Application of ecotoxicological studies in integrated environmental monitoring: Possibilities and problems

Developing an Approach for Integrating Chemical Analysis and Transcriptional Changes to Assess Contaminants in Water, Sediment, and Fish

Pharmaceuticals in aquatic environments pose threats to aquatic organisms because of their continuous release and potential accumulation. Monitoring methods for these contaminants are inadequate, with targeted analyses falling short in assessing water quality's impact on biota. The present study advocates for integrated strategies combining suspect and targeted chemical analyses with molecular biomarker approaches to better understand the risks posed by complex chemical mixtures to nontarget organisms. The research aimed to integrate chemical analysis and transcriptome changes in fathead minnows to prioritize contaminants, assess their effects, and apply this strategy in Wascana Creek, Canada. Analysis revealed higher pharmaceutical concentrations downstream of a wastewater-treatment plant, with clozapine being the most abundant in fathead minnows, showing notable bioavailability from water and sediment sources. Considering the importance of bioaccumulation factor and biota-sediment accumulation factor in risk assessment, these coefficients were calculated based on field data collected during spring, summer, and fall seasons in 2021. Bioaccumulation was classified as very bioaccumulative with values >5000 L kg-1, suggesting the ability of pharmaceuticals to accumulate in aquatic organisms. The study highlighted the intricate relationship between nutrient availability, water quality, and key pathways affected by pharmaceuticals, personal care products, and rubber components. Prioritization of these chemicals was done through suspect analysis, supported by identifying perturbed pathways (specifically signaling and cellular processes) using transcriptomic analysis in exposed fish. This strategy not only aids in environmental risk assessment but also serves as a practical model for other watersheds, streamlining risk-assessment processes to identify environmental hazards and work toward reducing risks from contaminants of emerging concern. Environ Toxicol Chem 2024;00:1-22. © 2024 SETAC.

Analysis of pharmacokinetic profile and ecotoxicological character of cefepime and its photodegradation products

An important problem is the impact of photodegradation on product toxicity in biological tests, which may be complex and context-dependent. Previous studies have described the pharmacology of cefepime, but the toxicological effects of its photodegradation products remain largely unknown. Therefore, photodegradation studies were undertaken in conditions similar to those occurring in biological systems insilico, in vitro, in vivo and ecotoxicological experiments. The structures of four cefepime photodegradation products were determined by UPLC-MS/MS method. The calculated in silico ADMET profile indicates that carcinogenic potential is expected for compounds CP-1, cefepime, CP-2 and CP-3. The Cell Line Cytomotovity Predictor 2.0 tool was used to predict the cytotoxic effects of cefepime and related compounds in non-transformed and cancer cell lines. The results indicate that possible actions include: non-small cell lung cancer, breast adenocarcinoma, prostate cancer and papillary renal cell carcinoma. OPERA models were used to predict absorption, distribution, metabolism and excretion (ADME) endpoints, and potential bioactivity of CP-2, cefepime and CP-4. The results obtained in silico show that after 96h of exposure, cefepime, CP-1, CP-2, and CP-3 are moderately toxic in the zebrafish model, while CP-4 is highly toxic. On the contrary, cefepime is more toxic to T. platyurus (highly toxic) compared to the zebrafish model, similar to products CP-4, CP-3 and CP-2. In vitro cytotoxicity studies were performed by MTT assay and in vivo acute embryo toxicity studies using Danio rerio embryos and larvae. In vitro showed an increase in the cytotoxicity of products with the longest exposure period i.e. for 8 h. Additionally, at a concentration of 200 μg/mL, statistically significant changes in metabolic activity were observed depending on the irradiation time. In vivo studies conducted with Zebrafish showed that both cefepime and its photodegradation products have only low toxicity. Assessment of potential ecotoxicity included Microbiotests on invertebrates (Thamnotoxkit F and Daphtoxkit F), and luminescence inhibition tests (LumiMara). The observed toxicity of the tested solutions towards both Thamnocephalus platyurus and Daphnia magna indicates that the parent substance (unexposed) has lower toxicity, which increases during irradiation. The acute toxicity (Lumi Mara) of nonirradiated cefepime solution is low for all tested strains (<10%), but mixtures of cefepime and its photoproducts showed growth inhibition against all tested strains (except #6, Photobacterium phoreum). Generally, it can be concluded that after UV-Vis irradiation, the mixture of cefepime phototransformation products shows a significant increase in toxicity.

Exploitation of environmental DNA (eDNA) for ecotoxicological research: A critical review on eDNA metabarcoding in assessing marine pollution

The rise in worldwide population has led to a noticeable spike in the production, consumption, and transportation of energy and food, contributing to elevated environmental pollution. Marine pollution is a significant global environmental issue with ongoing challenges, including plastic waste, oil spills, chemical pollutants, and nutrient runoff, threatening marine ecosystems, biodiversity, and human health. Pollution detection and assessment are crucial to understanding the state of marine ecosystems. Conventional approaches to pollution evaluation usually represent laborious and prolonged physical and chemical assessments, constraining their efficacy and expansion. The latest advances in environmental DNA (eDNA) are valuable methods for the detection and surveillance of pollution in the environment, offering enhanced sensibility, efficacy, and involvement. Molecular approaches allow genetic information extraction from natural resources like water, soil, or air. The application of eDNA enables an expanded evaluation of the environmental condition by detecting both identified and unidentified organisms and contaminants. eDNA methods are valuable for assessing community compositions, providing indirect insights into the intensity and quality of marine pollution through their effects on ecological communities. While eDNA itself is not direct evidence of pollution, its analysis offers a sensitive tool for monitoring changes in biodiversity, serving as an indicator of environmental health and allowing for the indirect estimation of the impact and extent of marine pollution on ecosystems. This review explores the potential of eDNA metabarcoding techniques for detecting and identifying marine pollutants. This review also provides evidence for the efficacy of eDNA assessment in identifying a diverse array of marine pollution caused by oil spills, harmful algal blooms, heavy metals, ballast water, and microplastics. In this report, scientists can expand their knowledge and incorporate eDNA methodologies into ecotoxicological research.

