Eco(geno)toxicity of the new commercial insecticide Platinum Neo, a mixture of the neonicotinoid thiamethoxam and the pyrethroid lambda-cyhalothrin.

New mixtures of pesticides are being placed on the market to increase the spectrum of phytosanitary action. Thus, the eco(geno)toxic effects of the new commercial mixture named Platinum Neo, as well as its constituents the neonicotinoid Thiamethoxam and the pyrethroid Lambda-Cyhalothrin, were investigated using the species Daphnia magna, Raphidocelis subcapitata, Danio rerio, and Allium cepa L. The lowest- and no-observed effect concentration (LOEC and NOEC) were measured in ecotoxicological tests. While Thiamethoxam was ecotoxic at ppm level, Lambda-Cyhalothrin and Platinum Neo formulation were ecotoxic at ppb level. The mitotic index (MI), chromosomal aberrations and micronucleus [MN] frequency were measured as indicators of phytogenotoxicity in A. cepa plants exposed for 12 h to the different insecticides and their mixture under different dilutions. There were significant alterations in the MI and MN frequency in comparison with the A. cepa negative control group, with Thiamethoxam, Lambda-Cyhalothrin, and Platinum Neo treatments all significantly reducing MI and increasing MN frequency. Thus, MI reduction was found at 13.7 mg L-1 for Thiamethoxam, 0.8 µg L-1 for Lambda-Cyahalothrin, and 2.7:2 µg L-1 for Platinum Neo, while MN induction was not observed at 14 mg L-1 for Thiamethoxam, 0.8 µg L-1 for Lambda-Cyahalothrin, and 1.4:1 µg L-1 for Platinum Neo. The insecticide eco(geno)toxicity hierarchy was Platinun Neo > Lambda-Cyhalothrin > Thiamethoxam, and the organism sensitivity hierarchy was daphnids > fish > algae > A. cepa. Eco(geno)toxicity studies of new pesticide mixtures can be useful for management, risk assessment, and avoiding impacts of these products on living beings.

Are hospital wastewater treatment plants a source of new resistant bacterial strains?

To understand which type of hospital waste may contain the highest amount of antibiotic resistant microorganisms that could be released into the environment, the bacterial strains entering and leaving a hospital wastewater treatment plant (HWTP) were identified and tested for their antibiotic susceptibility. To achieve this goal, samples were collected from three separate sites, inlet and outlet wastewater positions, and sludge generated in a septic tank. After microbiological characterization according to APHA, AWWA, and WEF protocols, the relative susceptibility of the bacterial strains to various antibiotic agents was assessed according to the Clinical and Laboratory Standards Institute guidelines, to determine whether there were higher numbers of resistant bacterial strains in the inlet wastewater sample than in the outlet wastewater and sludge samples. The results showed more antibiotic resistant bacteria in the sludge than in the inlet wastewater, and that the Enterobacteriaceae family was the predominant species in the collected samples. The most antibiotic-resistant families were found to be Streptococcacea and non-Enterobacteriaceae. Some bacterial strains were resistant to all the tested antibiotics. We conclude that the studied HWTP can be considered a source of resistant bacterial strains. It is suggested that outlet water and sludge generated in HWTPs should be monitored, and that efficient treatment to eliminate all bacteria from the different types of hospital waste released into the environment is adopted.

An alternative approach to assess ecotoxicological effects of agrochemical combinations used in Brazilian aquaculture farms.

Agrochemicals used for treating and preventing aquaculture diseases are usually present in combination with other compounds, and the toxicity resulting from their chemical interactions presents an important reason to assess the ecotoxicity of compound mixtures in view to better understanding the joint action of chemicals and avoiding their environmental impacts. In this study, we evaluated the acute aquatic ecotoxicity of several compounds used in Brazilian fish farming (Oxytetracycline [OXT], Trichlorfon [TRC], and BioFish® [BIO]), both individually and in binary and ternary mixtures. Initial test concentrations were prepared according to the recommended concentrations for aquaculture application, and from these, a geometric dilution series was tested on two important fresh water quality indicator species, the microcrustacean Daphnia magna and the bacterium Aliivibrio fischeri. At the recommended pond application rate, TRC and BIO applied individually showed toxicity to the tested organisms in terms of the lowest-observed-effect concentration (LOEC), and D. magna was always more sensitive than A. fischeri. For the two test organisms, the results obtained with the binary mixtures showed that the TRC and BIO mixture was more toxic than TRC and OXT, which in turn was more toxic than OXT and BIO. The toxicity from all agrochemicals in the ternary mixture was more than that of the agrochemical combinations in the binary mixtures. Given the results presented in this study, it is evident that the mode of action and availability of the tested compounds undergo changes that increase toxicity when they are present in combination, and therefore, aquaculture wastewater treatment should be adopted to ensure decontamination of agrochemical residues.

