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101.
102.
In regions with high livestock densities, the usage of antibiotics and metals for veterinary purposes or as growth promoters poses a risk in manured soils. We investigated to which degree the concentrations and depth distributions of Cu, Zn, Cr and As could be used as a tracer to discover contaminations with sulfonamides, tetracyclines and fluoroquinolones. Besides, we estimated the potential vertical translocation of antibiotics and compared the results to measured data. In the peri-urban region of Beijing, China, soil was sampled from agricultural fields and a dry riverbed contaminated by organic waste disposal. The antibiotic concentrations reached 110 μg kg?1 sulfamethazine, 111 μg kg?1 chlortetracycline and 62 μg kg?1 enrofloxacin in the topsoil of agricultural fields. Intriguingly, total concentrations of Cu, Zn, Cr and As were smaller than 65, 130, 36 and 10 mg kg?1 in surface soil, respectively, therewith fulfilling Chinese quality standards. Correlations between sulfamethazine concentrations and Cu or Zn suggest that in regions with high manure applications, one might use the frequently existing monitoring data for metals to identify potential pollution hotspots for antibiotics in topsoils. In the subsoils, we found sulfamethazine down to ≥2 m depth on agricultural sites and down to ≥4 m depth in the riverbed. As no translocation of metals was observed, subsoil antibiotic contamination could not be predicted from metal data. Nevertheless, sulfonamide stocks in the subsoil could be estimated with an accuracy of 35–200 % from fertilisation data and potential leaching rates. While this may not be sufficient for precise prediction of antibiotic exposure, it may very well be useful for the pre-identification of risk hotspots for subsequent in-depth assessment studies.  相似文献   
103.
EU Directive 91/414/EEC describes the authorization procedure for plant protection products. According to annex VI of this directive, the EU member states have to ensure that a plant protection product does not have unacceptable effects on the environment. The data requirements and the function of laboratory and field tests in the assessment procedure are discussed for the terrestrial compartment.  相似文献   
104.
Numerous evaluation tools for the built environment have been developed in recent decades only some however integrate the outdoor environment. In EcoEffect, a Swedish assessment system, the outdoor environment is one of five areas covered. The purpose of this article is to describe and discuss various issues that evolved during the testing and developing phase of the EcoEffect Outdoor tool. The tool is designed to cover all important health risks to people in an outdoor environment, to show the relationship between circumstances in the outdoor environment and the levels specified in Swedish legislation and to enable a speedy and accurate assessment of the outdoor environment on a property. The work has been carried out in cooperation with experts, residents and representatives of the construction and property sectors. The tool has been tested on existing properties, discussed in focus groups, and has been subject to theoretical development. The results have provided a basis for changing both the EcoEffect Outdoors tool and the framework of the EcoEffect system. Important conclusions here include the notion that a clear account should be given of the fundamental values of the tool, that environmental impact should be reported in the same way throughout the whole assessment process and that the tool has to adhere to both scientific and practical validity to be useful for the building sector.  相似文献   
105.
In temperate forest ecosystems, soil acts as a major sink for atmospheric N deposition. A (15)N labeling experiment in a hardwood forest on calcareous fluvisol was performed to study the processes involved. Low amounts of ammonium ((15)NH(4)(+)) or nitrate ((15)NO(3)(-)) were added to small plots. Soil samples were taken after periods ranging from 1 h to 1 yr. After 1 d, the litter layer retained approximately 28% of the (15)NH(4)(+) tracer and 19% of (15)NO(3)(-). The major fraction of deposited N went through the litter layer to reach the soil within the first hours following the tracer application. During the first day, a decrease in extractable (15)N in the soil was observed ((15)NH(4)(+): 50 to 5%; (15)NO(3)(-): 60 to 12%). During the same time, the amount of microbial (15)N remained almost constant and the (15)N immobilized in the soil (i.e., total (15)N recovered in the bulk soil minus extractable (15)N minus microbial (15)N) also decreased. Such results can therefore be understood as a net loss of (15)N from the soil. Such N loss is probably explained by NO(3)(-) leaching, which is enhanced by the well-developed soil structure. We presume that the N immobilization mainly occurs as an incorporation of deposited N into the soil organic matter. One year after the (15)N addition, recovery rates were similar and approximately three-quarters of the deposited N was recovered in the soil. We conclude that the processes relevant for the fate of atmospherically deposited N take place rapidly and that N recycling within the microbes-plants-soil organic matter (SOM) system prevents further losses in the long term.  相似文献   
106.
人们正加大努力以求最大限度地降低杀虫剂的使用,这些杀虫剂是控制茶树和其它作物的病虫害的基本手段 .在中国,由于土壤常常缺少碳酸钾,所以适量使用这种养料有助于减少对杀虫剂的需要 .已经证实,在土壤中加入钾后,茶树感染真菌病的比率下降 .  相似文献   
107.
Ali/(Ca + Mg) molar ratio in soil water has been used as an indicator to the effects of acid deposition on terrestrial ecosystems. However, the main factors controlling this ratio have not been well documented in southern and southwestern China. In this study, we presented the variation in inorganic aluminum (Ali) and Ali/(Ca + Mg) molar ratio in different sites and soil horizons based on two to three years monitoring data, and evaluated the main factors controlling Ali/(Ca + Mg) molar ratio using principle component analysis (PCA) and partial least square (PLS) regression. Monitoring data showed although Ali/(Ca + Mg) molar ratios in most soil water were lower than assumed critical 1.0, higher molar ratios were found in some soil water at TSP and LXH site. Besides acid loading, both soil properties and soil water chemistry affected the value of Ali/(Ca + Mg) molar ratio in soil water. Partial least square (PLS) indicated that they had different relative importance in different soil horizons. In A-horizon, soil aluminum saturation (AlS) had higher influence on Ali/(Ca + Mg) molar ratio than soil water chemistry did; higher soil aluminum saturation (AlS) led to higher Ali/(Ca + Mg) molar ratio in soil water. In the deeper horizons (i.e., B1-, B2- and BC-horizon), inorganic aluminum (Ali) in soil water had more and more important role in regulating Ali/(Ca + Mg) molar ratio. On regional scale, soil aluminum saturation (AlS) as well as cation exchange capacity (CEC) was the dominant factor controlling Ali/(Ca + Mg) molar ratio. This should be paid enough attention on when making regional acid rain control policy in China.  相似文献   
108.
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110.
Ozone-induced changes in ethylene production, ACC oxidase activity and the contents of ACC, MACC and free PAs were studied inPopulus nigra L. cv. Loenen with high ozone sensitivity as judged by the degree of chlorophyll degradation and premature leaf abscission. Ethylene production, ACC oxidase activity, ACC content and MACC levels were induced by the one-, two-, and three-week ozone exposure (36±9 ppb O3 for 11 hours a day). In addition, increases in PA levels, especially in spermidine, were measured in ozone treated plants. The role of free PAs and MACC synthesis as possible antisenescence reactions is discussed.  相似文献   
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