Ecological consequences when organisms avoid a contaminated environment: A study evaluating the toxicity of fipronil.

The ability of aquatic organisms to sense the surrounding environment chemically and interpret these signals correctly is crucial to their survival and ecological niche. This study applied the Heterogenous Multi-Habitat Assay System - HeMHAS to evaluate the avoidance potential of Daphnia magna to detect fipronil-contaminated habitats in a connected landscape after a short (48 h), previous, forced exposure to an environmentally relevant concentration of the same insecticide. The swimming of daphnids was also analyzed by recording the total distance covered. D. magna preferred areas with less contamination, although the effect of fipronil on their swimming ability (a decrease) was observed for all the concentrations tested. The application of non-forced multi-compartment exposure methodologies is a recent trend and is ecologically relevant as it is based on how contamination can really produce changes in an organism's habitat selection. Finally, we consider the importance of more non-forced exposure approaches where Stress Ecology can be aggregated to improve systemic understanding of the risk that contaminants pose to aquatic ecosystems from a broader landscape perspective.

Physiological responses on the reproductive, metabolism and stress endpoints of Astyanax lacustris females (Teleostei: Characiformes) after diclofenac and ibuprofen exposure.

Diclofenac (DCF) and ibuprofen (IBU) are pharmaceutical compounds frequently detected in aquatic compartments worldwide. Several hazard effects including developmental abnormalities and redox balance impairment have been elucidated in aquatic species, but multiple endocrine evaluations are scarce. Therefore, the present study aimed to assess the disruptive physiological effects and toxicity of DCF and IBU isolated and combined, using females of the native freshwater teleost Astyanax lacustris. In regards to NSAIDs bioavailability, the results showed absence of degradation of IBU and DCF after 7 days of exposure. IBU LC50 for A. lacustris was 137 mgL-1 and females exposed to IBU isolated increased thyroxine (T4) concentration at 24 h and decreased after 96 h; DCF exposure decreased triiodothyronine (T3) concentration at 96 h. Circulating levels of 17ß-estradiol (E2), cortisol (F) and testosterone (T) were not affected by any treatment. HPG and HPI axis genes fshß, pomc and vtg were upregulated after 24 h of IBU exposure, and dio2 was downregulated in DCF fish exposed group after 96 h compared to the mixture. Protein concentration was reduced in muscle and increased in the liver by DCF and mixtures exposures at 24 h; while liver lipids were increased in the mixture groups after 96 h. The study point out the capacity of NSAIDs to affect endocrine endpoints in A. lacustris females and induce changes in energetic substrate content after acute exposure to isolated and mixed NSAIDs treatments. Lastly, the present investigation brings new insights into the toxicity and endocrine disruptive activity of NSAIDs in Latin America teleost species and the aquatic environment.

Chlorination of Emerging Contaminants for Application in Potable Wastewater Reuse: Disinfection Byproduct Formation, Estrogen Activity, and Cytotoxicity.

With increasing water scarcity, many utilities are considering the potable reuse of wastewater as a source of drinking water. However, not all chemicals are removed in conventional wastewater treatment, and disinfection byproducts (DBPs) can form from these contaminants when disinfectants are applied during or after reuse treatment, especially if applied upstream of advanced treatment processes to control biofouling. We investigated the chlorination of seven priority emerging contaminants (17ß-estradiol, estrone, 17α-ethinylestradiol, bisphenol A (BPA), diclofenac, p-nonylphenol, and triclosan) in ultrapure water, and we also investigated the impact of chlorination on real samples from different treatment stages of an advanced reuse plant to evaluate the role of chlorination on the associated cytotoxicity and estrogenicity. Many DBPs were tentatively identified via liquid chromatography (LC)- and gas chromatography (GC)-high resolution mass spectrometry, including 28 not previously reported. These encompassed chlorinated, brominated, and oxidized analogs of the parent compounds as well as smaller halogenated molecules. Chlorinated BPA was the least cytotoxic of the DBPs formed but was highly estrogenic, whereas chlorinated hormones were highly cytotoxic. Estrogenicity decreased by ∼4-6 orders of magnitude for 17ß-estradiol and estrone following chlorination but increased 2 orders of magnitude for diclofenac. Estrogenicity of chlorinated BPA and p-nonylphenol were ∼50% of the natural/synthetic hormones. Potential seasonal differences in estrogen activity of unreacted vs reacted advanced wastewater treatment field samples were observed.

