The role of environmental groups in the control of noise

Much environmental protection and restoration activity has resulted directly from the efforts of citizen environmental groups. This paper describes significant contributions of such groups to the control of noise pollution and examines the techniques used to achieve the desired results. Some of the problems faced by noise control groups are discussed, and the prevailing climate for their present and future activities is assessed.     

The role of effluent monitoring in environmental control

Using effluent data from a British Columbia pulp mill, the authors demonstrate certain critical deficiencies associated with currently emplaced monitoring systems. The principal ingredient in effective environmental control is information, and current monitoring regimes entail an unacceptable level of information loss. Composite sampling systems fail to provide the two key types of information required for effective environmental control: (i) a high representational accuracy of the effluent profile; and (ii) the detection of most or all pollutant releases with potentially serious environmental consequences. In light of these conclusions, the authors make several recommendations concerning current and alternative sampling regimes.     

The application of geotechnical engineering techniques for the prevention and control of pollution

Recent innovations in the fields of geotechnical engineering, geochemistry, materials technology, hydrogeology and fluid mechanics are now increasingly being applied for the prevention and control of pollution arising from contaminated ground and landfill sites. In the field of geotechnical engineering the design and specification of low-permeability slurries for slurry trench cut-off walls and diaphragm walls is now increasingly being used as technique for leachate and groundwater control. In addition, the use of high-density polyethylene (HDPE), geomembranes and gas venting systems are now commonly used for the control of landfill gas. This paper describes the application of some of the available techniques with respect to leachate, groundwater and landfill gas control. © 1997 John Wiley & Sons, Ltd.     

连翘在黄土高原防治水土流失的作用浅析

简析了连翘在黄土高原干旱、半干旱地区防治水土流失、抗沙固土作用,并提出保护和利用连翘野生资源的措施。     

我国畜禽养殖污染防治的产业化探析

阐述了我国畜禽养殖污染治理产业化的产业与经济基础,并指出实现畜禽养殖污染治理产业化的主要途径,即应建立包括系统的政策机制、完善的金融体制和有效的科研支持保障体系。     

土壤中微塑料的污染防治综述

微塑料是一个新兴污染物,也是当今全球关注的热点,但有关土壤中微塑料的研究很少.对关于土壤中微塑料的来源、毒性及检测方法的相关文献及研究进行综述,提出了土壤中微塑料的污染防治对策及需要开展的具体工作,为土壤中微塑料的管控工作提供技术支持.     

Lead in women's and children's vitamins

A survey was conducted to determine the extent of lead (Pb) contamination in vitamins labeled for use by women and children. The Pb content of 324 multivitamin-mineral products was determined using microwave assisted nitric acid digestion and inductively coupled plasma mass spectrometry. Cryogenic grinding was used to composite soft samples such as oil filled capsules and candy-like products such as gummies and jelly beans. Estimates of Pb exposures from consumption of these products were derived for four population groups: young children (0-6 yrs), older children (7+ yrs), pregnant or lactating women, and adult women. The estimated median and maximum Pb exposures were 0.123 and 2.88 microg/day for young children, 0.356 and 1.78 microg/day for older children, 0.845 and 8.97 microg/day for pregnant and lactating women, and 0.842 and 4.92 microg/day for adult women. The overall median value for Pb exposure was 0.576 microg/day. Five samples would have provided exposures that exceeded 4 microg/day. Estimates of exposures were assessed with respect to safe/tolerable exposure levels that have been developed for the specific age and sex groups. These safe/tolerable levels are referred to as the provisional total tolerable intake levels (PTTI) and are 6, 15, 25, and 75 microg Pb/day for young children, older children, pregnant or lactating women, and adult women, respectively. Estimates of Pb exposures were below the PTTI levels for the four population groups. Median and maximum values were used instead of the mean and standard deviation because of the skewed distribution of results toward lower mass fraction and exposure.     

