Genotoxic assessment on river water using different biological systems

This paper reports genotoxicity and toxicity data in water samples collected in Sinos River, an important water course in the hydrographic region of Guaíba Lake, Rio Grande do Sul State, south of Brazil. This river is exposed to intense anthropic influence by numerous shoes, leather, petrochemical, and metallurgy industries. Water samples were collected at two moments (winter 2006 and spring 2006) at five sites of Sinos River and evaluated using in vitro V79 Chinese hamster lung fibroblasts (cytotoxicity, comet assay and micronucleus test) and Allium cepa test (toxicity and micronucleus test). Comet and micronucleus tests revealed that water samples collected exerted cytotoxic, toxic, genotoxic and mutagenic effects. The results showed the toxic action of organic and inorganic agents found in the water samples in all sites of Sinos River, for both data collections. The main causes behind pollution were the domestic and industrial toxic discharges. The V79 and A. cepa tests were proved efficient to detect toxicity and genotoxicity caused by complex mixtures. This study also showed the need for constant monitoring in sites with strong environmental degradation caused by industrial discharges and urban sewages.     

Effects of tertiary treatment by fungi on organic compounds in a kraft pulp mill effluent

Background, aim and scope  

Pulp and paper mills generate a plethora of pollutants depending upon the type of pulping process. Efforts to mitigate the environmental impact of such effluents have been made by developing more effective biological treatment systems in terms of biochemical oxygen demand, chemical oxygen demand, colour and lignin content. This study is the first that reports an evaluation of the effects of a tertiary treatment by fungi (Pleurotus sajor caju, Trametes versicolor and Phanerochaete chrysosporium and Rhizopus oryzae) on individual organic compounds of a Eucalyptus globulus bleached kraft pulp and paper mill final effluent after secondary treatment (final effluent).     

Towards Understanding the Impacts of the Pet Food Industry on World Fish and Seafood Supplies

The status of wild capture fisheries has induced many fisheries and conservation scientists to express concerns about the concept of using forage fish after reduction to fishmeal and fish oil, as feed for farmed animals, particularly in aquaculture. However, a very large quantity of forage fish is being also used untransformed (fresh or frozen) globally for other purposes, such as the pet food industry. So far, no attempts have been made to estimate this quantum, and have been omitted in previous fishmeal and fish oil exploitation surveys. On the basis of recently released data on the Australian importation of fresh or frozen fish for the canned cat food industry, here we show that the estimated amount of raw fishery products directly utilized by the cat food industry equates to 2.48 million metric tonnes per year. This estimate, plus the previously reported global fishmeal consumption for the production of dry pet food suggest that 13.5% of the total 39.0 million tonnes of wild caught forage fish is used for purposes other than human food production. This study attempts to bring forth information on the direct use of fresh or frozen forage fish in the pet food sector that appears to have received little attention to this date and that needs to be considered in the global debate on the ethical nature of current practices on the use of forage fish, a limited biological resource.     

Arsenic removal from water employing heterogeneous photocatalysis with TiO2 immobilized in PET bottles

Arsenic oxidation (As(III) to As(V)) and As(V) removal from water were assessed by using TiO₂ immobilized in PET (polyethylene terephthalate) bottles in the presence of natural sunlight and iron salts. The effect of many parameters was sequentially studied: TiO₂ concentration of the coating solution, Fe(II) concentration, pH, solar irradiation time; dissolved organic carbon concentration. The final conditions (TiO₂ concentration of the coating solution: 10%; Fe(II): 7.0 mg l⁻¹; solar exposure time: 120 min) were applied to natural water samples spiked with 500 μg l⁻¹ As(III) in order to verify the influence of natural water matrix. After treatment, As(III) and total As concentrations were lower than the limit of quantitation (2 μg l⁻¹) of the voltammetric method used, showing a removal over 99%, and giving evidence that As(III) was effectively oxidized to As(V). The results obtained demonstrated that TiO₂ can be easily immobilized on a PET surface in order to perform As(III) oxidation in water and that this TiO₂ immobilization, combined with coprecipitation of arsenic on Fe(III) hydroxides(oxides) could be an efficient way for inorganic arsenic removal from groundwaters.     