Analytical determination of tryptoquialanines A and B: Ensuring the quality and safety of orange juices.

Although orange juice is a popular beverage worldwide, fruit distribution, storage, and processing can facilitate fungal infection by Penicillium digitatum; leading to the production of tremorgenic alkaloids, specifically tryptoquialanines A (TA) and B (TB). An Analytical method was developed and validated based on QuEChERS and LC-MS/MS analysis to determine the levels of TA and TB in fresh, industrial, and homemade orange juices. Excellent linearity was observed in the method over a high range of 1-1000 µg/kg and low range of 1-75 µg/kg with R2 ≥ 0.998. The LOD and LOQ were 1 and 3 µg/kg, respectively. Recoveries showed values between 57 and 83 %, with RSD ≤ 13 %. Our data indicated a higher prevalence of mycotoxin TA in fresh and industrial orange juices. Reduction in TA and TB content after thermal and HPP treatments were ≤ 32 %. However, thermal treatment was more effective in reducing TA and TB contents.

How natural and anthropogenic factors should drive microplastic behavior and fate: The scenario of Brazilian urban freshwater.

Brazil maintains its position at the top of the global ranking of plastic producers, yet recycling efforts have been incipient. Recent data reveals an annual production of approximately 14 million tons of plastic waste, not accounting for the surge in the usage of plastic masks and related materials due to the COVID-19 pandemic. However, what remains largely unreported is that over half of post-consumer plastic packaging in Brazil is managed without any monitoring, and it remains unclear how this will contribute to the occurrence of plastic waste and microplastics in Brazilian freshwaters. This scenario requires the consideration of several other crucial factors. Studies have been carried out mainly in marine and estuarine waters, while data on freshwaters are lacking. Brazil has continental dimensions and the highest water availability on the planet, yet the demand for water is greatest in regions with medium to low supply. Many densely populated Brazilian urban areas face chronic flood problems, possess inadequate levels of wastewater treatment, and display inadequate solid waste management practices. Consequently, urban freshwater with tropical characteristics in Brazil presents an intriguing scenario and is complementary to the most commonly studied marine environments. In this study, we explore the nuances of pollution in Brazilian urban freshwater and discuss how various parameters, such as organic matter, suspended solids, temperature, and pH, among others, influence the behavior of microplastics and their interactions with organic and inorganic contaminants. Furthermore, we address how microplastic conditions, such as biofouling, the type of plastic, or degradation level, may impact their behavior. By analyzing how these conditions change, we propose priority themes for investigating the occurrence of microplastics in Brazilian urban freshwater systems under different degrees of human impact. Ultimately, this study aims to establish a network dedicated to standardized monitoring of microplastic pollution in Brazilian urban freshwaters.

Environmental concentrations of cadmium and fipronil, isolated and combined, impair the survival and reproduction of a Neotropical freshwater copepod.

Anthropogenic activities such as agriculture and industry increase contaminants that reach the water bodies, potentially threatening the biota. Most likely, these pollutants occur in complex mixtures. The effects on organisms can be potentiated (synergism) or reduced (antagonism) according to the interaction between the stressors or the species. Cadmium (Cd) is a toxic metal present in phosphate fertilizers, and fipronil is an insecticide broadly used in sugarcane crops. Copepods are important energy transfer links in aquatic environments, and effects on this group impact the whole trophic chain. In this study, we evaluated the responses of the freshwater Calanoida copepod Notodiaptomus iheringi, naturally present in water bodies that can be affected by sugarcane cultures in Brazil. The organisms were exposed to environmental concentrations of Cd and fipronil, isolated and in the mixture, in acute (48 h) and sub-chronic (8 d) tests. Our data indicate that both contaminants affect the survival of the organisms in acute or sub-chronic exposures. Cadmium did not affect egg production or hatching, while fipronil impacted these endpoints negatively. The Cd-fipronil combination resulted in antagonistic responses in survival (acute and sub-chronic) and egg production. A synergistic response was observed in egg hatching. Our results suggest that Cd presents a protective effect in the mixture with fipronil; however, it is not enough to prevent egg-hatching inhibition. These responses highlight how tricky it is to deal with pollutants' interaction in environmental concentrations since synergism is the most common response to metal-pesticide mixtures. Our data point out N. iheringi as a sensitive organism in the presence of contaminants and reflects the threat of chemical mixtures in concentrations found in water bodies close to sugarcane crops in Brazil.

