterations, increasing SOD (2-6 %), CAT (5-35 %) and GST (5-70 %) activities and GSH (7-37%) and MT (3-67%) levels. Earthworm antioxidant defenses were, however, able to prevent lipid peroxidation, which decreased (11-37%) following leachate exposure to concentrations above 12.5%, and PTC, which increased at 42 days (26%) and reduced at 56 days (12 %). This is the first PTC assessment in leachate-exposed earthworms. The increased carbonylation levels observed after 42 days alongside MDA decreases highlight the need for further research employing oxidative effect biomarkers other than MDA. Finally, an integrated approach employing the BRI was carried out, revealing mild initial changes evolving to moderate to major effects at the highest leachate exposure concentration, with an effect attenuation detected at the end of the experiment. In this sense, this study brings forth a significant novelty, employing a biomarker previously not assessed in earthworms, demonstrating an oxidative effect, alongside the use of the BRI as an integrative tool for the endpoints applied in this assessment.

Quantification and molecular characterization of intact rotavirus species A (RVA) in municipal solid waste leachate.

AIMS: Leachate comprises a solid waste decomposition product found fresh in collection trucks or as an effluent in landfills. This study aimed to assess the occurrence, concentrations, and genetic diversity of intact rotavirus species A (RVA) in solid waste leachate. METHODS AND RESULTS: Leachate samples were concentrated by ultracentrifugation, treated with propidium monoazide (PMA), and exposed to LED photolysis. Treated and untread samples were extracted using the QIAamp Fast DNA Stool mini kit, and nucleic acids were screened for RVA employing a Taqman® Real-time PCR. The PMA RT-qPCR method detected RVA in eight out of nine truck samples and in 15.40% (2/13) of the landfill leachate samples. The RVA concentrations in the PMA-treated samples ranged from 4.57 × 103 to 2.15 × 107 genomic copies (GC) 100 mL-1 in truck leachate and from 7.83 × 103 to 1.42 × 104 GC 100 mL-1 in landfill samples. Six truck leachate samples were characterized as RVA VP6 genogroup I2 by partial nucleotide sequencing. CONCLUSIONS: The high intact RVA detection rates and concentrations in truck leachate samples indicate potential infectivity and comprise a warning for solid waste collectors concerning hand-to-mouth contact and the splash route.

Occurrence of Klebsiella pneumoniae ST244 and ST11 extensively drug-resistant producing KPC, NDM, OXA-370 in wastewater, Brazil.

AIMS: To investigate the occurrence of carbapenem-resistant Klebsiella pneumoniae (CRKP) and their clonal relationships from hospital and municipal wastewater treatment plants (WWTPs). METHODS AND RESULTS: Eighteen Kl. pneumoniae strains recovered from three WWTPs were identified by matrix-assisted laser desorption-ionization-time of flight (MALDI-TOF). The antimicrobial susceptibility were evaluated by disk-diffusion and the carbapenemases production by Carbapenembac®. The carbapenemases genes were investigated by real-time PCR and the clonal relationship through multilocus sequence typing (MLST). Thirty nine % (7/18) of isolates were classified as multidrug-resistant (MDR), 61.1% (11/18) extensively drug-resistant (XDR), and 83.3% (15/18) showed carbapenemase activity. Three carbapenemase-encoding genes were found, blaKPC (55%), blaNDM (27.8%) and blaOXA-370 (11.1%) as well five sequencing types ST11, ST37, ST147, ST244, and ST281. ST11 and ST244, sharing four alleles were grouped into clonal complex 11 (CC11). CONCLUSIONS: Our results show the importance of monitoring antimicrobial resistance in WWTPs effluents to minimize the risk of spreading bacterial load and ARGs in aquatic ecosystems, using advanced treatment technologies to reduce these emerging pollutants at WWTPs.

Acute toxicity of single and combined rare earth element exposures towards Daphnia similis.

