胭脂红酸分光光度法测定废水中硼

用胭脂红酸分光光度法测定废水中的硼,着重进行了方法的条件和干扰试验。方法检测限为0.063mg/L,线性范围为0.21mg/L-1.25mg/L。5个实验室对5.00mg/L硼标准样品测得重复性相对标准差为3．4％,再次性相对标准差为3．6％;相对误差为－0．8％－1．4％,回收率在95．2％－104．6％之间。     

Advantages and risks of using steel slag in preparing composts from raw organic waste

It had been reported that iron and manganese oxides in steel slag enhanced the production of humic acid (HA) from low-molecular-weight compounds, such as phenolic acids, amino acids, and saccharides. In the present study, this function of steel slag was applied to the composting of raw organic wastes (ROWs). The degree of humification of HAs is an important factor in evaluating compost quality. Thus, HAs were extracted from the prepared composts and the humification parameters were determined, in terms of elemental compositions, acidic functional group contents, molecular weights, spectroscopic parameters from UV–vis absorption and ¹³C NMR spectra. The timing for adding steel slag affected the degree of humification of HAs in the composts. The weight average molecular weight of a HA when slag was added initially (29 kDa) was significantly higher than when slag was added after elevating the temperature of the compost pile (17–18 kDa). These results show that ROWs are decomposed to low-molecular-weight compounds after the pile temperature is elevated and the presence of slag enhances the polycondensation of these compounds to produce HAs with a higher degree of humification. Because the slag used in the present study contained several-tens ng g^?1 to several μg g^?1 of toxic elements (B, Cu, Cr, and Zn), leaching tests for these elements from the prepared composts were carried out. Levels for leaching boron from composts prepared by adding slag (0.2–0.4 mg L^?1) were obviously higher than the corresponding levels without slag (0.05 mg L^?1).     

Nitrogen fertilizer improves boron phytoextraction by Brassica juncea grown in contaminated sediments and alleviates plant stress

In this study we evaluated the effect of different fertilizer treatments on Brassica plants grown on boron-contaminated sediments. Experiments were conducted in the laboratory and on the lysimeter scale. At laboratory scale (microcosm), five different fertilizers were tested for a 35-d period. On the lysimeter scale, nitrogen fertilization was tested at three different doses and plants were allowed to grow until the end of the vegetative phase (70 d). Results showed that nitrogen application had effectively increased plant biomass production, while B uptake was not affected. Total B phytoextracted increased three-fold when the highest nitrogen dose was applied. Phytotoxicity on Brassica was evaluated by biochemical parameters. In plants grown in unfertilized B-contaminated sediments, the activity of antioxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX) and pyrogallol peroxidase (PPX) increased, whereas catalase (CAT) decreased with respect to control plants. Addition of N progressively mitigated the alteration of enzymatic activity, thus suggesting that N can aid in alleviating B-induced oxidative stress. SOD activity was restored to control levels just at the lowest N treatment, whereas the CAT inhibition was partially restored only at the highest one. N application also lowered the B-induced increase in APX and PPX activities. Increased glutathione reductase activity indicated the need to restore the oxidative balance of glutathione. Data also suggest a role of glutathione and phytochelatins in B defense mechanisms. Results suggest that the nitrogen fertilizer was effective in improving B phytoextraction by increasing Brassica biomass and by alleviating B-induced oxidative stress.     

Nitrate in groundwater: an isotopic multi-tracer approach

In spite of increasing efforts to reduce nitrogen inputs into groundwater from intensive agriculture, nitrate (NO3) remains one of the major pollutants of drinking-water resources worldwide. Determining the source(s) of NO3 contamination in groundwater is an important first step for improving groundwater quality by emission control, and it is with this aim that we investigated the viability of an isotopic multi-tracer approach (delta15N, delta11B, 87Sr/86Sr), in addition to conventional hydrogeologic analysis, in two small catchments of the Arguenon watershed (Brittany, France). The main anthropogenic sources (fertilizer, sewage effluent, and hog, cattle and poultry manure) were first characterized by their specific B, N and Sr isotope signatures, and compared to those observed in the ground- and surface waters. Chemical and isotopic evidence shows that both denitrification and mixing within the watershed have the effect of buffering NO3 contamination in the groundwater. Coupled delta11B, delta15N and 87Sr/86Sr results indicate that a large part of the NO3 contamination in the Arguenon watershed originates from the spreading of animal manure, with hog manure being a major contributor. Point sources, such as sewage effluents, contribute to the NO3 budget of the two watersheds.     

农业生态与土壤环境中硼元素的关系

论述了硼元素的地球化学特征及其分布状况，与硼元素有关的主要作物分类，作物产量和质量与硼元素的关系，影响硼元素有效态和作物吸收硼元素的因素，硼肥的种类和施用方法与效果。     

聚苯胺和氮化硼协效阻燃棉布的制备及性能研究

使用聚苯胺(PANI)与氮化硼(BN)作为阻燃体系,采用一步法对棉布进行阻燃改性,研究了PANI与BN的配比对Cotton-PANI-covered BN复合材料形貌的变化以及对阻燃性能、热稳定性的影响。由扫描电镜(SEM)和全反射傅里叶红外(ATR-FTIR)测试结果可知,PANI成功生长在棉布纤维表面。另外由于PANI的粘附性,BN能被粘附在棉织物表面,从而形成更为致密的包覆结构。研究发现,PANI和BN的存在,能大大提高棉布的热稳定性和成炭性。当PANI的浓度为2.7 wt%,BN的浓度为5.9 wt%时,改性棉布的残炭量能达到8.9%,比纯棉布(0.6%)增加了约14倍。同样,垂直燃烧实时图像能看出PANI/BN改性的棉布的残炭量更高,炭层也更完整,表明PANI和BN具有优良的阻燃效果。     

