RESUMO
Responses to the COVID-19 pandemic have been widely criticized for being too delayed and indecisive. As a result, the precautionary principle has been endorsed, applauded, and proposed to guide future responses to global public health emergencies. Drawing from controversial issues in response to COVID-19, especially in Vietnam, this paper critically discusses some key ethical and legal issues of employing the precautionary principle in public health emergencies. Engaging with discussions concerning this principle, especially in environmental law where the precautionary principle first appeared as a guiding principle with objective content(s), this paper formulates the precautionary principle as 'in dubio pro salus', which is about advising, justifying and demanding states to proactively prepare for scenarios arising out of any public health emergency. It distinguishes the precautionary principle into moderate and hard versions. A moderate version largely takes a holistic approach and fulfils a series of criteria specified in this paper, while a hard version either permits restrictive measures to be deployed primarily on a hypothetic basis or expresses an instrumental mentality. The hard version should be rejected because of the ethical and legal problems it raises, including risk-risk tradeoffs, internal paradoxes, unjustified causing of fear and unreasonable presupposition. Ultimately, this paper defends the moderate version.
Assuntos
COVID-19 , Saúde Pública , Humanos , Saúde Ambiental , Vietnã , Emergências , Pandemias , Medição de RiscoRESUMO
The use of pyrethroid and neonicotinoid insecticides has increased in Australia over the last decade, and as a consequence, increased concentrations of the neonicotinoid insecticide imidacloprid have been measured in Australian rivers. Previous studies have shown that non-target crustaceans, including commercially important species, can be extremely sensitive to these pesticides. Most shrimp farms in Australia are predominantly located adjacent to estuaries so they can obtain their required saline water, which support multiple land uses upstream (e.g. sugar-cane farming, banana farming, beef cattle and urbanisation). Larval and post-larval shrimp may be most susceptible to the impacts of these pesticides because of their high surface area to volume ratio and rapid growth requirements. However, given the uncertainties in the levels of insecticides in farm intake water and regarding the impacts of insecticide exposure on shrimp larvae, the risks that the increased use of new classes of pesticide pose towards survival of post-larval phase shrimp cannot be adequately predicted. To assess the potential for risk, toxicity in 20day past hatch post-larval Black Tiger shrimp (Penaeus monodon) to modern use insecticides, imidacloprid, bifenthin, and fipronil was measured as decreased survival and feeding inhibition. Post-larval phase shrimp were sensitive to fipronil, bifenthrin, and imidacloprid, in that order, at concentrations that were comparable to those that cause mortality other crustaceans. Bifenthrin and imidacloprid exposure reduced the ability of post-larval shrimp to capture live prey at environmentally realistic concentrations. Concentrations of a broad suite of pesticides were also measured in shrimp farm intake waters. Some pesticides were detected in every sample. Most of the pesticides detected were measured below concentrations that are toxic to post-larval shrimp as used in this study, although pesticides exceed guideline values, suggesting the possibility of indirect or mixture-related impacts. However, at two study sites, the concentrations of insecticides were sufficient to cause toxicity in shrimp post larvae, based on the risk assessment undertaken in this study.
Assuntos
Penaeidae/efeitos dos fármacos , Praguicidas/análise , Praguicidas/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Animais , Aquicultura , Estuários , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Penaeidae/crescimento & desenvolvimento , Queensland , Rios/química , Água do Mar/químicaRESUMO
Human rights constitute a universal concern in different countries' responses to COVID-19. Vietnam is internationally praised for its success in containing the pandemic; nevertheless, human rights issues are a key area that needs to be assessed and improved. Little legal and ethical research is available on human rights in Vietnam, particularly in its response to COVID-19, however. In Vietnam, decentralization took place during the pandemic: higher authorities delegated power to lower ones to make and implement public health measures. Unfortunately, many measures made and implemented decentrally caused human rights concerns or breaches. This article aims to study what makes such measures cause human rights concerns or breaches. It argues that several social, legal, and political factors, including an inadequate understanding of human rights, the undefined breadth of discretion, and lack of supervision, are underlying factors for such problematic decentralized measures. Accordingly, this paper proposes two solutions (i) improving the supervision of the decentralization process, and (ii) improving the understanding of human rights. While Vietnam should learn from the international community to improve its measures, lessons and experience from Vietnam can also contribute to a richer dialogue and better protection of human rights globally.