Using photocatalyzed-peroxonization to disinfect and denature genetic material of bacterial plasmids present in hospital wastewater.

The literature reports the presence of multiresistant microorganisms in wastewater discharged from municipal and hospital wastewater treatment plants (WWTPs). This has led to questions concerning the disinfection efficiency of the treatments applied. Thus, this study aimed to assess the efficiency of different chemical oxidation methods to disinfect and to degrade bacterial plasmids present in hospital wastewaters, to avoid the dispersion of antibiotic resistance genes in the environment. The methods tested were UV254nm alone or associated with an Ag or Ti-photocatalyst in photo-peroxonization (UV254 nm/H2O2/O3/Ag2O/Ag2CO3@PU or UV254 nm/H2O2/O3/TiO2@PU) under different pH conditions (4, 7, and 10). The application of plasmid DNA electrophoresis to hospital wastewater treated using an advanced oxidation process (AOP) achieved the total structural denaturation of microorganism plasmids at the three pH values tested. Also, UV254 nm alone was partially efficient in the disinfection of hospital wastewater. AOPs performed with the two functionalized catalysts resulted in 100% disinfection after 10 min at the three pH values tested. No intact plasmids were observed after 20 min of treatment with photocatalysis. This study could contribute to the development and improvement of wastewater treatment aimed at mitigating the spread of multiresistant microorganisms in the environment.

Swine slaughterhouse biowaste: an environmental sustainability assessment of composting, amended soil quality, and phytotoxicity.

In this article, the environmental sustainability of a circular economy concept applied to the management of biowaste was studied. To achieve this goal, the composting performance, compost-amended soil health, and phytotoxicity were assessed in the case of management of solid waste from a small swine slaughterhouse. Microorganisms present in a similar composting process were used as inoculums to improve the efficiency of composting. Addition of the inoculum promoted a faster and more efficient composting process than composting without the inoculum. The physical, chemical, and microbiological characteristics of soil were considered to be improved after compost application. Phytotoxicity tests in soils with and without compost amendment showed that a soil-compost mixture (90:10 and 70:30 mass ratios) was not phytotoxic to the plant species Sorghum saccharatum and Lepidium sativum, and that soil with compost showed higher plant biomass growth than that without compost amendment. The triple bottom line methodology used in this study can help in the assessment of circular economy activity in relation to the environmentally sustainable management of solid waste generated in small swine slaughterhouses.

Urban afforestation: using phytotoxicity endpoints to compare air pollution tolerance of two native Brazilian plants Aroeira (Schinus terebinthifolius) and Cuvatã (Cupania vernalis).

Urban afforestation can mitigate the effects of air pollution, but the suitability of plant species for this purpose needs to be determined according to pollution intensity and climate change. The goal of this study was to evaluate the sensitivity of different phytotoxicity endpoints using two native Brazilian plant species as models, Aroeira (Schinus terebinthifolius) and Cuvatã (Cupania vernalis). The sensitivity parameters evaluated could help in selecting the most air-pollution-tolerant plant species for use in urban afforestation programs. The two plant species were exposed, in a greenhouse, to the combustion gases of a diesel engine for 120 days, with daily intermittent gas exposure. Every 30 days, leaf injury (chlorosis and necrosis), biomass, and physiological/biochemical parameters (proteins, chlorophyll, and peroxidase enzyme activity) were evaluated for both plant species. For the two selected species, the endpoints studied can be ranked according to their sensitivity (or inversely the tolerance) to diesel oil combustion gases in the following order: peroxidase > biomass ≈ chlorophyll > protein > leaf injury. The endpoint responses of higher plants can be used to assess the suitability of particular plant species for use in urban afforestation areas with relatively intense vehicle traffic.

Degradation of recalcitrant textile azo-dyes by fenton-based process followed by biochar polishing.