Biomonitoring of Soil Contaminated with Herbicides

The state of environmental pollution is of random character, and it depends on climatic conditions, landforms, development and industrialization. It is estimated that in the last decade as many pollutants have been released into the environment as in the previous 70 years, and the pollution rate still increases. Many scientific reports indicate that, in addition to metals, pesticides are the most commonly detected compounds in the environment. This situation is mainly due to the irrational use of these chemicals by humans. Mostly, soil environment changes caused by the influence of pesticides can be determined by various chemical analyses, which require the use of sophisticated and expensive equipment. However, biological methods, such as those using microbiological activity and an abundance of microorganisms, e.g., organisms responsible for the cycle of organic matter and nutrients, tend to be neglected. For this reason, the aim of the present study is not only to assess the validity of other research studies that were performed based on the available literature but to compile methods and compare them, which allows for an in depth understanding of the complexity of soil processes following herbicide application by conducting comprehensive soil biomonitoring.

Emerging prospects of integrated bioanalytical systems in neuro-behavioral toxicology

Neurotoxicity effects of industrial contaminants are currently significantly under investigated and require innovative analytical approaches to assess health and environmental risks at individual, population and ecosystem levels. Behavioral changes assessed using small aquatic invertebrates as standard biological indicators of the aggregate toxic effects, have been broadly postulated as highly integrative indicators of neurotoxicity with physiological and ecological relevance. Despite recent increase in understanding of the emerging value of behavioral biotests, their wider implementation especially in high-throughput environmental risk assessment assays, is largely limited by the lack of advances in analytical technologies. To date, most of the behavioral biotests have only been performed with larger-volumes and lacked dynamic flow-through conditions. They also lack features necessary for development of higher throughput neuro-behavioral ecotoxicity assays such as miniaturization and integration of automated components. We postulate that some contemporary analytical limitations can be effectively addressed by innovative Lab-on-a-Chip (LOC) technologies, an emerging and multidisciplinary field poised to bring significant miniaturization to aquatic ecotoxicity testing. Recent developments in this emerging field demonstrate particular opportunities to study a plethora of behavioral responses of small model organisms in a high-throughput fashion. In this review, we highlight recent advances in this budding new interdisciplinary field of research. We also outline the existing challenges, barriers to development and provide a future outlook in the evolving field of neurobehavioral ecotoxicology.

Bioassay: A useful tool for evaluating reclaimed water safety

Wastewater reclamation and reuse has been proved to be an effective way to relieve the fresh water crisis. However, toxic contaminants remaining in reclaimed water could lead to potential risk for reuse, and the conventional water quality standards have difficulty guaranteeing the safety of reclaimed water. Bioassays can vividly reflect the integrated biological effects of multiple toxic substances in water as a whole, and could be a powerful tool for evaluating the safety of reclaimed water. Therefore, in this study, the advantages and disadvantages of using bioassays for evaluating the safety of reclaimed water were compared with those of conventional water quality standards. Although bioassays have been widely used to describe the toxic effects of reclaimed water and treatment efficiency of reclamation techniques, a single bioassay cannot reflect the complex toxicity of reclaimed water, and a battery of bioassays involving multiple biological effects or in vitro tests with specific toxicity mechanisms would be recommended. Furthermore, in order to evaluate the safety of reclaimed water based on bioassay results, various methods including potential toxicology, the toxicity unit classification system, and a potential eco-toxic effects probe are summarized as well. Especially, some integrated ranking methods based on a bioassay battery involving multiple toxicity effects are recommended as useful tools for evaluating the safety of reclaimed water, which will benefit the promotion and guarantee the rapid development of the reclamation and reuse of wastewater.

A multi-parametric study of the interaction between the Parati river and Babitonga Bay in terms of water quality

The Parati River contributes to the Babitonga Bay water complex, but the contents of the bay also influence the river during periods of inverted currents. In this study, the water quality along four stretches of the Parati River and Babitonga Bay was evaluated using chemical (physico-chemical and chromatographic analysis), microbiological (fluorescein diacetate hydrolysis) and ecotoxicological (Lumistox) methods to assess the reciprocal influence of the waters of this river-bay system. In addition, the most appropriate type of analysis for the monitoring of the estuarine region of the Parati River was identified. The results of six sampling campaigns showed that the type of contaminants and their levels varied temporally and spatially and thus the water quality also changed. Anthropogenic activity, such as banana cultivation and the release of sewage into the water system, is the primary cause of the contamination that affects the quality of the water in the Parati River estuary, which is a crucial ecological niche for the reproduction of various marine species. The ecotoxicity tests with Aliivibrio fischeri conducted to evaluate the water quality showed an integrative response, and the ecotoxicity data indicated that the Parati River does not have a significant influence on the water quality of Babitonga Bay.

Toxicity profiling of 24 l-phenylalanine derived ionic liquids based on pyridinium, imidazolium and cholinium cations and varying alkyl chains using rapid screening Vibrio fischeri bioassay

