Comparación ecotoxicológica al Cloruro de Sodio en Hydra vulgaris e Hydra viridissima

El aumento de la salinidad en los ecosistemas de agua dulce genera preocupación sobre los efectos adversos que puede provocar sobre las especies dulceacuícolas y el suelo. Las concentraciones óptimas de iones de sodio y calcio para que las especies del género Hydra tengan condiciones fisiológicas adecuadas son relativamente bajas. Este trabajo se enfocó en comparar la sensibilidad de H. vulgaris e H. viridissima frente al cloruro de sodio (NaCl). Las especies fueron mantenidas bajo condiciones de fotoperiodo, iluminación y temperatura controladas. Se obtuvieron las tasas de crecimiento y en ensayos de toxicidad aguda se calcularon las CE50 (Concentración efectiva media) y CL50 (Concentración letal media) como indicadores de la sensibilidad al NaCl. H. vulgaris fue más sensible al NaCl dado que la CL50-96h fue de 1,0 g/l NaCl (entre 0,8 - 1,2 g/l como intervalo de confianza al 95%), mientras que H. viridissima presentó una CL50-96h promedio de 2,6 g/l (entre 2,0 - 3,3 g/l como intervalo de confianza del 95%). Se considera que esta última fue más tolerante al NaCl, probablemente por la relación simbiótica con la microalga Chlorella vulgaris, ya que podría generar un efecto protector. Se espera que comprender el comportamiento de estos biomodelos respecto al aumento de la salinización permita la evaluación temprana de riesgos ecológicos en ecosistemas acuáticos tropicales.

The increase in salinity in freshwater ecosystems raises concern about the adverse effects that it can cause in freshwater species and the soil. The sodium and calcium ions optimum concentrations required for genus Hydra to have adequate physiological conditions are relatively low. This research compared the H. vulgaris and H. viridissima sodium chloride (NaCl) sensitivity. The species were propagated under photoperiod, lighting and temperature-controlled conditions. The growth rates were obtained and EC50 (mean effective concentration) and LC50 (mean lethal concentration) were calculated by means of acute toxicity tests as indicators of sensitivity to NaCl. For H. vulgaris the LC50-96h was 1.0 g/l of NaCl with a range between 0.8 - 1.2 g/l of NaCl, compared to H. viridissima presented an average LC50-96h of 2.6 g/l of NaCl with a 95% confidence interval between 2.0 - 3.3 g/l of NaCl. The H. viridissima was more tolerant, probably the symbiotic relationship with Chlorella vulgaris, can generate a protective effect. Understanding the behavior of these species with respect to increased salinization can allow an early assessment of ecological risks in tropical aquatic ecosystems.

Exposure of Artemia salinato glyphosate and bioremediation by isotherapy

Artemia salina, an ecotoxicity bioindicator, isa microcrustacean belonging to the order Anostraca. Glyphosate is an herbicide widely used to control weeds. However, its intoxication can cause serious damage to human health and the balance of the environment, given its effects as an endocrine disruptor.Objective:verify the possible protection of the artemia exposed to glyphosate by the addition of its isotherapic into water, by means of the evaluation of the behavioral and morphological features of nauplii and of the physical properties of remedies andtreated water, to elucidate the involved mechanisms. Methods:Artemia salinacysts were kept in culture bottles containing artificial seawatercontaining glyphosate at LC 10 (lethal concentration 10%), to promote hatching within 48 hours. The isotherapic preparations were inserted in each bottle in a 10% of the total water volume. Part of the nauplii was distributed in transparent tubes, being 10 nauplii per tube and 6 tubes per group, for behavioral analysis, and part were collected for a detailed morphological analysis, under an optical microscope. About 80 to 270 nauplii were analyzed per group. The reserved water was divided into aliquots for physicochemical analysis, that is, evaluation of the water dipole behavior by Cartwright ́s method.Results:Gly 6cH presented selective effects on nauplii hatching (p=0.02) and on defected/healthy ratio (p=0.001), representing some protective action. This result was dependent of the salinity of water and presented correspondence with the effects on solvatochromic dyes, indicating that charges and ions can be critical factors involved in the mechanism of action. We concluded that the use of isotherapics could be a plausible tool to reduce the environmental impact of the indiscriminate use of glyphosate, since these results can be reproduced in further studies.