The use of advanced oxidative processes (AOPs) is an efficient alternative for the treatment of textile wastewaters. The aim of this study was to assess the dye removal efficiency of a Fenton-based degradation process followed by a polishing step using biochar prepared from rice husk. Six recalcitrant textile dyes - Reactive Red 195 (D1), Synolon Brown S2 (D2), Orange Remazol RGB (D3), Yellow Synozol K3 (D4), Reactive Orange (D5), and Reactive Black 5 (D6) - were treated with Fenton and photo-Fenton processes (with and without biochar polishing) under optimized conditions. The results showed a general efficiency ranking: photo-Fenton + biochar ≈ Fenton + biochar > photo-Fenton ≈ Fenton. The Fenton process was also efficient for the regeneration of the dye-saturated biochar. The photo-Fenton + biochar process achieved the following color removal percentages: D1 (98.8%), D2 (99.7%), D3 (98.9%), D4 (96.3%), D5 (94.2%) and D6 (94.8%). This process was applied to a real conventionally-treated textile wastewater and analysis showed a reduction in BOD (87.5% degradation), COD (62.5% degradation) and color (93.5% mean removal). These results reveal the possibility for the reuse of the treated water for non-potable industrial uses, for example, floor washing or the cleaning of machines and toilet areas.

Using textile industrial sludge, sewage wastewater, and sewage sludge as inoculum to degrade recalcitrant textile dyes in a co-composting process: an assessment of biodegradation efficiency and compost phytotoxicity.

Recalcitrant dyes found in textile wastewater represent a threat for sustainable textile production due to their resistance to conventional treatments. This study assessed an alternative co-composting system for the treatment of recalcitrant textile dyes where textile industrial sludge, sewage wastewater, or sewage sludge were used as microbial compost inocula. The biodegradation efficiency of bioreactor trials and compost quality of the co-composting system were assessed by visible spectrophotometry and by a phytotoxicity test. The co-composting system (dry weight (dw) basis) consisted of 200 g of restaurant organic residues + 200 g sewage sludge (or 100 mL sewage wastewater, or 200 g textile sludge) + 100 mL of a 10% dye solution (Reactive Red 195, or Synolon Brown, or Orange Remazol, or Yellow Synozol, or Reactive Orange 122, or Reactive Black 5). After 60 days of composting, all dyes were biodegraded according to spectrophotometric data, with efficiency varying from 97.2 to 99.9%. Inoculum efficiency ranking was textile sludge > sewage sludge > sewage wastewater. Regarding compost quality, a phytotoxicity study with lettuce showed no toxicity effect. Thus, co-composting can be a low-cost and efficient method for recalcitrant textile dye biodegradation and for managing textile sludge in terms of waste recycling, contributing to environmental sustainability.

A 3D ecotoxi-topological profile: Using concentration-time-response surfaces to show peroxidase activity in Zea mays (L.) exposed to aluminium or arsenic in hydroponic conditions.

This study sought to use concentration-time-response surfaces to show the effects of exposure to toxic (semi-)metals on peroxidase activity in higher plants as a function of exposure-concentration and exposure-time. Maize (Zea mays L.) seedlings (i.e., leaves and roots) were exposed to arsenic (as As3+) or aluminium (as Al3+) under hydroponic conditions, and their biomass and peroxidase enzyme responses were assessed at different concentration-time-exposures. The 3D ecotoxi-profile generated with these data showed two distinct regions: the first region is formed by exposures (i.e., points for time-concentration pairings) that were not statistically different from the results of the control points (i.e., zero toxicant concentration and all exposure-times), whereas the second region is formed by exposure pairings with results that were statistically different to those obtained from control pairings. Overall, the data show that enzyme activity increased over a shorter exposure-time when there was an increase in the exposure-concentration of the toxicant, which can be seen on a 3-D toxicity profile. We propose that quantitative relationship ratios from different assessed endpoints (e.g., biomass and enzyme activity) and enzymatic concentration-time-response surfaces could be helpful in the field of environmental-policy management.

Sensitivity of different parameters for selection of higher plants in urban afforestation: Exposure of Guabiroba (Campomanesia xanthocarpa O. Berg.) to diesel engine exhaust.

