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New Miscanthus hybrids cultivated at a Polish metal-contaminated site demonstrate high stomatal regulation and reduced shoot Pb and Cd concentrations
2019
Rusinowski, Szymon | Krzyżak, Jacek | Clifton-Brown, John | Kane, Elaine | Mos, Michal | Webster, Richard | Sitko, Krzysztof | Pogrzeba, Marta
The increased bioeconomy targets for the biomass share of renewable energy production across Europe should be met using land unsuitable for food production. Miscanthus breeding programs targeted the production of plants with a diverse range of traits allowing a wider utilization of land resources for biofuel production without competing with arable crops. These traits include increasing tolerances to drought, chilling, and to metal(loid)s excess. Two novel Miscanthus hybrids, GNT41 and GNT34, were compared against Miscanthus x giganteus (Mxg) on metal-contaminated arable land in Poland. This study aimed at evaluating their yield, biomass quality and quantifying seasonal differences in photosynthetic and transpiration parameters. A secondary objective was to identify key physiological mechanisms underlying differences in metal accumulation between the investigated plants. The new hybrids produced a similar yield to Mxg (13–15 t ha−1 yr−1), had shorter shoots, higher Leaf Area Index and stem number. Based on gas exchange measurements, GNT34 exhibited isohydric (water-conserving) behavior. The stomatal response to light of the new hybrids was at least twice as fast as that of Mxg, a trait that is often associated with increased seasonal water use efficiency. This contributed to the almost 40% reduction in shoot Pb and Cd concentrations for the new hybrids as compared to Mxg. This suggested that promoting stomatal regulation in conjunction with improved water conservation may be a target for improving plants for wider use on metals contaminated land.
Show more [+] Less [-]Ecotoxicity of nanoparticles of CuO and ZnO in natural water
2010
Blinova, I. | Ivask, A. | Heinlaan, M. | Mortimer, M. | Kahru, A.
The acute toxicity of CuO and ZnO nanoparticles in artificial freshwater (AFW) and in natural waters to crustaceans Daphnia magna and Thamnocephalus platyurus and protozoan Tetrahymena thermophila was compared. The L(E)C50 values of nanoCuO for both crustaceans in natural water ranged from 90 to 224 mg Cu/l and were about 10-fold lower than L(E)C50 values of bulk CuO. In all test media, the L(E)C50 values for both bulk and nanoZnO (1.1–16 mg Zn/l) were considerably lower than those of nanoCuO. The natural waters remarkably (up to 140-fold) decreased the toxicity of nanoCuO (but not that of nanoZnO) to crustaceans depending mainly on the concentration of dissolved organic carbon (DOC). The toxicity of both nanoCuO and nanoZnO was mostly due to the solubilised ions as determined by specific metal-sensing bacteria. Natural waters remarkably reduced the toxicity of nanoCuO but not nanoZnO.
Show more [+] Less [-]Occurrence and behaviour of selected hydrophobic alkylphenolic compounds in the Danube River
2009
Micić, Vesna | Hofmann, Thilo
Six hydrophobic alkylphenolic compounds were investigated for the first time simultaneously in four different matrices in the Danube River. Maximum sediment concentrations were 2.83, 2.10, 0.28, and 0.035 mg kg⁻¹ for nonylphenol, nonylphenol monoethoxylate, nonylphenol diethoxylate and octylphenol. Maximum levels in suspended particulate matter (SPM) were 0.18, 0.12, 0.10, and 0.003 mg kg 1. No correlation between concentrations in SPM and sediments was found. Octylphenol monoethoxylate and octylphenol diethoxylate were recorded only in sediment at one location. In mussels and water only nonylphenol and octylphenol were found. Nonylphenol concentrations in mussels (up to 0.34 mg kg⁻¹) correlate with concentrations found in SPM and indicate a slight bioaccumulation. Concentrations in water were close to the limit of quantification. We assume in situ formation of nonylphenol monoethoxylate and nonylphenol in sediments at some locations. In some cases nonylphenol in sediments exceeded the provisional EU environmental quality standards.