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This study was conducted to compare the exposure levels of five heavy metals via different pathways based on the field samplings and questionnaire surveys of children residing in an informal e-waste processing village and a reference village in Viet Nam. The findings revealed that levels of the total average daily intake (ADI) of the five heavy metals collected from a child at the exposed village were 3.90 times higher (p < 0.01) than that of a child at the reference village. Ingestion of cooked rice was the largest contributor to the total ADI of the children tested at both villages. However, the risks from water drinking and dermal contact of soil were negligible. The total non-carcinogenic risk and carcinogenic risk in an exposed child were significantly higher (p < 0.01) than their respective risks in a reference child. The non-carcinogenic risk to an exposed child was likely to occur, while the risk to a reference child was negligible. The carcinogenic risks found in children from both of the villages, however, were higher than the acceptable values, indicating the potential health risks to the children from both villages. The susceptibility of children to heavy metal contaminations shown in this study suggests that a mitigating measure need to be initiated jointly by a public agency and a private organization to prevent children from the risks of being exposed to the contaminants.
Assuntos
Resíduo Eletrônico , Metais Pesados , Poluentes do Solo , Criança , China , Resíduo Eletrônico/análise , Exposição Ambiental/análise , Monitoramento Ambiental , Humanos , Metais Pesados/análise , Medição de Risco , Solo , Poluentes do Solo/análise , Vietnã/epidemiologiaRESUMO
The human hepatocarcinoma cell line PLC/PRF/5 is susceptible to hepatitis E virus (HEV) infection and is used for HEV isolation. It is difficult to use the cell line for this purpose directly from fecal specimens of swine or wild boar contaminated with porcine sapelovirus (PSV) because PSV infection results in rapid and extensive cytopathic effects in PLC/PRF/5 cells, interrupting the growth of HEV. Herein, we used a PSV infection-resistant cell line, N1380, derived from PLC/PRF/5 cells, and successfully isolated a HEV-4b strain from a PSV-positive swine fecal specimen. Our results indicated that N1380 cells are a useful tool for the isolation of HEV from swine or wild boar fecal specimens, even when the cells are co-infected with PSV.
Assuntos
Fezes/virologia , Vírus da Hepatite E/classificação , Vírus da Hepatite E/isolamento & purificação , Hepatite E/diagnóstico , Doenças dos Suínos , Animais , Linhagem Celular , Hepatite E/veterinária , Vírus da Hepatite E/genética , Picornaviridae/isolamento & purificação , Infecções por Picornaviridae/diagnóstico , SuínosRESUMO
The removal and fate of several indicator endocrine disrupting chemicals (EDCs) at two large municipal wastewater treatment plants (WWTPs) in Adelaide South Australia was investigated. Non-estrogens included the non-ionic surfactant breakdown compounds nonyl phenol mono- and di-ethoxylates, 4-t-octylphenol and 4-nonyl phenol; and, the plasticizer bisphenol A. Estrogens included 17ß-estradiol; estrone; and, 17α-ethynylestradiol. Effluent from Bolivar WWTP is polished using stabilisation lagoons followed by coagulation, dissolved air flotation/filtration and chlorination for non-potable reuse. Biosolids from both plants is applied to agricultural land as a soil conditioner. Non-estrogen indicator EDCs were detected at the highest concentration in sewage, effluent and sludge but estrogen indicator EDCs contributed the greatest potential for estrogenicity. The fate of indicator EDCs at various treatment stages is complex and includes biochemical modification/transformation and/or partitioning to either solid or liquid phases. Activated sludge treatment was an important removal barrier achieving moderate-high removal of predicted and YES (a yeast screen assay) measured estrogen equivalent values (EEq). Combined polishing treatment achieved high removal of candidate EDCs (97%). Mass balance indicates that the largest source of estrogenicity discharged from both WWTPs investigated is digested sludge which accounts for 18 and 22% respectively of the combined predicted and YES measured EEq measured in sewage at the two WWTPs.