Invisible Face of Boron Pollution in Fluvial Ecosystem: The Level in the Tissues of Sentinel and Nectonic Organisms

Turkey is the largest producer of borate products in the world. Among four largest boron mines in Turkey two of them are located in basins of Orhaneli and Emet Streams. In this study, boron levels in abiotic (water–sediment) and some biotic elements (sentinel organisms; Asellus aquaticus, Gammarus pulex,Chironomus tentans, Limnodrilus hoffmeisteri and nektonic organism; Squalius cii) of Orhaneli and Emet Streams were investigated and their ranks among the food chain were demonstrated. Since Orhaneli and Emet Streams confluence to form Mustafakemalpaşa Brook which feeds Uluabat Lake which is one of the most important Ramsar fields of the world, Boron levels in those two streams have importance in terms of both continuances of aquatic systems. Present study results have shown that boron levels in water of both streams are much higher (vary between 8.64 and 16.73 mg L⁻¹) than not only Turkish Standard but also limits determined by WHO, US EPA, and NAS. Boron levels determined in sediments of two streams vary between 18.05 and 36.7 mg kg⁻¹. The highest boron level in the biotic elements was determined in liver of Squalius cii (34.64 mg kg⁻¹), it is followed by Limnodrilus hoffmeisteri (2.84 mg kg⁻¹), Chironomus tentans (2.11 mg kg⁻¹), and Gammarus pulex (1.98 mg kg⁻¹).     

Effects assessment: boron compounds in the aquatic environment

In previous studies, boron compounds were considered to be of comparatively low toxicity in the aquatic environment, with predicted no effect concentration (PNEC) values ranging around 1 mg B/L (expressed as boron equivalent). In the present study, we describe an evaluation of toxicity data for boron available for the aquatic environment by different methods.For substances with rich datasets, it is often possible to perform a species sensitivity distribution (SSD). The typical outcome of an SSD is the Hazardous Concentration 5% (HC₅), the concentration at which 95% of all species are protected with a probability of 95%. The data set currently available on the toxic effects of boron compounds to aquatic organisms is comprehensive, but a careful evaluation of these data revealed that chronic data for aquatic insects and plants are missing. In the present study both the standard assessment factor approach as well as the SSD approach were applied. The standard approach led to a PNEC of 0.18 mg B/L (equivalent to 1.03 mg boric acid/L), while the SSD approach resulted in a PNEC of 0.34 mg B/L (equivalent to 1.94 mg boric acid/L). These evaluations indicate that boron compounds could be hazardous to aquatic organisms at concentrations close to the natural environmental background in some European regions. This suggests a possible high sensitivity of some ecosystems for anthropogenic input of boron compounds. Another concern is that the anthropogenic input of boron could lead to toxic effects in organisms adapted to low boron concentration.     

28-Homobrassinolide mitigates boron induced toxicity through enhanced antioxidant system in Vigna radiata plants

The objective of this study was to establish relationship between boron induced oxidative stress and antioxidant system in Vigna radiata plants and also to investigate whether brassinosteroids will enhance the level of antioxidant system that could confer tolerance to the plants from the boron induced oxidative stress. The mung bean (V. radiata cv. T-44) plants were administered with 0.50, 1.0 and 2.0 mM boron at 6 d stage for 7 d along with nutrient solution. At 13 d stage, the seedlings were sprayed with deionized water (control) or 10⁻⁸ M of 28-homobrassinolide and plants were harvested at 21 d stage to assess growth, leaf gas-exchange traits and biochemical parameters. The boron treatments diminished growth, water relations and photosynthetic attributes along with nitrate reductase and carbonic anhydrase activity in the concentration dependent manner whereas, it enhanced lipid peroxidation, electrolyte leakage, accumulation of H₂O₂ as well as proline, and various antioxidant enzymes in the leaves of mung bean which were more pronounced at higher concentrations of boron. However, the follow-up application of 28-homobrassinolide to the boron stressed plants improved growth, water relations and photosynthesis and further enhanced the various antioxidant enzymes viz. catalase, peroxidase and superoxide dismutase and content of proline. The elevated level of antioxidant enzymes as well as proline could have conferred tolerance to the B-stressed plants resulting in improved growth, water relations and photosynthetic attributes.     

Statistical approach for the source identification of boron in leachates from industrial landfills

Boron has been found in high concentrations in leachates from landfills located throughout Japan. However, the source(s) of boron in the leachates, i.e., what kind of waste(s) releases this element into the leachate, has not been clarified. In this study, boron concentrations in leachates from 48 industrial landfills were evaluated, in relation to the categories of waste constituting the landfill in each of the sites, by multiple regression analysis. The multiple regression analyses were carried out using the log-transformed boron concentration as a dependent variable and each of 19 categories of industrial waste (according to the Japanese Waste Disposal and Public Cleansing Law) as independent variables. Stepwise variable selection was employed in the analyses. Although the significant variable(s) selected varied according to the data sets analyzed (viz., data sets from least controlled landfill sites, from controlled landfill sites, and from both), cinders, slag, and waste plastics emerged as wastes with positive partial regression coefficients that significantly explained the boron levels in the leachates. These results indicated that cinders, slag, and waste plastics were the sources of high concentrations of boron in the leachates. The results of the present exploratory statistical analyses warrant a systematic survey of the boron contents of, and leachability from, cinders, slag, and waste plastics. Received: January 17, 2000 / Accepted: July 24, 2000