Urban afforestation can mitigate the effects of air pollution by acting as a sink for atmospheric emissions, but these emissions (e.g., combustion gases from diesel engines) can be a precursor of structural and physiological changes in higher plant species, which could compromise the success of afforestation projects. In this study, Guabiroba (Campomanesia xanthocarpa O. Berg.) plants were exposed in greenhouses to combustion gases emitted by a diesel engine over 120 days, with daily intermittent gas exposure. Every 30 days, leaf injury (chlorosis and necrosis), plant biomass and physiological/biochemical parameters (proteins, chlorophyll and peroxidase enzyme activity) were evaluated. The data obtained were used to construct a hierarchy of the sensitivity (and inversely, of the resistance or tolerance) of this higher plant species to the diesel oil combustion gases: peroxidase > biomass ≈ chlorophyll > protein > leaf injury. Variations in these parameters could be used for the early diagnosis of plant stress or as a marker for stress tolerance in trees. In the first case, a sensitive species could be used for the phytomonitoring of air quality and in the second case the lack of significant variations in these parameters would indicator tolerance of the plant species to air pollution. The results showed that Guabiroba, a plant native to the Atlantic forest, is sensitive to air pollution and could therefore be used for air quality monitoring, since all parameters analyzed were affected by the polluted air.

Comparing different methods for fast screening of microbiological quality of beach sand aimed at rapid-response remediation.

There is scientific evidence that beach sands are a significant contributor to the pathogen load to which visitors are exposed. To develop beach quality guidelines all beach zones must be included in microbiological evaluations, but monitoring methods for beach sand quality are relatively longstanding, expensive, laborious and require moderate laboratory infrastructure. This paper aimed to evaluate the microorganism activity in different beach zones applying and comparing a classical method of membrane filtration (MF) with two colorimetric screening methods based on fluorescein (FDA) and tetrazolium (TTC) salt biotransformation to evaluate a new rapid and low-cost method for beach sand microbiological contamination assessments. The colorimetric results can help beach managers to evaluate rapidly and at low cost the microbiological quality of different beach zones in order to decide whether remedial actions need to be adopted to prevent exposure of the public to microbes due to beach sand and/or water contamination.

Ecotoxicity assessment of particulate matter emitted from heavy-duty diesel-powered vehicles: influence of leaching conditions.

Concerns regarding the environmental impact of diesel exhaust particulate matter (DPM) have increased in recent years. Following emission to the atmosphere, these fine materials can sorb many contaminants at their surface, which can subsequently be released, for instance, due to physicochemical environmental changes. The desorption of contaminants from particulate matter will increase the environmental pollution and can promote ecotoxicological effects. In this context, the objective of this study was to assess the aquatic ecotoxicity profile of extracts of DPM obtained at two different pH values. Thus, after collecting particulate matter from the diesel exhaust of heavy engines, extracts were obtained with pure water (at pH 2.00 and 5.00) and with a mixture of three organic solvents (dichloromethane, n-hexane, and acetone). To assess the environmental impact of DPM, the exhaust extracts were used in a battery of aquatic bioassays including key organisms of the food chain: bacteria (Aliivibrio fischeri), algae (Scenedesmus subspicatus), daphnids (Daphnia magna), and fishes (Danio rerio). The aqueous leachate at natural pH (2.0) and solvent extracts were extremely ecotoxic, while the aqueous leachate at pH = 5.0 showed the lowest ecotoxicity. The global ranking of sensitivity for the biotests tested was daphnids > algae > bacteria > fishes. Thus, the use of this bioassay battery could improve our understanding of the impact of DPM on aquatic environments, which is dependent on the pH of the leaching process.

Genotoxicity assessment of particulate matter emitted from heavy-duty diesel-powered vehicles using the in vivo Vicia faba L. micronucleus test.

