Mainstreaming ecosystem-based climate change adaptation into integrated water resources management in the Mekong region

Regional Environmental Change - Efficient, equitable, and transboundary management of the water resources of the Mekong River Basin (MRB) is challenged by ongoing and accelerating alteration of the...     

Three-dimensional modeling of the lower trophic levels in the Ria de Aveiro (Portugal)

The water and the ecosystem dynamics of the Ria de Aveiro, a shallow, multi-branch lagoon located on the northwest coast of Portugal, are simulated using a new fully coupled 3D modeling system. This model couples the hydrodynamic model SELFE (semi-implicit Eulerian-Lagrangian finite element) and an ecological model extended from EcoSim 2.0 to represent zooplankton dynamics. The model application is based on an unstructured grid spatial discretization, which is particularly appropriate for this system given its complex geometry. The baroclinic circulation is calibrated and validated for different environmental conditions, leading to velocity errors smaller than 5 cm/s across the lagoon. Ecological simulations, focused on zooplankton dynamics represented by a site-specific formulation, are then presented and compared against field data for two contrasting environmental conditions: Autumn 2000 and Spring 2001. Results show that the fully coupled model is able to reproduce the dynamics of the ecosystem in the Spring 2001, fitting the model results inside the range of data variation. During this period zooplankton differences between data and model results are of about 0.005 mg C/l (60%), while other ecological tracers’ differences are generally smaller than 20–30% along the several branches of the lagoon. In the Autumn 2000, the model tends to overestimate zooplankton by a factor of 10 and to underestimate phytoplankton and ammonium, with discrepancies of about 0.1 mg C/l and 4.8 μmol N/l, respectively. Factors like the ecological conditions imposed at the boundaries, the input parameters of the ecological model and the simplification of the ecosystem structure, since phytoplankton is the only primary producer considered, may explain the observed differences.     

The water-soluble fraction of potentially toxic elements in contaminated soils: relationships between ecotoxicity, solubility and geochemical reactivity

To better understand the impacts posed by soil contamination to aquatic ecosystems it is crucial to characterise the links between ecotoxicity, chemical availability and geochemical reactivity of potentially toxic elements (PTE’s) in soils. We evaluated the adverse effects of water extracts obtained from soils contaminated by chemical industry and mining, using a test battery including organisms from different trophic levels (bacteria, algae and daphnids). These tests provided a quick assessment of the ecotoxicity of soils with respect to possible adverse effects on aquatic organisms although the ecotoxicological responses could be related to the solubility of PTE’s only to a limited extent.The analysis of results of bioassays together with the chemical characterisation of water extracts provided additional relevant insight into the role of conductivity, pH, Al, Fe, and Mn of soil extracts on toxicity to organisms. Furthermore, an important conclusion of this study was that the toxicity of extracts to the aquatic organisms could also be related to the soil properties (pH, Org C and Fe_ox) and to the reactivity of PTE’s in soils which in fact control the soluble fraction of the contaminants.The combined assessment of ecotoxicity in water fractions, solubility and geochemical reactivity of PTE’s in soils provided a more comprehensive understanding of the bioavailability of inorganic contaminants than ecotoxicological or chemical studies alone and can therefore be most useful for environmental risks assessment of contaminated soils.     

Assessing joint toxicity of chemicals in Enchytraeus albidus (Enchytraeidae) and Porcellionides pruinosus (Isopoda) using avoidance behaviour as an endpoint

Contamination problems are often characterized by complex mixtures of chemicals. There are two conceptual models usually used to evaluate patterns of mixture toxicity: Concentration Addition (CA) and Independent Action (IA). Deviations from these models as synergism, antagonism and dose dependency also occur. In the present study, single and mixture toxicity of atrazine, dimethoate, lindane, zinc and cadmium were tested in Porcellionides pruinosus and Enchytraeus albidus, using avoidance as test parameter. For both species patterns of antagonism were found when exposed to dimethoate and atrazine, synergism for lindane and dimethoate exposures (with the exception of lower doses in the isopod case study) and concentration addition for cadmium and zinc occurred, while the exposure to cadmium and dimethoate showed dissimilar patterns.This study highlights the importance of dose dependencies when testing chemical mixtures and that avoidance tests can also be used to asses the effects of mixture toxicity.     

A review of regulatory decisions for environmental protection: part I - challenges in the implementation of national soil policies

Since many soil studies have already revealed the possible risks to human health and the environment arising from contaminated soils it is therefore crucial to preserve soil quality under current and future conditions. In the last three decades a number of countries already introduced national policies and practices for the management of contaminated sites, and in 2002, an EU Thematic Strategy for Soil Protection was proposed by the European Commission. In this paper we review and analyse several national contaminated land policy regimes already in place in order to assess common elements and to identify specific needs in the development of national soil policies. We propose a framework that combines the D-P-S-I-R structure of policy evaluation with the Source-Pathway-Receptor approach to health risk assessment to support the development of effective country specific regulatory decisions for managing contaminated land in countries where these are yet to be implemented. The framework proposed allows decision makers to effectively use available information and to identify existing data gaps. As a result it is apparent that while there are technical aspects of site characterisation, risk assessment and remediation processes that could be commonly implemented at an EU level there are certain trans-scientific aspects that require political choices and need to be customized by EU Member States.     

Environmental performance evaluation of agro-industrial innovations – part 1: Ambitec-Life Cycle,a methodological approach for considering life cycle thinking

As sustainability considerations increasingly dominate the technology development debate worldwide, practical approaches to assess environmental performance of innovations have been warranted. The present study (Part 1) introduces Ambitec-Life Cycle, a method derived from Ambitec-Agro for considering life cycle thinking in the environmental performance evaluation (EPE) of agro-industrial innovations. An agro-industrial innovation case study related to residue recycling is presented, revealing steps in the product life cycle where opportunities are best for technological improvements. In Part 2 (this issue) of this study, a methodological approach for considering the environmental vulnerability of watersheds and to integrate this analysis in EPE methods is presented. This approach is applied to Ambitec-Life Cycle and to the same residue case study, allowing the identification of performance indicators with greater potential to cause impacts at the studied watersheds.     

Factorial analysis of the trihalomethane formation in the reaction of colloidal,hydrophobic, and transphilic fractions of DOM with free chlorine

Background, aim, and scope  

This study focuses on the factors that affect trihalomethane (THMs) formation when dissolved organic matter (DOM) fractions (colloidal, hydrophobic, and transphilic fractions) in aqueous solutions were disinfected with chlorine.     

Human exposure to fluoride from tea (Camellia sinensis) in a volcanic region—Canary Islands,Spain

Fluoride is highly present in the environment, especially in water and its derivatives. Excessive fluoride contribution to diet poses a health risk. Tea leaves accumulate fluoride and the consumption of tea (Camellia sinensis) could pose a risk to human by the excessive fluoride intake. Ninety tea samples were analyzed by potentiometry using a selective fluoride ion electrode. Mixed tea samples (2.82?±?1.11 mg/L) and black tea samples (2.28?±?0.79 mg/L) recorded the highest fluoride levels. The contribution of drinking water is important for increasing fluoride levels in teas. The daily consumption of two cups (250 mL per cup) of mixed and black teas prepared with La Laguna tap water does pose a health risk for children (4–8 years old) because of the high contribution percentages (74.4% and 63.6%, respectively) of the Tolerable Upper Intake Level set in 2.5 mg/day by the EFSA (European Food Safety Authority). A minor consumption in children (4–8 years old) and adults during pregnancy is advisable.