Population structure and connectivity of the European conger eel (Conger conger) across the north-eastern Atlantic and western Mediterranean: integrating molecular and otolith elemental approaches

Genetic variation (mtDNA) of the European conger eel, Conger conger, was compared across five locations in the north-eastern Atlantic (Madeira, Azores, South Portugal, North Portugal and Ireland) and one location in the western Mediterranean (Mallorca). Genetic diversity of conger eel was high, and differentiation among regions was not significant. Additionally, comparisons of element:Ca ratios (Sr:Ca, Ba:Ca, Mn:Ca and Mg:Ca) in otolith cores (larval phase) and edges (3?months prior to capture) among the Azores, North Portugal, Madeira and Mallorca regions for 2?years indicated that variation among regions were greater for edges than cores. Therefore, while benthic conger may display residency at regional scales, recruitment may not necessarily be derived from local spawning and larval retention. Furthermore, data from otoliths suggest a separated replenishment source for western Mediterranean and NE Atlantic stocks. The combination of genetics and otolith chemistry suggests?a population model for conger eel involving a broad-scale dispersal of larvae, with limited connectivity for benthic juvenile life stages at large spatial scales, although the existence of one or multiple spawning grounds for the species remains uncertain.     

Defining Nutrient and Biochemical Oxygen Demand Baselines for Tropical Rivers and Streams in São Paulo State (Brazil): A Comparison Between Reference and Impacted Sites

Determining reference concentrations in rivers and streams is an important tool for environmental management. Reference conditions for eutrophication-related water variables are unavailable for Brazilian freshwaters. We aimed to establish reference baselines for São Paulo State tropical rivers and streams for total phosphorus (TP) and nitrogen (TN), nitrogen-ammonia (NH₄ ⁺) and Biochemical Oxygen Demand (BOD) through the best professional judgment and the trisection methods. Data from 319 sites monitored by the São Paulo State Environmental Company (2005 to 2009) and from the 22 Water Resources Management Units in São Paulo State were assessed (N = 27,131). We verified that data from different management units dominated by similar land cover could be analyzed together (Analysis of Variance, P = 0.504). Cumulative frequency diagrams showed that industrialized management units were characterized by the worst water quality (e.g. average TP of 0.51 mg/L), followed by agricultural watersheds. TN and NH₄ ⁺ were associated with urban percentages and population density (Spearman Rank Correlation Test, P < 0.05). Best professional judgment and trisection (median of lower third of all sites) methods for determining reference concentrations showed agreement: 0.03 &; 0.04 mg/L (TP), 0.31 &; 0.34 mg/L (TN), 0.06 &; 0.10 mg-N/L (NH₄ ⁺) and 2 &; 2 mg/L (BOD), respectively. Our reference concentrations were similar to TP and TN reference values proposed for temperate water bodies. These baselines can help with water management in São Paulo State, as well as providing some of the first such information for tropical ecosystems.     

Model parameterization for aerobic decomposition of plant resources drowned during man-made lakes formation

The formation of man-made reservoirs generates several impacts on water quality. In order to minimize some of these impacts mathematical models are currently used. This paper aims to discuss the issue associated with the degradation of plant resources (leaves, branches, barks and litter) that remain within the watershed of the new man-made lakes and parameterize a kinetic model related to decay of plant detritus. In these environments, the short-term variation of limnological parameters is mainly connected with biomass decay drowned during the filling operation. The kinetics of the degradation processes in reservoirs are discussed on the basis of information with related to detritus sources and the chemical properties of different types of compounds (i.e. labile and refractory fractions). Overall, the parameterization of the (first order) kinetic model showed that refractory fractions (ca. 86%) are predominant and the mineralization is a slow process, constituting the main route for decomposition and being affected by changes of environmental variables. The mineralization of labile and hydrosoluble compounds (ca. 14%) is responsible for the short-term water quality variation owing to decomposition; basically, the intensities of these changes depend on the labile/soluble compounds content of detritus and its chemical composition.     

Effects of lead exposure on salivary glands of rats: insights into the oxidative biochemistry and glandular morphology

Environmental Science and Pollution Research - This study aimed to investigate the effects of lead (Pb) exposure on parotid and submandibular glands through morphological aspects as well as the...     

Packaging waste recycling in Europe: Is the industry paying for it?

This paper describes and examines the schemes established in five EU countries for the recycling of packaging waste. The changes in packaging waste management were mainly implemented since the Directive 94/62/EC on packaging and packaging waste entered into force. The analysis of the five systems allowed the authors to identify very different approaches to cope with the same problem: meet the recovery and recycling targets imposed by EU law. Packaging waste is a responsibility of the industry. However, local governments are generally in charge of waste management, particularly in countries with Green Dot schemes or similar extended producer responsibility systems. This leads to the need of establishing a system of financial transfers between the industry and the local governments (particularly regarding the extra costs involved with selective collection and sorting). Using the same methodological approach, the authors also compare the costs and benefits of recycling from the perspective of local public authorities for France, Portugal and Romania. Since the purpose of the current paper is to take note of who is paying for the incremental costs of recycling and whether the industry (i.e. the consumer) is paying for the net financial costs of packaging waste management, environmental impacts are not included in the analysis. The work carried out in this paper highlights some aspects that are prone to be improved and raises several questions that will require further research. In the three countries analyzed more closely in this paper the industry is not paying the net financial cost of packaging waste management. In fact, if the savings attained by diverting packaging waste from other treatment (e.g. landfilling) and the public subsidies to the investment on the “recycling system” are not considered, it seems that the industry should increase the financial support to local authorities (by 125% in France, 50% in Portugal and 170% in Romania). However, in France and Portugal the industry is paying local authorities more than just the incremental costs of recycling (full costs of selective collection and sorting minus the avoided costs). To provide a more definitive judgment on the fairness of the systems it will be necessary to assess the cost efficiency of waste management operators (and judge whether operators are claiming costs or eliciting “prices”).     

