Evaluation of genotoxicity and toxicity of water and sediment samples from a Brazilian stream influenced by tannery industries

This paper reports results of genotoxicity and toxicity studies of water and sediment samples collected from the Estancia Velha stream of southern Brazil, a stream transporting both domestic sewage and effluents from regional factories working in the leather industry. Three sites were selected: in the stream headwaters (Site 1), located downstream of an urban area (Site 2), and near the basin outfall (Site 3). Results obtained with Allium cepa showed no evidence of chromosomal mutation, either in water or in sediment, during winter or summer seasons, but samples collected below Site 1 showed high toxicity. Physical and chemical analyses showed high concentrations of pollutants at these sites. Ecotoxicity tests with Daphnia magna and Ceriodaphnia dubia measured toxicity in water from Sites 2 and 3 in summer 2004. A toxic effect on Hyalella azteca was only found in sediment from Site 3 during winter 2003 and summer 2004. The results suggest that the synergy among different compounds in domestic and industrial sewage discharges can make it difficult to maintain system stability.     

Antiviral Activity of Ctn[15-34], A Cathelicidin-Derived Eicosapeptide,Against Infectious Myonecrosis Virus in <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis> Primary Hemocyte Cultures

The shrimp farming has been converted into a mature aquaculture industry dealing with over millions of metric tonnes of processed commodities. Nevertheless, the global shrimp productions are constantly threatened by disease outbreaks, mainly triggered by rapidly disseminating viruses. Infectious myonecrosis virus (IMNV) is one of these epizootic agents affecting shrimp production in Brazil, of which no treatment exists. Herein, the antiviral activity against IMNV of an eicosapeptide, named Ctn[15-34], derived from a member of the cathelicidin family of antimicrobial peptides, was demonstrated. Cultures of hemocytes from Litopenaeus vannamei were established that support IMNV replication and infectivity titration. The cytotoxic effect of IMNV in culture and the in vitro anti-IMNV activity of Ctn[15-34] were assessed using a high-sensitive fluorescent-based method in combination with quantitative PCR. The Ctn[15-34] (<12.5 µM) neutralized the toxic effects of IMNV at loads sufficient to kill 50% of shrimp hemocytes. This study reported for the first time the replication of IMNV in vitro and the employment of a straightforward methodology to assess cell viability and viral/antiviral activities. In addition, it provided the basis for the development of the anti-infective multi-effector Ctn[15-34] eicosapeptide and analogs as components of antiviral formulations against shrimp viral diseases.     

Solid wastes from the enzyme production as a potential biosorbent to treat colored effluents containing crystal violet dye

Environmental Science and Pollution Research - Sugarcane bagasse, a largely available waste worldwide, was submitted to solid-state fermentation (SSF) using the fungus Metarhizium anisopliae,...     

The effect of continuous exposure of copper on the properties and extracellular polymeric substances (EPS) of bulking activated sludge

Introduction  

This study investigated the effect of copper on chemical oxygen demand (COD) removal efficiency and on the properties (mainly settling and dewatering) and the composition of extracellular polymeric substances (EPS) when 20 mg/L Cu(II) was continuously dosed to a sequencing batch reactor (SBR) inoculated with activated sludge.     

Bisphenol A migration from plastic materials: direct insight of ecotoxicity in Daphnia magna

Bisphenol A (BPA) is an endocrine disrupting chemical (EDC) whose migration from food packaging is recognized worldwide. However, the real overall food contamination and related consequences are yet largely unknown. Among humans, children’s exposure to BPA has been emphasized because of the immaturity of their biological systems. The main aim of this study was to assess the reproductive impact of BPA leached from commercially available plastic containers used or related to child nutrition, performing ecotoxicological tests using the biomonitoring species Daphnia magna. Acute and chronic tests, as well as single and multigenerational tests were done. Migration of BPA from several baby bottles and other plastic containers evaluated by GC-MS indicated that a broader range of foodstuff may be contaminated when packed in plastics. Ecotoxicological test results performed using defined concentrations of BPA were in agreement with literature, although a precocious maturity of daphnids was detected at 3.0 mg/L. Curiously, an increased reproductive output (neonates per female) was observed when daphnids were bred in the polycarbonate (PC) containers (145.1?±?4.3 % to 264.7?±?3.8 %), both in single as in multigenerational tests, in comparison with the negative control group (100.3?±?1.6 %). A strong correlated dose-dependent ecotoxicological effect was observed, providing evidence that BPA leached from plastic food packaging materials act as functional estrogen in vivo at very low concentrations. In contrast, neonate production by daphnids cultured in polypropylene and non-PC bottles was slightly but not significantly enhanced (92.5?±?2.0 % to 118.8?±?1.8 %). Multigenerational tests also revealed magnification of the adverse effects, not only on fecundity but also on mortality, which represents a worrying trend for organisms that are chronically exposed to xenoestrogens for many generations. Two plausible explanations for the observed results could be given: a non-monotonic dose–response relationship or a mixture toxicity effect.     

