Genotoxic endpoints in the earthworms sub-lethal assay to evaluate natural soils contaminated by metals and radionuclides

Copper toxicity on Eisenia fetida in a vineyard soil: a combined study with standard tests, genotoxicity assessment and gut metagenomic analysis

Copper (Cu) toxicity is a pressing concern for several soils, especially in organic viticulture. The objective of this work was to assess Cu toxicity on the non-target organism Eisenia fetida, employing both traditional and novel tools for early identification of Cu-induced damages. In addition to traditional tests like avoidance and reproductive toxicity experiments, other tests such as the single cell gel electrophoresis (SCGE) and gut microbiome analysis were evaluated to identify early and more sensitive pollution biomarkers. Four sub-lethal Cu concentrations were studied, and the results showed strong dose-dependent responses by the earthworm avoidance test and the exceeding of habitat threshold limit at the higher Cu doses. An inverse proportionality was observed between reproductive output and soil Cu concentration. Bioaccumulation was not detected in earthworms; soil concentrations of potentially bioavailable Cu were not affected by E. fetida presence or by time. On the contrary, the SCGE test revealed dose-dependent genotoxicity for the 'tail length' parameter already at the second day of Cu exposition. Gut microbiome analysis a modulation of microbial composition, with the most aboundant families being Pectobateriaceae, Comamonadaceae and Microscillaceae. Bacillaceae increased over time and showed adaptability to copper up to 165 mg/kg, while at the highest dose even the sensitive Acetobacteriaceae family was affected. The research provided new insights into the ecotoxicity of Cu sub-lethal doses highlighting both alterations at earthworms' cellular level and changes in their gut microbiota.

Transfer of elements from soil to earthworms and ground beetles in boreal forest

Data on the transfer of elements (such as heavy metals) and their radionuclides into organisms is needed for assessing environmental risks. The current data on many elements, species and environments is limited, but more information can be obtained both from field studies and experimental laboratory studies. However, it is essential to evaluate whether experimental studies adequately predict transfer in natural conditions. Moreover, because of the sparsity of species-specific empirical data, it is a common practice in current radioecological modelling to use data available for related species under the assumption that transfer into organisms is similar within broader taxonomic groups. Earthworms and ground beetles are examples of important invertebrates living near soil surface in terrestrial ecosystems. In this study, the transfer of 34 elements from soil to these organisms was studied in a field study conducted in boreal forest. The earthworm concentrations were compared to the values obtained in an experimental mesocosm study using soil from the field site and were found to be highly correlated. This indicates that the results of mesocosm studies can be used for predicting the transfer of elements from soil to fauna in natural conditions. Furthermore, concentrations in individual earthworm and beetle species were found to be similar to those observed in broader groups of related species, indicating that the generic approach used in current radioecological models may be useful for predicting uptake of elements into single species.

Measuring DNA modifications with the comet assay: a compendium of protocols

The comet assay is a versatile method to detect nuclear DNA damage in individual eukaryotic cells, from yeast to human. The types of damage detected encompass DNA strand breaks and alkali-labile sites (e.g., apurinic/apyrimidinic sites), alkylated and oxidized nucleobases, DNA-DNA crosslinks, UV-induced cyclobutane pyrimidine dimers and some chemically induced DNA adducts. Depending on the specimen type, there are important modifications to the comet assay protocol to avoid the formation of additional DNA damage during the processing of samples and to ensure sufficient sensitivity to detect differences in damage levels between sample groups. Various applications of the comet assay have been validated by research groups in academia, industry and regulatory agencies, and its strengths are highlighted by the adoption of the comet assay as an in vivo test for genotoxicity in animal organs by the Organisation for Economic Co-operation and Development. The present document includes a series of consensus protocols that describe the application of the comet assay to a wide variety of cell types, species and types of DNA damage, thereby demonstrating its versatility.

Radium uptake by earthworms E. fetida after exposure to contaminated soil

Radium-226 is one of the most important radionuclides for assessing the radiation exposure in terrestrial ecosystems in terms of its significant contribution to the internal and total dose rates. A laboratory culture of Eisenia fetida was exposed to soil contaminated with ²²⁶Ra and ²³⁸U during two months. These nuclides entered the soil as a result of industrial radium production (Vodny, Komi Republic, Russia). The concentrations of ²²⁶Ra and ²³⁸U were 89000 ± 9000 and 2130 ± 270 Bq kg^-1 of soil. Bioaccumulation of ²²⁶Ra was investigated in E. fetida exposed to the radioactive soil or to a mixture containing the same radioactive soil diluted with peat and sand. The activity concentrations of ²²⁶Ra in E. fetida were higher after exposure to the contaminated soil compared to the mixture. The literature data on the radium accumulation in earthworms were considered also. Our experiments showed that the concentration ratio (CR) of ²²⁶Ra in E. fetida varied from 5.5 × 10^-4 to 4.5 × 10^-3 Bq kg^-1 f.w./Bq kg^-1 d.w. The average CRs were (6.7 ± 1.7) × 10^-4 for the earthworms E. fetida from the soil mixture and (3.2 ± 1.2) × 10^-3 for those from the radioactive soil. These CRs for ²²⁶Ra were up to two orders of magnitude lower than the values calculated by us from the results obtained by other researchers for natural earthworm populations in areas with lower levels radioactivity.

Toxicity analysis and biomarker response of Quinalphos Organophosphate Insecticide (QOI) on eco-friendly exotic Eudrilus eugeniae earthworm

An ever-increasing use of pesticides in agricultural fields has led to a catastrophic decline in crop quality and, ultimately soil fertility. To control various pests, quinalphos is commonly used in India's tea plantations. This study aims to investigate the effects of the Quinalphos organophosphate insecticide on the non-target beneficial organism Eudrilus eugeniae earthworms and the biomarkers that respond to its effects. Earthworm species, especially E. eugeniae, remains as the most trustworthy and well-suited model organism for conducting a wide variety of environmental studies. The median lethal concentration (LC₅₀) was identified as 3.561 µg cm^-2 (contact filter paper) and 1.054 mg kg^-2 (artificial soil toxicity). The 5% and 10% of LC₅₀ value 3.561 µg cm^-2 was exposed to earthworm to analyze the sublethal effects at pre-clitellum, clitellum, and post-clitellum segments. Specific enzymatic activities of neurotransmitter enzyme acetylcholinesterase; antioxidant enzymes such as lipid peroxidase, superoxide dismutase, and catalase; and detoxification enzymes including glutathione S transferase, reduced glutathione, carboxylesterase, and Cytochrome P450 were analyzed. Exposure of E. eugeniae earthworm to subacute exposures of pesticides caused significant alterations in these stress markers in a concentration-dependent manner. Morphological abnormalities like bulginess, coiling, and bleeding were observed after exposure of the insecticide treatments. Histological cellular disintegration, a reduced NRRT time, and an inhibited proteolytic zone were also identified in pesticide-exposed earthworms. Studies demonstrate that the organophosphate insecticide quinalphos causes acute toxicity in E. eugeniae; hence, it is suggested that non-target eco-friendly E. eugeniae earthworms may be at risk if exposed to the excessive concentrations of quinalphos organophosphate insecticide in soil.