A library of 24 pyridinium-, imidazolium-, and cholinium-based ionic liquids (ILs) with varying alkyl chain from C₂ to C₁₆ was toxicologically profiled using naturally luminescent marine bacteria Vibrio fischeri. The toxicity (30-min EC₅₀) of studied ILs to Vibrio fischeri ranged from 7.82 µM (4.2 mg/L) (PyC₁₂Phe) to 3096 µM (1227 mg/L) (ImidC₂Phe), i.e. from "toxic" (EC₅₀ 1-10 mg/L) to "not harmful" (EC₅₀ > 100 mg/L). Inhibition of the bacterial luminescence upon 30-min exposure to ILs correlated well with bacterial viability (exposure for 4 h). The toxicity of studied ILs was largely driven by the length of the alkyl chain (hydrophobicity) and not the type of cationic part of the IL: starting from C₁₀ all the ILs irrespective of the cationic part proved "toxic". The toxicity of the studied ILs was increasing in parallel to their hydrophobicity up to log K_ow = 1 (C₈-C₁₀) and then levelling up, being consistent with the previously obtained analogous data sets. The "cut-off" effect reported in this study for longer chain length members of the ILs series leads to the "limit" toxicity level for this type of ILs to be ca. 8 mM. Two open-access online tools (www.molinspiration.com and www.vcclab.org) have been applied for the calculation of the K_ow values for the 24 ILs reported in this study and 21 ILs reported in the literature. This lead to plotting two nonlinear monotonic correlations between the values of experimental log (1/EC₅₀) and calculated log K_ow. The limitation of the online tools and an effect of the ILs structure on the "cut-off" effect have been discussed. The challenge of developing low microbial toxicity surface active ILs remains a significant task to overcome. Our results shed light on the new approaches for designing environmentally benign ILs and functional surfactants. As the hydrophobicity of the ILs significantly correlated with the toxicity, the Vibrio fischeri assay could be considered a powerful tool in providing toxicity data for building and evaluating the QSAR toxicity models for ILs.

Towards a multi-bioassay-based index for toxicity assessment of fluvial waters

Despite their proven reliability for revealing 'acceptable' degrees of toxicity in waste- and reclaimed waters, bioassays are rarely used to assess the toxicity of hazardous contaminants present in natural waters. In this study, we used organisms from different trophic levels to assess the toxicity of water samples collected from four different South Korean rivers. The main objective was to develop a multi-descriptor index of toxicity for undiluted river water. The responses of six test organisms (Aliivibrio fischeri, Pseudokirchneriella subcapitata, Heterocypris incongruens, Moina macrocopa, Danio rerio and Lemna minor) after laboratory exposure to water samples were considered for this index, as well as the frequency of teratologies in diatom assemblages. Each individual test was attributed a toxicity class and score (three levels; no toxicity = 0, low toxicity = 1, confirmed toxicity = 2) based on the organism's response after exposure and a total score was calculated. The proposed index also considers the number of test organisms that received the highest toxicity score (value = 2). An overall toxicity category was then attributed to the water sample based on those two metrics: A = no toxicity, B = slight toxicity, C = moderate toxicity; D = toxicity and E = high toxicity. The susceptibility of the test organisms varied greatly and the sensitivity of their response also differed among bioassays. The combined responses of organisms from different trophic levels and with different life strategies provided multi-level diagnostic information about the intensity and the nature of contamination.

Evaluating features of periphytic diatom communities as biomonitoring tools in fresh, brackish and marine waters

The aims of this study were to assess the biodiversity of periphytic diatom assemblages in fresh, brackish and marine waterbodies of Korea, and to assess the effect of environmental and anthropogenic factors on parameters such as the quantity and biovolume of lipid bodies and deformations of diatoms as early warning measures of anthropogenic impact. Diatom samples were collected from 31 sites (14 freshwater, 10 brackish and 7 marine), which included less impacted (upstream) and impacted (downstream) sites in each water type. Our results showed higher abundance and biodiversity of periphytic diatoms at the less impacted sites in terms of species richness, Shannon index, cell count and biovolume of the communities than at the impacted sites for freshwater and estuarine sites, but not for marine sites. 84 diatom species were noted in freshwater, 80 in brackish water and 40 in marine waters. In comparison to diatoms of the impacted sites, those of less impacted freshwater, brackish and marine sites had less lipid bodies (also less biovolume) and a lower percentage of teratological frustules, and showed more mobile forms in the community. Principal component analysis (PCA) also showed clear segregation of impacted from less impacted sites by the extent of the presence of lipid bodies (higher both in number and biovolume) and deformities in diatom frustules. Pearson correlation analysis revealed that lipid body induction and deformities were positively correlated with metals (Cd, Co, Cr, Cu, Fe, Pb and Zn) and nutrients (total phosphorus and total nitrogen), whereas they showed negative correlation with salinity, dissolved oxygen, suspended solutes and pH. Life-forms, lipid bodies and deformities in diatoms may be an effective biomonitoring tool for assessing biological effects of pollutants in non-marine aquatic ecosystems in Korea.

Rapid in situ toxicity testing with luminescent bacteria Photorhabdus luminescens and Vibrio fischeri adapted to a small portable luminometer

The present study demonstrates development of a rapid testing protocol based on a small portable luminometer using flash kinetic assessment of bacterial bioluminescence. The laboratory comparisons based on six model organic toxicants and two metals showed significant correlations between responses of freshwater bacteria Photorhabdus luminescens and standard marine bacterial species Vibrio fisheri. While P. luminescens was less sensitive in standard arrangements, the responses of both organisms were comparable in the newly introduced portable luminometer setup. The applicability and reproducibility of the portable luminometer protocol was further demonstrated in the assessment of 43 European wastewater effluents that were simultaneously tested for toxicity and analysed for 150 organic and 20 inorganic contaminants grouped into 13 major chemical classes. Clear association between the toxic responses in both compared bacterial species and the elevated levels of inorganic compounds (toxic metals), chlorophenols and benzotriazole anticorrosives was observed. The new protocol with a portable luminometer provides a fast (30 s) response and may be used as a tool for rapid in situ toxicity evaluation of freshwater environmental samples such as effluents.

