Heavy metals in the liver and muscle of <Emphasis Type="Italic">Micropogonias manni</Emphasis> fish from Budi Lake,Araucania Region,Chile: potential risk for humans

The concentrations of cadmium, lead, manganese and zinc were determined in the fish species Micropogonias manni captured in Budi Lake, Araucanía Region (Chile). The measurements were made by atomic absorption spectroscopy, and the analysis considered the sex, weight and size of the species; the representative samples were taken from the liver and muscle tissue. The method was validated using certified reference material (DOLT-1). The ranges of concentrations found in the muscle tissue were: Cd, not determinate (n.d.)–0.26; Pb, n.d.–1.88; Mn, 0.02–12.17 and Zn, 0.48–39.04 mg kg⁻¹ (dry weight). The concentrations in muscle tissue were generally lower than those found in the liver. With respect to the average concentrations recorded for each metal in the edible part of the fish (muscle tissue), it was found that the levels of Cd, Pb, Mn and Zn are within the ranges published by other authors in similar works and below the maximum concentration limits permitted by current legislation (FAO/WHO 2004; EU 2001) and do not constitute a health hazard for consumers of this species. The results were subjected to statistical analysis to evaluate the correlations between the content of the various metals and the sex, weight and size of each sample.     

Integrated pollution evaluation of the Tagus River in Central Spain

The aim of this study was to integrate hydrochemical and sediment data in order to obtain a picture of the pollution state of the Tagus River along central Spain. This area is of special interest because tributaries from the Madrid region are discharged and no previous data were available. Waters and sediments were sampled between 2002 and 2004 from selected sites before and after Jarama River confluence (Madrid city input). The samples were analysed for more than 50 parameters, including those of physico-chemical nature and those reporting the pollution caused by both metals and organic compounds. The quality of waters for different uses has been tested and statistical quality indexes of both global and partial type has also been established. Sediments pollution state was evaluated by comparison with general quality standards. A high degree of pollution and general degradation was observed in the Tagus River downstream the Jarama River input. The pollution of waters is mainly related to parameters indicators of organic pollution from urban sewage. In sediments, a dramatic increase in the concentration of trace metals was found in different points, exceeding toxicological threshold. Further studies would be necessary for organic pollutants and also to evaluate the remobilization potential.     

Assessment and monitoring of nutrient loading in the sediments of tidal creeks receiving shrimp farm effluent in Quang Ninh, Vietnam

Coastal shrimp farming may lead to the contamination of sediments of surrounding estuarine and marine ecosystems as shrimp farm effluent often contains high levels of pollutants including a range of organic compounds (from uneaten feed, shrimp feces, and living and dead organisms) which can accumulate in the sediments of receiving waterways. The assessment and monitoring of sediment quality in tidal creeks receiving shrimp farm effluent can support environmental protection and decision making for sustainable development in coastal areas since sediment quality often shows essential information on long-term aquatic ecosystem health. Within this context, this paper investigates nutrient loadings in the sediments of tidal creeks receiving shrimp farm effluent in Quang Ninh, Vietnam, which now have a high concentration of intensive and semi-intensive shrimp farms. Sediment samples taken from inside creek sections directly receiving effluent from concentrated shrimp farms (IEC), from main creeks adjacent to points of effluent discharge outside concentrated shrimp farms (OEC), and few kilometers away from shrimp farms (ASF) as reference sites were collected and analyzed before and after shrimp crops to investigate spatial and temporal variation. The results showed that there were statistically significant differences in the concentrations of total nitrogen, total phosphorus, and total organic carbon among IEC, OEC, and ASF sites while the seasonal variation being limited over study times. A sediment nutrient index (SNI) computed from coefficient scores of the factor analysis efficiently summarizes sediment nutrient loads, which are high, albeit quite variable, in canals directly receiving effluents from farms but then decline sharply with distance from shrimp farms. The visualization and monitoring of sediment quality data including SNI on maps can strongly support managers to manage eutrophication at concentrated shrimp farming areas, contributing to sustainable development and management at coastal zones.     

Sorption and desorption of carbamazepine, naproxen and triclosan in a soil irrigated with raw wastewater: estimation of the sorption parameters by considering the initial mass of the compounds in the soil

The amphipod Hyalella azteca was exposed for 28 d to different combinations of Zn contaminated sediment and food. Sediment exposure (+clean food) resulted in increased Zn body burdens, increased mortality and decreased body mass when the molar concentrations of simultaneously extracted Zn were greater than the molar concentration of Acid Volatile Sulfide (SEM_Zn-AVS > 0), suggesting that dissolved Zn was a dominant route of exposure. No adverse effect was noted in the foodexposure (+clean sediment), suggesting selective feeding or regulation. Combined exposure (sediment + food) significantly increased adverse effects in comparison with sediment exposure, indicating contribution of dietary Zn to toxicity and bioaccumulation. The observed enhanced toxicity also supports the assumption on the presence of an avoidance/selective feeding reaction of the amphipods in the single sediment or food exposures. During 14 d post-exposure in clean medium, the organisms from the same combined exposure history received two feeding regimes, i.e. clean food and Zn spiked food. Elevated Zn bioaccumulation and reduced reproduction were noted in amphipods that were offered Zn spiked food compared to the respective organisms that were fed clean food. This was explained by the failure of avoidance/selective feeding behavior in the absence of an alternative food source (sediment), forcing the amphipods to take up Zn while feeding. Increasing Zn body burdens rejected the assumption that Zn uptake from food was regulated by H. azteca. Our results show that the selective feeding behavior should be accounted for when assessing ecological effects of Zn or other contaminants, especially when contaminated food is a potential exposure route.     