Assessment of heavy metal pollution transfer and human exposure risks from the consumption of chicken grown in mining-surrounding areas

The purpose of this study was to assess heavy metal contamination in soil, plants, earthworms, and chicken in farmlands adjacent to an old mining site and to evaluate the potential exposure risks to humans through the consumption of chicken. For this purpose, soil, earthworms, plant, chickens, and eggs were sampled from 5 sites following a gradient of contamination. All samples were analyzed for heavy metals (Pb, Cd, Cu, and Zn). A food chain model was used in order to characterize heavy metal transfer between soil-plant-earthworm and chicken organs. Furthermore, target hazard quotient (THQ), estimated daily intake (EDI), and hazard index (HI) were employed to assess human health risks posed by heavy metal contamination. Despite the higher level of Pb, our data related to the calculation of EDI and THQ suggested that local consumers are more at risk of Cd contamination. The calculated HI showed values ranging from 2.58 to 4.74 for adults, and up to 12.34 for children, indicating a considerable risk to the health of local inhabitants, especially children. This study highlighted the crucial role of diets based on chickens grown in contaminated areas, on health risks especially for children.

An integrated approach for chemical water quality assessment of an urban river stretch through Effect-Based Methods and emerging pollutants analysis with a focus on genotoxicity

The impact of emerging chemical pollutants, on both status and functionality of aquatic ecosystems is worldwide recognized as a relevant issue of concern that should be assessed and managed by researchers, policymakers, and all relevant stakeholders. In Europe, the Reach Regulation has registered more than 100.000 chemical substances daily released in the environment. Furthermore, the effects related to the mixture of substances present in aquatic ecosystems may not be predictable on the basis of chemical analyses alone. This evidence, coupled with the dramatic effects of climate changes on water resources through water scarcity and flooding, makes urgent the application of innovative, fast and reliable monitoring methods. In this context, Effect-Based Methods (EBMs) have been applied in the urban stretch of the Tiber River (Central Italy) with the aim of understanding if detrimental pressures affect aquatic environmental health. In particular, different eco-genotoxicological assays have been used in order to detect genotoxic activity of chemicals present in the river, concurrently characterized by chemical analysis. Teratogenicity and embryo-toxicity have been studied in order to cover additional endpoints. The EBMs have highlighted the presence of diffuse chemical pollution and ecotoxicological effects in the three sampling stations, genotoxicological effects have been also detected through the use of different tests and organisms. The chemical analyses confirmed that in the aquatic ecosystems there is a diffuse presence, even at low concentrations, of emerging contaminants such as pharmaceuticals, not routinely monitored pesticides, personal care products, PFAS. The results of this study can help to identify an appropriate battery of EBMs for future studies and the application of more appropriate measures in order to monitor, mitigate or eliminate chemical contamination and remediate its adverse/detrimental effects on the ecosystem health.

Ecotoxicity of trace elements to chicken GALLUS gallus domesticus exposed to a gradient of polymetallic-polluted sites

Mining activity may cause heavy metal accumulation, which threatens human and animal health by their long-term persistence in the environment. This study aims to assess the impact of polymetallic pollution on chicken (Gallus domesticus) from old lead mining sites in northeast of Tunisia: Jebel Ressas (JR). Samples of soil and chickens were collected from five sites being ranked along a gradient of heavy metal contamination. Heavy metal loads were evaluated in soil samples and in chicken liver and kidney. Biochemical evaluation of oxidative stress parameters termed as Catalase (CAT), Glutathione-S-Transferase (GST), and Malondialdehydes (MDA) accumulation was monitored. Metallothionein protein level was assessed as a specific response to heavy metals. DNA alteration was achieved using MNi frequency in the investigated tissues. Finally, the evaluation of gene expression levels of CAT, GST, mt1, mt4, P53, bcl2, caspase3 and DNA-ligase was performed. Our data showed the highest loads of Cd, Cu, Zn and Pb in tissues of animals from site 3, being more pronounced in kidney. Biochemical data suggested a significant increase in antioxidant enzymes activities in all sites respect to control except in site 3 were CAT and GST were inhibited. DNA alteration was observed in all tissues being very pronounced in animals from site 3. Overall, transcriptomic data showed that genes involved in apoptosis were up-regulated in animals exposed to the most contaminated soils. Our data suggest that chicken and selected biomarkers offer a suitable model for biomonitoring assessment of heavy metals transfer through the food web in mining sites. Finally, the obtained results of heavy metals accumulation and related alterations should be carefully considered in view of the controversial relationship between distribution and toxicology of contaminants in exposed organisms.

The first evidence of accumulation and avoidance behavior of macroinvertebrates in a forest soil spiked with human-made iron nanoparticles: A field experiment

Both earthworms and terrestrial isopods have been used to evaluate the quality of contaminated soil by NPs. However, most experiments have been conducted in the laboratory and under greenhouse conditions. Besides, little is known of Fe accumulation in earthworms from iron NPs (Fe NPs) under natural conditions. Therefore, the objective of this research was to evaluate the effect of manufactured NPs on the accumulation of Fe in macroinvertebrates from forest soil. Our results revealed that earthworms consume low amounts of Fe in a concentration of 1000 mg Fe NPs kg⁻¹ of dry soil, with a behavior constant over time. Besides, we observed that earthworms could not detect Fe at low concentrations (1 or 10 mg Fe NPs kg⁻¹), so they do not limit soil consumption, which translates into high amounts of Fe in their bodies. By contrast, the content of Fe in organisms is inversely proportional to increasing concentrations in the soil (R² = -0.41, p < 0.05). Therefore, although studies are needed, in addition to considering environmental factors and the physicochemical properties of the soil, endogenous worms in the evaluated area could, under natural conditions, be useful to inform us of contamination of NP manufactured from Faith. Besides, for future research, a novel methodology should be considered to demonstrate more realistic avoidance behavior under field conditions.