A Multidisciplinary Assessment of River Surface Water Quality in Areas Heavily Influenced by Human Activities

The present study could serve as a multidisciplinary approach for the assessment of river surface water quality with the use of chemical and biological methods. Specifically, physicochemical parameters, heavy metals, and pesticides were measured in water samples from three different stations (sampling station S1, S2, and S3) along Asopos River (Greece). In parallel, algal species (primary producers)-such as Scenedesmus rubescens and Chlorococcum sp.; consumer invertebrate species, such as the fairy shrimp Thamnocephalus platyurus and the rotifer Brachionus calyciflorus; as well as human lymphocytes-were exposed to those samples for assessing their toxic and genotoxic/mutagenic effects. According to the results, although the values of almost all of the physicochemical parameters tested, heavy metals (zinc, cadmium, lead, and mercury) and pesticides were lower than or within the respective environmental quality standards, thus offering no clear evidence for their natural or anthropogenic origin. Values recorded for nickel, chromium, hexavalent chromium, and malathion represent a typical case of mixed influence from natural and anthropogenic enrichments. In contrast, the algal growth arrest, the acute toxic effects on the freshwater invertebrates, and the increased micronuclei frequencies observed in human lymphocytes showed the presence of human-derived hazardous substances, which were hardly determinable with the use of conventional chemical methods. Given that the presence of priority pollutants in river surface waters, heavily burdened by anthropogenic activities, could give no clear evidence for their biological risk, the results of the present study showed that chemical and biological assays should be applied in parallel, thus serving as a reliable tool for the assessment of river water quality.

Multidimensional evaluation of soil pollution from railway tracks

Railway transport is a source of pollution to soils and living organisms by e.g. PAHs, PCBs, oil-derived products, pesticides and heavy metals. Soil toxicity evaluation requires chemical analyses, indicating the type and content of particular pollutants, as well as biological analyses, which allow assessing the reaction of organisms to these pollutants. This paper is focused on a multi-aspect evaluation of the degree of toxicity and pollution of soil in selected railway areas from north-eastern Poland by application of numerous biotests and chemical analyses. The soils were sampled on railway tracks from the following railway stations: Białystok Fabryczny, Siemianówka, Hajnówka, Iława Główna and Waliły. The most toxic soils occur on the railway tracks at Białystok Fabryczny and Siemianówka. They had a significant toxic effect on test organisms from various trophic levels. The contents of PAHs, PCBs, heavy metals, oil-derived hydrocarbons and pesticide residues were determined in the examined soils. In all cases the detected pollutants did not exceed the admissible levels. The highest content of oil-derived substances was noted in soils from Białystok Fabryczny and concentrations were moderate in soils from Siemianówka. Although the pollutants determined in soils from railway tracks did not exceed the admissible values, they had a toxic effect on numerous test organisms from different trophic levels. This suggests a synergistic effect of low concentrations (within the admissible levels) of several pollutants together, which resulted in a toxic effect on the organisms. Thus, there is a strong need of not only chemical, but also ecotoxicological analyses during the evaluation of environmental conditions. Based on data obtained from biological and chemical analyses, we concluded that railway transport may pose a hazard to the natural environment to a larger extent that hitherto expected.

Assessment of sediment ecotoxicological status as a complementary tool for the evaluation of surface water quality: the Ebro river basin case study

According to the European Water Framework Directive (WFD), assessment of surface water status is based on ecological and chemical status that is not always in coherence. In these situations, ecotoxicity tests could help to obtain a better characterization of the ecosystems. The general aim of this work is to design a methodology to study the ecotoxicological status of freshwater systems. This could be useful and complementary to ecological status, for a better ecological characterization of freshwater systems. For this purpose, sediments from thirteen sampling sites within the Ebro river watershed (NE Spain) were collected for ecotoxicity characterization. The ecotoxicity of pore water has been evaluated employing the test organisms Vibrio fischeri, Pseudokirschneriella subcapitata and Daphnia magna, while whole sediment ecotoxicity was evaluated using Vibrio fischeri, Daphnia magna, Nitzschia palea and Chironomus riparius. An analysis of acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) was performed to evaluate the sediment toxicity associated to bioavailable metals. Moreover, data about priority pollutants defined by the WFD in water, sediment and fish as well as data of surface water status of each sampling point were provided by the Monitoring and Control Program of the Ebro Water bodies. In general terms, whole sediment bioassays have shown more toxicity than pore water tests. Among the different organisms used, P. subcapitata and C. riparius were the most sensitive in pore water and whole sediment, respectively. Our evaluation of the ecotoxicological status showed high coincidences with the ecological status, established according to the WFD, especially when ecosystem disruption due to numerous stressors (presence of metals and organic pollution) was observed. These results allow us to confirm that, when chemical stressors affect the ecosystem functioning negatively, an ecotoxicological approach, provided by suitable bioassays in pore water and whole sediment, could detect these changes with accurate sensitivity.

Removal of antineoplastic drugs cyclophosphamide, ifosfamide, and 5-fluorouracil and a vasodilator drug pentoxifylline from wastewaters by ozonation

We investigated the ozonation of the antineoplastic drugs cyclophosphamide (CP), ifosfamide (IF), and 5-fluorouracil (5-FU) and of the vasodilator pentoxifylline (PEN) in distilled water, in pharmaceutical wastewater, and in hospital effluent at pH 5-11. Under an alkaline pH of 11, all of the target compounds rapidly degraded through the attack of hydroxyl radicals, which resulted in their complete removal within 5 min at an ozone supply rate of 3 g O3/h. Under acidic pH conditions, such as pH 5.6, CP and IF exhibited slower removal rates; however, compounds with unsaturated C-C bonds, such as 5-FU and PEN, were still removed at rapid rates under acidic conditions. Although the parent compounds were removed within minutes, the resulting ozonation byproducts were resistant to further ozonation and possessed increased Microtox acute toxicity. In distilled water, the resulting ozonation products exhibited minimal mineralization but high acute toxicity, whereas in naturally buffered pharmaceutical and hospital effluents, the byproducts were more amenable to removal and detoxification.