The increasing use of Rare Earth Elements (REE) in emerging technologies, medicine and agriculture has led to chronic aquatic compartment contamination. In this context, this aimed to evaluate the acute toxic effects of lanthanum (La), neodymium (Nd) and samarium (Sm), as both single and binary and ternary mixtures on the survival of the microcrustacean Daphnia similis. A metal solution medium with (MS) and without EDTA and cyanocobalamin (MSq) as chelators was employed as the assay dilution water to assess REE bioavailability effects. In the single exposure experiments, toxicity in the MS medium decreased following the order La > Sm > Nd, while the opposite was noted for the MSq medium, which was also more toxic than the MS medium. The highest MS toxicity was observed for the binary Nd + La (1:1) mixture (EC50 48 h of 11.57 ± 1.22 mg.L-1) and the lowest, in the ternary Sm + La + Nd (2:2:1) mixture (EC50 48 h 41.48 ± 1.40 mg.L-1). The highest toxicity in the MSq medium was observed in the single assays and in the binary Sm + Nd (1:1) mixture (EC50 48 h 10.60 ± 1.57 mg.L-1), and the lowest, in the ternary Sm + La + Nd (1:2:2) mixture (EC50 48 h 36.76 ± 1.54 mg.L-1). Concerning the MS medium, 75 % of interactions were additive, 19 % antagonistic, and 6 % synergistic. In the MSq medium, 56 % of interactions were synergistic and 44 % additive. The higher toxicity observed in the MSq medium indicates that the absence of chelators can increase the concentrations of more toxic free ions, suggesting that the MS medium should be avoided in REE assays. Additive interactions were observed in greater or equivalent amounts in both media and were independent of elemental mixture ratios. These findings improve the understanding of environmental REE effects, contributing to the establishment of future guidelines and ecological risk calculations.

Effects of rare earth elements (REE) on terrestrial organisms: current status and future directions.

Rare Earth Elements (REE) are becoming increasingly important economically and highly exploited, thus contributing to REE increases in ecosystems. The ecotoxicological effects of REE on the terrestrial environment are, however, not fully understood and information on the biological effects of REE is urgently required for environmental risk assessments. In this review, studies and gaps in the existing scientific literature regarding the toxicological effects of REE on terrestrial organisms are presented. A total of 41 articles from the Web of Science database are discussed. La and Ce are the most studied elements, while little information is found concerning heavy REE. Most studies have been performed on plant species and few investigations are available for animals. Plant effects such as reduced mitotic index, germination and photosynthesis and antioxidant system enzyme alterations have been reported. Invertebrate effects include mortality, reproduction alterations and reduced locomotion. Based on the limited number of articles on terrestrial environment REE effects, this review highlights the need for more detailed studies in order to elucidate the effects associated with the REE hormesis and perform complete risk assessments with the establishment of safe REE usage limits.

Contamination assessment of soil and groundwater of a deactivated dumpsite in Brazil.

The final disposal of solid waste in dumpsites can result in the migration of leachate components through the soil, contaminating it as well as the groundwater. The purpose of this manuscript was to analyze the contamination of a dumpsite along with three unlined leachate ponds that operated for approximately 25 years. Soil, surface water from three leachate lagoons, and groundwater samples were collected. Chemical analyses such as chloride, ammonia nitrogen, and total organic carbon were performed. The present work also aimed at elaborating the local flow pattern map and the assessment of subsoil. The results showed local subsoil mostly clayey, also occurring a region of sandy predominance, and great variation of rocky outcrops depth. The groundwater flow occurs from the waste towards one of the leachate lagoons. The leachate lagoon located closer to deposited area presented the highest concentration of all contaminants measured. Groundwater and soil showed low ammonia nitrogen with a maximum value of 2 mg.L-1. Elevated chloride levels were detected in all matrices studied. In soil depth, the concentration varied ​​between 17 and 1270 mg.L-1 and in groundwater between 843 and 3,252 mg.L-1. Results suggest the migration of leachate components through the local soil. The concentration of total organic carbon measured in soil was of 10-982 mg.L-1, suggesting its natural presence.

A comprehensive assessment of leachate contamination at a non-operational open dumpsite: mycoflora screening, metal soil pollution indices, and ecotoxicological risks.