Metals and low dose IR: Molecular effects of combined exposures using HepG2 cells as a biological model

Uranium mining sites produce residues rich in metals and radionuclides, that may contaminate all environmental matrices, exposing human and non-human biota to low doses of ionizing radiation (LDIR) and to the chemical toxicity of several metals. To date, experimental and radio-epidemiological studies do not provide conclusive evidence of LDIR induced cancer. However, co-exposures (LDIR plus other contaminants), may increase the risks. To determine the potential for genotoxic effects in human cells induced by the exposure to LDIR plus metals, HEPG2 cells were exposed to different concentrations of a uranium mine effluent for 96 h. DNA damage was evaluated using the comet assay and changes in the expression of tumor suppressor and oncogenes were determined using qPCR. Results show that effluent concentrations higher than 5%, induce significant DNA damage. Also, a significant under-expression of ATM and TP53 genes and a significant overexpression of GADD45a gene was observed. Results show that the exposure to complex mixtures cannot be disregarded, as effects were detected at very low doses. This study highlights the need for further studies to clarify the risks of exposure to LDIR along with other stressors, to fully review the IR exposure risk limits established for human and non-human biota.

Toxicological effect of Parthenium hysterophorus and milk processing industry sludge on earthworms, Eisenia fetida

Production of large quantities of organic waste all over the world poses major environmental and disposal problems. The present study was conducted to explore the deleterious effects of Parthenium hysterophorus and milk processing industry sludge on the health of earthworm, Eisenia fetida. Earthworms were allowed to grow in the mixture of cow dung:Parthenium hysterophorus (75:25) and cow dung:milk processing industry sludge (60:40) for 60 days. The biochemical markers viz. superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels and histological changes in earthworm's intestine were assessed after 15, 30, 45, and 60 days of exposure. The results revealed increased MDA level, while SOD, CAT, and GPx activities showed variation in both treatments. Furthermore, histopathological changes revealed damage in the intestinal tissue in both treatments during all intervals. More severe effects were registered in P. hysterophorus treatment. Obtained results may contribute to the understanding of P. hysterophorus and milk processing industry sludge induced toxic effects on earthworms and to identify defense mechanism of Eisenia fetida.

Chemical availability versus bioavailability of potentially toxic elements in mining and quarry soils

Abandoned mining and quarry areas are sources of potentially toxic elements (PTEs), through lixiviates or transfer processes of bioavailable fractions from mining wastes and tailings. In this study, earthworms (Eisenia fetida Savigny, 1826) were exposed for 28 days to two mining soils from a lead/zinc mine and two quarry soils from an old serpentine quarry. Despite their pseudo total metal contents, a previous characterization of these soils pointed out for a low chemical availability of PTEs. Therefore, a multibiomarker approach was used and the response of E. fetida to soils was assessed through the analysis of neurotoxic, oxidative stress, energy metabolism and DNA damage biomarkers (acetylcholinesterase, catalase, glutathione-s-transferase, lactate dehydrogenase, lipid peroxidation and DNA strand breaks). Metal bioaccumulation was also assessed to evaluate bioavailability and organism's exposure. Results showed that high contents of PTEs were recorded in the whole body of earthworms exposed to lead/zinc mine. However, the bioaccumulation factors for worms exposed to soils from both sampling sites were <1 due to the high PTEs contents in soils. Earthworms exposed to both types of soils displayed neurotoxic and energy metabolism effects. However, significant levels of oxidative stress and DNA damage were recorded only for earthworms exposed to lead/zinc mine soils. This study demonstrated that despite the low availability of PTEs showed by previous sequential chemical extractions, the results obtained from the direct toxicity assessment performed in this study, highlight the importance of a multibiomarker approach using soil organisms to provide a better evaluation of soils pollution.

Biochemical responses and DNA damage induced by herbicide QYR301 in earthworm (Eisenia fetida)

QYR301, a novel herbicidal inhibitor of 4-hydroxyphenylpyruvate dioxygenase (HPPD), has great potential for resistant weed control in paddy fields, but massive use of pesticides may result in toxicity to soil non-target organisms. Thus, this study was designed to assess subchronic toxicity of different doses of QYR301 in artificial soil (0, 0.1, 1.0, 2.5, and 5.0 mg kg^-1) to earthworms (Eisenia fetida) on days 7, 14, 21, and 28 after exposure, using biomarkers of reactive oxygen species (ROS) and malondialdehyde (MDA) contents, activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and glutathione-S-transferase (GST), and DNA damage. The ROS content significantly increased for all treatments on 7 and 14 days then decreased, and recovered to control level for 0.1 and 1.0 mg kg^-1 treatment on day 28. Concerning enzymes activities, QYR301 increased POD, SOD, and GST activities, but inhibited CAT activity. Except for POD activity, SOD, CAT, and GST activities of 0.1 mg kg^-1 group recovered to control level on day 28. Also, the MDA content of 0.1 mg kg^-1 group reached control level on day 28. However, DNA damage was observed for all treatments throughout the experiment and it increased with increasing doses and time except for 5.0 mg kg^-1 treatment on day 28. These results suggested that QYR301 induced excessive ROS production leading to oxidative stress in earthworms, which caused lipid membrane peroxidation and DNA damage ultimately. The findings could provide a theoretical foundation for assessing ecological damage of QYR301 to soils and a guide for future QYR301 applications.

Setal-epidermal, muscular and enzymatic anomalies induced by certain agrochemicals in the earthworm Eudrilus eugeniae (Kinberg)

Eudrilus eugeniae, the vermicomposing worm, is found in considerable numbers in agricultural fields in India due to their eventual transfer through vermimanure. These worms are very often exposed to pesticides, herbicides, chemical fertilisers and other soil amendments. This paper reports the effects of variable concentrations of urea, phosphogypsum (PG), paper mill sludge (PMS) and two organophosphorus agrochemicals, monocrotophos and glyphosate, on certain morphological, histological and biochemical parameters of E. eugeniae. Results indicated setal anomalies, epidermal lesions, clitellar swelling and constriction of the body. Disintegration of connective tissue, vacuolation of dermis and significant alterations in protein, lipid peroxidation levels and activities of lactate dehydrogenase, acetylcholinesterase and catalase have also been observed in the treated worms. It is proposed that setae, connective tissue, protein and enzymes in E. eugeniae could be useful markers to evaluate toxicity due to the test chemicals.

Spent lubricant oil-contaminated soil toxicity to Eisenia andrei before and after bioremediation

Bioremediation is very efficient in biodegrading petroleum hydrocarbons. However, the decrease in these target contaminants in soils is not necessarily followed by a decrease in toxicity. The remaining contaminants can be enough to retain toxicity, while incomplete degradation of several compounds can generate sub-products, which can be even more toxic. In this context, the aim of this study was to assess acute and chronic toxicity in Eisenia andrei exposed to soil contaminated with 5% spent lubricant oil before and after 22 months of bioremediation in 150 L aerobic reactors. Applied bioremediation strategies were biostimulation (BIOS), bioaugmentation by adding mature compost from municipal solid waste (BIOA₁) and bioaugmentation by adding non-mature compost from municipal solid waste (BIOA₂). After 22 months, total petroleum hydrocarbons (TPH) were reduced 71% in BIOS and 73% in both BIOA₁ and BIOA₂. Polycyclic aromatic hydrocarbons (PAH) were reduced in about 98% in all treatments (BIOS, BIOA₁ and BIOA₂). At the 14^th day of exposure, mortality rates were 7 ± 2, 20 ± 0, 75 ± 25, 93 ± 12 and 100 ± 0% for Eisenia andrei exposed to CONT (soil with no oil addition), BIOS, OLU (soil newly contaminated with 5% spent oil), BIOA₁ and BIOA₂, respectively. After 14 days, surviving specimens in both BIOS and OLU soils exhibited anatomic deformations, less biomass than the controls, and decrease in juvenile forms and coelomocytes. After 28 days, the mortality rate for BIOS and OLU soils increased to 97 and 100%, respectively. Therefore, even with a reduction of 71-73% for TPH and 98% for PAH, toxic effects remained in all soils bioremediated, probably due to the remaining hydrocarbons and/or hydrocarbon biodegradation products. The results indicate that both chemical analyses and toxicological monitoring are required to follow-up soil remediation progress.