Chemical pollution and toxicity of water samples from stream receiving leachate from controlled municipal solid waste (MSW) landfill

The present study was aimed to determine the impact of municipal waste landfill on the pollution level of surface waters, and to investigate whether the choice and number of physical and chemical parameters monitored are sufficient for determining the actual risk related to bioavailability and mobility of contaminants. In 2007-2012, water samples were collected from the stream flowing through the site at two sampling locations, i.e. before the stream׳s entry to the landfill, and at the stream outlet from the landfill. The impact of leachate on the quality of stream water was observed in all samples. In 2007-2010, high values of TOC and conductivity in samples collected down the stream from the landfill were observed; the toxicity of these samples was much greater than that of samples collected up the stream from the landfill. In 2010-2012, a significant decrease of conductivity and TOC was observed, which may be related to the modernization of the landfill. Three tests were used to evaluate the toxicity of sampled water. As a novelty the application of Phytotoxkit F™ for determining water toxicity should be considered. Microtox(®) showed the lowest sensitivity of evaluating the toxicity of water samples, while Phytotoxkit F™ showed the highest. High mortality rates of Thamnocephalus platyurus in Thamnotoxkit F™ test can be caused by high conductivity, high concentration of TOC or the presence of compounds which are not accounted for in the water quality monitoring program.

Relationships between nuclear magnetic resonance parameters used to characterize weathering spilled oil and soil toxicity in central Patagonia

Oil spill in the Central Patagonian zone was studied to evaluate if any relationship exists between the parameters used to characterize weathering spilled oil and soil toxicity for two plant species and to evaluate if the phytotoxicity to local species would be a good index for the soil contamination. Nuclear magnetic resonance (NMR) structural indexes and column chromatography compositional indexes were determined to characterize the oil spill in the soil samples. Bioassays were also carried out using Lactuca sativa L (reference) and Atriplex lampa (native species) as test organisms. Measurements of the total petroleum hydrocarbon (TPH) and the electrical conductivity (EC) of the soil were carried out to evaluate the effect on the bioassays. The principal components analysis of the parameters determined by NMR, compositional indexes, EC, TPH, and toxicology data shows that the first three principal components accounted for the 78% of the total variance (40%, 25%, and 13% for the first, second, and third PC, respectively). A good agreement was found between information obtained by compositional indexes and NMR structural indexes. Soil toxicity increases with the increase of EC and TPH. Other factors, such as, the presence of branched and aromatic hydrocarbons is also significant. The statistical evaluation showed that the Euclidean distances (3D) between the background and each one of the samples might be a better indicator of the soil contamination, compared with chemical criterion of TPH.

Integrated assessment of runoff from livestock farming operations: Analytical chemistry, in vitro bioassays, and in vivo fish exposures

Animal waste from livestock farming operations can contain varying levels of natural and synthetic androgens and/or estrogens, which can contaminate surrounding waterways. In the present study, surface stream water was collected from 6 basins containing livestock farming operations. Aqueous concentrations of 12 hormones were determined via chemical analyses. Relative androgenic and estrogenic activity was measured using in vitro cell assays (MDA-kb2 and T47D-Kbluc assays, respectively). In parallel, 48-h static-renewal in vivo exposures were conducted to examine potential endocrine-disrupting effects in fathead minnows. Mature fish were exposed to surface water dilutions (0%, 25%, 50%, and 100%) and 10-ng/L of 17α-ethynylestradiol or 50-ng/L of 17β-trenbolone as positive controls. Hepatic expression of vitellogenin and estrogen receptor α mRNA, gonadal ex vivo testosterone and 17β-estradiol production, and plasma vitellogenin concentrations were examined. Potentially estrogenic and androgenic steroids were detected at low nanogram per liter concentrations. In vitro estrogenic activity was detected in all samples, whereas androgenic activity was detected in only 1 sample. In vivo exposures to the surface water had no significant dose-dependent effect on any of the biological endpoints, with the exception of increased male testosterone production in 1 exposure. The present study, which combines analytical chemistry measurements, in vitro bioassays, and in vivo fish exposures, highlights the integrated value and future use of a combination of techniques to obtain a comprehensive characterization of an environmental chemical mixture.

Evaluation of usefulness of Microbial Assay for Risk Assessment (MARA) in the cyanobacterial toxicity estimation

The aim of the study was to elucidate the usefulness of the Microbial Assay for Risk Assessment (MARA) to evaluate toxicity in samples containing cyanobacterial products. Cyanobacterial extracts with different cyanotoxin contents and pure cyanotoxins-microcystin-LR, cylindrospermopsin and anatoxin-a-were tested. On the basis of the microbial reaction, MARA indicated only slight or no toxicity in the studied extracts. Similarly, no or low toxicity of pure toxins was detected at the concentrations used (up to 10 μg/ml). Weak relationships between the reactions of individual organisms exposed to cyanotoxin-containing extracts and to the same pure toxins were observed. On the other hand, inhibition of some organisms, such as Pichia anomalia, whose growth was not impacted by pure cyanotoxins, indicated the presence of other biologically active compounds in the studied extracts. In conclusion, MARA assay is not enough sensitive to be used as a good tool for cyanotoxin screening. It may, however, be applied in searching for antimicrobial/antifungal cyanobacteria-derived compounds.

Amendment application in a multi-contaminated mine soil: effects on soil enzymatic activities and ecotoxicological characteristics

Several amendments were tested on soils obtained from an arsenopyrite mine, further planted with Arrhenatherum elatius and Festuca curvifolia, in order to assess their ability to improve soil's ecotoxicological characteristics. The properties used to assess the effects were: soil enzymatic activities (dehydrogenase, β-glucosidase, acid phosphatase, urease, protease and cellulase), terrestrial bioassays (Eisenia fetida mortality and avoidance behaviour), and aquatic bioassays using a soil leachate (Daphnia magna immobilisation and Vibrio fischeri bioluminescence inhibition). The treatment with FeSO4 1 % w/w was able to reduce extractable As in soil, but increased the extractable Cu, Mn and Zn concentrations, as a consequence of the decrease in soil pH, in relation to the unamended soil, from 5.0 to 3.4, respectively. As a consequence, this treatment had a detrimental effect in some of the soil enzymatic activities (e.g. dehydrogenase, acid phosphatase, urease and cellulase), did not allow plant growth, induced E. fetida mortality in the highest concentration tested (100 % w/w), and its soil leachate was very toxic towards D. magna and V. fischeri. The combined application of FeSO4 1 % w/w with other treatments (e.g. CaCO3 1 % w/w and paper mill 1 % w/w) allowed a decrease in extractable As and metals, and a soil pH value closer to neutrality. As a consequence, dehydrogenase activity, plant growth and some of the bioassays identified those as better soil treatments to this type of multi-contaminated soil.