Exposure to fipronil, 2,4-D and vinasse influences macroinvertebrate assemblage structure: An experimental mesocosm approach.

Sugarcane is one of the main monocultures in Brazil and widely uses herbicide 2,4-D and fipronil insecticide. In addition, vinasse can be mentioned as it is widely used in this plantation. These compounds occurring simultaneously in the aquatic environment can potentiate the deleterious effects on organisms. Thus, this study aimed to evaluate the composition, abundance and ecological indices of the benthic macroinvertebrate community, as well as its ability to reestablish itself considering environmental contamination by the pesticides Regent® 800WG (active ingredient - a.i. fipronil) (F) and DMA® 806BR (a.i. 2,4-D) (D) and vinasse (V), alone and in mixtures: pesticides - M and the three contaminants - MV. The study was conducted using open-air mesocosms. The macroinvertebrate community was monitored by colonization structures, the physical-chemical parameters, metals and pesticides were determined and the effects of contaminants were evaluated over the exposure time in 1, 7, 14, 28, 75 to 150 days. A multiple regression was performed between the water parameters and significant relationships were found between parameters associated with vinasse contamination (pH, total nitrogen, turbidity, and dissolved oxygen) and concentration of fipronil and the ecological variables studied. Over time, changes were observed in the composition of the community. The dominance and richness increased in treatments V and MV. The family Chironomidae and subclass Oligochaeta were more sensitive to the treatment V and MV, while individuals from the families Phoridae, Ephydridae and Sciomyzidae were occasionally found (depending on the experimental time) in these treatments. The insects were sensitive to treatments F and M, disappearing in these mesocosms after contamination, reappearing only after 75 days. The results reveal that sugarcane management practices associated with the use of pesticides and vinasse as fertilizer pose risks to the macroinvertebrate community with consequences for the trophic chains, given its importance in freshwater ecosystems and adjacent terrestrial environments.

Toxicity of fipronil and 2,4-D pesticides in Daphnia similis: a multiple endpoint approach.

In Brazil, among the pesticides widely applied simultaneously in sugarcane monocultures are the Regent® 800 WG insecticide (active ingredient (a.i.) fipronil) and the DMA® 806 BR herbicide (a.i. 2,4-D). Thus, this study aimed to investigate, through different endpoints, the effects of the fipronil and 2,4-D pesticides, isolated and as mixtures, on the cladoceran Daphnia similis. To do this, acute toxicity tests were carried out with the compounds acting in isolation and in mixture, where the survival of the organisms was evaluated, and chronic toxicity tests with the isolated compounds, where reproduction and maternal and neonatal body length were evaluated. In this study, the physiological endpoints of D. similis were also analyzed, through the analysis of feeding rates (filtration and ingestion) in exposure and post-exposure scenarios, in order to verify the cladoceran food recovery capacity. In addition, D. similis data were compared with other species when exposed to the studied pesticides, using species sensitivity distribution curves. Acute toxicity tests of the fipronil and 2,4-D showed an average EC50-48 h of 66.68 µg a.i./L and 327.07 mg a.i./L, respectively. In both cases, D. similis showed lower sensitivity compared to other species. For the mixture test, the evaluation by the IA model (independent action) and deviation DR (dose ratio dependent) indicated the occurrence of mostly antagonistic effects. The chronic test with fipronil showed a decrease in the fecundity of the organism at a concentration of 16 µg a.i./L, a concentration already found in aquatic environments. For 2,4-D, no significant differences were observed for reproduction at the concentrations tested. Regarding the maternal body length, there were no significant changes when D. similis were exposed to both fipronil and 2,4-D, but these differences were observed in the body length of the neonates only for 2,4-D. There were no significant changes in the feeding rates of the organisms when exposed to both pesticides.