DNA damage in earthworms by exposure of Persistent Organic Pollutants in low basin of Coatzacoalcos River, Mexico

Persistent Organic Pollutants (POPs) are stable organic chemicals that represent a potential risk for ecosystems due to their high toxicity, persistence and biomagnification through food chains. Bioindicators in ecosystems have emerged to assess the effect of environmental pollutants. Earthworms are some of the most common bioindicator organisms in terrestrial ecosystems. The main objective of this study was to evaluate the geontoxicity of POP exposure in wild earthworms captured at different levels of urbanization throughout the lower basin of the Coatzacoalcos River (industrial, urban and rural areas). POP soil and earthworm tissue concentrations were measured via Gas-Mass Chromatography, and earthworm DNA damage was evaluated through the comet assay. The greatest concentrations of ΣPOPs, DDT and HCH were found in soil from industrial sites, followed by urban and rural areas (504.68, 383.10, 298.16; 22.6, 4.6, 2.6 and 433.7, 364, 255.6 mg/kg, respectively). Unlike other pollutants, mean ΣPCBs values were highest for industrial soil samples, followed by those from rural and urban areas (41.10, 33.97 and 12.44 mg/kg respectively). For all earthworm tissue POP analyses, the highest concentrations were found in individuals from industrial sites, followed by the urban and rural areas. Furthermore, the highest levels of DNA damage were registered in the industrial area, followed by the urban and rural areas. These assays suggest a strong links among regional soil contamination, POPs bioavailability and the potential risk of detrimental health effects for organisms that inhabit surface soil (soil life). Earthworms contribute vital ecosystem services that could be affected by these results. This work provides evidence of the potential ecological risk that exists in the Lower Basin of the Coatzacoalcos River.

Histological anomalies and alterations in enzyme activities of the earthworm Glyphidrillus tuberosus exposed to high concentrations of phosphogypsum

Phosphogypsum (PG) is the major solid waste generated by phosphate fertilizer plants and is used worldwide as sulfur and calcium supplement in agricultural soil. Considering the probability of elevated doses of PG during agricultural applications, this study was carried out to assess its impact on the connective tissue, tissue cholinesterase (ChE) activity, lactate dehydrogenase (LDH) activity, and lipid peroxidation (LPX) level of the tropical earthworm Glyphidrillus tuberosus (Stephenson) found in abundance in the rice fields in India. Consistent loss of connective tissue and sloughing of the intestinal epithelium were observed in worms exposed to 10%, 15%, and 20% concentrations of PG in soil over an incubation period of 30 days. ChE, LDH activities, and the level of LPX indicated highly significant variation (p < 0.01) between pre and postclitellar regions of the worm and concentrations of treatment. ChE activity was higher in postclitellar with respect to preclitellar region; however, the values for LDH activity and LPX level were higher in preclitellar region in comparison to postclitellar region in both PG treated and control worms. It was concluded that PG concentration at and beyond 10% could cause damage to muscle fibers and bring about significant alterations in these enzyme activities in G.tuberosus thus affecting the physiology and ecological functions of these worms.

Toxicokinetic and toxicodynamic of depleted uranium in the zebrafish, Danio rerio

This study investigated the accumulation pattern and biological effects (genotoxicity and histopathology) to adult zebrafish (male and female) exposed to a nominal waterborne concentration of 20 μg L^-1 of depleted uranium (DU) for 28 days followed by 27 days of depuration. Accumulation pattern showed that (i) DU accumulated in brain, (ii) levels in digestive tract were higher than those measured in gills and (iii) levels remained high in kidney, brain and ovary despite the 27 days of depuration period. Genotoxicity, assessed by comet assay, was significant not only during DU exposure, but also during depuration phase. Gonads, in particular the testes, were more sensitive than gills. The histology of gonads indicated severe biological damages in males. This study improved knowledge of ecotoxic profile of uranium, for which a large range of biological effects has already been demonstrated.

Silver (nano)materials cause genotoxicity in Enchytraeus crypticus, as determined by the comet assay

Enchytraeids have been used in standard ecotoxicity testing for approximately 20 yr. Since adopting the standard test for survival and reproduction, a number of additional tools have been developed, including transcriptomics and enzymatic biomarkers. So far, a genotoxicity tool and endpoint have not been used; hence, the goals of the present study included optimization of the in vivo alkaline comet assay in Enchytraeus crypticus. Further, the effect of silver nanomaterial (Ag NM300K, dispersed, 15 nm) was tested and compared with silver nitrate. Hydrogen peroxide was used as a positive control. The various steps were optimized. The fully detailed standard operating procedure is presented. Silver materials caused genotoxicity, this being differentiated for the nano and non-nano forms. Silver nitrate caused genotoxicity after 3 d of exposure in a dose-related manner, although after 7 d the effects were either reduced or repaired. Ag NM300K caused higher genotoxicity after 7 d for the lowest concentration, highlighting a potential nonmonotonic dose-response effect. Overall, the comet assay showed the power to discriminate effects between materials and also toxicity at low relevant doses. Environ Toxicol Chem 2018;37:184-191. © 2017 SETAC.

Antioxidant activities of ethanolic and acidic ethanolic extracts of astringent persimmon in H2O2-stimulated Caco-2 human colonic epithelial cells

The aim of this study was to investigate the protective effects of ethanol (EAP) and acidic ethanol extracts (AEAP) of astringent persimmon fruits (Diospyros kaki) against hydrogen peroxide (H2O2)-induced oxidative stress in Caco-2 epithelial cells. Levels of reactive oxygen species (ROS) and reduced glutathione (GSH), activities of superoxide dismutase (SOD) and catalase (CAT), as well as protein and DNA damage were measured. Treatment with H2O2 induced oxidative stress in Caco-2 cells but had no effect on SOD activity. Both EAP and AEAP protected the cells against oxidative damage and exhibited similar effects on cellular ROS scavenging activity and protein carbonyl levels. However, AEAP was more potent than EAP in normalizing CAT activity and cytosolic GSH level, and in protecting against DNA damage. These results demonstrated that astringent persimmon fruit extracts were biologically active, and that the tannin-rich fraction (AEAP) possesses stronger protective activity against H2O2-induced oxidative stress in Caco-2 cells.