北京怀沙河水质污染与防治对策简

在对北京怀沙河的水质进行调查的基础上提出相应的防治对策.结果表明：怀沙河水质已重度富营养化,主要污染物为总氮、总磷,大部分河段总氮质量浓度严重超过Ⅴ类水环境标准,总磷质量浓度超过Ⅲ类水环境标准,综合评价整个流域,水环境为劣Ⅴ类,水资源质量属重富营型,远未达到规划要求的Ⅱ类水环境标准.提出的相应治理对策有：继续加大水环境保护及治理措施;加大清洁小流域建设力度;对潜在的污染因素及早发现,及早治理;采取严格的管理措施;加大水环境保护法规的宣传,提高群众环境保护意识;加大执法力度,提高违法成本,对违法水案件进行严查;加强水质监测和管护工作.该成果对建设清洁型小流域具有参考意义.     

Production of B-group vitamins by plant growth-promoting Pseudomonas fluorescens strain 267 and the importance of vitamins in the colonization and nodulation of red clover

 We have estimated the production of water-soluble B vitamins by plant growth-promoting rhizobacterium Pseudomonas fluorescens strain 267 in a minimal medium with different C sources and at different pH values. In the minimal medium, strain 267 produced large amounts of niacin (0.92 μg ml^–1) and pantothenic acid (0.75 μg ml^–1), but also other vitamins such as biotin, thiamine, cobalamine and pyridoxine. The production of B vitamins was dependent on the C source and pH of the growth medium. By random Tn5 mutagenesis, thiamine and niacin auxotrophs were isolated from P. fluorescens strain 267 and mutants were used to evaluate the vitamin production on colonization of clover roots under controlled conditions. Red clover root colonization decreased by about 1 order of magnitude in the case of the niacin auxotroph. The vitamin auxotrophs of P. fluorescens in a mixed inoculation of clover with R. leguminosarum bv. trifolii strain 24.1 showed no plant growth-promotion activity. Received: 23 May 2000     

A role for pectin in the control of cell expansion

Uptake of nutrients and water depends on the growth of roots through elongation of individual cells near the root tip. Many of the numerous components of Type I primary cell walls, those of dicotyledons and monocotyledons other than grasses (Poaceae), have been determined, and many hypotheses have been proposed for the control of cell expansion. This important aspect of plant growth still needs elucidation, however. A model is proposed in which pectin, which occurs as a calcium (Ca) pectate gel between the load-bearing cellulose microfibrils and xyloglucan (XG) chains, controls the rate at which cells expand. It is considered that the increasing tension generated by the expanding cell is transmitted to interlocked XG chains and cellulose microfibrils. The resulting deformation of the embedded Ca pectate gel elicits the excretion of protons from the cytoplasm, possibly via compounds such as cell wall-associated kinases, that weakens the Ca pectate gel, permitting slippage of XG molecules through the action of expansin. Further slippage is prevented by deformation of the pectic gel, proton diffusion, and the transfer of residual tension to adjacent XG chains. Evidence for this model is based on the effects of pH, Ca, and aluminum (Al) on root elongation and on the reactions of these cations with Ca pectate. This model allows for genetic selection of plants and adaptation of individual plants to root environmental conditions.     

High pressure liquid chromatographic separation and identification of vitamins D2 and D3 in the presence of fat-soluble vitamins in dosage forms.

A simple and rapid qualitative method is described for determining the presence of vitamin D2 (ergocalciferol) and/or vitamin D3 (cholecalciferol) in various preparations by reverse phase high pressure liquid chromatography (HPLC). When both D2 and D3 are present, this method effectively separates and identifies each vitamin D form by its respective retention time. A significant difference between vitamins D2 and D3 exists in their antirachitic activity in poultry. Preparations can be tested rapidly by this method to ascertain that the correct D vitamin form has been added. Fat-soluble vitamins such as vitamins A, E, K1, and K3 do not interfere. Vitamins D2 and D3 were separated at the baseline in model preparations. As little as 2 ng each of vitamin D2 and vitamin D3 can be separated and identified.     