Insights into sorption and molecular transport of atrazine, testosterone, and progesterone onto polyamide microplastics in different aquatic matrices.

Microplastics can act as vectors of a wide class of contaminants in aquatic environments. The sorption behavior of two hormones known to cause adverse effects in biota even in low concentrations (testosterone-TTR and progesterone-PGT), and a pesticide with a high environmental persistence known as endocrine disruptor chemical (atrazine-ATZ) onto polyamide (PA) microplastics is investigated under different aquatic matrices using kinetic and isotherm experiments. The sorption equilibrium is achieved in 48 h, and the experimental results are better fitted by pseudo-2nd-order model. Langmuir isotherm better describes the sorption of the contaminants onto PA microplastics. PGT presents the highest sorption efficiency at around 90%, followed by TTR at 70% and ATZ at approximately 20%. Moreover, ATZ is the contaminant with the highest desorption efficiency (∼65%), indicating its preference for staying solubilized in water. Combining classical molecular dynamics and density functional theory calculations, the sorption energies were calculated as 12-15 kcal mol-1, 13-16 kcal mol-1, and 19-22 kcal mol-1 for PGT, TTR, and ATZ, respectively, showing that PGT needs less energy to be transferred from the solvent network to the PA surface, in agreement with experimental results. The sorption mechanism is driven by hydrogen bonds onto PA outer surface, while the electrostatic interactions dominate the PA inner surface sorption. Moreover, the sorption efficiency is statistically different between the investigated matrices, indicating that physicochemical characteristics of water systems could influence the interactions between PA-contaminant. In seawater, the phenomena of salting-out/in and competitive sorption with saline ions are observed for three contaminants. The PA-contaminant complexes are more polar and soluble than the dissociated ones, which increases the contaminant's co-transport by PA in water.

Short and long-term exposure to the pesticides fipronil and 2,4-D: Effects on behavior and life history of Daphnia magna.

The high levels of contamination in aquatic ecosystems caused by pesticides and the organisms' consequent continuous exposure to it has made them vulnerable to damage. However, mobile organisms can avoid this continued exposure to contaminants by moving to less disturbed habitats. Therefore, through the use of the Heterogenous Multi-Habitat Assay System (HeMHAS), our objective was to evaluate the ability of Daphnia magna to detect and avoid habitats contaminated by fipronil and 2,4-D, in a spatially connected landscape. Further, the role of contamination by these pesticides, isolated and in mixtures, concerning the colonization of habitats by daphnids was also evaluated. Given that not all organisms successfully escape contamination, the chronic toxicity of the same pesticides using different parameters for D. magna (maternal survival, fecundity and maternal body length) was also evaluated. When evaluating the avoidance response by D. magna exposed to pesticides, there was no preference for the less contaminated areas for both compounds. However, organisms did not move to contaminated zones in the colonization experiments, with no immigration of daphnids to the zones with intermediate and the highest levels of fipronil, nor to the highest concentration of 2,4-D. Finally, the colonization by daphnids was significantly prevented when exposed to a mixture of the pesticides, in which the areas with the highest combinations of pesticide concentrations were not colonized by D. magna. Regarding the long-term chronic effects, negative consequences were observed, particularly for maternal body length, fecundity and maternal survival, due to the exposure to fipronil. Considering that pesticides can limit the areas colonized by organisms by making them unattractive, the risk of local population extinction may be underestimated if only standard endpoints involving forced exposure are studied.

Combined effects of landscape composition and agrochemicals on frog communities amid sugarcane-dominated agroecosystems.