Radioactively contaminated areas: Bioindicator species and biomarkers of effect in an early warning scheme for a preliminary risk assessment

Concerns about the impacts on public health and on the natural environment have been raised regarding the full range of operational activities related to uranium mining and the rest of the nuclear fuel cycle (including nuclear accidents), nuclear tests and depleted uranium from military ammunitions. However, the environmental impacts of such activities, as well as their ecotoxicological/toxicological profile, are still poorly studied. Herein, it is discussed if organisms can be used as bioindicators of human health effects, posed by lifetime exposure to radioactively contaminated areas. To do so, information was gathered from several studies performed on vertebrates, invertebrate species and humans, living in these contaminated areas. The retrieved information was compared, to determine which are the most used bioindicators and biomarkers and also the similarities between human and non-human biota responses. The data evaluated are used to support the proposal for an early warning scheme, based on bioindicator species and on the most sensitive and commonly shared biomarkers, to perform a screening evaluation of radioactively contaminated sites. This scheme could be used to support decision-making for a deeper evaluation of risks to human health, making it possible to screen a large number of areas, without disturbing and alarming local populations.

Biomarker responses of Eisenia andrei to a polymetallic gradient near a lead mining site in North Tunisia

Eisenia andrei earthworms were exposed for 7 and 14 days to six samples of soil taken from around an abandoned lead (Pb) mine and characterized by different levels of metal contamination (S6-S1, this latter being the most contaminated soil). The organisms were analyzed for metal bioaccumulation and for biological parameters as biomarkers of stress (lysosomal membrane stability; lipofuscin lysosomal content; lysosomal/cytoplasmic volume ratio) and genotoxicity (Micronucleus frequency). Chemical analysis showed the loads of Pb, Cd, Zn, and Cu in the worms following exposure. Among the stress biomarkers, lysosomal membrane stability was significantly affected in the coelomocytes of the earthworms exposed already 7 days to different contaminated soils. Organisms exposed for 14 days to S1 showed in the cells of the chloragogenous tissue, a particularly relevant increase in lipofuscin, a biomarker of oxidative stress, and an increase in the lysosome/cytoplasm volume ratio, indicating stressful condition at the tissue level. Moreover, in the same conditions, a decrease in total body weight was observed. At the longer exposure time, the coelomocytes of worms exposed to S1, S2, and S3 (soils with higher metal concentrations) showed a significant increase in micronuclei (MNi) frequency. Expressions of the P21 and topoisomerase genes, which are involved in DNA repair, showed significant up-regulation in the cells of worms exposed to S1, S2, S3, S4 and to a less extend S6. This may indicate that the worms were only able to successfully reduce the level of DNA damage in S4 and S5 if considering MN frequency data. The biomarker data was integrated by the Earthworm Expert System, allowing an objective interpretation of the complex biological data and clearly defining the areas in which the presence of chemicals is toxic for the edaphic organisms.

Multibiomarker toxicity characterization of uranium mine drainages to the fish Carassius auratus

The release of acidic effluents, naturally enriched in metals and radionuclides, is the main legacy of uranium mines. Generally, metals dissolved by these acidic effluents can cause significant alterations in exposed organisms, with distinct toxicological outcomes. In this study, 72 individuals of the freshwater fish species Carassius auratus were exposed in situ for different periods (8, 16, 24, and 48 h) to water from a pond (treatment pond (TP)) with a chemically treated effluent and a reference pond (PRP), in the vicinity of the Cunha Baixa uranium mine (Portugal). Comparing the water of the two ponds, the PRP pond was characterized by higher pH and oxygen values and lower conductivity and hardness values. Regarding total metal concentrations, among others, magnesium (56,000 μg/L), sodium (17,400 μg/L), zinc (86 μg/L), manganese (6340 μg/L), and uranium (1380 μg/L) concentrations in the TP pond were above the values obtained for the PRP pond. The values of manganese and uranium exceeded the values of quality criteria established for surface waters for cyprinids and for irrigation purposes. After exposure to pond water, significant differences were recorded for several biomarkers: (i) between ponds for acetylcholinesterase (AChE) with higher activities for animals from the PRP and glutathione-S-transferase (GST) activities that were particularly enhanced in animals from the TP pond; (ii) between ponds and exposure periods for lactate dehydrogenase (LDH) activity, since organisms from PRP pond presented always higher values than those from the TP pond, and among these, organisms exposed for the longer period presented a further depression in LDH activity; and (iii) between exposure periods for erythrocyte micronucleus. GSTs and LDH were the most sensitive biomarkers within the timeframe of the in situ assay performed. Despite the alleged efficacy of the chemical treatment (evidenced by a significantly lower pH), some metals persisted in the treated effluent (TP pond), potentially contributing to the induction of oxidative stress or increased conjugation metabolic activity in fish.

Lethal and sub-lethal effects of five pesticides used in rice farming on the earthworm Eisenia fetida

The toxicity of five pesticides typically used in rice farming (trichlorfon, dimethoate, carbendazim, tebuconazole and prochloraz) was evaluated on different lethal and sub-lethal endpoints of the earthworm Eisenia fetida. The evaluated endpoints included: avoidance behaviour after an exposure period of 2 days; and mortality, weight loss, enzymatic activities (cholinesterase, lactate dehydrogenase and alkaline phosphatase) and histopathological effects after an exposure period of 14 days. Carbendazim was found to be highly toxic to E. fetida (LC50=2mg/kg d.w.), significantly reducing earthworm weight and showing an avoidance response at soil concentrations that are close to those predicted in rice-fields and in surrounding ecosystems. The insecticide dimethoate showed a moderate acute toxicity (LC50=28mg/kg d.w.), whereas the rest of tested pesticides showed low toxicity potential (LC50 values above 100mg/kg d.w.). For these pesticides, however, weight loss was identified as a sensitive endpoint, with NOEC values approximately 2 times or lower than the calculated LC10 values. The investigated effects on the enzymatic activities of E. fetida and the observed histopathological alterations (longitudinal and circular muscle lesions, edematous tissues, endothelial degeneration and necrosis) proved to be sensitive biomarkers to monitor pesticide contamination and are proposed as alternative measures to evaluate pesticide risks on agro-ecosystems.