The potential effect of iron defortification on iron-deficiency anaemia in the US population

OBJECTIVE: To quantify the potential effect of iron defortification in the USA on iron-deficiency anaemia (IDA). METHODS: Monte Carlo models were built to simulate iron nutrition in the US population. A hypothetical cohort of 15 000 persons from the general population was used in 15-year simulations to compare the prevalence of IDA with and without fortification. RESULTS: With iron fortification, the prevalence of IDA was 2.4% for children aged 3-5 years, 5.4% for women aged 20-49 years, and 0.14% for men aged 20-49 years. The corresponding IDA estimates under iron defortification were 4.5%, 8.2% and 0.46%, respectively. Defortification had little effect on the distribution of iron indicators at or above the 50th percentile within each of these three groups and little effect on the distributions of iron indicators among adult men. CONCLUSION: Iron defortification is likely to increase IDA among children and women of reproductive age, but is not likely to have meaningful effects on the iron status of men or the majority of women and children.     

The role of bacteria in the biological control of Gaeumannomyces graminis by suppressive soils

The suppression of Gaeumannomyces graminis var. tritici by certain soils or following certain soil treatments is considered to be an expression of either specific or general antagonism sensu Gerlagh (1968). Specific antagonism is effective in dilutions as high as 1 in 1,000, can be transferred from soil to soil, operates near or on wheat roots, is destroyed by 60°C moist heat for 30 min. or desiccation, is fostered by wheat monoculture but may be lost from a soil by fallow or rotation with certain crops, especially legume hay or pasture crops. Strains of Pseudomonas fluorescens may be involved. General antagonism is a soil property which cannot be transferred and is resistant to 80°C moist heat for 30 min, to methyl bromide and chloropicrin, but not to autoclaving. Take-all control by organic amendments, minimum tillage, or a soil temperature of 28°C may be expressions of increased general antagonism.In much of the southern Australian wheat belt, where take-all can cause heavy crop losses, some general but rarely specific antagonism is apparently operative. Both types of antagonism are probably operative in long-term wheat growing areas of the Pacific Northwest U.S.A. where take-all is virtually nonexistent.     

防病促生枯萎病拮抗菌“98-I”对4种枯萎病防治效果研究

经8年系统试验研究从330个细菌菌株中筛选出1株防病促生枯萎病拮抗菌“98-I”，经鉴定属蜡质芽孢杆菌。该菌对黄瓜枯萎病、西瓜枯萎病、青椒枯萎病和番茄枯萎病4种土传病害均有显著防治效果，其平皿孢子萌发抑制率分别为79．2％、75．1％、72．3％和95．7％，且该菌对多种蔬菜有促生和促进种子发芽功效。     

Nitrogen fertilizers and the amount of vitamins in plants: A review

Effect of mineral fertilizers on the vitamin content of plants has received very little attention by scientists in English‐speaking countries, especially in recent years. A review of the literature, however, has revealed a rich source of information mostly published in non‐English journals. Based on these reports, nitrogen fertilizers, especially at high rates, seem to decrease the concentration of vitamin C in many different fruits and vegetables, among them potatoes, tomatoes and citrus fruits, the major sources of this vitamin in human nutrition in many societies. Nitrogen fertilizers are also shown to increase the concentrations of carotenes and vitamin B₁ in plants. Since excess use of nitrogen fertilizers increases the concentration of NO₃ in plant foods and simultaneously decreases that of ascorbic acid, a known inhibitor for the formation of carcinogenic N‐nitroso compounds from nitrite, it appears that the use of these fertilizers may have a double negative effect on the quality of food plants. Vitamin C and several carotenoids have antioxidant properties and reportedly reduce the risk of cardiovascular diseases and some forms of cancer. Whether long‐term consumption of food plants grown with excess use of nitrogen fertilizers would have an overall positive or negative effect on the total intake of antioxidative vitamins by consumers warrants investigation.     