Research progress on ecotoxicological effects of antidepressants / 预防医学

Abstract：@#With the increasing rise in antidepressant consumption, more and more antidepressants and their metabolic products enter into water and soil environments. This will cause toxicity to animals living in these environments, and antidepressants may be transferred to humans via food chain, leading to human health risks. Based on national and international publications pertaining to environmental pollution and toxic effects of antidepressants during the period between 2005 and 2021, this review summarizes the biological accumulation, acute toxicity, reproductive and developmental toxicity, metabolic effects and biological behavior changes of antidepressants, so as to provide insights into the elucidation of the impact of antidepressants on human health risks.

Ensaios toxicológicos aplicados à análise de águas contaminadas por fármacos / Toxicological tests applied to the analysis of water contaminated by drugs

RESUMO Fármacos de diversas classes têm sido detectados no ambiente aquático nos últimos anos. A presença desses compostos químicos deve-se, sobretudo, ao lançamento de esgoto in natura ou à remoção incompleta durante as etapas do tratamento de esgoto. Embora tais materiais sejam detectados em baixas concentrações (ng.L-1 - µg.L-1), os impactos de alguns fármacos à biota aquática já são conhecidos, sendo os efeitos na saúde humana, especialmente aqueles relacionados à exposição crônica, ainda pouco conhecidos e/ou controversos. Ensaios biológicos são ferramentas valiosas para avaliar a toxicidade de fármacos aos organismos expostos, e a sua adoção conjunta aos ensaios de tratabilidade da água e efluentes permitiria preencher lacunas de conhecimento e a construção de consenso na literatura científica sobre os seus efeitos toxicológicos. Pelo exposto, este artigo de revisão apresenta uma visão geral da ocorrência de fármacos em amostras ambientais do país e a toxicidade observada por meio de diferentes ensaios biológicos.

ABSTRACT Drugs of several classes have been detected in the aquatic environment in recent years. The presence of these chemicals is mainly due to the discharge of raw sewage or to their incomplete removal in sewage treatment plants. Although they have been detected at low concentrations (ng.L-1 - µg.L-1), the effects of pharmaceutical compounds on the aquatic biota are already acknowledged, being the effects on human health, especially those related to chronic exposure, still unknown and/or controversial. Biological assays are valuable tools for assessing drug toxicity to exposed organisms and their joint adoption in water and effluent treatability trials would fill up knowledge gaps and build consensus in the scientific literature on their toxicological effects. This review paper presents an overview of the occurrence of drugs in several Brazilian environmental samples and compiles the toxicity observed by means of different biological assays.

Estudo da biodegradabilidade de fluoroquinolona por meio da utilização de biomassas aeróbias e anaeróbias / Study of fluoroquinolone biodegradability by using aerobic and anaerobic biomass

RESUMO Os antibióticos como o norfloxacino constituem os fármacos mais utilizados na Medicina, com consumos expressivos no mundo todo. Por ser quimicamente estável, após sua administração a maior parte do fármaco é excretada de forma inalterada e, geralmente, é removida apenas parcialmente nas estações de tratamento de esgoto (ETEs). Assim, o presente trabalho buscou avaliar a eficiência dos processos biológicos na remediação de norfloxacino investigando os mecanismos de remoção envolvidos. O objetivo foi verificar a biodegradabilidade do fármaco e sua toxicidade. Para realização dos ensaios de biodegradabilidade, coletaram-se lodos na ETE Arrudas (Sabará, Minas Gerais) dos processos de tratamento com lodos ativados, reatores upflow anaerobic sludge blanket (UASB) e biodigestor anaeróbio. Reatores em escala de bancada foram montados com lodo aclimatado e não aclimatado. Amostras tiveram a biodegradabilidade acompanhada por meio da determinação do carbono orgânico total e da absortividade molar do norfloxacino por espectrofotometria de UV/Vis. Determinou-se a toxicidade por intermédio de ensaios com a bactéria Aliivibrio fischeri. Entre as biomassas utilizadas, a mais eficiente na remoção do norfloxacino foi advinda dos reatores UASB (23%), seguida do biodigestor anaeróbio (18%) e, então, dos lodos ativados (13%). Quanto à ecotoxicidade, a degradação anaeróbia promoveu a eliminação da toxicidade do antibiótico, enquanto com relação à degradação aeróbia os efluentes gerados permanecem tóxicos.