DNA damage in different Eisenia andrei coelomocytes sub-populations after in vitro exposure to hydrogen peroxide

Earthworms play an essential role in providing soil fertility and may represent an important soil contamination bio-indicator. They are able to ingest soil particles, adsorb substances throughout the intestinal epithelium into the coelomic cavity, where chemicals can come in direct contact with coelomic fluid. Earthworm coelomic fluid shelters leucocytes (coelomocytes) that differ significantly both structurally and functionally. Cellular variability could lead to different susceptibility towards contaminants possibly present in soil ecosystem. In order to define population specific dose response to chemicals and to identify a homogeneous cell population to be used as a relevant biomarker, we investigated different coelomocytes subpopulation, obtained by Percoll density gradient centrifugation (5–35 %), exposed ex vivo to H₂O₂ in the range of concentration 15–120 µM. DNA damage levels were assessed by the comet assay on unseparated coelomocytes and on three enriched cellular fractions (light, medium and heavy density subpopulations). All tested samples showed a dose–response genotoxic effect following H₂O₂ exposure. Moreover, light density sub-population appeared more susceptible to oxidative insult highlighted by a significant increase in DNA damage indexes at lower concentrations of H₂O₂. Present data suggested that in these experimental condition coelomocytes light fraction may represent a more sensitive biomarker of genotoxic insult.

Biomarker responses in the earthworm, Dichogaster curgensis exposed to fly ash polluted soils

Earthworms are globally accepted as a model organism in terrestrial ecotoxicology for assessment of environmental pollution. This study evaluated and compared effects of fly ash polluted soils collected from two geographically different thermal power plants on biomarker responses in the earthworm, Dichogaster curgensis. To evaluate relationship between distance sampling and biomarker responses in the earthworm D. curgensis, soil samples at 0.5, 1 and 3km from thermal plant were analyzed for physico-chemical properties and metal concentrations. Biochemical alterations, lysosomal membrane stability, genotoxic effects, and histological changes were examined on 1, 7, and 14 d of exposure to fly ash contaminated soils collected from different thermal power plants. The activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels were significantly increased, while glutathione reductase (GR) activity was found to be decreased in treated animals. Catalase (CAT) and glutathione-S- transferase (GST) activities were found to be increased initially up to 7d exposure and further decreased on 14d exposure. D. curgensis exposed to fly ash contaminated soils showed significant lysosomal membrane destabilization and DNA damage. Extensive histopathological changes were observed in the tissues of the body wall and intestinal tract of the exposed D. curgensis along with accumulation of heavy metals. These results demonstrate that soil pollution around thermal power plants has adverse biological effects of on the indicator organism D. curgensis and no correlation was found between distance and extent of biological biochemical responses.

Effects of benzo[a]pyrene on growth, the antioxidant system, and DNA damage in earthworms (Eisenia fetida) in 2 different soil types under laboratory conditions

The aims of the present study were to compare the toxic effects of benzo[a]pyrene (BaP) and to screen for rapid and sensitive biomarkers that can be used to assess the environmental risks of BaP in earthworms in different natural soil types. The authors exposed Eisenia fetida to 2 types of soil (red soil and fluvo-aquic soil) spiked with different concentrations (0 mg kg(-1), 1 mg kg(-1), 10 mg kg(-1), 100 mg kg(-1), and 500 mg kg(-1)) of BaP for 7 d or 14 d. Benzo[a]pyrene-induced weight variation altered the activities of antioxidant enzymes (superoxide dismutase [SOD]; catalase [CAT]; and guaiacol peroxidase [POD]) and changed the content of malondialdehyde (MDA). In addition, using the comet assay, the authors determined the DNA damage in earthworms. The results revealed that the comet assay was suitable for evaluating the genotoxicity of BaP in the soil, even at the lowest examined concentration. The MDA content was the least sensitive indicator of BaP toxicity. A 3-way analysis of variance (ANOVA) was used to determine whether the soil type, exposure concentration, and duration affected the BaP toxicity. The antioxidant enzyme activities and the MDA content were shown to be significantly correlated with the exposure concentration. The percentage of weight variation (p < 0.001), CAT activity (p < 0.05), and SOD activity (p < 0.01) were significantly affected by the soil type, and the POD activity (p < 0.01), CAT activity (p < 0.001), and SOD activity (p < 0.001) were significantly affected by the exposure duration. Therefore, measuring DNA damage in earthworms is a simple and efficient means of assessing BaP genotoxicity in a terrestrial environment, and the effects of the soil type and exposure time on the other parameters that were investigated in E. fetida, which were used as responsive biomarkers, should be considered.

The impact of uranium mine contamination of soils on plant litter decomposition

As part of a tier 3 risk assessment performed for a uranium mining area, the ability of soils with different degrees of metal contamination to degrade organic matter was assessed using litter bags filled with leaves of Quercus robur, Pinus pinaster, Salix atrocinerea, or a mixture of the three species. Litter bags were exposed at different sites within the mine area and at a reference area for 3, 6, 9, and 12 months. Biomass loss, nitrogen (N), phosphorus (P), carbon (C) and total fatty acid, total phenolic, and ergosterol contents were assessed for each litter bag retrieved from the field. The decomposition of litter at each site seemed to be governed by a complex interaction of many different factors. After 12 months of exposure, leaves from the most contaminated sites were distinguishable from those from the reference site. In the reference site, the greatest percentages of biomass loss were attained by Q. robur and P. pinaster leaves. These species displayed the second highest and the lowest C-to-N ratios, respectively. In addition, the high P content of the litter from these two species may have favored microbial colonization. The results suggest that the decomposition of P. pinaster and Q. robur leaves may have been favored at the reference site by the high abundance of both species at this site and the subsequent adaptation of the microbial community to their litter. Our study shows that different species of leaf litter should be used to discriminate between contaminated sites with different levels of contamination.

Contribution for the derivation of a soil screening value (SSV) for uranium, using a natural reference soil

In order to regulate the management of contaminated land, many countries have been deriving soil screening values (SSV). However, the ecotoxicological data available for uranium is still insufficient and incapable to generate SSVs for European soils. In this sense, and so as to make up for this shortcoming, a battery of ecotoxicological assays focusing on soil functions and organisms, and a wide range of endpoints was carried out, using a natural soil artificially spiked with uranium. In terrestrial ecotoxicology, it is widely recognized that soils have different properties that can influence the bioavailability and the toxicity of chemicals. In this context, SSVs derived for artificial soils or for other types of natural soils, may lead to unfeasible environmental risk assessment. Hence, the use of natural regional representative soils is of great importance in the derivation of SSVs. A Portuguese natural reference soil PTRS1, from a granitic region, was thereby applied as test substrate. This study allowed the determination of NOEC, LOEC, EC₂₀ and EC₅₀ values for uranium. Dehydrogenase and urease enzymes displayed the lowest values (34.9 and <134.5 mg U Kg, respectively). Eisenia andrei and Enchytraeus crypticus revealed to be more sensitive to uranium than Folsomia candida. EC₅₀ values of 631.00, 518.65 and 851.64 mg U Kg were recorded for the three species, respectively. Concerning plants, only Lactuca sativa was affected by U at concentrations up to 1000 mg U kg¹. The outcomes of the study may in part be constrained by physical and chemical characteristics of soils, hence contributing to the discrepancy between the toxicity data generated in this study and that available in the literature. Following the assessment factor method, a predicted no effect concentration (PNEC) value of 15.5 mg kg⁻¹_dw was obtained for U. This PNEC value is proposed as a SSV for soils similar to the PTRS1.

