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Результаты 291-300 из 2,512
Trends in atmospheric deposition fluxes of sulphur and nitrogen in Czech forests Полный текст
2014
Hůnová, Iva | Maznová, Jana | Kurfürst, Pavel
We present the temporal trends and spatial changes of deposition of sulphur and nitrogen in Czech forests based on records from long-term monitoring. A statistically significant trend for sulphur was detected at most of the sites measuring for wet, dry, and total deposition fluxes and at many of these the trend was also present for the period after 2000. The spatial pattern of the changes in sulphur deposition flux between 1995 and 2011 shows the decrease over the entire forested area in a wide range of 18.1–0.2 g m−2 year−1 with the most pronounced improvement in formerly most impacted regions. Nitrogen still represents a considerable stress in many areas. The value of nitrogen deposition flux of 1 g m−2 year−1 is exceeded over a significant portion of the country. On an equivalent basis, the ion ratios of NO3−/SO42− and NH4+/SO42− in precipitation show significantly increasing trends in time similarly to those of pH.
Показать больше [+] Меньше [-]Effects of storage temperature and duration on release of antimony and bisphenol A from polyethylene terephthalate drinking water bottles of China Полный текст
2014
Fan, Ying-Ying | Zheng, Jian-Lun | Ren, Jing-Hua | Luo, Jun | Cui, Xin-Yi | Ma, Lena Q.
We investigated effects of storage temperature and duration on release of antimony (Sb) and bisphenol A (BPA) from 16 brands of polyethylene terephthalate (PET) drinking water bottles in China. After 1-week storage, Sb release increased from 1.88–8.32 ng/L at 4 °C, to 2.10–18.4 ng/L at 25 °C and to 20.3–2604 ng/L at 70 °C. The corresponding releases for BPA were less at 0.26–18.7, 0.62–22.6, and 2.89–38.9 ng/L. Both Sb and BPA release increased with storage duration up to 4-week, but their releasing rates decreased with storage time, indicating that Sb and BPA release from PET bottles may become stable under long term storage. Human health risk was evaluated based on the worst case, i.e., storage at 70 °C for 4-week. Chronic daily intake (CDI) caused by BPA release was below USEPA regulation, Sb release in one brand exceeded USEPA regulated CDI (400 ng/kg bw/d) with values of 409 and 1430 ng/kg bw/d for adult and children.
Показать больше [+] Меньше [-]Allometric relationships to liver tissue concentrations of cyclic volatile methyl siloxanes in Atlantic cod Полный текст
2014
Warner, Nicholas A. | Nøst, Therese H. | Andrade, Héctor | Christensen, Guttorm
Spatial distribution and relationship of allometric measurements (length, weight and age) to liver concentrations of cyclic volatile methyl siloxanes (cVMS) including octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclosiloxane (D6) in Atlantic cod (Gadus morhua) collected near the community of Tromsø in Northern Norway were assessed. These congeners were benchmarked against known persistent polychlorinated biphenyls (PCBs 153 and 180) to assess accumulation behavior of cVMS. D5 was the dominate cVMS detected in all fish livers with lipid normalized concentrations up to 10 times or greater than those observed for PCB 153 and 180. D4 and D6 concentration were negatively correlated with fish length and weight, indicating a greater elimination capacity compared to uptake processes with increasing fish size for these chemicals. These results indicate relationships between allometric measurements and cVMS concentrations may account for concentration variations observed within fish and should be assessed in future studies evaluating cVMS bioaccumulation potential.
Показать больше [+] Меньше [-]Metal pollution in a contaminated bay: Relationship between metal geochemical fractionation in sediments and accumulation in a polychaete Полный текст
2014
Fan, Wenhong | Xu, Zhizhen | Wang, Wen-Xiong
Jinzhou Bay in Northern China has been seriously contaminated with metals due to the impacts of smelting activities. In this study, we investigated the relationship between metal accumulation in a deposit-feeding polychaete Neanthes japonica and metal concentration and geochemical fractionation (Cd, Cu, Pb, Zn and Ni) in sediments of Jinzhou Bay. Compared with the historical data, metals in the more mobile geochemical fraction (exchangeable and carbonate fractions) were gradually partitioned into the more stable fraction (Fe–Mn oxides) over time. Metal concentration and geochemical fractionation in sediment significantly affected metal bioavailability and accumulation in polychaetes, except for Ni. Metal accumulation in polychaetes was significantly influenced by Fe or Mn content, and to a lesser degree by organic matter. Prediction of metal bioaccumulation in polychaetes was greatly improved by normalizing metal concentrations to Mn content in sediment. The geochemical fractionation of metals in sediments including the exchangeable, organic matter and Fe–Mn oxides were important in controlling the sediment metal bioavailability to polychaetes.
Показать больше [+] Меньше [-]Evidence of widespread ozone-induced visible injury on plants in Beijing, China Полный текст
2014
Feng, Zhaozhong | Sun, Jingsong | Wan, Wuxing | Hu, Enzhu | Calatayud, Vicent
Despite the high ozone levels measured in China, and in Beijing in particular, reports of ozone-induced visible injury in vegetation are very scarce. Visible injury was investigated on July and August 2013 in the main parks, forest and agricultural areas of Beijing. Ozone injury was widespread in the area, being observed in 28 different species. Symptoms were more frequent in rural areas and mountains from northern Beijing, downwind from the city, and less frequent in city gardens. Among crops, injury to different types of beans (genera Phaseolus, Canavalia and Vigna) was common, and it was also observed in watermelon, grape vine, and in gourds. Native species such as ailanthus, several pines and ash species were also symptomatic. The black locust, the rose of Sharon and the Japanese morning glory were among the injured ornamental plants. Target species for broader bio-monitoring surveys in temperate China have been identified.