Show more [+] Less [-]Detection of phosphorus species in sediments of artificial landscape lakes in China by fractionation and phosphorus-31 nuclear magnetic resonance spectroscopy
2009
Liu, Jinyong | Wang, Hui | Yang, Haijun | Ma, Yanjun | Cai, Ouchen
Phosphorus (P) pollution in the sediments of seven artificial landscape lakes was studied via fractionation and phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy. The lake sediments accumulated significant amounts of P from supplementation with reclaimed water and from runoff from the golf course lawns. The differences in total sediment P among lakes were correlated to the varied pollution extent from the lawns. One striking feature of the artificial lake sediments was the insufficiency of NaOH-extracted Al, which plays an important role in avoiding internal P release during anoxia. Another characteristic was the dominance of orthophosphate in the NaOH-EDTA extractants of the sediments, due to the heavy external P pollution. Phytate, considered prevalent in many soils and lake sediments, as well as polyphosphates and phosphonates which have appeared in some natural lake sediments, was not detected. The rank order of present biogenic P species was monoester-P > DNA-P > pyrophosphate > lipid-P. Mineral fixation and biological conversion of phosphorus were investigated in artificial lake sediments in China.
Show more [+] Less [-]Water quality in the Tibetan Plateau: Metal contents of four selected rivers
2008
Huang, Xiang | Sillanpaa, Mika | Duo, Bu | Gjessing, Egil T.
The water used by 85% of the Asian population originates in Tibetan Plateau. During April and May of 2006, water samples were collected from four major Asian rivers in the Plateau (i.e. the Salween, Mekong, Yangtze River and Yarlung Tsangpo) and analyzed for Cu, Pb, Zn, Ag, Mo, Cd, Co, Cr, Ni, Li, Mn, Al, Fe, Mg and Hg. The results showed that elements such as Mg were rather high in Tibetan rivers, giving a mean electrical conductance of 36 mS/m. In a few locations, the results also showed relatively high concentrations of Al and Fe (>1 mg/L). However, the concentrations of Cu, Zn, Ag, Cd, and Cr were generally low. Contamination with Pb was identified at a few locations in the Salween and Ni at a few sites in the Yangtze River. For the first time, total dissolved metal contents in source water of four major Asian rivers were evaluated at the same time.
Show more [+] Less [-]Organic phosphorus species in surface sediments of a large, shallow, eutrophic lake, Lake Taihu, China
2009
Bai, Xiuling | Ding, Shiming | Fan, Chengxin | Liu, Tao | Shi, Dan | Zhang, Lu
Organic phosphorus (P) fractions in surface sediments from a large shallow, eutrophic Lake Taihu, China, were extracted with 0.1 M NaOH after pre-treatment of the sediments with a solution composed of 0.1 M EDTA and 2% (w/v) Na₂S₂O₄. Composition of organic P in the extracts was then characterized by ³¹P nuclear magnetic resonance spectroscopy (³¹P NMR). Several P species, including phosphonates, orthophosphate, orthophosphate monoesters, phospholipids, DNA, pyrophosphate and polyphosphate, were detected in the NaOH extracts. The proportion of extracted organic P to total P in sediments was negatively correlated with total P in the water column, as were the proportions for orthophosphate monoesters and DNA. This implies that the majority of organic P in surface sediments is likely stabilized in some way, and does not directly contribute to the internal loading of P from sediments. Organic phosphorus species in surface sediments of Lake Taihu.
Show more [+] Less [-]Long-term nitrate increases in two oligotrophic lakes, due to the leaching of atmospherically-deposited N from moorland ranker soils
2008
Tipping, E. | Thacker, S.A. | Wilson, D. | Hall, J.R.