Phytotoxkit/Phytotestkit and Microtox® as tools for toxicity assessment of sediments

The aim of the study was to use bioassays to evaluate the toxicity of pore water, sediments and sediments elutriates. Furthermore, a possible relationship between observed toxicity and results of chemical analysis was examined. Sediment (0-10 cm) samples were collected from 21 locations in Zeslawice reservoir, Southern Poland using an Ekman sampler. Toxicity assessment of the sediment and pore water samples was performed using direct-contact tests Phytotoxkit/Phytotestkit and Microtox®. Inhibition of seed germination in the test plants was from -25 to 38 percent for sediment and from 0 to 50 percent for pore water, whereas inhibition of root growth was within a range from -42 to 37 percent for sediment and from -49 to 37 percent for pore water. Depending on the sediments, Vibrio fischeri luminescence inhibition was from -18 to 40 percent for sediments elutriates and from -12 to 28 percent for pore water. The toxicity tests showed a positive correlation between metals and the root growth inhibition in Lepidium sativum and Sinapis alba as well as the luminescence inhibition in V. fischeri. No significant correlations were found between the inhibition of luminescence and the phytotoxicity assays, so these analyses do not show a similar sensitivity to toxicants in the sediments. While estimating the sensitivity of the performed biotests, the highest number of toxic responses was recorded in the Microtox® test towards V. fischeri. Among the plant species, Sorghum saccharatum appears to be the most sensitive plant species. Most of the examined sediment samples (67 percent) were classified as class II (low-toxic samples, low acute hazard) and 33 percent of the examined samples were class I (no essential toxic effect, non-toxic sample, no acute hazard) in terms of toxicity. Most of the pore water samples (71 percent) were also classified as class II.

Identification of toxicity variations in a stream affected by industrial effluents using Daphnia magna and Ulva pertusa

A comprehensive toxicity monitoring study from August to October 2011 using Daphnia magna and Ulva pertusa was conducted to identify the cause of toxicity in a stream receiving industrial effluents (IEs) from a textile and leather products manufacturing complex. Acute toxicity toward both species was observed consistently in IE, which influenced toxicity of downstream (DS) water. A toxicity identification evaluation (TIE) confirmed that both Cu and Zn were key toxicants in the IE, and that the calculated toxicity based on Cu and Zn concentrations well simulated the variation in the observed toxicity (r(2)=0.9216 and 0.7256 for D. magna and U. pertusa, respectively). In particular, U. pertusa was sensitive enough to detect acute toxicity in DS and was useful to identify Zn as a key toxicant. Activities of catalase, superoxide dismutase, glutathione peroxidase, glutathione S-transferase, and malondialdehyde were induced significantly in D. magna, although acute toxicity was not observed. In addition, higher levels of antioxidant enzymes were expressed in DS than upstream waters, likely due to the Cu and Zn from IE. Overall, TIE procedures with a battery of bioassays were effective for identifying the cause of lethal and sub-lethal toxicity in effluent and stream water.

Sensitivity of different aquatic bioassays in the assessment of a new natural formicide

Agrochemicals have the potential to cause deleterious effects on living organisms and therefore they must be subjected to various (eco)toxicological studies and monitoring programs in order to protect human health and the environment. The aim of this study was to assess the ecotoxicity of a new natural formicide with a battery of three classical and three ecotox-kit tests. The former tests were performed with Aliivibrio fischeri bacteria (Lumistox test), the cladoceran Daphnia magna and Pseudokirchneriella subcapitata algae, and the latter with Thamnotoxkit F(TM) (Thamnocephalus platyurus), Ostracodtoxkit F® (Heterocypris incongruens) and LuminoTox (photosynthetic enzyme complexes). In the range of formicide concentrations tested (from 0.06 to 2.0 g L(-1)), the measurement endpoint values varied from 0.79 g L(-1) for the algal test to > 2 g L(-1) for the LuminoTox and Ostracodtoxkit F® tests. Hierarchical sensitivity ranking based on the no-observed effect concentration (NOEC) values established to assess the formicide ecotoxicity was as follows: algal growth inhibition test ≈ daphnid immobilization test ≈ bacterial luminescence inhibition test > Thamnotoxkit F™ > LuminoTox > Ostracodtoxkit F®. Overall, results from the battery of bioassays showed that this formicide preparation presents low ecotoxicity as compared to the aquatic ecotoxicity of presently commercialized formicides. In conclusion, classical aquatic bioassays are more sensitive than ecotox-kit tests in the assessment and monitoring of the new natural formicide.

Seasonal alterations of landfill leachate composition and toxic potency in semi-arid regions

The present study investigates seasonal variations of leachate composition and its toxic potency on different species, such as the brine shrimp Artemia franciscana (formerly Artemia salina), the fairy shrimp Thamnocephalus platyurus, the estuarine rotifer Brachionus plicatilis and the microalgal flagellate Dunaliella tertiolecta. In specific, leachate regularly collected from the municipal landfill site of Aigeira (Peloponissos, Greece) during the year 2011, showed significant alterations of almost all its physicochemical parameters with time. Further analysis showed that seasonal alterations of leachate composition are related with the amount of rainfall obtained throughout the year. In fact, rainfall-related parameters, such as conductivity (Cond), nitrates (NO(3)(-)), total nitrogen (TN), ammonium (NH(4)-N), total dissolved solids (TDS) and the BOD(5)/NH(4)-N ratio could merely reflect the leachate strength and toxicity, as verified by the significant correlations occurred among each of them with the toxic endpoints, 24 h LC(50) and/or 72 h IC(50), obtained in all species tested. According to the result of the present study, it could be suggested that the aforementioned leachate parameters could be used independently, or in combination as a low-cost effective tools for estimating leachate strength and toxic potency, at least in the case of semi-arid areas such as the most of the Mediterranean countries.