Thermal decomposition of specifically phosphorylated D-glucoses and their role in the control of the Maillard reaction

One of the main shortcomings of the information available on the Maillard reaction is the lack of knowledge to control the different pathways, especially when it is desired to direct the reaction away from the formation of carcinogenic and other toxic substances to more aroma and color generation. The use of specifically phosphorylated sugars may impart some elements of control over the aroma profile generated by the Maillard reaction. Thermal decomposition of 1- and 6-phosphorylated glucoses was studied in the presence and absence of ammonia and selected amino acids through pyrolysis/gas chromatography/mass spectrometry using nonpolar PLOT and medium polar DB-1 columns. The analysis of the data has indicated that glucose-1-phosphate relative to glucose undergoes more extensive phosphate-catalyzed ring opening followed by formation of sugar-derived reactive intermediates as was indicated by a 9-fold increase in the amount of trimethylpyrazine and a 5-fold increase in the amount of 2,3-dimethylpyrazine, when pyrolyzed in the presence of glycine. In addition, glucose-1-phosphate alone generated a 6-fold excess of acetol as compared to glucose. On the other hand, glucose-6-phosphate enhanced retro-aldol reactions initiated from a C-6 hydroxyl group and increased the subsequent formation of furfural and 4-cyclopentene-1,3-dione. Furthermore, it also stabilized 1- and 3-deoxyglucosone intermediates and enhanced the formation of six carbon atom-containing Maillard products derived directly from them through elimination reactions such as 1,6-dimethyl-2,4-dihydroxy-3-(2H)-furanone (acetylformoin), 2-acetylpyrrole, 5-methylfurfural, 5-hydroxymethylfurfural, and 4-hydroxy-2,5-dimethyl-3-(2H)-furanone (Furaneol), due to the enhanced leaving group ability of the phosphate moiety at the C-6 carbon. However, Maillard products generated through the nucleophilic action of the C-6 hydroxyl group such as 2-acetylfuran and 2,3-dihydro-3,5-dihydroxy-4H-pyran-4-one were retarded, due to the blocked nucleophilic atom at C-6.     

Microwave-assisted rapid determination of vitamins a and e in beverages

A new rapid procedure for the determination of vitamins A and E in beverages has been developed and validated. Key steps include a microwave-assisted saponification of the sample and a single-step extraction of the vitamins prior to HPLC analysis. All sample preparation steps are carried out consecutively in the same vial. The vitamins are determined using normal-phase (Si-60) HPLC with fluorescence detection. The method is applicable to beverages with a content of all-trans-retinol >0.14 mg/L and/or a content of alpha-tocopherol >1 mg/L. Recoveries determined by spiking experiments ranged from 91.3 to 106.3%. The precision of the method is characterized by relative standard deviations of <2% for alpha-tocopherol and <5% for all-trans-retinol.     

油葵秆生物篱和作物残茬组合抗风蚀效果研究

土壤风蚀是干旱半干旱地区主要的土地退化过程，在最不适宜种植乔木防风林的半干旱农牧交错带地区，生物篱是一种有效的风障形式，它能减轻风速从而减轻风蚀。试验结果表明，在近地面(距地面5 cm)生物篱保护下的留茬地风速比对照裸地近地面平均降低81.25％，风蚀量减少53.96％；在篱高或茬高0～5倍范围内，随着离生物篱或留茬的距离增大，生物篱的保护作用逐渐增强，贡献率逐渐增大，更远则保护作用下降。在与不同作物残茬的组合中，生物篱与草谷子留茬组合下的抗风蚀效果更为突出，其次是油菜茬，最后是苜蓿茬，并且得出在残茬影响下，风速随高度递增的变化规律都符合指数递增规律，相关系数都达到0.84以上。