Diesel exhaust particulate matter (PM) can have an impact on the environment due to its chemical constitution. A large number of substances such as organic compounds, sulfates, nitrogen derivatives and metals are adsorbed to the particles and desorption of these contaminants could promote genotoxic effects. The objective of this study was to assess the in vivo genotoxicity profile of diesel exhaust PM from heavy-duty engines. Extracts were obtained through leaching with pure water and chemical extraction using three organic solvents (dichloromethane, hexane, and acetone). The in vivo Vicia faba micronucleus test (ISO 29200 protocol) was used to assess the environmental impact of the samples collected from diesel exhaust PM. The solid diesel PM (soot) dissolved in water, and the different extracts, showed positive results for micronucleus formation. After the addition of EDTA, the aqueous extracts did not show a genotoxic effect. The absence of metals in the organic solvent extract indicated that organic compounds also had a genotoxic effect, which was not observed for a similar sample cleaned in a C18 column. Thus, considering the ecological importance of higher plants in relation to ecosystems (in contrast to Salmonella spp., which are commonly used in mutagenicity studies), the Vicia micronucleus test was demonstrated to be appropriate for complementing prokaryotic or in vitro tests on diesel exhaust particulate matter included in risk assessments.

Use of agro-industrial organic sludge amendment to remediate degraded soil: chemical and eco(geno)toxicological differences between fresh and stabilized sludge and establishment of application rates.

Soil degraded by coal mining activities can be remediated by amendment with agro-industrial organic sludge. However, the environmental impacts associated with this management practice must be properly addressed. In this context, the objective of this study was to evaluate the eco(geno)toxicity of a fresh and a stabilized sludge before use in a laboratory soil remediation test. Chemical analysis of the complex mixtures (degraded soil, fresh sludge, and stabilized sludge) was carried out, as well as a battery of eco(geno)toxicity tests on microbiological enzymes (fluorescein hydrolysis), earthworms, and higher plants (including Vicia faba genotoxicity test), according to published methodologies. The results of these tests showed that fresh sludge was more toxic than sludge stabilized over 6 months toward earthworms and higher plants (lettuce, corn, and wild cabbage), while phyto(geno)toxicity tests with V. faba indicated the same genotoxicity levels for the two types of sludge. In the soil remediation simulation using different mixtures of degraded soil and stabilized sludge, the proportions of 50:50% (dry weight basis) provided the lowest phyto(geno)toxicity effects and this mixture can be used for the revegetation of the contaminated site.

Leachates from solid wastes: chemical and eco(geno)toxicological differences between leachates obtained from fresh and stabilized industrial organic sludge.

The chemical and ecotoxicological characteristics of fresh and stabilized industrial organic sludge leachates were compared to obtain information regarding how the stabilization process can influence the ecotoxic potential of this industrial waste, which could be used for the amendment of degraded soil. Physicochemical analysis of the sludge leachates, as well as a battery of eco(geno)toxicity tests on bacteria, algae, daphnids, and higher plants (including Vicia faba genotoxicity test) and the determination of hydrolytic enzyme activity, was performed according to standard methods. The chemical comparison of the two types of leachate showed that the samples obtained from stabilized sludge had a lower organic content and higher metal content than leachates of the fresh sludge. The eco(geno)toxicological results obtained with aquatic organisms showed that the stabilized sludge leachate was more toxic than the fresh sludge leachate, both originating from the same industrial organic sludge sample. Nevertheless, phytotoxicity tests carried out with a reference peat soil irrigated with stabilized sludge leachate showed the same toxicity as the fresh sludge leachate. In the case of the industrial solid organic sludge studied, stabilization through a biodegradation process promoted a higher metal mobility/bioavailability/eco(geno)toxicity in the stabilized sludge leachate compared to the fresh sludge leachate.

Arsenate (As V) in water: quantitative sensitivity relationships among biomarker, ecotoxicity and genotoxicity endpoints.

It is useful to test ecotoxicity and genotoxicity endpoints in the environmental impact assessment. Here, we compare and discuss ecotoxicity and genotoxicity effects in organisms in response to exposure to arsenate (As V) in solution. Eco(geno)toxicity responses in Aliivibrio fischeri, Lytechinus variegatus, Daphnia magna, Skeletonema costatum and Vicia faba were analyzed by assessing different endpoints: biomass growth, peroxidase activity, mitotic index, micronucleus frequency, and lethality in accordance with the international protocols. Quantitative sensitivity relationships (QSR) between these endpoints were established in order to rank endpoint sensitivity. The results for the QSR values based on the lowest observed effect concentration (LOEC) ratios varied from 2 (for ratio of root peroxidase activity to leaf peroxidase activity) to 2286 (for ratio of higher plant biomass growth to root peroxidase activity). The QSR values allowed the following sensitivity ranking to be established: higher plant enzymatic activity>daphnids≈echinoderms>bacteria≈algae>higher plant biomass growth. The LOEC values for the mitotic index and micronucleus frequency (LOEC=0.25mgAsL(-1)) were similar to the lowest LOEC values observed in aquatic organisms. This approach to the QSR of different endpoints could form the basis for monitoring and predicting early effects of pollutants before they give rise to significant changes in natural community structures.