Assuntos
Disruptores Endócrinos/análise , Reciclagem/métodos , Esgotos/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Arquitetura de Instituições de Saúde , Austrália do Sul , Purificação da Água/instrumentaçãoRESUMO
Thermoplastic fiber-reinforced polymer composites (TP-FRPC) are gaining popularity in industry owing to characteristics such as fast part fabrication, ductile material properties and high resistance to environmental degradation. However, TP-FRPC are prone to time-dependent deformation effects like creep under sustained loading, which can lead to significant dimensional changes and affect the safe operation of structures. Previous research in this context has focused, mainly, on testing of flat coupons. In this study, a creep testing method for TP-FRPC tubular coupons was developed. Specimens were fabricated using tape winding and subjected to well-defined loading conditions, i.e., pure hoop tensile and pure axial compressive stress. Strain gauges and digital image correlation were both employed for strain measurements and were found to be in good agreement. The evolution of strain rate, Poisson's ratio and creep compliance were investigated. The prediction of experimental data by the Burgers model and the Findley's power law model were explored. The research findings suggest that the developed experimental and analysis approach provides valuable information for the design of material systems and structures.
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Post-mortem reproduction is a complex and contested matter attracting attention from a diverse group of scholars and resulting in various responses from a range of countries. Vietnam has been reluctant to deal directly with this matter and has, accordingly, permitted post-mortem reproduction implicitly. First, by analysing Vietnam's post-mortem reproduction cases, this paper reflects on the manner in which Vietnamese authorities have handled each case in the context of the contemporary legal framework, and it reveals the moral questions arising therefrom. The article then offers an account of Vietnamese social norms as an explanation for the tendency to conduct post-mortem reproduction. In arguing that a deeper and more thorough examination of the moral and ethical reasoning is required, the paper advocates in favour of supportive post-mortem reproduction regulation. In doing so, the paper seeks to reconcile the Vietnamese legal framework and post-mortem reproduction experiences of other countries. The article concludes that Vietnam and countries sharing the similar cultural traits should permit post-mortem reproduction explicitly. This would require full engagement with the ethical and legal issues arising, and careful promulgation of regulations and guidelines based on comparative experiences of a range of countries in handling this matter.
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Porcine sapelovirus (PSV) is a causative agent of acute diarrhoea, pneumonia and reproductive disorders in swine. Since PSV infection interrupts the growth of other viruses due to its high replication capability in cell culture, the prevention of PSV replication is a keystone to the isolation of non-PSV agents from PSV-contaminated samples. In the present study, we established the PSV infection-resistant cell line N1380 and isolated three mammalian orthoreoviruses (MRV) strains, sR1521, sR1677 and sR1590, from swine in Taiwan. These Taiwanese isolates induced an extensive cytopathic effect in N1380 cells upon infection. The complete and empty virus particles were purified from the cell culture supernatants. Next-generation sequencing analyses revealed that the complete virus particles contained 10 segments, including 3 large (L1, L2 and L3), 3 medium (M1, M2 and M3) and 4 small (S1, S2, S3 and S4) segments. In contrast, the empty virus particles without genome were non-infectious. Phylogenetic analyses revealed that the Taiwanese strains belong to serotype 2 MRV (MRV2). We established an ELISA for the detection of IgG antibody against MRV2 by using the empty virus particles as the antigen. A total of 540 swine and 95 wild boar serum samples were collected in Japan, and the positive rates were 100% and 52.6%, respectively. These results demonstrated that MRV infection occurred frequently in both swine and wild boar in Japan. We established a cell line that is efficient for the isolation of MRV, and the ELISA based on the naturally occurring empty particles would be of great value for the surveillance of MRV-related diseases.