Linking trace metals and agricultural land use in volcanic soils--a multivariate approach

The concern about the environmental impacts caused by agriculture intensification is growing as large amounts of nutrients and contaminants are introduced into soil ecosystems. Volcanic soils are unique naturally fertile resources extensively used for agricultural purposes, with particular physical and chemical properties that may result in possible accumulation of toxic substances, such as metals. Within this particular geological context, the present study aims to evaluate the impact of different agricultural systems (conventional, traditional and organic) in trace metal (TM) soil pollution and define the tracers for each one. Physicochemical properties and TM contents in agricultural topsoils were determined. Enrichment Factors (EF) were calculated to distinguish geogenic and anthropogenic contribution to TM contents in agricultural soils. An ensemble of multivariate statistical analyses (PCA and FDA) was performed to reduce the multidimensional space of variables and samples, thus defining a set of TM as tracers of distinct agricultural farming systems. Results show that agricultural soils have low organic matter content (<5%) compared to reference soil (>30%); in addition, electric conductivity in conventional farming soils is higher (262.3 ± 162.6 μS cm(-1)) while pH is lower (5.8 ± 0.3). Regarding metal inputs, V, Ba and Hg soil contents are mainly of geogenic origin, while Li, P, K, Cr, Mn, Ni, Cu, Zn, As, Mo, Cd and Pb result primarily from anthropogenic inputs. Li revealed to be a tracer of agricultural pollution in conventional farming soils, whereas V allowed the discrimination of traditional farming soils. This study points to agriculture as a diffuse source of anthropogenic TM soil pollution and is the first step to identify priority chemicals affecting agricultural Andosols.

Uranium mining in Portugal: a review of the environmental legacies of the largest mines and environmental and human health impacts

The history of uranium mining in Portugal during almost one century has followed international demand peaks of both radium and uranium, which in turn were driven by medical, military, and civil applications. Nowadays, following price drop in the 1980s, mining activities decreased and ceased in 2001. The current challenge is to deal with environmental legacies left by old uranium mines, mainly located in Viseu and Guarda districts. In 2001, based on several radiological surveys carried out, the Portuguese government assumed the remediation costs of abandoned mine areas for environmental safety and public health protection. Detailed environmental and public health risk assessments were performed under the scope of studies both requested by the government and by funded research projects. It was found that the existing risks, due to radiological and chemical exposures to metals and radionuclide's, were particularly high at the old milling facilities and mines where in situ and heap leaching of low-grade ore occurred. The different studies, involving both humans and non-human species from different trophic levels, demonstrated the existence of effects at different levels of biological organization (molecular, cellular, tissues, individuals, and populations) and on ecosystem services. To mitigate the risks, the environmental rehabilitation works at the Urgeiriça mine complex are almost complete, while at Cunha Baixa mine, they are presently in progress. These works and environmental improvements achieved and expected are described herein.

Toxicological responses of earthworm (Eisenia fetida) exposed to metal-contaminated soils

The aim of this study was to evaluate the toxicological responses of earthworm (Eisenia fetida) induced by field-contaminated, metal-polluted soils. Biochemical responses and DNA damage of earthworm exposed to two multi-metal-contaminated soils in a steel industry park and a natural reference soil in Zijin Mountain for 2, 7, 14, and 28 days were studied. Results showed that three enzyme activities, including superoxide dismutase (SOD), acetylcholinesterase (AChE), and cellulase, in earthworm in metal-contaminated soils were significantly different from those of the reference soil. Cellulase and AChE were more sensitive than SOD to soil contamination. The Olive tail moment of the comet assay after 2-day exposure increased 56.5 and 552.0 % in two contaminated soils, respectively, compared to the reference soil. Our findings show that cellulase and DNA damage levels can be used as potential biomarkers for exposure of earthworm to metal-polluted soils.

Community-level effects in edaphic fauna from an abandoned mining area: integration with chemical and toxicological lines of evidence

As a part of the Ecological Risk Assessment of a deactivated uranium mining area (Cunha Baixa), the aim of this study was to assess the drivers of litter arthropod community (ecological line of evidence) inhabiting soils with different degrees of contamination. Litter arthropods were collected in the mining area using a total of 70 pitfall traps, in the spring and autumn of 2004. Unlike information previously collected in the chemical and ecotoxicological lines of evidence, we found no clear evidence of impacts of soil contamination on the edaphic arthropod assemblage. Multivariate analyses were unable to extract relevant environmental gradients related to contamination, as most of the sites shared the same taxa overall. Given the consistency of the chemical and ecotoxicological lines of evidence, we must conclude that the litter arthropod assemblage underestimated the impacts of contamination in this abandoned mining area. In part, this could be due to the uncertainty caused by confounding factors that affect the litter arthropod community in the area. Nevertheless, despite the overall lack of responsiveness of the epigeic arthropod community data, a few taxa were negatively correlated with metal concentrations (Clubionidae and Staphylinidae), while Pseudoscorpionida were associated with the toxicological profile of the sites. These evidences suggest that community-level approaches with other animal and plant assemblages are necessary to reduce uncertainty relatively to the assessment of risks in higher evaluation tiers in the Cunha Baixa mine area.

Differential gene expression in Iberian green frogs (Pelophylax perezi) inhabiting a deactivated uranium mine

Iberian green frogs (Pelophylax perezi) were found inhabiting a deactivated uranium mine, especially an effluent pond, seriously contaminated with metals and radionuclides. These animals were previously assessed for oxidative stress parameters and did not revealed significant alterations. In order to better understand which mechanisms may be involved in the ability to withstand permanent contamination gene expression analysis was performed in the liver, through suppression subtractive hybridization (SSH). The SSH outcome in the liver revealed the up-regulation of genes coding for the ribosomal protein L7a and for several proteins typical from blood plasma: fibrinogen, hemoglobin and albumin. Besides their normal function, some of these proteins can play an important role as protective agents against oxidative stress. This work provides new insights on possible basal protection mechanisms that may act in organisms exposed chronically to contamination.