The final disposal of municipal solid waste (MSW) in dumpsites is still a reality worldwide, especially in low- and middle-income countries, leading to leachate-contaminated zones. Therefore, the aim of this study was to carry out soil and leachate physicochemical, microbiological, and toxicological characterizations from a non-operational dumpsite. The L-01 pond samples presented the highest physicochemical parameters, especially chloride (Cl; 4101 ± 44.8 mg L-1), electrical conductivity (EC; 10,452 ± 0.1 mS cm-1), and chemical oxygen demand (COD; 760 ± 6.6 mg L-1) indicating the presence of leachate, explained by its close proximity to the landfill cell. Pond L-03 presented higher parameters compared to pond L-02, except for N-ammoniacal and phosphorus levels, explained by the local geological configuration, configured as a slope from the landfill cell towards L-03. Seven filamentous and/or yeast fungi genera were identified, including the opportunistic pathogenic fungi Candida krusei (4 CFU) in an outcrop sample. Regarding soil samples, Br, Se, and I were present at high concentrations leading to high soil contamination (CF ≤ 6). Pond L-02 presented the highest CF for Br (18.14 ± 18.41 mg kg-1) and I (10.63 ± 3.66 mg kg-1), while pond L-03 presented the highest CF for Se (7.60 ± 1.33 mg kg-1). The most severe lethal effect for Artemia salina was observed for L-03 samples (LC50: 79.91%), while only samples from L-01 were toxic to Danio rerio (LC50: 32.99%). The highest lethality for Eisenia andrei was observed for L-02 samples (LC50: 50.30%). The applied risk characterization indicates high risk of all proposed scenarios for both aquatic (RQ 375-909) and terrestrial environments (RQ > 1.4 × 105). These findings indicate that the investigated dumpsite is contaminated by both leachate and metals, high risks to living organisms and adjacent water resources, also potentially affecting human health.

Fluoroquinolone-contaminated poultry litter strongly affects earthworms as verified through lethal and sub-lethal evaluations.

Poultry litter is one of the main sources of fluoroquinolones (FQs) in agricultural soils. In this study, our main goal was to investigate FQ-contaminated poultry litter effects on Eisenia andrei earthworms. To achieve this, acute and chronic tests covered several endpoints, such as avoidance, biomass, lethality, reproduction and changes to immune cells. FQs (enrofloxacin and ciprofloxacin) were determined in a poultry litter sample through high performance liquid chromatography with a fluorescence detector. The avoidance test indicates that poultry litter strongly repels earthworms, even at the lowest concentration (50 g kg-1). In the acute test, the lethal concentration of poultry litter to 50% of the earthworms (LC50), was estimated at 28.5 g kg-1 and a significant biomass loss (p < 0.05) occurred at 40 g kg-1. In the chronic test, a significant reproduction effect was observed at 20 g kg-1. Cell typing, density and feasibility indicated significant effects ranging from 5 to 20 g kg-1. A high risk quotient was estimated based on recommended poultry litter applications in field studies. Although FQ contamination in poultry litter and soils has been widely reported in previous studies, this is, to the best of our knowledge, the first toxicological assessment concerning earthworms exposed to FQ-contaminated poultry litter.

Biochemical metal accumulation effects and metalloprotein metal detoxification in environmentally exposed tropical Perna perna mussels.

Marine bivalves have been widely applied as environmental contamination bioindicators, although studies concerning tropical species are less available compared to temperate climate species. Assessments regarding Perna perna mytilid mussels, in particular, are scarce, even though this is an extremely important species in economic terms in tropical countries, such as Brazil. To this end, Perna perna mytilids were sampled from two tropical bays in Southeastern Brazil, one anthropogenically impacted and one previously considered a reference site for metal contamination. Gill metallothionein (MT), reduced glutathione (GSH), carboxylesterase (CarbE) and lipid peroxidation (LPO) were determined by UV-vis spectrophotometry, and metal and metalloid contents were determined by inductively coupled plasma mass spectrometry (ICP-MS). Metalloprotein metal detoxification routes in heat-stable cellular gill fractions were assessed by size exclusion high performance chromatography (SEC-HPLC) coupled to an ICP-MS. Several associations between metals and oxidative stress endpoints were observed at all four sampling sites through a Principal Component Analysis. As, Cd, Ni and Se contents, in particular, seem to directly affect CarbE activity. MT is implicated in playing a dual role in both metal detoxification and radical oxygen species scavenging. Differential SEC-HPLC-ICP-MS metal-binding profiles, and, thus, detoxification mechanisms, were observed, with probable As-, Cu- and Ni-GSH complexation and binding to low molecular weight proteins. Perna perna mussels were proven adequate tropical bioindicators, and further monitoring efforts are recommended, due to lack of data regarding biochemical metal effects in tropical species. Integrated assessments, as performed herein demonstrate, are invaluable in evaluating contaminated aquatic environments, resulting in more accurate ecological risk assessments.