Assuntos
Orthoreovirus de Mamíferos/isolamento & purificação , Infecções por Picornaviridae/veterinária , Picornaviridae/patogenicidade , Infecções por Reoviridae/veterinária , Doenças dos Suínos/virologia , Animais , Anticorpos Antivirais/sangue , Western Blotting/veterinária , Sistemas CRISPR-Cas , Linhagem Celular , Eletroforese em Gel de Poliacrilamida/veterinária , Ensaio de Imunoadsorção Enzimática/veterinária , Fezes/virologia , Sequenciamento de Nucleotídeos em Larga Escala/veterinária , Imunoglobulina G/sangue , Microscopia Eletrônica/veterinária , Orthoreovirus de Mamíferos/genética , Orthoreovirus de Mamíferos/imunologia , Filogenia , Infecções por Picornaviridae/virologia , RNA Viral/genética , Infecções por Reoviridae/virologia , SuínosRESUMO
We isolated a novel simian sapelovirus (SSV), Cam13, from fecal specimen of a cynomolgus monkey by using PLC/PRF/5 cells. The SSV infection of the cells induced an extensive cytopathic effect. Two types of virus particles with identical diameter (~32 nm) but different densities (1.348 g/cm3 and 1.295 g/cm3) were observed in the cell culture supernatants. The RNA genome of Cam13 possesses 8,155 nucleotides and a poly(A) tail, and it has a typical sapelovirus genome organization consisting of a 5' terminal untranslated region, a large open reading frame (ORF), and a 3' terminal untranslated region. The ORF encodes a single polyprotein that is subsequently processed into a leader protein (L), four structural proteins (VP1, VP2, VP3, and VP4) and seven functional proteins (2A, 2B, 2C, 3A, 3B, 3C, and 3D). We confirmed that 293 T, HepG2/C3A, Hep2C, Huh7 and primary cynomolgus monkey kidney cells were susceptible to SSV infection. In contrast, PK-15, Vero, Vero E6, RD-A, A549, and primary green monkey kidney cells were not susceptible to SSV infection. We established an ELISA for the detection of IgG antibodies against SSV by using the virus particles as the antigen. A total of 327 serum samples from cynomolgus monkeys and 61 serum samples from Japanese monkeys were examined, and the positive rates were 88.4% and 18%, respectively. These results demonstrated that SSV infection occurred frequently in the monkeys. Since Cam13 shared 76.54%-79.52% nucleotide sequence identities with other known SSVs, and constellated in a separate lineage in the phylogeny based on the entire genome sequence, we propose that Cam13 is a new genotype of the simian sapelovirus species.
Assuntos
Fezes/virologia , Genoma Viral/genética , Macaca fascicularis/virologia , Picornaviridae/genética , Vírion/genética , Regiões 3' não Traduzidas/genética , Regiões 5' não Traduzidas/genética , Células A549 , Animais , Sequência de Bases/genética , Linhagem Celular Tumoral , Chlorocebus aethiops , Células HEK293 , Células Hep G2 , Humanos , Fases de Leitura Aberta/genética , Filogenia , Picornaviridae/classificação , Picornaviridae/isolamento & purificação , Análise de Sequência de DNA/métodos , Células Vero , Vírion/isolamento & purificaçãoRESUMO
Biomarkers are frequently used to determine the exposure of fish to petroleum hydrocarbons following an oil spill. These biomarkers must be chosen carefully if they are to be used to determine sublethal toxic impacts as well as oil exposure. Many commonly used biomarkers relate to the metabolism of high molecular weight, typically pyrogenic, polycyclic aromatic hydrocarbons (PAHs), which are not abundant in unweathered crude oil. The goal of this study was to compare the efficacy of different biomarkers, including histological examination and transcriptomic profiling, in showing exposure to oil and the potential for sublethal toxic impacts. To achieve these goals, subadults/adults of the spotted dragonet (Repomucenus calcaratus) were exposed to a representative light, unweathered Australian oil for 96 h, so that the physiological changes that occur with exposure could be documented. Fish were then transferred to clean sediment for 90 h to quantify recovery. Biomarker changes, including PAH metabolites, 7-ethoxyresorufin O-deethylase (EROD), and histopathology, are presented in this work. In addition, a de novo transcriptome for the spotted dragonet was assembled, and differential transcript abundance was determined for the gill and liver of petroleum-exposed fish relative to a control. Increased levels of some biliary phenanthrene metabolites were seen throughout the exposure period. EROD levels showed modest, but not significant, increases. Transcriptomic differences were noted in the abundances of transcripts with a role in inflammation, primary metabolism and cardiac function. The patterns of transcript abundance in the gill and the liver changed in a manner that reflected exposure and recovery. The histology showed elevated prevalence of lesions, most notably vacuolization in liver and heart tissue, multi-organ necrosis, and lamellar epithelial lifting and telangiectasia in the gill. These findings suggest that short-term exposures to low molecular weight PAHs could elicit changes in the health of fish that are well predicted by the transcriptome. Furthermore, when light oil is released into the environment, exposure and subsequent risk would be better estimated using phenanthrene metabolite levels rather than EROD. This study also adds to the weight of evidence that exposure to low molecular weight PAHs may cause cardiac problems in fish. Further study is needed to determine the impact of these changes on reproductive capacity, long-term survival, and other population specific parameters.