Identification of specific malformations of sea urchin larvae for toxicity assessment: application to marine pisciculture effluents

Standard toxicity screening tests are useful tools in the management of impacted coastal ecosystems. To our knowledge, this is the first time that the sea urchin embryo development test has been used to evaluate the potential impact of effluents from land-based aquaculture farms in coastal areas. The toxicity of effluents from 8 land-based turbot farms was determined by calculating the percentage of abnormal larvae, according to two criteria: (a) standard, considering as normal pyramid-shaped larvae with differentiated components, and (b) skeletal, a new criterion that considers detailed skeletal characteristics. The skeletal criterion appeared to be more sensitive and enabled calculation of effective concentrations EC(5), EC(10), EC(20) and EC(50), unlike the classical criterion. Inclusion of the skeleton criterion in the sea urchin embryo development test may be useful for categorizing the relatively low toxicity of discharges from land-based marine fish farms. Further studies are encouraged to establish any causative relationships between pollutants and specific larval deformities.

Environmental impact of industrial sludge stabilization/solidification products: chemical or ecotoxicological hazard evaluation?

Nowadays, the classification of industrial solid wastes is not based on risk analysis, thus the aim of this study was to compare the toxicity classifications based on the chemical and ecotoxicological characterization of four industrial sludges submitted to a two-step stabilization/solidification (S/S) processes. To classify S/S products as hazardous or non-hazardous, values cited in Brazilian chemical waste regulations were adopted and compared to the results obtained with a battery of biotests (bacteria, alga and daphnids) which were carried out with soluble and leaching fractions. In some cases the hazardous potential of industrial sludge was underestimated, since the S/S products obtained from the metal-mechanics and automotive sludges were chemically classified as non-hazardous (but non-inert) when the ecotoxicity tests showed toxicity values for leaching and soluble fractions. In other cases, the environmental impact was overestimated, since the S/S products of the textile sludges were chemically classified as non-inert (but non-hazardous) while ecotoxicity tests did not reveal any effects on bacteria, daphnids and algae. From the results of the chemical and ecotoxicological analyses we concluded that: (i) current regulations related to solid waste classification based on leachability and solubility tests do not ensure reliable results with respect to environmental protection; (ii) the two-step process was very effective in terms of metal immobilization, even at higher metal-concentrations. Considering that S/S products will be subject to environmental conditions, it is of great interest to test the ecotoxicity potential of the contaminants release from these products with a view to avoiding environmental impact given the unreliability of ecotoxicological estimations originating from chemical analysis.

A comparative study on toxicity identification of industrial effluents using Daphnia magna

In this study, acute toxicity monitoring and toxicity identification evaluation procedures were applied to identify causative toxicants in industrial effluents. Effluents from a metal plating factory and a rubber products factory were acutely toxic toward Daphnia magna and the toxicity varied over different sampling events (2.9-5.9 and 1.7-7.6 TU, respectively). For the rubber products effluent, it was confirmed that zinc (5.65-13.18 mg L(-1)) was found to be a major cause of toxicity, which is likely originated from zinc 2-mercaptobenzothiazole and zinc diethyldithiocarbamate used as vulcanization accelerators. For the metal plating effluent, it appeared that the presence of high concentrations of Cl(-) and SO(4)(2-) (8,539-11,400 and 3,588-4,850 mg L(-1), respectively) caused the observed toxicity. These toxicants likely originated from sodium bisulfate (NaHSO(3)) and sodium hypochlorite (NaOCl) used as reducing and oxidizing agents. Though copper was found to be present in levels much higher than the EC(50) (50% effective concentration) value, this was not attributable to the toxicity of metal plating effluent likely due to complexation with dissolved organic matter.

Evaluation of the hazardous impact of landfill leachates by toxicity and biodegradability tests

The aim of our research was to assess the ecotoxicity and biodegradability of leachates originating from two parts of a municipal landfill before and after biological treatment in the existing treatment plant. Biotests represent important tools for adequate environmental characterization of landfill leachates and could be helpful in reliable assessment and monitoring of the treatment plant efficiency. For ecotoxicity testing of landfill leachate before and after biological treatment, different organisms were chosen: the bacteria Vibrio fischeri, a mixed culture of activated sludge, duckweed Lemna minor, white mustard Sinapis alba, brine shrimp Artemia salina, and water flea Daphnia magna. For assessment of biodegradability, the method for determination of oxygen demand in a closed respirometer was used. The investigated leachates were heavily polluted, and in some cases, effluent limits were exceeded even after treatment. Results indicated that toxicity tests and physico-chemical parameters determined before and after treatment equivalently assess the efficiency of the existing treatment plant. However, the investigated leachates showed higher toxicity to Daphnia magna and especially to Lemna minor in contrast to Vibrio fischeri and Artemia salina (neither was sensitive to any of the leachates). No leachates were readily biodegradable. Experiments confirmed that the battery of toxicity tests should be applied for more comprehensive assessment of landfill leachate treatment and for reliable assessment of the treated leachate's subsequent environmental impact. It was confirmed that treated leachate, in spite of its better physico-chemical characteristics, still represents a potential environmental risk and thus should not be released into the environment.