Global demand for crops will continue increasing over the next few decades to cover both food and biofuel needs. This demand will put further pressure to expand arable land and replace natural habitats. However, we are only beginning to understand the combined effects of agrochemicals and land-use change on tropical freshwater biodiversity. In this study, we analyzed how pond-dwelling anuran larvae responded to pond characteristics, landscape composition, and agrochemical contamination in a sugarcane-dominated agroecosystem in Brazil. Then we used an information theoretical approach with generalized linear models to relate species richness and abundance to predictor variables. The variation in tadpole abundance was associated with both agrochemical concentration (e.g., ametryn, diuron, and malathion) and landscape variables (e.g., percentage of forest, percentage of agriculture, and distance to closest forest). The relationship between species abundance and agrochemicals was species-specific. For example, the abundances of Scinax fuscovarius and Physalaemus nattereri were negatively associated with ametryn, and Dendropsophus nanus was negatively associated with tebuthiuron, whereas that of Leptodactylus fuscus was positively associated with malathion. Conversely, species richness was associated with distance to forest fragments and aquatic vegetation heterogeneity, but not agrochemicals. Although we were unable to assign a specific mechanism to the variation in tadpole abundance based on field observations, the lower abundance of three species in ponds with high concentrations of agrochemicals suggest they negatively impact some frog species inhabiting agroecosystems. We recommend conserving ponds near forest fragments, with abundant stratified vegetation, and far from agrochemical runoffs to safeguard more sensitive pond-breeding species.

Impact of agricultural runoff and domestic sewage discharge on the spatial-temporal occurrence of emerging contaminants in an urban stream in São Paulo, Brazil.

Ribeirão das Pedras, a 10-km-long stream from the source to mouth, is part of a predominantly urban catchment located in Campinas metropolitan area in the state of São Paulo, Brazil, and it is also surrounded by sugarcane farms. Monthly sampling of 31 selected emerging contaminants (ECs) was conducted for 1 year (October 2018 to October 2019) in five points, including the spring, agricultural, and urban areas, to assess the dynamics and impact of ECs on the stream. The ECs were quantified using LC-MS/MS analysis. Out of the 31 ECs monitored in this study, 13 were detected in the Ribeirão das Pedras catchment, which were mainly pesticides and caffeine. Eight ECs (hexazinone, malathion, desethylatrazine (DEA), desisopropylatrazine (DIA), fipronil, ametryn, 2-hidroxyatrazine, and diuron) were detected with risk quotients higher than 1, indicating some level of environmental concern. Statistical analyses showed that caffeine, hexazinone, atrazine, DEA, and DIA were the most statistically important contaminants in temporal analysis, with caffeine concentrations varying randomly. Hexazinone, atrazine, DIA, and DEA concentrations increased from November 2018 to January 2019, and atrazine, hexazinone, and DEA concentrations increased from June 2019 to September 2019. Spatial analysis indicates that the spring of Ribeirão das Pedras is the only statistically different sampling point, with lower concentrations of EC. Points 3 and 5, both located in urban areas next to the stream's mouth, differ from each other due to the possible dilution of caffeine downstream of point 3 and domestic sewage discharge upstream of point 5.

Avoidance responses by Danio rerio reveal interactive effects of warming, pesticides and their mixtures.

Temperature variations and thermal extremes events caused by climate change can have profound implications for the toxicity of pesticides in aquatic organisms. Using an innovative system (Heterogeneous Multi-Habitat Test System - HeMHAS) that allows the simulation of different scenarios within a spatially heterogeneous landscape, the effects on the habitat selection of Danio rerio fish caused by the pesticides fipronil and 2,4-D were studied as single compounds and in mixture and integrated with air temperature variation (20, 24 and 28 °C). As a result, D. rerio detected and avoided both pesticides at air temperatures of 20 and 24 °C; however, at 28 °C no significant difference was observed in habitat choice by fish. Additionally, when pesticides were mixed in a heterogeneously contaminated landscape, it was observed that D. rerio detected contamination and preferred the clean zone at 20 and 24 °C; however, at 28 °C the potential to escape from the most contaminated areas was impaired. Thus, contamination by both pesticides made the habitat selection behavior of fish at 20 and 24 °C more noticeable. In addition, the association between pesticides and temperature showed negative effects on the response of fish to detect and escape from contaminated environments, suggesting the influence of temperature in altering the ability of the organism to provide an efficient response to stress.

One planet: one health. A call to support the initiative on a global science-policy body on chemicals and waste.