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Monitoramento Ambiental/métodos , Perciformes/fisiologia , Petróleo/toxicidade , Animais , Austrália , Bile/metabolismo , Citocromo P-450 CYP1A1/metabolismo , Ontologia Genética , Sedimentos Geológicos/química , Metaboloma , Anotação de Sequência Molecular , Especificidade de Órgãos/efeitos dos fármacos , Perciformes/genética , Poluição por Petróleo , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Software , Poluentes Químicos da Água/toxicidadeRESUMO
The contact assay measuring the inhibition of Arthrobacter globiformis dehydrogenase activity as an endpoint to evaluate the toxicity of solid samples was tested in an international ring-test to validate its performance for ISO standardization (ISO/CD 18187). This work reports the results of the ring-test involving 9 laboratories from six countries. At least 8 valid data sets were obtained for each sample and more than three quarters of the participants attained the validity criteria defined in the standard. The coefficient of variation within (CVr) and between (CVR) laboratories was generally on average <15% and <30% for negative and positive controls, respectively. Regarding solid samples, the laboratories provided a similar ranking of the samples based on their toxicity, despite some variation in the LOEC values. The logarithmic within-lab standard deviation <0.50 for soils and <0.25 for wastes evidenced a good repeatability. The between-lab variability assessed by a CVR <30%, minimum-maximum factor <4 and a reproducibility standard deviation (SDR) <0.13 for a great part of the solid samples, confirmed the test reproducibility. Overall, this assay proved to be robust, sensitive and feasible for routine use towards the quality assessment of soils and wastes.
Assuntos
Arthrobacter/enzimologia , Bioensaio , Hidrolases/metabolismo , Resíduos Industriais/análise , Metais Pesados/análise , Poluentes do Solo/análise , Cinza de Carvão/análise , Monitoramento Ambiental , Sedimentos Geológicos/análise , Vidro/análise , Laboratórios , Mineração , Reprodutibilidade dos Testes , Madeira/análiseRESUMO
Acute and chronic bioassays provide essential basis for establishment of environmental quality standards. The effects of Cu on a pulmonate snail, Physa acuta, were investigated at a number of sublethal and lethal endpoints. Cu exposure suppressed movement and triggered an escape response in P. acuta at low and high concentrations, respectively, exerting acute toxic effects on adult snails exposed to a 96 h LC50 of 23.8 µg L-1. Following 16 d exposure of Cu to the egg masses, successful hatching decreased with increasing Cu concentration. High Cu concentrations (12.5 and 25 µg L-1) resulted in inhibition of eye and shell development at the veliger stage, and a deformed shell, abnormal eyes, and different morphological shapes with lesions and hemorrhages were observed after 9 days of exposure. A large number of eggs exposed to 2.5-25 µg L-1 Cu remained in the veliger and hippo stages for 2-7 days, with no further development. Results from reproduction tests showed that adult snails exposed to various Cu treatments produced more than three broods, with the total number of eggs ranging from 770 to 1,289, revealing little difference between the control and Cu-treated groups (p > 0.05). However, snails exposed to 12.5 and 25 µg L-1 Cu produced polynuclear eggs in one egg capsule. The hatching success rate and shell length of the filial generation were significantly reduced in a dose-dependent manner (p < 0.05). The shell length of newly hatched snails was shorter in the reproduction test than in the hatching test, indicating inherent Cu toxicity in the filial generation from the exposed parent strain. The present study provides essential data regarding Cu toxicity in pulmonate snail P. acuta.
