The Science of the total environment
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Sci. Total Environ. · Sep 2018
Indonesia's globally significant seagrass meadows are under widespread threat.
Indonesia's marine ecosystems form a fundamental part of the world's natural heritage, representing a global maxima of marine biodiversity and supporting the world's second largest production of seafood. Seagrasses are a key part of that support. In the absence of empirical data we present evidence from expert opinions as to the state of Indonesia's seagrass ecosystems, their support for ecosystem services, with a focus on fisheries, and the damaging activities that threaten their existence. ⋯ The perilous state of Indonesia's seagrasses will compromise their resilience to climate change and result in a loss of their high ecosystem service value. Community supported management initiatives provide one mechanism for seagrass protection. Exemplars highlight the need for increased local level autonomy for the management of marine resources, opening up opportunities for incentive type conservation schemes.
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Sci. Total Environ. · Sep 2018
ReviewEnvironmental mixtures of nanomaterials and chemicals: The Trojan-horse phenomenon and its relevance for ecotoxicity.
The usage of engineered nanomaterials (NM) offers many novel products and applications with advanced features, but at the same time raises concerns with regard to potential adverse biological effects. Upon release and emission, NM may interact with chemicals in the environment, potentially leading to a co-exposure of organisms and the occurrence of mixture effects. A prominent idea is that NM may act as carriers of chemicals, facilitating and enhancing the entry of substances into cells or organisms, subsequently leading to an increased toxicity. ⋯ A closer inspection of the studies demonstrated that the existing evidence for interference of NM-chemical mixture exposure with uptake and toxicity points into different directions compared to the original Trojan-horse hypothesis. We could discriminate at least 7 different categories to capture the evidence ranging from no changes in uptake and toxicity to an increase in uptake and toxicity upon mixture exposure. Concluding recommendations for the consideration of relevant processes are given, including a proposal for a nomenclature to describe NM-chemical mixture interactions in consistent terms.
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Sci. Total Environ. · Aug 2018
Capability of crop water content for revealing variability of winter wheat grain yield and soil moisture under limited irrigation.
Winter wheat (Triticum aestivum L.) is a major crop in the Guanzhong Plain, China. Understanding its water status is important for irrigation planning. A few crop water indicators, such as the leaf equivalent water thickness (EWT: g cm-2), leaf water content (LWC: %) and canopy water content (CWC: kg m-2), have been estimated using remote sensing techniques for a wide range of crops, yet their suitability and utility for revealing winter wheat growth and soil moisture status have not been well studied. ⋯ CWC had a consistent relationship with grain yield over different growing seasons, but the performances of EWT and LWC were growing-season specific. The partial least squares regression was the most accurate method for estimating LWC (R2=0.72; RMSE=3.6%) and comparable capability for EWT and CWC. Finally, the work highlights the usefulness of crop water indicators to assess crop growth, productivity, and soil water status and demonstrates the potential of various spectral processing methods for retrieving crop water contents from canopy reflectance spectrums.
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Sci. Total Environ. · Jul 2018
Quantifying and evaluating the impacts of cooperation in transboundary river basins on the Water-Energy-Food nexus: The Blue Nile Basin.
Efficient utilization of the limited Water, Energy, and Food (WEF) resources in stressed transboundary river basins requires understanding their interlinkages in different transboundary cooperation conditions. The Blue Nile Basin, a transboundary river basin between Ethiopia and Sudan, is used to illustrate the impacts of cooperation between riparian countries on the Water-Energy-Food nexus (WEF nexus). These impacts are quantified and evaluated using a daily model that simulates hydrological processes, irrigation water requirements, and water allocation to hydro-energy generation and irrigation water supply. ⋯ Those scenarios result from combinations of three cooperation states: unilateral action, coordination, and collaboration; and infrastructure development settings including the Grand Ethiopian Renaissance Dam and planned irrigation schemes in Sudan. The results show that the economic gain of the Blue Nile Basin from WEF increases with raising the cooperation level between Ethiopia and Sudan to collaboration. However, the economic gain of each riparian country does not necessarily follow the same pattern as the economic gain of the basin.
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Sci. Total Environ. · Jun 2018
Impacts of irrigation water sources and geochemical conditions on vertical distribution of pharmaceutical and personal care products (PPCPs) in the vadose zone soils.
Groundwater pollution by emerging contaminants, such as pharmaceutical and personal care products (PPCPs), has caused increasing concerns around the world. The vadose zone is an active zone where lithosphere, hydrosphere and biosphere interact. It is an important medium for PPCPs removal and entry into groundwater from irrigation using wastewater or polluted surface water. ⋯ Redundancy analysis (RDA) indicated a significant correlation between PPCPs concentrations in the vadose zone soils and geochemical variables, including available potassium and silt content. This study provides important evidence on the influential factors of PPCPs accumulation and migration in the vadose zone soils resulted from wastewater irrigation. The incomplete removal of PPCPs poses certain risks in subsurface environment, potentially challenging groundwater quality and drinking water safety.