Dibenzothiophene oxidation by horseradish peroxidase in organic media: effect of the DBT:H2O2 molar ratio and H2O2 addition mode

Its is well known that in the biodesulfurization (BDS) process the low water solubility of sulfur compounds hinders its transference from the oil phase to the cells being the rate-limiting step in the metabolism of dibenzothiophenes (DBT). Thus sulfur compounds derivatives with high water solubility could be more easily transported increasing the BDS efficiency. The present work performed a stepwise evaluation of the enzymatic oxidation of DBT by horseradish peroxidase (HRP). Reactions were carried out in monophasic organic media containing 25% (v/v) acetonitrile. The following parameters were evaluated: DBT:H2O2 molar ratio (1:1-1:20); H2O2 addition mode (single or stepwise); pH (6.0-8.0) and temperature (37-50 degrees C). Best results were observed in a reaction medium at pH 8.0 presenting HRP 0.06IUml(-1), DBT 0.267mM, DBT:H2O2 molar ratio of 1:20 (stepwise hydrogen peroxide addition) and incubated at 45 degrees C for 60min. Under these conditions 60% of DBT was converted into dibenzothiophene sulfoxide (12%) and dibenzothiophene sulfone (46%). The DBT oxidation rate observed in this work, of 5mmolmin(-1)g(-1) of HRP, was 250-fold higher than the BDS rate, 20mumolmin(-1)g(-1) of catalyst. As such a combined enzyme-microbial desulfurization process could be envisaged. Products were determined by HPLC RP C-18.     

Influence of humic substances on the photolysis of aqueous pesticide residues

The present work investigated the direct and indirect photolysis of pesticide residues (atrazine, imazaquin, iprodione), in aqueous solutions and under UV-visible radiation (280-480nm). Different kinds of humic substances (HS) were added to samples in order to evaluate their behaviour as possible photocatalysts and their effect on the photolysis of pesticides. The fulvic acids were purchased from the International Humic Substances Society, and they were added to samples in concentrations ranging from 1 to 150 mgl(-1). Titanium dioxide was used as the photocatalyst, in concentration ranging from 10 to 150 mgl(-1). Pesticides photolysis were measured by UV-visible absorption spectroscopy and differential pulse polarography with all used pesticides, reaching total degradation after 2h of irradiation, thus indicating a fast direct photolysis. Photocatalysis by TiO(2) could increase the pesticides photolysis rate up to 40%. This effect, however, was not observed for imazaquin photolysis. Again, except for imazaquin, HS presence showed a positive effect in increasing pesticide degradation, but only within specific concentration ranges (below 10mg l(-1) for iprodione and about 30mgl(-1) for atrazine). Above these ranges HS induce a decrease in the pesticides photolysis rate. Spin-trapping measurements by electronic paramagnetic resonance spectroscopy, using the spin-trap DMPO, showed that HS are able to photogenerate hydroxyl radicals, increasing the pesticides molecule degradation. However, the HS also react with the photogenerated hydroxyl radical, influencing the pesticide photolysis, leading to a decrease in the photolysis rate and causing it to be strongly dependent on the nature and concentration of residues in the water to be treated.     

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.     

Cephalopods and cetaceans as indicators of offshore bioavailability of cadmium off Central South Brazil Bight

Regarding Brazilian coast, industrial and urban developments are concentrated along Central South Brazil Bight. Samples from inshore and offshore species from the concerned area were analyzed, comprising 24 cetaceans (9 species) and 32 squids (2 species). Cadmium was determined by GFAAS and our results were in agreement with certified values (DOLT-2, NRCC). Mean cadmium concentration (in microg/g, wet weight) observed in the digestive gland of sexually mature Argentine short-finned squids (Illex argentinus) was 1002.9. To our knowledge this is the highest cadmium level ever reported for a cephalopod. Concerning cetaceans, our results include one of the highest renal cadmium concentrations described for striped dolphins (71.29 microg/g, wet weight). Anthropogenic action, upwelling and cannibalism of Argentine short-finned squid on the studied area are possible reasons for such remarkable cadmium concentrations.     

A semi-quantitative assessment of occupational risks using bow-tie representation

This work proposes a semi-quantitative risk assessment methodology, which was applied and tested in the Ship Building Industry. It covers a wide range of risks related to occupational accidents in a shipbuilding yard environment, more specifically at Arsenal do Alfeite, a large shipyard in Portugal. The initial qualitative analysis focuses on the bow-tie diagram technique but it also integrates concepts and classifications schemes defined by the Eurostat within the European Statistics on Accidents at Work (ESAW) Project. The structure of the diagram enables the identification of the relevant accident’s causal pathways and their consequences at the same time as it identifies the existing or needed safety barriers. In what concerns the semi-quantitative assessment, the accident risk level and acceptance criteria were established through a scoring system, using national data on accident statistics for the sub-sector: Ship Building & Repairing (code NACE 35.1). The statistical data was supplied by GEP (the Office of Strategy & Planning of the Portuguese Ministry of Labour & Social Solidarity). The authors present and discuss a specific case study, in the shipyard’s technological area of surface treatment and protection, to demonstrate the method’s applicability and usefulness.