Aquatic ecotoxicity assessment of a new natural formicide.

BACKGROUND, AIM AND SCOPE: Agrochemicals could reach aquatic ecosystems and damage ecosystem functionality. Natural formicide could be an alternative to use in comparison with the more toxic formicides available on the market. Thus, the objective of this study was to assess the ecotoxicity of the new natural formicide Macex® with a battery of classical aquatic ecotoxicity tests. MATERIAL AND METHODS: Bacteria (Aliivibrio fischeri), algae (Pseudokirchneriella subcapitata), hydra (Hydra attenuata), daphnids (Daphnia magna), and fish (Danio rerio) tests were performed in accordance with international standardized methodologies. RESULTS: In the range of formicide concentrations tested (0.03 to 2.0 g L(-1)) EC(50) values varied from 0.49 to >2.0 g L(-1), with P. subcapitata being the most sensitive species and H. attenuata and D. rerio the most tolerant species to this product in aqueous solutions. CONCLUSIONS: This new formicide preparation can be classed as a product of low toxicity compared to the aquatic ecotoxicity of the most common commercialized formicides.

Terrestrial short-term ecotoxicity of a green formicide.

When ants become annoying, large quantities of formicide are applied to terrestrial ecosystems in tropical regions, but awareness of the health and environmental impacts related to the use of synthetic pesticides has been increasing. The use of green pesticides to combat target organisms could reduce these impacts. In this regard, terrestrial ecotoxicity tests with higher plants (Brassica olaracea, Lactuca sativa and Mucuna aterrima), annelids (Eisenia foetida), Collembola (Folsomia candida) and soil enzyme activity analysis (diacetate fluorescein hydrolysis) were used to evaluate short-term terrestrial ecotoxicity of a green pesticide prepared from naturally-occurring organic compounds. At the highest formicide concentration tested in these experiments (i.e., 50 g kg(-1) soil) no toxicity toward terrestrial organisms was observed. The lack of short-term terrestrial ecotoxicity suggest that this green formicide can be classed as an environmentally friendly product as compared to the ecotoxicity of the most commonly used commercialized formicides.

Cadmium phytotoxicity: Quantitative sensitivity relationships between classical endpoints and antioxidative enzyme biomarkers.

In this work, cadmium phytotoxicity and quantitative sensitivity relationships between different hierarchical endpoints in plants cultivated in a contaminated soil were studied. Thus, germination rate, biomass growth and antioxidative enzyme activity (i.e. superoxide dismutase, peroxidase, catalase and glutathione reductase) in three terrestrial plants (Avena sativa L., Brassica campestris L. cv. Chinensis, Lactuca sativa L. cv. hanson) were analyzed. Plant growth tests were carried out according to an International Standard Organization method and the results were analyzed by ANOVA followed by Williams' test. The concentration of Cd2+ that had the smallest observed significant negative effect (LOEC) on plant biomass was 6.25, 12.5 and 50 mg Cd/kg dry soil for lettuce, oat and Chinese cabbage, respectively. Activity of all enzymes studied increased significantly compared to enzyme activity in plant controls. For lettuce, LOEC values (mg Cd/kg dry soil) for enzymic activity ranged from 0.05 (glutathione reductase) to 0.39 (catalase). For oat, LOEC values (mg Cd/kg dry soil) ranged from 0.19 (for superoxide dismutase and glutathione reductase) to 0.39 (for catalase and peroxidase). For Chinese cabbage, LOEC values (mg Cd/kg dry soil) ranged from 0.19 (peroxidase, catalase and glutathione reductase) to 0.39 (superoxide dismutase). Classical (i.e. germination and biomass) and biochemical (i.e. enzyme activity) endpoints were compared to establish a sensitivity ranking, which was: enzyme activity>biomass>germination rate. For cadmium-soil contamination, the determination of quantitative sensitivity relationships (QSR) between classical and antioxidative enzyme biomarkers showed that the most sensitive plant species have, generally, the lowest QSR values.