Impacts of ozone on the biomass and yield of rice in open-top chambers

ＩｎｔｒｏｄｕｃｔｉｏｎＯｚｏｎｅ(Ｏ3)ｆｏｒｍｅｄａｓｐｈｏｔｏｃｈｅｍｉｃａｌｓｍｏｇｉｓｔｈｅｍｏｓｔｄａｎｇｅｒａｎｄｗｉｄｅｓｐｒｅａｄｃｏｍｐｏｎｅｎｔｉｎｔｈｅａｉｒｐｏｌｌｕｔｉｏｎ.Ｎｏｗａｄａｙｓ,ｔｈｅｔｙｐｉｃａｌｄａｉｌｙｍａｘｉｍｕｍＯ3ｃｏｎｃｅｎｔｒａｔｉｏｎｓｉｎｕｒｂａｎｓｕｂｕｒｂａｎａｎｄａｒｅａｓｈａｖｅｒｅａｃｈｅｄ100～400ｎｌ/Ｌａｎｄ50～120ｎｌ/Ｌ,ｒｅｓｐｅｃｔｉｖｅｌｙ.Ｕｎｄｅｒｃｅｒｔａｉｎｍｅｔｅｏｒｏｌｏｇｉｃａｌｃｏｎｄｉｔｉｏｎｒｕｒａｌ…     

Comparison of degradation reactions of Acid Yellow 61 in both oxidation processes of H2O2/UV and O3

ＩｎｔｒｏｄｕｃｔｉｏｎＣｏｌｏｒｓｕｂｓｔａｎｃｅｓｉｎｄｙｅｉｎｇｅｆｆｌｕｅｎｔｓｎｏｒｍａｌｌｙｃａｕｓｅｃｅｒｔａｉｎｄｉｆｆｉｃｕｌｔｉｅｓｉｎｔｒａｄｉｔｉｏｎａｌｂｉｏｌｏｇｉｃａｌｔｒｅａｔｍｅｎｔｐｒｏｃｅｓｓｅｓｄｕｅｔｏｔｈｅｄｙｅｍｏｌｅｃｕｌｅｓａｒｅｈｉｇｈｌｙｓｔｒｕｃｔｕｒｅｄｐｏｌｙｍｅｒｓａｎｄｔｈｅｉｒｔｏｘｉｃｉｔｙ (Ｈａｍｚａ ,1980 ;Ｇｉｎｏｃｃｈｉｎｉｏ ,1984 ;ＭａＫａｙ ,1980 ) .Ｉｔｉｓｎｅｃｅｓｓａｒｙｔｏｉｍｐｒｏｖｅｔｈｅｔｒｅａｔｍｅｎｔｅ…     

Changes in the soil environment from excessive application of fertilizers and manures to two contrasting intensive cropping systems on the North China Plain

Effects of excessive fertilizer and manure applications on the soil environment were compared in greenhouse vegetable systems shifted from wheat-maize rotations 5-15years previously and in wheat-maize rotations. N, P and K surpluses to the greenhouses were 4328, 1337 and 1466kgha(-1)year(-1), respectively compared to 346, 65 and -163kgha(-1)year(-1) to wheat-maize fields. Subsequently, substantial mineral N and available P and K accumulated in the soil and leaching occurred down the soil profile in the greenhouses. Soil pH under vegetables was significantly lower than in the wheat-maize fields, while the EC was significantly higher in the vegetable soils. The mean Cd concentration in the vegetable soils was 2.8 times that in the wheat-maize rotations. Due to excessive fertilizer application in greenhouse vegetable production in northeast China, excessive salt and nitrate concentrations may accumulate and soil quality may deteriorate faster than in conventional wheat-maize rotations.     

The relationship of root porosity and radial oxygen loss on arsenic tolerance and uptake in rice grains and straw

The correlations among arsenic (As) accumulation in grains and straw, rates of radial oxygen loss (ROL), and porosity of roots using 25 rice cultivars were investigated based on two pot experiments: (1) soil with addition of 100 mg As kg^?1 for analysis of As in grains and straw, and (2) deoxygenated solution for analyzing rates of ROL and porosity of roots. The results showed that there were great differences in grain As (0.71–1.72 mg kg^?1) and straw As (15.6–31.7 mg kg^?1), rates of ROL (7.40–13.24 mmol O₂ kg^?1 root d.w. h^?1), and porosity (20.91–33.08%) among the cultivars. There were significant negative correlations between As in grains or straw and ROL and porosity, and significant positive correlations between rates of ROL and porosities, respectively. Rice cultivars with high porosities tended to possess higher rates of ROL, and had higher capacities for limiting the transfer of As to aboveground tissues.     

Solid phase microextraction applied to the analysis of organophosphorus insecticides in fruits

Trace amounts of organophosphorus pesticides (OPs) were determined in various fruits by headspace solid phase microextraction (HS-SPME) and gas chromatography–nitrogen phosphorous detection (GC-NPD). Sampling from the headspace enhanced method selectivity, whereas at the same time improved fiber life time and method sensitivity. Diazinon, parathion, methyl parathion, malathion and fenithrothion were determined in various fruits: more than 150 samples of 21 types of fruits were studied. SPME-GC-NPD provided a useful and very efficient analytical tool: method linearity ranged from 1.2 to 700 ng/ml. Limits of detection (LODs) and quantitation (LOQs) ranged from 0.03 to 3 ng/ml and 0.12 to 10 ng/ml respectively, values well below the residue limits set by the EU. Less than 2% of the samples were found positive containing amounts higher than the EU limits. The effect of fruit peeling and washing was also investigated.     

