Assessment of organic and inorganic contaminants in sediments of an urban tropical eutrophic reservoir

Although the Ibirité reservoir (an urban tropical eutrophic reservoir) has been the recipient of the discharge of a large volume of raw urban sewage, the key cause of ecosystem degradation has been historically solely attributed to the discharge of effluents from an oil refinery. This fact motivated an investigation to unravel the compositions of contaminants in the sediments to evaluate their distributions, possible sources, and potential impacts on sediment–water quality. The concentrations of polycyclic aromatic and aliphatic hydrocarbons and of metals and metalloids were, in general, significantly lower than some selected polluted sites used for comparison. Calculated distribution indexes showed that the hydrocarbon sources were petrogenic, pyrogenic, and biogenic. Only a few PAHs exceeded the threshold effects level (TEL) guideline. Industrial activities are the presumed sources of metals and metalloids except for copper, which is from copper sulfate used as algaecide in the reservoir. The bioavailable concentrations of some metal and metalloid exceeded the TEL–PEL guidelines. The acid volatile sulfide concentration was greater than that of the simultaneously extracted metals in the clayey–silty reservoir sediments, whereas the opposite result was observed for the sandy sediments of the tributaries. The sediment interstitial water toxic units were >1 for metals, thus indicating that metals are potentially toxic to the benthos. Considering the data set generated in this study, it can be concluded that the degradation of Ibirité reservoir and its tributaries cannot be solely attributed to the input of hydrocarbons, but predominantly to the discharge of raw urban sewage and effluents from other industrial sources.     

Evaluation of surface water quality in aquatic bodies under the influence of uranium mining (MG, Brazil)

The quality of the water in a uranium-ore-mining area located in Caldas (Minas Gerais State, Brazil) and in a reservoir (Antas reservoir) that receives the neutralized acid solution leaching from the waste heaps generated by uranium mining was investigated. The samples were collected during four periods (October 2008, January, April and July 2009) from six sampling stations. Physical and chemical analyses were performed on the water samples, and the data obtained were compared with those of the Brazilian Environmental Standards and WHO standard. The water samples obtained from waste rock piles showed high uranium concentrations (5.62 mg L^?1), high manganese values (75 mg L^?1) and low average pH values (3.4). The evaluation of the water quality at the point considered the limit between the Ore Treatment Unit of the Brazilian Nuclear Industries and the environment (Consulta Creek) indicated contamination by fluoride, manganese, uranium and zinc. The Antas reservoir showed seasonal variations in water quality, with mean concentrations for fluoride (0.50 mg L^?1), sulfate (16 mg L^?1) and hardness (20 mg L^?1) which were low in January, evidencing the effect of rainwater flowing into the system. The concentrations for fluoride, sulfate and manganese were close or above to the limits established by current legislation at the point where the treated mining effluent was discharged and downstream from this point. This study demonstrated that the effluent discharged by the UTM affected the quality of the water in the Antas reservoir, and thus the treatments currently used for effluent need to be reviewed.     

Bioluminescent yeast estrogen assay (BLYES) as a sensitive tool to monitor surface and drinking water for estrogenicity

Estrogenic Endocrine Disrupting Chemicals (EDCs) are a concern due to their ubiquity and recognized adverse effects to humans and wildlife. Methods to assess exposure to and associated risks of their presence in aquatic environment are still under development. The aim of this work is to assess estrogenicity of raw and treated waters with different degrees of pollution. Chemical analyses of selected EDCs were performed by liquid chromatography-tandem mass spectrometry, and estrogenic activity was evaluated using in vitro bioluminescent yeast estrogen assay (BLYES). Most raw water samples (18/20) presented at least one EDC and 16 rendered positive in BLYES. When EDCs were detected, the bioassay usually provided a positive response, except when only bisphenol A was detected at low concentrations. The highest values of estrogenic activity were detected in the most polluted sites. The maximum estrogenic activity observed was 8.7 ng equiv. of E2 L(-1). We compared potencies observed in the bioassay to the relative potency of target compounds and their concentrations failed to fully explain the biological response. This indicates that bioassay is more sensitive than the chemical approach either detecting estrogenic target compounds at lower concentrations, other non-target compounds or even synergistic effects, which should be considered on further investigations. We have not detected either estrogenic activity or estrogenic compounds in drinking water. BLYES showed good sensitivity with a detection limit of 0.1 ng equiv. E2 L(-1) and it seems to be a suitable tool for water monitoring.     