Ecotoxicological evaluation of imazalil transformation products on Eisenia Andrei.

Data concerning the toxicity of the transformation products of some pesticides considered emerging contaminants are still incipient. This study aimed to evaluate acute (filter paper contact and avoidance test) and chronic (assays carried out in Red yellow Ultisoil) effects of the transformation products of the fungicide imazalil (IMZ) by heterogeneous photocatalysis (TiO2/UV) in Eisenia andrei. Some endpoints, i.e. biomass variation, disorder in reproduction and avoidance behavior, cytotoxicity (cell density and feasibility), and coelomic fluid (eleocytes and amoebocytes, immune cell) and antioxidant system (catalase (CAT) and glutathione S-transferase (GST)) changes were assessed. The studied degradation times (6, 18, 35 and 90 min) represented 70; 35; 10 and 0% of the initial IMZ concentration (5 mg L-1). No lethality and no significant difference in biomass variations were noted in the acute contact test. Decreased GST and increased CAT activities, as well as cell typing alterations and decreased cell viability and density detected at the 90-min degradation timepoint (PDT-90) indicate direct cytotoxic IMZ transformation product effects. In the avoidance test, no significant earthworm repulsion or attraction was observed. PDT-90 transformation products were responsible for losses in biomass and a reduction in the number of earthworm cocoons and juveniles present in soil. No cytotoxic effects were observed in the long term, although increased CAT and decreased GST activities were observed. Investigations on the relative toxicity of IMZ transformation products are relevant for future discussions regarding the environmental treatment, control and destination of this compound and its derivatives.

Lethal and long-term effects of landfill leachate on Eisenia andrei earthworms: Behavior, reproduction and risk assessment.

Leachate is difficult to biodegrade, and presents variable physical, chemical and biological characteristics, as well as high toxicological potential for soil, groundwater and water bodies. In this context, untreated leachate toxicity was evaluated through acute and chronic exposures in Eisenia andrei earthworms. Physico-chemical leachate characterizations indicate a complex composition, with high organic matter (COD - 10,634 mg L-1) and ammoniacal nitrogen (2388 mg L-1) concentrations. Metals with carcinogenic potential, such as Cr, As and Pb, were present at 0.60, 0.14 and 0.01 µg L-1, respectively and endocrine disrupting compounds were detected in estradiol equivalents of 660 ± 50 ng L-1. Acute tests with Eisenia andrei indicated an LC50 (72 h) of 1.3 ± 0.1 µL cm-2 in a filter paper contact test and 53.9 ± 1.3 mL kg-1 in natural soil (14 days). The EC50 in a behavioral test was estimated as 31.6 ± 6.8 mL kg-1, indicating an escape effect for concentrations ranging from 35.0 to 70.0 mL kg-1 and habitat loss from 87.5 mL kg-1 of leachate exposure. Chronic exposure (56 days) led to reproduction effects, resulting in a 4-fold decreased cocoon production and 7-fold juvenile decrease. This effect was mainly attributed to the possible presence of endocrine disrupting compounds. An estimated NOAEL of 1.7 mL L-1 and LOAEL of 3.5 mL L-1 were estimated for earthworms exposed to the assessed effluent. Extremely high-risk quotients (RQ ≥ 1) were estimated based on leachate application in irrigation. Thus, adequate municipal solid waste management is paramount, especially with regard to generated by-products, which can result in high toxicological risks for terrestrial organisms.

Role of Sonic hedgehog signaling in cell cycle, oxidative stress, and autophagy of temozolomide resistant glioblastoma.

The first-line chemotherapy treatment for Glioblastoma (GBM) - the most aggressive and frequent brain tumor - is temozolomide (TMZ). The Sonic hedgehog (SHH) pathway is involved with GBM tumorigenesis and TMZ chemoresistance. The role of SHH pathway inhibition in the potentiation of TMZ's effects using T98G, U251, and GBM11 cell lines is investigated herein. The combination of GANT-61 and TMZ over 72 hr suggested a synergistic effect. All TMZ-resistant cell lines displayed a significant decrease in cell viability, increased DNA fragmentation and loss of membrane integrity. For T98G cells, G2 /M arrest was observed, while U251 cells presented a significant increase in reactive oxygen species production and catalase activity. All the cell lines presented acidic vesicles formation correlated to Beclin-1 overexpression. The combined treatment also enhanced GLI1 expression, indicating the presence of select resistant cells. The selective inhibition of the SHH pathway potentiated the cytotoxic effect of TMZ, thus becoming a promising in vitro strategy for GBM treatment.