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Cobre/toxicidade , Caracois Helix/fisiologia , Poluentes Químicos da Água/toxicidade , Animais , Reprodução/efeitos dos fármacos , Caramujos/efeitos dos fármacos , Testes de ToxicidadeRESUMO
Removal of a persistent antiepileptic drug carbamazepine (CBZ) in aqueous solutions was investigated by using solar photolysis combined with free available chlorine (FAC). The combination of chlorination with simulated or natural sunlight markedly enhanced removal of CBZ in 10 mM phosphate buffer solution (pH 7.0) and river water (pH 7.0) compared with sunlight or FAC alone. Further analysis indicated that the observed enhancements in CBZ removal can be attributed to the in situ hydroxyl radical (HO) and ozone (O3) production during FAC photolysis. During 70 min simulated sunlight photolysis combined with FAC treatment, HO reaction contributed to 35.8% removal of CBZ and O3 reaction contributed to 40.6% removal, while only 5.3% of CBZ was removed by HOCl reaction. The oxidation products of CBZ, epoxide CBZ, 10,11-dihydro-10,11-dihydroxy CBZ, 1-(2-benzaldehyde)-4-hydro-(1H,3H)-quinazoline-2-one (BQM), 1-(2-benzaldehyde)-(1H,3H)-quinazoline-2,4-dione (BQD) and 4-aldehyde-9-acridone, were mainly formed from the HO and O3 attack at the double bond on the central heterocyclic ring of CBZ. Formation of these oxidation products did not cause any increase or decrease in toxicity to microbial species tested through Microbial Assay for Toxicity Risk Assessment (MARA). The initial FAC concentration and pH had a major influence on the removal process of CBZ during FAC photolysis, while temperature had a minor effect only. The combination of chlorination with natural sunlight could provide an effective approach for removal of CBZ and other contaminants during water treatment.
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Carbamazepina/química , Fotólise , Cloro , Luz Solar , Poluentes Químicos da Água/químicaRESUMO
Ferrate(VI) (Fe(VI)) has been known to react with emerging organic contaminants containing electron-rich organic moieties, such as phenols, anilines, olefins, reduced sulfur and deprotonated amines. Oxidation of fluoroquinolone antibiotics, ciprofloxacin (CIP) and enrofloxacin (ENR), by Fe(VI) were investigated for their reaction products and toxicity changes as well as biodegradability of these products. Ten products were identified for both CIP and ENR reactions with Fe(VI) using a high-resolution accurate-mass Orbitrap mass analyzer. Structural changes to the CIP and ENR molecule included dealkylation, formation of alcohols and amides in piperazine ring and oxygen transfer to the double bond in quinolone structure. An enamine formation mechanism was tentatively proposed to facilitate the interpretation of CIP and ENR oxidation pathways. Toxicity evaluation using Microbial Assay for toxicity Risk Assessment (MARA) bioassay indicated that Fe(VI) oxidation products of CIP and ENR contributed negligible antibacterial potency and Fe(VI) oxidation treatment can remove the residual toxicity of CIP and ENR impacted source waters. The Fe(VI) oxidation treatment resulted in formation of relatively more biodegradable products (based on in silico assessment) than their corresponding parent compounds. The results showed that Fe(VI) has a good potential to degrade fluoroquinolone antibiotics and their antimicrobial potency in natural waters.
Assuntos
Ciprofloxacina/isolamento & purificação , Fluoroquinolonas/isolamento & purificação , Ferro/química , Poluentes Químicos da Água/isolamento & purificação , Ciprofloxacina/química , Enrofloxacina , Fluoroquinolonas/química , Testes de Sensibilidade Microbiana , Oxirredução , Testes de Toxicidade , Poluentes Químicos da Água/químicaRESUMO
The contamination of major continental river systems by endocrine-active chemicals (EACs) derived from the discharge of wastewater treatment plant (WWTP) effluents can affect human and ecosystem health. As part of a long-term effort to develop a native fish model organism for assessment of endocrine disruption in Australia's largest watershed, the Murray-Darling River Basin, the present study evaluated endocrine disruption in adult males of the native Australian Murray rainbowfish (Melanotaenia fluviatilis) exposed to effluent from an activated sludge WWTP and water from the Murray River during a 28-d, continuous-flow, on-site experiment. Analysis of the WWTP effluent and river water detected estrone and 17ß-estradiol at concentrations up to approximately 25 ng L(-1) . Anti-estrogenicity of effluent samples was detected in vitro using yeast-based bioassays (yeast estrogen screen) throughout the experiment, but estrogenicity was limited to the first week of the experiment. Histological evaluation of the testes indicated significant suppression of spermatogenesis by WWTP effluent after 28 d of exposure. Plasma vitellogenin concentrations and expression of vitellogenin messenger RNA in liver were not significantly affected by exposure to WWTP effluent. The combination of low contaminant concentrations in the WWTP effluent, limited endocrine disrupting effects in the Murray rainbowfish, and high in-stream dilution factors (>99%) suggest minimal endocrine disruption impacts on native Australian fish in the Murray River downstream from the WWTP outfall.