Effect of fly ash on biochemical responses and DNA damage in earthworm, Dichogaster curgensis

Fly ash is receiving alarming attention due to its hazardous nature, widespread usage, and the manner of disposal; leading to environmental deterioration. We carried out bio-monitoring and risk assessment of fly ash in earthworms as a model system. Dichogaster curgensis were allowed to grow in presence or absence of fly ash (0-40%, w/w) for 1, 7, and 14 d. The biochemical markers viz. catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione S-transferase (GST), and malondialdehyde (MDA) level were measured. The comet and neutral red retention assays were performed on earthworm coelomocytes to assess genetic damages and lysosomal membrane stability. The results revealed increased activities of SOD, GPx, GST, and MDA level in a dose-response manner while GR activity was decreased with increasing concentrations of fly ash. No obvious trend was observed in the CAT activity and fly ash concentration. Lysosomal membrane destabilization was noted in the earthworms exposed to 5% and more fly ash concentration in a dose and time dependent manner. The comet assay demonstrated that the fly ash induced DNA damage and DNA-protein crosslinks in earthworm coelomocytes.

Comparative acute toxicity of twenty-four insecticides to earthworm, Eisenia fetida

In this study, we used two different types of bioassay, a contact filter paper toxicity bioassay and a soil toxicity bioassay, to compare the acute toxicity of twenty-four insecticides belonging to six chemical categories on earthworm species, Eisenia fetida. Results of the contact filter paper toxicity bioassay indicated that neonicotinoids were super toxic to E. fetida (48 h-LC(50) value ranged from 0.0088 to 0.45 μg cm(-2)), pyrethroids were very toxic (48 h-LC(50) values ranged from 10.55 to 25.7 μg cm(-2)) and insect growth regulators (IGRs) were moderately toxic (48 h-LC(50) values ranged from 117.6 to 564.6 μg cm(-2)) to the worms. However, antibiotics, carbamates and organophosphates induced variable toxicity responses in E. fetida, and were very to extremely toxic (48 h-LC(50) values ranged from 3.64 to 75.75 μg cm(-2)). Results of the soil toxicity bioassays showed a different pattern of toxicity except that neonicotinoids were the most toxic even under the soil toxicity bioassay system. The acute toxicity of neonicotinoids was higher than those of antibiotics, carbamates, IGRs and organophosphates. In contrast, pyrethroids were the least toxic to the worms under the soil toxicity bioassay system. It was concluded that irrespective of bioassay systems, earthworms were more susceptible to neonicotinoids than other modern synthetic insecticides.

Evaluation of the sensitivity of genotoxicity and cytotoxicity endpoints in earthworms exposed in situ to uranium mining wastes

Earthworms were exposed for 56 days to a contaminated soil from an abandoned uranium mine and to the natural reference soil LUFA 2.2. The exposure occurred in situ: the containers with contaminated soil were placed near the mine pit; the containers with reference soil were placed in a reference site. For the assessment of metals bioaccumulation, DNA damages, cell-to-cell variation in DNA content, Median Fluorescence Intensity (MFI), coelomocytes frequency and proliferation, organisms were sampled after 0, 1, 2, 7, 14 and 56 days of exposure. For the assessment of radionuclides bioaccumulation, animals were sampled after 0, 14 and 56 days of exposure. As for growth, organisms were sampled after 0, 14, 28 and 56 days of exposure. The reproduction assay was performed according to the OECD (2004) guideline. DNA damages were assessed by comet assay and flow cytometry was used to determine cell-to-cell variation in DNA content, Median Fluorescence Intensity (MFI), coelomocytes frequency and proliferation. Results have shown a myriad of effects in the organisms exposed to the contaminated soil, namely: the inhibition of reproduction, growth reduction, DNA damages, cytotoxicity, changes in eleocytes fluorescence intensity, coelomocytes proliferation and bioaccumulation of metals and radionuclides. Our results showed that the evaluation of genotoxicity and cytotoxicity endpoints, along with other parameters at an individual level in standard reproduction assays conducted in situ, are important to improve the risk assessment process of areas contaminated with uranium and other radioactive mining wastes.

Histopathological changes in the earthworm Eisenia andrei associated with the exposure to metals and radionuclides

Earthworms were exposed for 56 d to a contaminated soil, from an abandoned uranium mine, and to the natural reference soil LUFA 2.2. Histological changes in earthworm's body wall (epidermis, circular and longitudinal muscles) and gastrointestinal tract (chloragogenous tissue and intestinal epithelium) were assessed, after 0, 14 and 56 d of exposure. Results have shown alterations in all the studied tissues after 14 d of exposure (except for the intestinal epithelium), yet more severe effects were registered after 56 d of exposure. Herein we report histopathological alterations as a good biomarker for the evaluation of soil quality. We also demonstrate that morphological changes in the body wall and gastrointestinal tract, are important endpoints that could be added to earthworm's standardized tests, for the evaluation of soil toxicity, as part of the risk assessment of contaminated areas.

Antioxidant response and metal accumulation in tissues of Iberian green frogs (Pelophylax perezi) inhabiting a deactivated uranium mine

Human mining activities tend often to generate greatly impacted areas which remain contaminated for long periods of time, giving rise to extreme habitats. Mining sites are usually characterized for the production of metal rich effluents with very low pH. In this work we analyzed physical and chemical parameters of water from a deactivated uranium mine pond (M) and a reference site (REF) as well as their metal content. Furthermore, we determined and compared metal accumulation in liver, kidney, bones, muscle and skin of Pelophylax perezi from REF with P. perezi from M. We also determined the enzymatic activities of glutathione-S-transferases (GSTs), catalase (CAT), glutathione reductase (Gred), and glutathione peroxidase (GPx; both selenium-dependent and selenium-independent) in liver, kidney, lung and heart. Additionally, lipoperoxidation (LPO) was also assessed in the same tissues via thiobarbituric acid reactive substances (TBARS) assay and lactate dehydrogenase (LDH) activity was determined in muscle. Our results revealed that the majority of metals were in higher concentrations in tissues of organisms from M. This trend was especially evident for U whose content reached a difference of 1350 fold between REF and M organisms. None of the organs tested for antioxidant defenses revealed LPO, nonetheless, with exception for liver, all organs from the M frogs presented increased total GPx activity and selenium-dependent GPx. However, this response was significant only for the lung, probably as a consequence of the significant inhibition of CAT upstream and to cope with the subsequent increase in H(2)O(2). Lungs were the organs displaying greater responsiveness of the anti-oxidant stress system in frogs from the uranium mine area.

A risk analysis model for radioactive wastes

Hazardous wastes affect natural environmental systems to a significant extend, and therefore, it is necessary to control their harm through risk analysis. Herein, an effective risk methodology is proposed by considering their uncertain behaviors on stochastic, statistical and probabilistic bases. The basic element is attachment of a convenient probability distribution function (pdf) to a given waste quality measurement sequence. In this paper, (40)K contaminant measurements are adapted for risk assessment application after derivation of necessary fundamental formulations. The spatial contaminant distribution of (40)K is presented in the forms of maps and three-dimensional surfaces.