The chemical pollution crisis severely threatens human and environmental health globally. To tackle this challenge the establishment of an overarching international science-policy body has recently been suggested. We strongly support this initiative based on the awareness that humanity has already likely left the safe operating space within planetary boundaries for novel entities including chemical pollution. Immediate action is essential and needs to be informed by sound scientific knowledge and data compiled and critically evaluated by an overarching science-policy interface body. Major challenges for such a body are (i) to foster global knowledge production on exposure, impacts and governance going beyond data-rich regions (e.g., Europe and North America), (ii) to cover the entirety of hazardous chemicals, mixtures and wastes, (iii) to follow a one-health perspective considering the risks posed by chemicals and waste on ecosystem and human health, and (iv) to strive for solution-oriented assessments based on systems thinking. Based on multiple evidence on urgent action on a global scale, we call scientists and practitioners to mobilize their scientific networks and to intensify science-policy interaction with national governments to support the negotiations on the establishment of an intergovernmental body based on scientific knowledge explaining the anticipated benefit for human and environmental health.

Ecological risk assessment of pesticides in urban streams of the Brazilian Amazon.

The use of pesticides in households and peri-urban areas of the Amazon has increased notably during the last years. Yet, the presence of these contaminants in Amazonian freshwater ecosystems remains unexplored. Here, we assessed the exposure to 18 pesticides and 5 transformation products in the Amazon River and in the urban streams of Manaus, Santarém, Macapá, and Belém (Brazil). Pesticide concentrations were analyzed by liquid and gas chromatography methods. Ecological risks were assessed following a two-tiered approach. First, hazard quotients and an overall hazard index were calculated using toxicity data for standard test species of primary producers, invertebrates, and fish. Second, the pesticides showing moderate-to-high ecological risks in the first tier were evaluated using Species Sensitivity Distributions (SSDs). Our study shows that pesticides are widespread in urban and peri-urban areas of the Brazilian Amazon. The frequency of detection was higher in urban streams than in the Amazon River, with some samples taken in Manaus, Santarém, and Belém containing up to 8 compounds. Most pesticides were measured at relatively low concentrations (ng L-1), except for malathion, carbendazim and the bulk concentration of chlorpyrifos, which were monitored at concentrations above 100 ng L-1. Based on the first-tier assessment, we found moderate-to-high risks for freshwater invertebrates for malathion, chlorpyrifos, and chlorpyrifos-methyl, and moderate risks for malathion to fish. The risk assessment performed with SSDs indicated high risks of malathion and chlorpyrifos-methyl in urban areas, with up to 15% and 5% of invertebrate species potentially affected, respectively. The bulk concentrations of chlorpyrifos resulted in high risks in some urban areas (14-22% of species affected) and in areas of the main river (32-44%) impacted by agriculture. We conclude that pesticide residues may contribute to a biodiversity impact in the Amazon and should be further monitored in urban and peri-urban areas, particularly after heavy rainfall events.

Lethal and sublethal toxicity of pesticides and vinasse used in sugarcane cultivation to Ceriodaphnia silvestrii (Crustacea: Cladocera).

With the growing use of agrochemicals in Brazil, there is also a growing need for more realistic toxicity assessments that aid in understanding the potential risks of environmental-realistic agrochemical (mixture) exposures in the natural ecosystems. The aim of the present study was therefore to evaluate the lethal and sublethal effects of environmental realistic (single and mixture) concentrations of the pesticides DMA® 806 BR (active ingredient - a.i. 2,4-D) and Regent® 800 WG (a.i. fipronil) and sugarcane vinasse to the Neotropical cladoceran Ceriodaphnia silvestrii. This evaluation was carried out through lethal (survival), sublethal (reproduction and intrinsic rates of population increase - r) and post-exposure (feeding rate and also reproduction) tests conducted in situ and with water from mesocosms contaminated with the recommended doses of these compounds. The results showed high acute toxicity for treatments containing fipronil and vinasse when acting in isolation, with survival rates only returning to control values on the last sampling day (75 days post application). Reproduction of surviving cladocerans was reduced in all treatments until the end of the experiment and were potentiated effect in the mixture of the three test compounds. The intrinsic rates of population increase were reduced in all treatments except the single 2,4-D treatment. Post-exposure feeding rate and reproduction, however, were not impaired under the conditions analyzed. The results show the high toxicity of recommended doses of fipronil and vinasse (and especially their mixture) and the importance of evaluating the risks of agrochemical mixtures at environmental-realistic concentrations.