Lethal and sublethal effects of acetamiprid on Eisenia andrei: Behavior, reproduction, cytotoxicity and oxidative stress.

The neonicotinoid acetamiprid has been suggested as a worldwide substitute for organophosphates, due to its lower toxicity. The present study assessed several acetamiprid effects on Eisenia andrei earthworms in acute contact (ranging from 1.6 × 10-5 to 0.16 µg cm-2 acetamiprid), behavioral (0.1, 0.5, 1 mg kg-1) and chronic (0.001, 0.01, 0.05 and 0.1 mg kg-1 acetamiprid) assays carried out in natural soil. Reproduction, cytotoxicity (coelomocyte density and viability), immune cell typing (eleocytes and amoebocytes) and antioxidant defense system (glutathione (GSH), catalase (CAT) and glutathione S-transferase (GST)) responses were determined. The LC50 in the acute contact test was calculated as 1.86 × 10-2 µg cm-2. Acetamiprid concentrations of 0.5 and 1 mg kg-1 led to earthworm avoidance responses (NR = 61.09 ±â€¯10.01%) and habitat loss (NR = 78.02 ±â€¯12.03%), respectively. Reproduction was also affected, with a decreased number of cocoons and hatchlings per cocoon observed at 0.05 and 0.1 mg kg-1. Amoebocytes were the predominant immune system cells during the 15th and 30th assay days, while eleocytes were the main cells observed at the 45th day. CAT activities on the 30th and 45th day of exposure were increased at the lowest acetamiprid concentrations (0.001 and 0.01 mg kg-1) and decreased with increasing pesticide concentration (0.05 and 0.1 mg kg-1). Maximum GST activities and GSH levels were noted at 0.01 mg kg-1 acetamiprid. However, increasing concentrations led to GST inhibition, while GSH levels were maintained. A long-term acetamiprid exposure affected earthworm reproduction, behavior and immune and antioxidant systems, which could affect the ecological soil balance and, consequently, the entire food chain.

Sublethal psychotropic pharmaceutical effects on the model organism Danio rerio: Oxidative stress and metal dishomeostasis.

Contaminants of emerging concern have become an important environmental problem, especially pharmaceutically active compounds (PhACs), since, after use, these drugs return to the environment, contaminating aquatic ecosystems. Some may display the ability to bioaccumulate and biomagnify throughout the food chain, leading to potential environmental and human deleterious effects which are, however, still largely unknown. In this context, the aim of the present study was to evaluate the effect of two psychotropic drugs commonly found in the environment, carbamazepine (CBZ) and clonazepam (CZP), both isolated and co-administrated, on oxidative stress biomarkers and essential metal homeostasis in Danio rerio fish specimens. No studies are available to data in this regard concerning CZP effects on fish. Reduced Glutathione (GSH), Metallothionein (MT), Catalase (CAT) and Glutathione S-Transferase (GST) were determined, as well as essential metals in fish liver, kidney and brains. Significant oxidative stress effects were observed for several biomarkers, where brain GST activity was the most affected, mainly with regard to CBZ exposure, while GST and CAT activity in the liver were downregulated in the co-administration mixture. In addition, dishomeostasis of several essential elements was detected in all analyzed organs, with a synergistic action of CBZ and CZP in brain, decreasing basal Mg, Al, K, Fe, Co, Ni and Cu levels in this organ, the target site for these drugs in humans. The brain organ was the most affected as observed by altered GST activity and metal dyshomeostasis concerning exposure to both compounds. These compounds, thus, present health risks to the aquatic biota, due to the evidenced deleterious effects and their constant release into the environment due to widespread use. Steps are needed to implement adequate legislation for risk analysis and decision-making in order to mitigate the effects of these emerging contaminants on aquatic ecosystem health.