Evaluating Hydrologically Connected Surface Water and Groundwater Using a Groundwater Model

Determination of the nature and extent of the connection between groundwater and surface water is of paramount importance to managing water supplies. The development of analyses that detail the surface water‐groundwater system may lead to more effective utilization of available water. A tool was developed to help determine the effects of groundwater and surface water interactions. The software tool includes two graphic user interfaces to allow full compatibility with numerical MODFLOW groundwater models. This case study shows the tool, in conjunction with MODFLOW groundwater models and carefully designed scenarios, can successfully calculate the rates of stream‐groundwater interactions, thereby providing the basis for designating management areas with the most significant hydrologic impact. This tool can be applied in other regions with similar settings and needs for integrated water management.     

Understanding the conflicting values associated with motorized recreation in protected areas

The International Union for the Conservation of Nature World Parks Congress in 2014 reported that the quality of management of protected areas is crucial in halting the loss of the world’s biodiversity and meeting global environmental challenges. However, increasingly high-impact activities, including motorized recreation are occurring in protected areas such as national parks, creating an ongoing clash of values and further compromising protected area management. This paper discusses the values of protected areas in the context of increasingly high-impact motorized usage, the impact of divergent values placed on green spaces such as national parks, and perceptions about these spaces. Given the changing global context of this millennium, and increasing populations requiring space for high-impact activities including motorized recreation, rethinking recreation in protected areas is needed. A protected area classification to accommodate high-impact activities away from vulnerable natural areas may assist in maintaining protected area quality.     

Optimization of Microwave-Assisted and Conventional Heating Comparative Synthesis of Poly(lactic acid) by Direct Melt Polycondensation from Agroindustrial Banana (Musa AAA Cavendish) and Pineapple (Ananas comosus) Fermented Wastes

In Costa Rica, a lot of pineapple (Ananas comosus) and banana (Musa AAA) agroindustrial residues are generated each year. These residues can be used to obtain l-lactic acid by fermentation, ultrafiltration and electrodialysis. Poly(l-lactic acid) (PLLA) is a biodegradable and renewable polyester with many industrial and biomedical applications. There is a growing interest to improve the energetic efficiency of the synthesis of PLLA, because the main issue to produce this polymer is the high productive cost compared with petrochemical traditional commodities. In this research, the synthesis of PLLA through two different techniques was compared: microwave-assisted and conventional heating. On microwave synthesis the best results were obtained using lower temperatures and lower reaction times than the conventional heated synthesis. The reaction time was reduced from 15 h by conventional heating to 4.5 h using microwave-assisted synthesis.     

The Effect of Chain Extender on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate): Thermal Degradation,Crystallization, and Rheological Behaviours

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a semi-polycrystalline biopolymer from the polyhydroxyalkanonate family has in recent years become a commercial bioplastic with mechanical properties comparable to isotactic polypropylene and enhanced O₂, CO₂ and H₂O barrier properties. However, its brittleness and sensitivity to thermal and hydrolysis degradations restrict its applications. To overcome the problems associated with degradation during processing blending of PHBV and an epoxy-functionalized chain extender (Joncryl^® ADR-4368 S) was conducted in a twin screw extruder. The effect of concentration of the chain extender on thermal, crystallization and rheological behaviours of PHBV was investigated. Thermal gravimetric analysis results indicated improvement in the resistance to thermal decomposition of PHBV by introducing the chain extender. This was accompanied with calculation of thermal degradation activation energy (E_a) using the Flyn–Walls–Ozawa method which confirmed increase of E_a with the increase in content of the chain extender. The rheological behaviour and crystallization of modified PHBV was characterized by rotational rheometry and differential scanning calorimetry techniques, respectively. The results show that addition of chain extender enhanced viscosity of PHBV and also reduce the rate of crystallization.     

Solar CPC pilot plant photocatalytic degradation of bisphenol A in waters and wastewaters using suspended and supported-TiO2. Influence of photogenerated species

Photocatalytic degradation of bisphenol A (BPA) in waters and wastewaters in the presence of titanium dioxide (TiO₂) was performed under different conditions. Suspensions of the TiO₂ were used to compare the degradation efficiency of BPA (20 mg L^?1) in batch and compound parabolic collector (CPC) reactors. A TiO₂ catalyst supported on glass spheres was prepared (sol–gel method) and used in a CPC solar pilot plant for the photodegradation of BPA (100 μg L^?1). The influence of OH·, O₂ ^·?, and h ⁺ on the BPA degradation were evaluated. The radicals OH· and O₂ ^·? were proved to be the main species involved on BPA photodegradation. Total organic carbon (TOC) and carboxylic acids were determined to evaluate the BPA mineralization during the photodegradation process. Some toxicological effects of BPA and its photoproducts on Eisenia andrei earthworms were evaluated. The results show that the optimal concentration of suspended TiO₂ to degrade BPA in batch or CPC reactors was 0.1 g L^?1. According to biological tests, the BPA LC₅₀ in 24 h for E. andrei was of 1.7?×?10^?2 mg cm^?2. The photocatalytic degradation of BPA mediated by TiO₂ supported on glass spheres suffered strong influence of the water matrix. On real municipal wastewater treatment plant (MWWTP) secondary effluent, 30 % of BPA remains in solution; nevertheless, the method has the enormous advantage since it eliminates the need of catalyst removal step, reducing the cost of treatment.