Behavioral and reproductive effects in Poecilia vivipara males from a tropical estuary affected by estrogenic contaminants.

Contamination of aquatic habitats by endocrine disruptor chemicals is a major concern globally. This study evaluated histochemical, behavioral, and reproductive effects on adult male Poecilia vivipara sampled from Capibaribe River Estuarine System (CRES), compared to laboratory control males after breeding with virgin control females. CRES is contaminated by a mixture of estrogenic contaminants estrone, 17ß-estradiol, estriol, 17α-Ethinylestradiol, bisphenol A and caffeine in concentrations averaging 13.9; 4.2; 19.5; 8.6; 27 and 23.2 ng L-1, respectively. Estrogenic risk in 17ß-estradiol-equivalent-concentrations is above probable no effect concentrations. Males sampled from CRES indicated liver phosphoprotein induction, decreased number of contacts and copulation attempts when paired with control females, slower swimming speed and lower female impregnation success rates, compared to control males. A reduction of 62% in fecundity was observed in control females paired with field sampled males compared with control males. Our results highlight hazards posed to fish reproduction by estrogenic micropollutants.

New benzotriazoles generated during textile dyeing process: Synthesis, hazard, water occurrence and aquatic risk assessment.

Phenylbenzotriazoles (PBTA) can be generated unintentionally during textile dyeing factories by reduction of dinitrophenylazo dyes and their subsequent chlorination in disinfection process. Eight non-chlorinated PBTAs (non-Cl PBTA) and their related chlorinated PBTAs have been found in rivers and presented mutagenic activity. No data on their aquatic toxicity are available. In this work, two new phenylbenzotriazoles, non-Cl PBTA-9 and PBTA-9, derived from the dye C.I. Disperse Violet 93 (DV93) were synthesized and chemically/toxicologically characterized. Both compounds were more mutagenic than the parental dye in the Salmonella/microsome assay in the presence of metabolic activation (S9). Mutagenicity studies in vivo with mammals would confirm their potential hazard to humans. The two compounds were acutely toxic to Daphnia similis. We developed an analytical method to simultaneously quantify non-Cl PBTA-9, PBTA-9 and DV93 in river waters. Non-Cl PBTA-9 was found in sites under influence of textile effluents but at concentrations that do not pose risk to the aquatic life according to the P-PNEC calculated based on the acute toxicity tests. PBTA-9 was not detected in any samples analyzed. More studies on the aquatic toxicity and water occurrence of PBTAs should be conducted to verify the relevance of this class of compounds as aquatic contaminants.

Predicting zebrafish spatial avoidance triggered by discharges of dairy wastewater: An experimental approach based on self-purification in a model river.

Wastewater discharges from dairy industries can cause a range of harmful effects in aquatic ecosystems, including a decline in biodiversity due to species evasion. Therefore, it is important to know the purification potential of rivers for the removal of pollutants released in dairy wastewater (DWW). The hypothesis adopted in this work was that the release of DWW into stretches of the Ribeirão dos Pombos River (São Paulo State, Brazil) might trigger an avoidance response, resulting in fish migrating to other regions, with the response being greater when the self-cleaning potential of the river is smaller. Therefore, the goals of the present study were to: (i) investigate how land use and seasonality of the rainfall regime influence the quality of the water in different areas of the river (P1: river source; P2: urban region; P3: rural region); (ii) assess the potential of the river to purify DWW; and (iii) evaluate the potential toxicity and repellency of DWW to the freshwater fish Danio rerio, using acute toxicity (mortality) and non-forced avoidance tests, respectively. P1 was shown to be the most preserved area. The chemical composition of the river varied seasonally, with higher concentrations of Cl- and SO42- at P3 during the rainy period. The river purification potential for DWW was higher at P2, due to greater microbiological activity (associated with higher BOD). The DWW was more acutely toxic in water from P2. The avoidance response was strongly determined by the concentration of DWW, especially for water from P2. The high capacity for self-cleaning at P2 did not seem sufficient to maintain the stability of the ecosystem. Finally, the non-forced exposure system proved to be a suitable approach that can assist in predicting how contaminants may affect the spatial distributions of organisms.