During the last 50 years nitrate concentrations in Buttermere and Wastwater (Cumbria, UK) have risen significantly, by 70 and 100%, respectively. By estimating contemporary nitrate fluxes in the lakes' catchments and in sub-catchments and comparing them with the fractional areas of different soil types, it is deduced that the surface water nitrate is derived almost entirely from organic-rich ranker soils that have a limited ability to retain atmospherically-deposited nitrogen. Little or no nitrate leaches from the other major soil type, a brown podzol, despite it having a lower C:N ratio (12.0 g g-1) than the ranker (17.0 g g-1), nor is there much contribution from the small areas of improved (chemically fertilised) grassland within the catchments. Although some nitrate leaching is occurring, total N losses are appreciably smaller than atmospheric inputs, so the catchment soils are currently accumulating between 3 and 4 g N m-2 a-1. Increases in lakewater nitrate concentrations over 50 years are due to the limited ability of ranker soils to retain atmospherically-deposited nitrogen.
Show more [+] Less [-]Isozyme markers associated with O3 tolerance indicate shift in genetic structure of ponderosa and Jeffrey pine in Sequoia National Park, California
2007
Staszak, J. | Grulke, N.E. | Marrett, M.J. | Prus-Glowacki, W.
Effects of canopy ozone (O3) exposure and signatures of genetic structure using isozyme markers associated with O3 tolerance were analyzed in 20-, 80-, and >200-yr-old ponderosa (Pinus ponderosa Dougl. ex Laws.) and Jeffrey pine (Pinus jeffreyi Grev. & Balf.) in Sequoia National Park, California. For both species, the number of alleles and genotypes per loci was higher in parental trees relative to saplings. In ponderosa pine, the heterozygosity value increased, and the fixation index indicated reduction of homozygosity with increasing tree age class. The opposite tendencies were observed for Jeffrey pine. Utilizing canopy attributes known to be responsive to O3 exposure, ponderosa pine was more symptomatic than Jeffrey pine, and saplings were more symptomatic than old growth trees. We suggest that these trends are related to differing sensitivity of the two species to O3 exposure, and to higher O3 exposures and drought stress that younger trees may have experienced during germination and establishment. Genetic variation in isozyme markers associated with ozone tolerance differed between parental trees and their progeny in two closely related species of yellow pine.
Show more [+] Less [-]Risk of tuberculosis in high-rise and high density dwellings: An exploratory spatial analysis
2013
Lai, Poh C. | Low, Chien-Tat | Tse, Wing-Sze Cindy | Tsui, Chun-Kan | Sun Ra, | Hui, Pak-Kwan
Studies have shown that socioeconomic and environmental factors have direct/indirect influences on TB. This research focuses on TB prevalence of Hong Kong in relation to its compact urban development comprising of high-rise and high-density residential dwellings caused by rapid population growth and limited land resources. It has been postulated that occupants living on higher levels of a building would benefit from better ventilation and direct sunlight and thus less likely to contract infectious respiratory diseases. On the contrary, those on lower floors amid the dense clusters of high-rises are more susceptible to TB infection because of poorer air quality from street-level pollution and lesser exposure to direct sunlight. However, there have not been published studies to support these claims. As TB continues to threaten public health in Hong Kong, this study seeks to understand the effects of housing development on TB occurrences in an urban setting.
Show more [+] Less [-]Modelling concentrations of decamethylcyclopentasiloxane in two UK rivers using LF2000-WQX
2010
Price, Oliver R. | Williams, Dick (Richard J) | Zhang, Zhong | Van Egmond, Roger
Current regulatory environmental exposure assessments for decamethylcyclopentasiloxane (D5), used in a range of personal care products, are based on a number of erroneous assumptions. Using an estimated D5 flux to waste water of 11.6 mg cap−1 d−1, a 95.2% removal rate in Sewage Treatment Plants (STP) and a dilution factor of 10 results in modelled surface water concentrations that are up to an order of magnitude higher than concentrations observed downstream of STPs in two UK rivers. A GIS-based water quality model (LF2000-WQX) was used to predict concentrations of D5 in two UK rivers. Assuming the STP removal rate is reasonable, a waste water flux of 2.4 mg cap−1 d−1 is needed in order to obtain a reasonable match between predicted and observed in-river concentrations. This flux is consistent with measured effluent concentrations. The results highlight major uncertainties in estimating chemical emission rates for volatile chemicals used in personal care products and suggest that measured concentrations in waste water are needed to refine exposure assessments. Surface water modelling of decamethylcyclopentasiloxane.
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