Lead and zinc accumulation and tolerance in populations of six wetland plants

Wetland plants such as Typha latifolia and Phragmites australis have been indicated to show a lack of evolution of metal tolerance in metal-contaminated populations. The aim of the present study is to verify whether other common wetland plants such as Alternanthera philoxeroides and Beckmannia syzigachne, also possess the same characteristics. Lead and zinc tolerances in populations of six species collected from contaminated and clean sites were examined by hydroponics. In general, the contaminated populations did not show higher metal tolerance and accumulation than the controls. Similar growth responses and tolerance indices in the same metal treatment solution between contaminated and control populations suggest that metal tolerance in wetland plants are generally not further evolved by contaminated environment. The reasons may be related to the special root anatomy in wetland plants, the alleviated metal toxicity by the reduced rooting conditions and the relatively high innate metal tolerance in some species.     

Effects of sampling,preparation and defecation on metal concentrations in selected invertebrates at urban sites

In order to obtain basic information for designing standardized test preparation methods, the heavy metals Zn, Cu, Cd and Pb were measured in gastropods (Xerolenta obvia), oligochaetes (Lumbricus terrestris), isopods (Armadillidium vulgare, Trachelipus rathkei) and carabids (Harpalus rubripes, Calathus fuscipes) using different sampling methods and different modes of sample treatment. In some of the experiments, higher Zn, Cd and Pb, and lower Cu-contents were observed in isopods and carabids trapped with formalin-pitfalls compared to manually collected specimens (which were allowed to defecate). Defecation had marked effects on the levels of all four metals investigated in oligochaetes, and on Cd and Pb in gastropods and isopods. Cellulose was fed as an accelerator of gut passage and showed a significant effect on the Pb concentration in the soft body of gastropods. Deionate-washed isopods (A. vulgare) showed higher Cd concentrations than ultrasonic-cleaned individuals. No marked differences were observed between heat-dried and freeze-dried isopods. Carabids showed strong sex-specific differences in metal concentrations. Based on these and previous results, invertebrates should be: collected in vivo, allowed to defecate, be freeze-fixed and (at least in arthropods) ultrasonic-cleaned, determined to species level and in certain groups (carabids) also to sex, and then be sized or sorted by size (age) before further preparation and analysis. If any of these treatments is impractical, comparable sampling and preparation methods are recommended as a minimum requirement in order to avoid bias in the results and/or interpretation.     

Spatial distribution and vertical variation of arsenic in Guangdong soil profiles, China

Total of 260 soil profiles were reported to investigate the arsenic spatial distribution and vertical variation in Guangdong province. The arsenic concentration followed an approximately lognormal distribution. The arsenic geometric mean concentration of 10.4 mg/kg is higher than that of China. An upper baseline concentration of 23.4 mg/kg was estimated for surface soils. The influence of soil properties on arsenic concentration was not important. Arsenic spatial distributions presented similar patterns that high arsenic concentration mainly located in limestone, and sandshale areas, indicating that soil arsenic distribution was dependent on bedrock properties than anthropogenic inputs. Moreover, from A- to C-horizon arsenic geometric mean concentrations had an increasing tendency of 10.4, 10.7 to 11.3 mg/kg. This vertical variation may be related to the lower soil organic matter and soil degradation and erosion. Consequently, the soil arsenic export into surface and groundwaters would reach 1040 t year-1 in the study area.     

Use of dolomite phosphate rock (DPR) fertilizers to reduce phosphorus leaching from sandy soil

There is increasing concern over P leaching from sandy soils applied with water-soluble P fertilizers. Laboratory column leaching experiments were conducted to evaluate P leaching from a typical acidic sandy soil in Florida amended with DPR fertilizers developed from dolomite phosphate rock (DPR) and N-Viro soil. Ten leaching events were carried out at an interval of 7 days, with a total leaching volume of 1,183 mm equivalent to the mean annual rainfall of this region during the period of 2001-2003. Leachates were collected and analyzed for total P and inorganic P. Phosphorus in the leachate was dominantly reactive, accounting for 67.7-99.9% of total P leached. Phosphorus leaching loss mainly occurred in the first three leaching events, accounting for 62.0-98.8% of the total P leached over the whole period. The percentage of P leached (in the total P added) from the soil amended with water-soluble P fertilizer was higher than those receiving the DPR fertilizers. The former was up to 96.6%, whereas the latter ranged from 0.3% to 3.8%. These results indicate that the use of N-Viro-based DPR fertilizers can reduce P leaching from sandy soils.     

Fuzzy risk assessment of oil and gas offshore wells

Risk evaluation of offshore wells is a challenging task, given that much of the available data is highly uncertain and vague, and many of the mechanisms are complex and difficult to understand. Consequently, a systematic approach is required to handle both quantitative and qualitative data as well as means to update existing information when new knowledge and data become available. Each Basic Risk Item (BRI) in a hierarchical framework is expressed as a fuzzy number, which is a combination of the likelihood of a failure event and the associated failure consequence. Analytical Hierarchy Process (AHP) is used to estimate weights required for grouping non-commensurate risk sources. Evidential Reasoning (ER) is employed to incorporate new data for updating existing risk estimates. It is envisaged that the proposed approach could serve as a basis for benchmarking acceptable risks in offshore wells.