Показать больше [+] Меньше [-]A systematic evaluation of agglomeration of Ag and TiO2 nanoparticles under freshwater relevant conditions Полный текст
2014
Topuz, Emel | Sigg, Laura | Talinli, Ilhan
This study aims to investigate effects of freshwater components in order to predict agglomeration behavior of silver nanoparticles coated with citrate (AgNP-Cit), polyvinylpyrrolidone (AgNP-PVP), and of TiO2 nanoparticles. Agglomeration studies were conducted in various media based on combinations of ions, natural organic matter (humic, fulvic acid) and surfactants (sodium dodecyl sulfate, alkyl ethoxylate), at a constant ionic strength of 10 mM over time for up to 1 week. Agglomeration level of AgNP-Cit and TiO2 was mostly dependent on the concentration of Ca2+ in media, and their size strongly increased to micrometer scale over 1 week. However, AgNP-Cit and TiO2 were stabilized to particle size around 500 nm in the presence of NOM, surfactants and carbonate over 1 week. AgNP-PVP maintained their original size in all media except in the presence of Mg2+ ions which led to significant agglomeration. Behavior of these engineered nanoparticles was similar in a natural freshwater medium.
Показать больше [+] Меньше [-]Pharmaceuticals occurrence in a WWTP with significant industrial contribution and its input into the river system Полный текст
2014
Collado, N. | Rodriguez-Mozaz, S. | Gros, M. | Rubirola, A. | Barceló, D. | Comas, J. | Rodriguez-Roda, I. | Buttiglieri, G.
Occurrence and removal of 81 representative Pharmaceutical Active Compounds (PhACs) were assessed in a municipal WWTP located in a highly industrialized area, with partial water reuse after UV tertiary treatment and discharge to a Mediterranean river. Water monitoring was performed in an integrated way at different points in the WWTP and river along three seasons.Consistent differences between therapeutic classes were observed in terms of influent concentration, removal efficiencies and seasonal variation. Conventional (primary and secondary) treatment was unable to completely remove numerous compounds and UV-based tertiary treatment played a complementary role for some of them. Industrial activity influence was highlighted in terms of PhACs presence and seasonal distribution.Even if global WWTP effluent impact on the studied river appeared to be minor, PhACs resulted widespread pollutants in river waters. Contamination can be particularly critical in summer in water scarcity areas, when water flow decreases considerably.
Показать больше [+] Меньше [-]Toxicokinetics of metals in the earthworm Lumbricus rubellus exposed to natural polluted soils – relevance of laboratory tests to the field situation Полный текст
2014
Giska, Iwona | van Gestel, Cornelis A.M. | Skip, Borys | Laskowski, Ryszard
The aim of this study was to estimate the bioavailability of essential (Zn, Cu) and non-essential metals (Cd, Pb) to the earthworm Lumbricus rubellus exposed to soils originating from a gradient of metal pollution in Southern Poland. Metal uptake and elimination kinetics were determined and related to soils properties. Experimental results were compared with tissue metal concentrations observed in earthworms from the studied transect. Cd and Pb were intensively accumulated by the earthworms, with very slow or no elimination. Their uptake rate constants, based on 0.01 M CaCl2-extractable concentrations in the soils, increased with soil pH. Internal concentrations of Cu and Zn were maintained by the earthworms at a stable level, suggesting efficient regulation of these metals by the animals. The estimated uptake and elimination kinetics parameters enabled fairly accurate prediction of metal concentrations reached within a life span of L. rubellus in nature.
Показать больше [+] Меньше [-]Ecological responses to contamination: A meta-analysis of experimental marine studies Полный текст
2014
O'Brien, Allyson L. | Keough, Michael J.
Identifying general response patterns to contamination in the environment is critical for reliable assessments of ecosystem health. However, it is not often clear if there are biases in the information used to understand general effects of contamination. To investigate this we conducted a review of 314 studies that experimentally manipulated contaminants and measured the effects on marine invertebrate taxa. The majority of studies investigated the effects of metals (54%) on individual taxa (mainly bivalves, amphipods, copepods). Ecologically relevant responses to contamination were measured in only 22% of the studies. A meta-analysis using studies that measured ecological responses to copper illustrated a general negative effect of copper and highlighted the bias towards field or laboratory experiments that measure community or individual-level responses. There is a need for diversification of studies that investigate the ecological effects of contamination as an important advancement in ecotoxicology and ecological research and environmentally relevant risk assessments.
Показать больше [+] Меньше [-]Air pollution and hospital admissions for respiratory diseases in Lanzhou, China Полный текст
2014
Tao, Yan | Mi, Shengquan | Zhou, Shuhong | Wang, Shigong | Xie, Xiaoyun
Lanzhou is among the most seriously air-polluted cities in China as a whole, due to its unique topography, climate, industrial structure and so on. We studied the relationship between different air pollution and respiratory hospitalizations from 2001 to 2005, the total of respiratory hospital admissions were 28,057. The data were analyzed using Poisson regression models after controlling for the long time trend for air pollutants, the “day of week” effect and confounding meteorological factors. Three air pollutants (PM10, SO2, NO2) had a lag effect, the lag was 3–5 days for PM10, 1–3 days for SO2 and 1–4 days for NO2. The relative risks were calculated for increases in the inter-quartile range of the pollutants (139 μg/m3 in PM10, 61 μg/m3 in SO2 and 31 μg/m3 in NO2). Results showed that there were significant associations between air pollutants and respiratory hospital admissions, and stronger effects were observed for females and aged ≥65 yrs in Lanzhou.
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