Median lethal concentration of formaldehyde and its genotoxic potential in bullfrog tadpoles (Lithobates catesbeianus)

In order to avoid that contaminated frog farms animals escaping in the environment and become potential vector of emergent diseases, studies with disinfection protocol are strictly necessary. The formaldehyde is one of the compounds tested in fungal disinfection protocols and also used in aquaculture. This study aimed to determine the median lethal concentration (LC_50–96h) of formaldehyde in bullfrog tadpoles and to evaluate the possible genotoxic effects in acute exposition. Accordingly, the animals were exposed to formaldehyde in the concentrations of 6, 9, 12, 15, and 18 mg L^?1, and after 96 h blood samples were drawn for the micronucleus (MN) test. The LC_50–96h was 10.53 mg L^?1, and the MN frequency increased in proportion to the formaldehyde concentrations, with an estimated frequency in the negative control being 1.35 MN/individual. We concluded that formaldehyde is genotoxic to tadpoles of bullfrogs in the tested concentrations, and the choice of this chemical should be contemplated before its use in animals in captivity.     

Detection of hormones in surface and drinking water in Brazil by LC-ESI-MS/MS and ecotoxicological assessment with <Emphasis Type="Italic">Daphnia magna</Emphasis>

The growing use of pharmaceutical drug is mainly due to several diseases in human and in animal husbandry. As these drugs are discharged into waterways via wastewater, they cause a major impact on the environment. Many of these drugs are hormones; in which even at low concentrations can alter metabolic and physiological functions in many organisms. Hormones were found in surface water, groundwater, soil, and sediment at concentrations from nanograms to milligrams per liter of volume—quantities known to cause changes in the endocrine system of aquatic organisms. This study aimed to develop a methodology for hormone detection (estriol, estrone, 17β-estradiol, 17α-ethinylestradiol, progesterone, and testosterone) on surface and treated water samples. Sample toxicity was assessed by ecotoxicology tests using Daphnia magna. A liquid chromatograph coupled to a mass spectrometer with an electrospray ionization source (LC-ESI-MS/MS) was used for the analysis. The results showed that samples were contaminated by the hormones estriol, estrone, progesterone, 17β-estradiol, and 17α-ethinylestradiol during the sampling period, and the highest concentrations measured were 90, 28, 26, 137, and 194 ng·L^?1, respectively. This indicates the inflow of sewage containing these hormones at some points in the Piracicaba River in the State of Sao Paulo—Brazil. Results indicated little toxicity of the hormone estriol in D. magna, indicating that chronic studies with this microcrustacean are necessary.     

Electrochemical degradation of amoxicillin in acidic aqueous medium using TiO2-based electrodes modified by oxides of transition metals

Environmental Science and Pollution Research - One of the most widely used antibiotics is amoxicillin (AMX), which is the most widely used in humans and animals, but it is discharged metabolically...     

Degradation features of pesticides: a review on (metallo)porphyrin-mediated catalytic processes

Environmental Science and Pollution Research - Pesticides have been used to kill pests such as insects, fungi, rodents, and unwanted plants. Since these compounds are potentially toxic to the...     

Uniform predation risk in nature: common,inconspicuous, and a source of error to predation risk experiments

Previous studies indicate that when predation risk is uniform across habitats, foragers concentrate their exploitation in fewer patches. Although uniform predation risk may seem rare in nature, some scenarios might cause it. Testing all scenarios in a single experiment is unfeasible; therefore, we developed a model that points whether concentration of exploitation in specific habitats due to uniform risk requires parameter values similar to what is found in literature. This model was based on Brown’s (Behav Ecol Sociobiol 22:37–47, 1988) fitness function but rescaled to multiple habitats and predators, including uniform risk predators. Deriving function’s maximum allowed comparisons with giving-up density studies. Results showed that uniform predation risk had a u-shaped effect in habitat exploitation, causing a concentration of habitat exploitation at probabilities of survival from 0.2 to 0.8. However, the length of this interval and degree of concentration depended on the value of safety to forager fitness. Heterogeneous, nonuniform, predation risk decreases habitat exploitation where it was higher, therefore suppressing the effect of uniform risk on prey behavior. Time spent in the focal habitat and metabolic costs reduced the detectability of habitat concentration, while total time did not. We also found that uniform risk reduced accuracy of heterogeneous risk measurements. Future studies should aim to control all possible predators, as even the mild ones can induce complex behavior.