ABSTRACT Antibiotics, such as norfloxacin, are the most widely used drugs in medicine, with significant consumption in the world. By being chemically stable, most of the drug is excreted unchanged after administration, and is generally only partially removed in the sewage treatment plants (STPs). Thus, the efficiency of biological processes in the remediation of norfloxacin was investigated by the present work, verifying the removal mechanisms involved. Its objective was to verify the drug's biodegradability and toxicity. In order to perform biodegradability tests, sludges were collected in Arrudas STP (Sabara, Minas Gerais) from the treatment processes with activated sludge, upflow anaerobic sludge blanket (UASB) reactors and anaerobic biodigester. Bench-scale reactors were assembled with acclimatized and non-acclimatized sludge. Samples had their biodegradability monitored by determination of total organic carbon and norfloxacin molar absorptivity by UV/Vis spectrophotometry. The toxicity was determined by tests with Aliivibrio fischeri. Among the used biomass, UASB reactors was the most efficient in removing norfloxacin (23%), followed by anaerobic biodigester (18%), and activated sludge (13%). Regarding ecotoxicity, the anaerobic degradation promoted the elimination of antibiotic toxicity, while with aerobic degradation, the effluents generated remained toxic.

Nanosuspension of quercetin: preparation, characterization and effects against Aedes aegypti larvae

Abstract Aedes aegypti (Diptera: Culicidae) is the main vector of some neglected diseases, including dengue. It is very important to develop formulations that increase effectiveness of vector control with low toxicity. Quercetin is a plant-derived flavonoid that modulates the development of some insects. The low water solubility of quercetin impairs the development of water-dispersible commercial products. To circumvent this problem, the preparation of nanoformulations is considered promising. Thus, this study aimed to evaluate the effect of bulk and quercetin nanosuspension against A. aegypti larvae and also to investigate their ecotoxicity. Quercetin nanosuspension was produced by a solvent displacement method followed by solvent evaporation and was maintained in two different temperatures (4 and 25 ºC). Its size distribution and zeta potential were monitored along 30 days. The influence of quercetin nanosuspension and bulk-quercetin was investigated at various concentrations against A. aegypti and the green algae Chlorella vulgaris. The quercetin nanosuspension presented higher stability at 4 ºC and negative zeta potential values. Quercetin nanosuspension and bulk-quercetin adversely affected the larvae development, especially at the highest concentrations. Larvae mortality was between 44% and 100% (48 h) for quercetin nanosuspension at 100 and 500 ppm, respectively. The bulk-quercetin induced around 50% mortality regardless the concentration used at this same time-period. Absence of emerging mosquitoes from water was observed on the survival larvae of all the treated groups. Quercetin nanosuspension was less toxic than bulk-quercetin against C. vulgaris, especially at higher concentrations. These data indicate that quercetin nanosuspension may represent a potential larvicide for A. aegypti control, once they induced larvae death and inhibited the survival ones to emerge from water. In addition, it did not demonstrated ecotoxicity against a non-target organism, highlighting its better properties, when compared to the bulk-quercetin.

Ecotoxicidad de nanopartículas metálicas y superparamagnéticas de óxido de hierro en dos especies / Ecotoxicity of metalic and superparamagnetics iron oxide nanoparticles in two species