Predictors of cut-out after cephalomedullary nail fixation of pertrochanteric fractures: a retrospective study of 813 patients.

BACKGROUND: Cut-out is the most common mechanical complication of the osteosynthesis of pertrochanteric fractures. This complication determines a significant increase in morbidity in elderly patient. Cut-out is defined as the varus collapse of the femoral head-neck fragment with the extrusion of the cephalic screw. Surgical treatment of cut-out might lead to further complications, longer rehabilitation, increased social burden and healthcare system costs. The aim of the study is to identify the predictors of cut-out to prevent its occurrence. MATERIALS AND METHODS: Study population included all patients affected by extracapsular fracture of the proximal femur who were admitted and treated with short cephalomedullary nailing at the Cattinara Hospital-ASUITS of Trieste between 2009 and 2014. A retrospective analysis of clinical and radiographic data was carried out and cut-out cases recorded. The data collected on the study population were analyzed to find an eventual correlation with the occurrence of cut-out. The independent variables were age, gender, side of the fracture, ASA class, Evans classification, nailing system, quality of reduction, TAD, CalTAD, and Parker ratio. RESULTS: The study population counted 813 cases, with an F:M ratio of 4:1 and a mean age of 84.7 years. The cut-out was recorded in 18 cases (2.2%). There was no statistically significant association between cut-out and age, sex, side of fracture, ASA class, and nailing system. The Evans classification, the quality of reduction, the TAD, the CalTAD, and the Parker's ratio demonstrated a significant correlation at univariate analysis with cut-out. The results of multivariate analysis confirmed that TAD, Parker AP, and quality of reduction were independently significantly correlated to cut-out. CONCLUSION: The results of the present study demonstrate that good quality of reduction and correct position of the lag screw are likely to decrease the risk of cut-out complication. A nomogram for cut-out prediction is proposed for clinical validation.

Lethal and sub-lethal evaluation of Indigo Carmine dye and byproducts after TiO2 photocatalysis in the immune system of Eisenia andrei earthworms.

The Indigo carmine (IC) dye has been widely used in textile industries, even though it has been considered toxic for rats, pigs and humans. Owing to its toxicity, wastes containing this compound should be treated to minimize or eliminate their toxic effects on the biota. As an alternative to wastewater treatment, advanced oxidative processes (AOPs) have been highlighted due to their high capacity to destruct organic molecules. In this context, this study aimed to evaluate Indigo Carmine toxicity to soil organisms using the earthworm Eisenia andrei as a model-organism and also verify the efficiency of AOP in reducing its toxicity to these organisms. To this end, lethal (mortality) and sub-lethal (loss or gain of biomass, reproduction, behavior, morphological changes and immune system cells) effects caused by this substance and its degradation products in these annelids were evaluated. Morphological changes were observed even in organisms exposed to low concentrations, while mortality was the major effect observed in individuals exposed to high levels of indigo carmine dye. The organisms exposed to the IC during the contact test showed mortality after 72h of exposure (LC50 = 75.79mgcm-2), while those exposed to photoproducts showed mortality after 48h (LC50 = 243min). In the chronic study, the organisms displayed a mortality rate of 14%, while those exposed to the photoproduct reached up to 32.7%. A negative influence of the dye on the reproduction rate was observed, while by-products affected juvenile survival. A loss of viability and alterations in the cellular proportion was verified during the chronic test. However, the compounds did not alter the behavior of the annelids in the leak test (RL ranged from 20% to 30%). Although photocatalysis has been presented as an alternative technology for the treatment of waste containing the indigo carmine dye, this process produced byproducts even more toxic than the original compounds to E. andrei.

A comprehensive overview on solid waste leachate effects on terrestrial organisms.