Ground water contamination with 238U, 234U, 235U, 226Ra and 210Pb from past uranium mining: cove wash,Arizona

The objectives of the study are to present a critical review of the ²³⁸U, ²³⁴U, ²³⁵U, ²²⁶Ra and ²¹⁰Pb levels in water samples from the EPA studies (U.S. EPA in Abandoned uranium mines and the Navajo Nation: Red Valley chapter screening assessment report. Region 9 Superfund Program, San Francisco, 2004, Abandoned uranium mines and the Navajo Nation: Northern aum region screening assessment report. Region 9 Superfund Program, San Francisco, 2006, Health and environmental impacts of uranium contamination, 5-year plan. Region 9 Superfund Program, San Franciso, 2008) and the dose assessment for the population due to ingestion of water containing ²³⁸U and ²³⁴U. The water quality data were taken from Sect. “Data analysis” of the published report, titled Abandoned Uranium Mines Project Arizona, New Mexico, Utah–Navajo Lands 1994–2000, Project Atlas. Total uranium concentration was above the maximum concentration level for drinking water (7.410–1 Bq/L) in 19 % of the water samples, while ²³⁸U and ²³⁴U concentrations were above in 14 and 17 % of the water samples, respectively. ²²⁶Ra and ²¹⁰Pb concentrations in water samples were in the range of 3.7 × 10^?1 to 5.55 × 102 Bq/L and 1.11 to 4.33 × 102 Bq/L, respectively. For only two samples, the ²²⁶Ra concentrations exceeded the MCL for total Ra for drinking water (0.185 Bq/L). However, the ²¹⁰Pb/²²⁶Ra ratios varied from 0.11 to 47.00, and ratios above 1.00 were observed in 71 % of the samples. Secular equilibrium of the natural uranium series was not observed in the data record for most of the water samples. Moreover, the ²³⁵U/^totalU mass ratios ranged from 0.06 to 5.9 %, and the natural mass ratio of ²³⁵U to ^totalU (0.72 %) was observed in only 16 % of the water samples, ratios above or below the natural ratio could not be explained based on data reported by U.S. EPA. In addition, statistical evaluations showed no correlations among the distribution of the radionuclide concentrations in the majority of the water samples, indicating more than one source of contamination could contribute to the sampled sources. The effective doses due to ingestion of the minimum uranium concentrations in water samples exceed the average dose considering inhalation and ingestion of regular diet for other populations around the world (1 μSv/year). The maximum doses due to ingestion of ²³⁸U or ²³⁴U were above the international limit for effective dose for members of the public (1 mSv/year), except for inhabitants of two chapters. The highest effective dose was estimated for inhabitants of Cove, and it was almost 20 times the international limit for members of the public. These results indicate that ingestion of water from some of the sampled sources poses health risks.     

Potential toxic elements in stream sediments,soils and waters in an abandoned radium mine (central Portugal)

Environmental Geochemistry and Health - The Alto da Várzea radium mine (AV) exploited ore and U-bearing minerals, such as autunite and torbernite. The mine was exploited underground from 1911...     

Optimal Space-time Coverage and Exploration Costs in Groundwater Monitoring Networks

A method to determine the optimal subset of stations from a reference level groundwater monitoring network is proposed. The method considers the redundancy of data from historical time series, the times associated with the total distance required to run through the entire monitoring network, and the sum of the times for each monitoring station. The method was applied to a hypothetical case-study consisting of a monitoring network with 32 stations. Cost-benefit analysis was performed to determine the number of stations to include in the new design versus loss of information. This optimisation problem was solved with simulated annealing. Results showed that the relative reduction in exploration costs more than compensates for the relative loss in data representativeness.     

Toxicological response of silver catfish (Rhamdia quelen) after acute exposure to a commercial insecticide containing thiamethoxam

Abstract

This study assessed the hematological, enzymatic and osmoregulatory responses of silver catfish (Rhamdia quelen) exposed to sublethal concentrations (1.125 and 3.750?µg/L) of a commercial thiamethoxam-containing insecticide used on rice crops. Groups of 6 fish per tank (in triplicate, n?=?3, total 54 fish) were exposed for up to 96?h to different concentrations of the compound. After this period, fish were placed in clean water for 48?h. Two fish from each tank (6 per treatment) that had been exposed to the insecticide for 24?h were anesthetized with eugenol and blood was collected to evaluate hematological and biochemical parameters. Blood, liver and muscle were collected for determination of metabolic parameters, plasma cortisol, Cl^-, Na⁺ and K⁺ levels and H⁺-ATPase and Na⁺/K⁺-ATPase activity in the gill. H⁺-ATPase activity was higher in fish exposed to 1.125?µg/L insecticide at 24?h compared to control (0.0?µg/L). Differences in cortisol levels were evidenced throughout the experimental period. These results indicated that exposure to the insecticide changed the hematological, biochemical and metabolic profile of the animals, suggesting concern about environmental safety. Therefore, we discourage the use of this pesticide in areas that come into contact with water bodies inhabited by fish.