Introducción: la nanotecnología y el empleo de materiales a nano escala son un área relativamente nueva de la ciencia y la tecnología con un gran crecimiento en el mercado global. Muchos de los productos no cuentan con estudios que garanticen su uso seguro, tanto para el hombre como para los ecosistemas. Los estudios ecotoxicológicos permiten evaluar los efectos de un determinado xenobiótico sobre especies representativas de los diferentes compartimentos ambientales. Objetivo: evaluar los efectos tóxicos de nanopartículas de Ag, Au, Ag/Ag y superparamagnéticas de óxido de hierro, en dos especies bioindicadoras de los ecosistemas terrestre y acuático. Métodos: como parte de los estudios de seguridad se realizaron ensayos de toxicidad aguda por contacto en lombriz de tierra de la especie Eisenia andrei, con una duración de 96 horas y estudios en anfibios de la especie Osteopillus septentrionales en diferentes etapas del desarrollo (embrionario y larval). Se evaluó la ocurrencia de mortalidad y de efectos tóxicos, en el caso del ensayo en lombriz de tierra; se determinó además la viabilidad celular. Resultados: los efectos tóxicos más significativos en el caso de la lombriz de tierra fueron, la ocurrencia de alteraciones fisiológicas y conductuales al ser expuesta a NPs de Ag de 3 nm y superparamagnéticas de óxido de hierro, estas últimas provocaron citotoxicidad a la concentración 1,38 mg/mL. En el caso de los anfibios se evidenció toxicidad en NPs de Ag 3 nm y superparamagnéticas de óxido de hierro. Conclusiones: todas las nanopartículas mostraron efectos tóxicos en las especies bioindicadoras evaluadas(AU)

Introduction: Nanotechnology and the use of nanoscale materials are a relatively new area of science and technology with big growth in the global market. Many of these products don't have studies that guarantee their safe use, both for man and for ecosystems. Ecotoxicological studies allow the evaluation of the effects of a particular xenobiotic on representative species of the different environmental compartments. Objective: To evaluate the toxic effects of nanoparticles of Ag, Au, Ag / Ag and super paramagnetic iron oxide in two bioindicators of terrestrial and aquatic ecosystems. Methods: Acute contact toxicity tests were carried out on ground worm of the Eisenia andrei species, with a duration of 96 hours and studies on amphibians of the species Osteopillus septentrionales at different stages of development (embryonic and larval). The occurrence of mortality and toxic effects was evaluated in the case of earthworm test; cell viability was also determined. Results: The most significant toxic effects in the case of earthworms were the occurrence of physiological and behavioral alterations when exposed to 3 nm Ag of superparamagnetic iron oxide nanoparticles, where the latter caused cytotoxicity at concentration of 1.38 mg / mL. In the case of amphibians, toxicity was evidenced in Ag 3 nm nanoparticles and superparamagnetic iron oxide. Conclusions: All nanoparticles showed toxic effects in the evaluated bioindicator species(AU)

Toxicidade aguda e risco ambiental do antibiótico oxitetraciclina para tilápia (Oreochromis niloticus), Daphnia magna e Lemna minor / Acute toxicity and environmental risk of oxytetracycline antibiotc for tilapia (Oreochromis niloticus), Daphnia magna, and Lemna minor

O objetivo deste estudo foi classificar o antibiótico Terramicina(r) de acordo com a toxicidade aguda e o risco de intoxicação ambiental para Oreochromis niloticus, Daphnia magna e Lemna minor, com base no seu ingrediente ativo oxitetraciclina (OTC). Além disso, observou-se a ocorrência de sinais de intoxicação aguda em peixes e o efeito da diluição do antibiótico sobre as variáveis de qualidade de água. Alevinos, neonatos e frondes foram expostos a concentrações de OTC. De acordo com os resultados dos testes de toxicidade aguda, a Terramicina(r) foi classificada pela toxicidade aguda e pelo risco de intoxicação ambiental. Para O. niloticus, a CL(I)50; 48h calculada foi de 6,92 mg L-1, para D. magna a CE(I)50; 48h foi de 0,17mg.L-1, enquanto para L. minor a CI(I)50;7d foi de 0,68 mg L-1. A Terramicina(r) foi classificada como muito tóxica para O. niloticus e extremamente tóxica para D. magna e L. minor e causa risco de intoxicação ambiental para os três organismos testados. Concentrações de 7,5 e 8,0 mg L-1 de OTC reduziram a concentração de oxigênio dissolvido na água. De acordo com este estudo, a Terramicina(r) não deve ser utilizada na aquicultura, pois é altamente tóxica e causa risco de intoxicação ambiental aos organismos teste.(AU)