Distribution of microbiological indicators of fecal pollution in the riverine substrates

Distribution of fecal microorganisms in water, periphyton, and sediment was studied along the ?rnovnica river (Croatia) over a 1.5-year period. It was found that periphyton was inhabited by the highest number of investigated bacteria, while lower numbers of them were found in sediment and the lowest in surface water of the river. The concentrations of fecal microorganisms in periphyton and partly in sediment were found to be significantly higher in the middle of the river course, near the town of ?rnovnica, while according to the analysis of surface water the highest degree of pollution was reached on its estuary. The results were explained with respect to bacterial?Calgal associations. Considering the fact that most of the river microorganisms are associated with periphyton and sediment particles and only a small number of them is in the free-living form, microbiological analysis of both periphyton and sediment together with water samples has been suggested when fecal pollution of a river is concerned.     

Cultivable microbiome and its resistance to antimicrobials isolated from <Emphasis Type="Italic">Zaprionus indianus</Emphasis>

The objective of this study was to identify Z. indianus in PEJC and PESCAN. Listed are the following methods: to isolate bacteria from the integument of the Z. indianus species collected and to check the resistance of microorganisms to antibiotics. Collections of Z. indianus were performed in four seasons of the two parks. The results obtained suggest that the low amount of Z. indianus collected can be justified by environmental factors such as high average temperature and low average humidity. It is noted that there is a predominance of bacteria of the Enterobacteriaceae family found in both the PEJC and the PESCAN. The antibiogram performed for the isolated PEJC bacteria shows statistical significance when comparing the edge and inside values of the park. Studies with fungi were also carried out, and it was evidenced that Trichophyton spp. was the genus that most inhabited the two environments studied. The ability of fluconazole and ketoconazole to inhibit fungal growth was also investigated, and considering the concentration tested may suggest that they have good action spectra. Plasmid profile data show that 60% of antibiotic-resistant bacteria have plasmids. The values found show that Z. indianus can act as vectors of microorganisms that affect the healthy animals and humans and that these organisms may be influenced by seasons.     

Marine debris contamination along undeveloped tropical beaches from northeast Brazil

We hypothesize that floating debris leaving polluted coastal bays accumulate on nearby pristine beaches. We examined composition, quantities and distribution of marine debris along approximately 150 km of relatively undeveloped, tropical beaches in Costa do Dendê (Bahia, Brazil). The study site is located south of Salvador City, the largest urban settlement from NE Brazil. Strong spatial variations were observed. Plastics accounted for 76% of the sampled items, followed by styrofoam (14%). Small plastic fragments resultant from the breakdown of larger items are ubiquitous all over the area. Because the dominant littoral drift in Bahia is southward, average beach debris densities (9.1 items/m) along Costa do Dendê were threefold higher than densities previously observed north of Salvador City. River-dominated and stable beaches had higher debris quantities than unstable, erosional beaches. Areas immediately south of the major regional embayments (Camamu and Todos os Santos) were the preferential accumulation sites, indicating that rivers draining populous areas are the major source of debris to the study site. Our results provide baseline information for future assessments. Management actions should focus on input prevention at the hydrographic basin level rather than on cleaning services on beaches.     

Correction to: Ecological restoration as a strategy for mitigating and adapting to climate change: lessons and challenges from Brazil

Mitigation and Adaptation Strategies for Global Change - The original version of the article unfortunately contained an error.     

Feasibility of rice straw as a raw material for the production of soda cellulose pulp

The main objective of this work is to evaluate the suitability of rice straw and soda–anthraquinone (soda–AQ) pulping process to produce pulp and paper. To reach this aim, it was used a central composite factorial design to study the influence of operational variables (temperature (155–185 °C), cooking time (30–90 min), soda concentration (10–20%), anthraquinone concentration (0–1%) and liquid/solid ratio (6–8)), in soda–anthraquinone cooking of rice straw on pulps and paper sheets properties obtained.Based on the yield values obtained, nearly one half of the raw material can be efficiently converted into cellulose pulp and paper sheets. Also, the Kappa number/viscosity ratio of the pulp facilitates its efficient bleaching. Finally, based on the values for above-described physical properties, the pulp can be used to obtain paper or board and recycled paper (as % virgin fibre).In Spain are produced annually 757,000 t of rice straw. If we considered an average yield process of 45%, it would be possible to obtain 340,000 tons of pulp. These tons would be absorbed by the market taking into account the necessities in cellulosic pulp consumption.