Genotoxicity study of photolytically treated 2-chloropyridine aqueous solutions

2-Chloropyridine (2-CPY) has been identified as a trace organic chemical in process streams, wastewater and even drinking water. Furthermore, it appears to be formed as a secondary pollutant during the decomposition of specific insecticides. As reported in our previous work, 2-CPY was readily removed and slowly mineralised when subjected to ultraviolet (UV) irradiation at 254 nm. Moreover, 2-CPY was found to be genotoxic at 100 microg ml(-1) but it was not genotoxic at or below 50 microg ml(-1). In this work 2-CPY aqueous solutions were treated by means of UV irradiation at 254 nm. 2-CPY mineralisation history under different conditions is shown. 2-CPY was found to mineralise completely upon prolonged irradiation. Identified products of 2-CPY photolytic decomposition are presented. Solution genotoxicity was tested as a function of treatment time. Aqueous solution samples, taken at different photo-treatment times were tested in cultured human lymphocytes applying the cytokinesis block micronucleus (CBMN) assay. It was found that the solution was genotoxic even when 2-CPY had been practically removed. This shows that photo-treatment of 2-CPY produces genotoxic products. Upon prolonged irradiation solution genotoxicity values approached the control value.

Phytotoxicity of sulfamethazine soil pollutant to six legume plant species

The effect of traces of sulfamethazine (SMZ) in soil (0.01, 0.1, 0.25, 1, 5, 15, and 20 mM) on cellular distribution of cytochrome c oxidase activity, shoot and root growth, and leachate electroconductivity was analyzed in germinating seeds of yellow lupin, pea, lentil, soybean, adzuki bean, and alfalfa. Results showed that a high activity of cytochrome c oxidase in mitochondria correlated with high seed vigor and viability. The appearance of necroses and root decay was associated with a decrease in the activity of mitochondrial cytochrome c oxidase but was accompanied by an increase in cytosolic cytochrome c oxidase activity. A short exposure period of seeds (3 and 6 d) to sulfamethazine did not influence germination. Elongation of roots and stems was more sensitive than germination rate as an indicator of soil contamination by sulfamethazine. Among all tested leguminous plants, yellow lupin was the most reliable bioindicator of SMZ contaminated soil.

Overview of ecotoxicological studies performed in the Venice Lagoon (Italy)

This work reports on the state of the art of the bioindicators used to assess environmental quality (regarding chemical pollutant impacts) in the Venice lagoon. After a brief description of the roles, advantages and limitations of bioindicators in marine and transitional environments and a summary of the Venice lagoon characteristics, the ecotoxicological methods used during scientific studies and research projects in the Lagoon are reported. Since not all data are available and no database can be formulated, the main evidence from toxicity bioassays, biomarkers and bioaccumulation analyses since the end of the 1970s is spatially synthesized using maps and discussed according to the four Venice lagoon basins. The majority of indicators showed that the Lido basin (north-central lagoon), affected by the presence of the industrial area and the city of Venice, is the one most highly impacted (particularly in the sites located within or in front of the industrial area, which showed very high sediment toxicity and high levels of DNA damage). The Malamocco basin (south-central lagoon) seems to be the least problematic. The southern basin (Chioggia basin) was shown to be impacted by urban contaminants from the town of Chioggia. The northern basin (Treporti basin) presented both impacted sites (high toxicity and high bioaccumulation factor) and relatively unpolluted sites (absence of toxicity, absence of imposex and low levels of bioaccumulation). This review can serve as a basis on which to select pragmatic, cost-effective biomonitoring techniques for environmental effects in lagoon ecosystems.

Development of a novel biotoxicity screening assay for analytical use

A new biotoxicity assay has been developed and employed as an analytical screening tool. The proposed biotoxicity assay is simple and represents the first example of the use of Lactobacillus plantarum as a test micro-organism. The applicability of this method was demonstrated by evaluating the pollution of water due to the presence of several toxicants. Traditional parameters such as effective concentration (EC(50)) and lowest observed effect concentration (LOEC) provided by all the biotoxicity tests were employed in a screening method based on a binary toxic/non-toxic response. The threshold of the response was characterized by defining a mortality index (I(m)), which in this case was obtained by monitoring the consumption of glucose in the culture medium (Somogyi-Nelson method) or by turbidimetric measurements. Cut-off values established by the current legislation (or other preset values) were used as criteria to classify samples as positive or negative. Bacterial growth was inhibited by the presence of heavy metals such as mercury, cadmium, lead, copper and zinc. This methodology was applied to study the toxicity of heavy metals in different water samples.

Application of a microbiotests battery for complete toxicity assessment of rivers

Acute hazard classification based on selected microbiotests was proposed to assess and compare the toxicity of rivers including surface-water, sediment and soil from floodplains. No direct relationship between the classification of pollution for surface-water based on physical-chemical parameters and proposed acute hazard classification based on organisms' sensitivity was observed. The quality of water according to hazard classification was better than in the mandatory classification of pollution, with the domination of Class II (slight acute hazard). The samples of sediment and soil were more toxic and represented Class II or Class III (acute hazard). The results indicated a need to complete the mandatory monitoring of surface-water in rivers with biological monitoring with toxicity assessment of rivers including water, sediment and soil from floodplains based on acute hazard classification. This integral approach enables a complete evaluation of the toxicity of aquatic life together with an estimation of negative changes in river systems.

Toxicity identification in metal plating effluent: implications in establishing effluent discharge limits using bioassays in Korea

Because of complexity and diversity of toxicants in effluent, chemical analysis alone gives very limited information on identifying toxic chemicals to test organisms. Toxicity identification evaluation (TIE) techniques have been widely used to identify toxicants in various samples including industrial wastewater as well as natural waters. In response to new regulation for effluent discharge in Korea, which will be effective from 2011, a necessity of studies emerges that investigates toxicity levels in industrial effluents. This work was a preliminary study examining toxicity levels in effluent from one metal plating factory using Daphnia magna (48 h immobility) and identifying toxicity-causing substances. Toxicity tests showed variability on different sampling occasions and the results of TIE methods indicated that both organic compounds and metals contributed to the observed toxicity in metal plating effluent. Further studies are necessary to help reduce effluent toxicity especially from direct dischargers, who will have to comply with the new regulation.