The aim of this study was to classify the antibiotic Terramycin(r) according to acute toxicity and the environmental risk that it poses for Oreochromis niloticus, Daphnia magna, and Lemna minor based on its active ingredient oxytetracycline (OTC). In addition, the occurrence of acute poisoning signs in fish and antibiotic dilution effect in the water quality variables were observed. For this purpose, fingerlings, neonates, and while were exposed to the concentrations of OTC. According to OTC acute toxicity test results, the Terramycin(r) was classified by acute toxicity and environmental poisoning risk classes. To O. niloticus, the calculated LC(I)50;48h was 6.92 mg L-1, for D. magna the EC(I)50;48h was 0.17 mg L-1, while for L. minor, IC(I)50;7d was 0.68 mg L-1. Terramycin(r) was classified as very toxic to O. niloticus, and highly toxic to D. magna and L. minor and cause risk of environmental poisoning for the three organismis tested. Concentrations of 7.5 and 8.0 mg L-1 OTC reduce the concentration of dissolved oxygen in the water. According to this study, Terramycin(r) should not be used in aquaculture, as it is highly toxic and causes risk of environmental toxicity test organisms.(AU)

Disposição continental de sedimentos de dragagem em solos tropicais: avaliação do risco ecológico de metais baseada em bioensaios com organismos aquáticos e edáficos / Disposal of dredged sediments in tropical soils: metal ecological risk assessment based on bioassays with aquatic and edaphic organisms

A ecotoxicidade associada à disposição continental de sedimentos de dragagem (oriundo da Baía de Guanabara, Rio de Janeiro) em latossolos e chernossolos foi estudada através de bioensaios agudos com o cladócero Daphnia similis e o oligoqueta Eisenia andrei; e de bioensaios crônicos com a alga doce Pseudokirchneriella subcaptata. Os teores de metais no dragado estavam acima dos preconizados pela legislação brasileira para disposição de materiais dragados. Os bioensaios empregados sugerem níveis maiores de toxicidade para as misturas de latossolo:dragado, em comparação aos tratamentos de chernossolo:dragado. No caso do chernossolo, a abundância de argilominerais 2:1, associada à alta fertilidade, parece ser capaz de reduzir a ecotoxicidade potencial. Em latossolo, mesmo as menores dosagens de aplicação de sedimento (3,33 e 6,66%) foram capazes de provocar efeitos adversos significativos aos microcrustáceos e às algas. Em misturas de chernossolo, efeitos significativos foram observados somente para doses de 6,58 e 13,16% para microcrustáceos e algas, respectivamente. Tais dados indicaram a ocorrência potencial de risco ecotoxicológico para as comunidades aquáticas vizinhas em cenários em que solos misturados com materiais dragados pudessem ser lixiviados e soluções tóxicas atingissem sistemas fluviais vizinhos. O ensaio agudo de papel de contato com E. andrei também acusou a ocorrência potencial de efeitos adversos sobre a fauna edáfica, a partir das doses de 13,12 e 19,74% em latossolo e chernossolo, respectivamente. O emprego do referido ensaio parece ser extremamente promissor no monitoramento da ecotoxicidade potencial de solos impactados pela disposição de resíduos sólidos e/ou contaminados por metais.

Potential ecotoxicity associated with the disposal of dredged sediments (from the Guanabara Bay, Rio de Janeiro, Brazil) in ferralsols and chernosols was studied through acute bioassays with micro-crustaceans (Daphnia similis) and earthworms (Eisenia andrei); and through chronic assays with algae (Pseudokirchenriella subcaptata). Total metal concentrations in the sediment were higher than the limits established by Brazilian legislation for dredged sediment disposal. The bioassays suggest the occurrence of more significant effects on ferralsols mixtures compared to chernosols treatments. In chernosol mixtures, the abundance of 2:1 clay minerals is apparently able to reduce the ecotoxicity. In ferralsol mixtures, lower dosages of sediment application (3.33 and 6.66%) caused significant effects on micro-crustaceans and algae. In chernosol treatments, adverse effects on in micro-crustaceans and algae were only observed for the doses of 6.58 and 13.16%, respectively. Such data indicate occurrence of potential risks on aquatic biota in the scenario where sediment-amended soils could be leached and such solutions could contaminate surrounding fluvial systems. The bioassay with E. andrei using contact paper also suggests the occurrence of potential adverse effects on edaphic biota. In addition, such tests with E. andrei demonstrate that they are highly applicable as alternative tools to monitor potential ecotoxicity associated with terrestrial disposal of solid residues containing domestic wastes and/or contaminated with metals.