Leachate is a highly complex waste with high toxicological potential that poses a significant threat to the terrestrial environment. Determining leachate physicochemical parameters and identifying xenobiotics alone is, however, not enough to determine the real environmental impacts. In this context, the use of terrestrial model organisms has been highlighted as a tool in ecotoxicological leachate assessments and as a guiding principle in risk assessments. In this context, this review aimed to present the most current state of knowledge concerning leachate toxicity and the bioassays employed in this evaluation concerning terrestrial plants and animals. To this end, a literature search on leachate effects on terrestrial organisms was carried out using ten search terms, in 32 different combinations, at the Web of Science and Scopus databases. A total of 74 eligible articles were selected. The retrieved studies analyzed 42 different plant and animal species and employed nine endpoints, namely phytotoxicity, genotoxicity, bioaccumulation, antioxidant system, cytotoxicity, reproduction, physiological changes, behavior and lethality. A frequent association of toxic leachate effects with metals was observed, mainly Pb, Cd, Cr, Mg, Zn and Cr, which can cause antioxidant system alterations and cyto- and genotoxicity. These elements have also been associated to reproductive effects in earthworms and mice. Specifically concerning plants, most of the retrieved studies employed Allium cepa in toxicity assays, reporting phytotoxic effects frequently associated to metals and soil parameter changes. Animal studies, on the other hand, mostly employed mice and evaluated genotoxicity and antioxidant system effects. Even with the description of toxic leachate effects in both plants and animals, a lack of knowledge is still noted concerning reproductive, physiological, cytotoxic, and behavioral effects in terrestrial species. We, thus, suggest that further studies be carried out on other animals, advancing our understanding on potential environmental leachate effects, also allowing for human health risk assessments.

Antioxidant system alterations, oxidative, and genotoxic effects in Danio rerio (zebrafish) exposed to leachate from a dumpsite.

Water body contamination by leachate originated from dumpsites is a concern for municipal solid waste (MSW) management. In this context, this study aimed to evaluate antioxidant system alterations and oxidative and genotoxic effects in Danio rerio (zebrafish) exposed to leachate from a closed dumpsite. Groups comprising 50 fish were exposed (96 h) to different leachate concentrations (5, 15, 30, and 50%) to evaluate effects on liver and brain superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) activities and reduced glutathione (GSH) and metallothionein (MT) concentrations, as well as malondialdehyde (MDA) and protein carbonylation (PTC) levels. Blood genotoxicity was evaluated by the comet assay. The investigated dumpsite leachate pond presented high chloride concentrations (Cl-; 2288.4 ± 69.5 mg L-1) and high electrical conductivity (EC; 8434.0 mS cm-1), indicating the presence of leachate. Concerning Danio rerio exposure, higher SOD (37%), CAT (67%), and GST (39%) activities and higher GSH (57%) concentrations were observed in liver following exposure to 50% leachate, while decreased brain GST (42%) activities and GSH (90%) levels were observed at the same leachate concentration. A significant increase in the olive tail moment (OTM; 280%) indicative of genotoxicity in blood was observed. A principal component analysis indicated that increased enzymatic activities and high levels of both GSH and MT were not sufficient to prevent the accumulation of reactive oxygen species, resulting in PTC and genotoxicity. Therefore, leachate exposure causes sublethal Danio rerio effects, altering the antioxidant system, increasing ROS production, and leading to PTC and genotoxicity. The findings demonstrate the need to further develop sublethal level assessments in zebrafish using leachate from different sources to subsidize risk assessments regarding MSW management.

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.

Rare Earth Element Accumulation in Fiddler Crabs (Minuca rapax) from the Rio Doce Tropical Estuary Strongly Affected by Mine Tailings Following the Fundão Disaster.

A mining tailing dam rupture in Brazil in November 2015 released millions of tons of mining waste into the Rio Doce ecosystem, leading to long-term aquatic ecosystem impacts. Although multiple lines of evidence indicate tailings associations with potentially toxic elements in estuarine sediments and biological impact and bioaccumulation pathways in fishes, the extent of contamination in base benthic species is still largely unknown. Moreover, Rare Earth Elements (REE) have not received any attention in this regard. This study assessed REE in fiddler crabs (Minuca rapax) sampled from the Rio Doce estuary in 2017, nearly 2 years after the disaster. The ΣREE in crab hepatopancreas and muscle were high (327.83 mg kg-1 w.w. and 33.84 mg kg-1 w.w., respectively, compared to other assessments in crabs, indicating a preference for REE bioaccumulation in the hepatopancreas compared to muscle. Neodimium, La, and Ce were detected at the highest concentrations. The REE from the Rio Doce Basin were, thus, transported and deposited in the estuary with the mine tailings slurry, leading to bioaccumulation in crabs. This may lead to trophic effects and other ecological impacts not readily measured by typical impact assessment studies, revealing an invisible and not typically acknowledged damage to the Rio Doce estuary.