Avaliação do risco de potencial ecotoxicológico de resíduos de 17? estradiol obtidos pós-processo oxidativo a base de peróxido de hidrogênio destinados a remoção deste hormônio / Assessment of potential ecotoxicological risk from products of estradiol 17? after process of oxidation with hydrogen peroxide for environmental removal of this hormone

The increasing disposal of medicines into the environment has increased concern about the possible environmental impact of such actions, in both the medium and long term. Estrogens have been found in soil, surface water and groundwater. The aim of this study was to assess the ecotoxicity of chemical residues originating from in situ oxidation of 17β estradiol with hydrogen peroxide, a process of chemical remediation which is used to remove these hormones in acetone solution, at various pHs. Analyses were carried out by high resolution gas chromatography and a bioassay in which the single-cell species Euglena gracilis was the test organism. The results were obtained by comparing analyses done before and after the AOP (advanced oxidation process). It was observed that at pH 5.0, with a treatment time of 20 minutes, there was a good yield, but with some change in the behavior of the test organism. With a pH of 7.0, with 20 minutes time, the yield was low but there was no demonstration of ecotoxicological activity...

Com o crescente descarte de medicamentos no meio ambiente, observa-se o aumento da preocupação com o impacto ambiental que tal ação pode acarretar, tanto a médio como em longo prazo. Os estrogênios vêm sendo encontrados no solo, em águas superficiais e subterrâneas. O objetivo deste estudo foi avaliar a ecotoxicidade dos resíduos químicos originados a partir da oxidação do 17? estradiol, via peróxido de hidrogênio, em um processo destinado à remoção química destes hormônios em solução de acetona, e em diferentes pHs. As análises foram feitas utilizando cromatografia gasosa de alta resolução e bioteste com algas do gênero Euglenas gracillis. Os resultados foram baseados nas comparações de análises pré-processo oxidativo avançado (POA) e pós POA. Observou-se que os resultados obtidos na condição de pH 5,0, com tempo de 20 minutos, apresentou um bom rendimento, porém com mudança de comportamento dos bioindicadores. Em pH 7,0, com tempo de 20 minutos, o rendimento foi menor, porém não houve demonstração de atividade ecotoxicológica...

Avaliação de impactos do efluente do tratamento combinado de lixiviado de aterro de resíduos sólidos urbanos e esgoto doméstico sobre a biota aquática / Assessment of impacts of combined treatment of solid urban waste landfill leachate and sewage on aquatic biota

Foi monitorado o impacto do tratamento combinado de lixiviado e esgoto doméstico de uma estação de tratamento operando em escala piloto por processo de lodos ativados, sobre peixes do gênero Tilapia: Biomarcadores de toxicidade (concentração de metalotioneínas, atividade da acetilcolinesterase, metábolitos de HPA e presença de micronúcleos) foram utilizados na avaliação dos riscos de danos aos organismos aquáticos devido à interação com poluentes contidos nos efluentes pós-tratamento. A concentração de metalotioneínas não apresentou variação significativa entre os grupos expostos e de controle. A atividade da enzima acetilcolinesterase foi inibida em apenas um dos grupos expostos, indicando possível presença de agentes inibidores no efluente tratado. A avaliação dos metabólitos dos HPA naftaleno, pireno, benzo(a)pireno e 1-hidroxipireno sinalizou a provável presença desses compostos em ao menos um dos afluentes do tratamento combinado. As frequências de micronúcleos e outras anormalidade nucleares eritrocitárias também apontam para maior incidência de danos genotóxicos em células dos organismos expostos do que nos controles. O uso de biomarcadores mostrou-se importante para possibilitar uma avaliação de danos subletais presentes em organismos expostos à fonte de poluição estudada.

The impact on tilapia fish of combined treatment of landfill leachate and domestic sewage was monitored in a waste treatment plant that operated on a pilot scale using the activated sludge process. Biomarkers of sub-lethal toxicity were used to indicate the possibility of damage to organisms due to interaction with pollutants. The concentration of metallothioneins did not indicate the increased presence of metals in fish exposed than in control groups. Acetylcholinesterase enzyme activity was inhibited in only one of the exposed groups, indicating the possible presence of organophosphate and/or carbamate pesticides in treated effluent. The PAHs used as biomarkers (naphthalene, pyrene, benzo(a)pyrene and 1-hydroxypyrene) indicated that exposed fish had a greater absorption of PAHs than control groups of fish, indicating the likely presence of these compounds in at least one of the combined treatment effluents. The frequencies of micronuclei and other erythrocytic nuclear abnormalities also indicate greater genotoxic damage in cells of organisms exposed than in control groups. The use of biomarkers proved to be important to permit an evaluation of sub-lethal damage present in organisms exposed to the pollution source studied.

Comparison between the efficiency of two bioindicators for determining surface water quality in an urban environment / Comparação entre a eficiência de dois bioindicadores para a determinação da qualidade de águas superficiais em um ambiente urbano

This study evaluated the efficiency of two bioindicators, fecal coliforms and ecotoxicity tests, set out in CONAMA Resolution 274/00 and CONAMA Resolution 357/05, in assessment of water quality. For this study, Lake Paranoá, Federal District of Brazil, was chosen, since it is a water body directly contaminated by effluents from a sewage treatment plant. Four sampling points were chosen in accordance with the map of recreational water quality published weekly by CAESB/DF, after analysis of fecal coliforms. Samples from these points were collected for 6 months and tested on Danio rerio fish (acute toxicity) and on the microcrustacean Ceriodaphnia dubia (acute and chronic toxicity), besides measuring chemical and physico-chemical parameters. The data obtained show great consistency between the observed biological parameters, suggesting that in this urban aquatic environment, under great anthropogenic pressure, the fecal coliform bioindicator seems to be more restrictive and enough to evaluate the safety of surface water.

Este trabalho comparou a eficiência dos bioindicadores coliformes fecais ou termotolerantes e ensaios de ecotoxicidade, propostos pelas Resoluções Conama 274/00 e Conama 357/05, na avaliação da qualidade de água. Para a realização desse estudo foi escolhido o Lago Paranoá, Brasília, Distrito Federal, por ser um corpo hídrico impactado diretamente pelo lançamento de efluentes de uma estação de tratamento de esgotos. Foram definidos quatro pontos de acordo com o mapa de balneabilidade, publicado semanalmente pela Caesb/DF, em função do teor de coliformes termotolerantes. Amostras desses pontos colhidas durante seis meses foram testadas com o peixe Danio rerio (toxicidade aguda) e o com o microcrustáceo Ceriodaphnia dubia (toxicidade aguda e crônica), além da determinação de parâmetros químicos e físico-químicos. Os resultados obtidos mostraram grande equivalência entre os parâmetros biológicos observados, sugerindo que nesse ambiente sob grande influência antrópica, o bioindicador coliformes termotolerantes foi mais restritivo e suficiente para avaliar a segurança das águas superficiais.

Ecotoxicological characterization of tannery wastewater in Dhaka, Bangladesh.

Tanning industries are one of the main economic activities in Bangladesh. It has been well documented that wastewater discharged from tanneries without appropriate treatment results in detrimental effects on the ecosystem. No ecotoxicity evaluation of any aquatic environment in Bangladesh has been conducted so far. In this study, a battery of toxicity bioassays and chemical analysis were carried out from water samples obtained from three sampling points: upstream from discharging site on River Buriganga (S1), raw wastewater effluent (S2), and downstream the discharging sluice gate (S3), in the Hazaribagh tannery area of Dhaka City, Bangladesh. While S1 and S3 water samples did not show significant toxicity in the bioassays tested, S2 exhibited high acute toxicity to the bacterium Vibrio fischeri (15-min Microtox® test, EC50 = 9.8%), the higher plant Lactuca sativa (5-day root elongation inhibition test, EC50 = 14.2%), and the microcrustacean Daphnia magna (24-hour mobility test, EC50 = 31.5%). The results suggested that the raw wastewater effluent had detrimental effects on broad spectrum of organisms in the aquatic ecosystem and bacterium was the most sensitive. The chemical analysis revealed that sample S2 contained an extremely high concentration of chromium (47 g l-1). Additionally, microbiological analysis indicated that the sampling area is impacted by fecal pollution, increasing the environmental health risk for its inhabitants.