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351.
David W. Stevens 《Environmental management》1996,20(6):841-847
Single-species listings under provisions of the federal Endangered Species Act (ESA) have caused, or have been accused of causing, significant regional economic impact. In an attempt to avoid such adverse effects on regional economic development, the state of California passed the Natural Communities Conservation Planning Act (NCCP) in 1991. It is a voluntary, consensus-based approach to balancing protection of sensitive biota and biodiversity with regional economic development. The pilot NCCP program for the conservation of several threatened, endangered, and category 1 species, plus an additional 35 coastal sage scrub-related species in southern California, was completed and submitted to the public for review and comment in December 1995. This program proposes the voluntary establishment of a 86,600-ha multispecies reserve system. Once completed, participating landowners will receive ESA Section 10(a) incidental take permits for present and identified future projects. Utility rights-of-way are incorporated into the program as important connective linkages between reserve units and other adjacent important habitat areas. All data and information regarding the proposed results of the NCCP are subject to change pending agency response to public comments on the draft Habitat Conservation Plan and joint EIR/EIS. 相似文献
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IntroductionThecontentofCuintheenvironmentisusually20to30ppminnoncontaminatedsoil(Nriagu,1979;Salomons,1984),butismorethan2000ppminminingareasandinthevicinityofsmelters(Freedman,1980;Humphreys,1984).IthasbeendemonstratedthatcoppersolubilitydependsonpHinsoils,anditisob… 相似文献
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356.
Ciucani G Mosbaek H Trapp S 《Environmental science and pollution research international》2004,11(4):267-272
BACKGROUND: Organotins have been used world-wide as antifoulants in ship paints. Repeatedly, severe effects on aquatic species have resulted. The use of organotins for this purpose was ruled out, and dumping of contaminated harbor sludge into the sea was prohibited. Land-based dumping is seen as an alternative. OBJECTIVE: This study investigates sorption, uptake and translocation of tributyltin (TBT) to willow trees in order to evaluate phytoremediation as treatment option. The study considers the influence of pH on the plant uptake of organotins. EXPERIMENTAL SET-UP: Chemicals investigated were the weak base tributyltin chloride (TBTCl) and the neutral tributyltin hydride (TBTH). Organotins were extracted from solution and plant material with toluene, and analyzed as tin by AAS with graphite oven. The pH in solution varied from pH 4 to pH 7. The sorption to living and dead roots, stems and leaves was measured in shaking experiments. The uptake into intact trees was measured at nominal levels of 1 and 10 mg TBT/l for TBTH and TBTCl at low and high pH. RESULTS: The sorption to roots and leaves dropped for dead tissue, but did not vary much with pH. The sorption to stems increased for dead stems and with pH. The solubility of TBTCl in water was below 10 mg/l and lowest at pH 4. Concentrations of TBTCl and TBTH in solutions with trees dropped rapidly to low values. Highest TBT contents in trees were found in roots and lower stems. The concentrations followed the concentrations in solution. The pH had only a small effect on the plant uptake of TBTCl, and no effect on the uptake of TBTH. No effective translocation to higher stems or leaves was found. DISCUSSION: An ion trap mechanism that accumulates the weak base TBTCl in the xylem sap of plants and leads to upward translocation could not be detected. Neither TBTCl at low or high pH, nor the neutral lipophilic chemical TBTH, were translocated effectively to leaves. The TBT+ cation sorbed strongly to plant tissue. The exact mechanism for the strong sorption of the cation is unknown, but similar effects have been observed for algae, liposomes and isolated biomembranes. CONCLUSIONS: Both the uptake of the neutral TBTH and the uptake of the neutral molecule form of TBTCl into willows was as is to be expected from theory. The cation TBT+ showed an unexpected behavior which has been observed before. No ion trap occurs, and the phytoextraction of TBT is not feasible. OUTLOOK: Planting trees, or other appropriate vegetation, could have a beneficial remediation effect by aeration of the TBT-contaminated soil or sludge. In a follow-up paper, the toxicity of TBT to willow trees will be described. 相似文献
357.
砷矿尾砂污染及其治理研究 总被引:9,自引:0,他引:9
调查了广东省连南瑶族自治县寨岗铁屎坪土法炼砷废墟及其周边砷污染状况.发现渗流水含砷高达43.72 mg/L,渗流水随雨水沿山坡、溪流流入下游,对周边的水体、土壤、农作物等造成严重污染.同时发现全缘凤尾蕨、龙船蕨、野苎麻、白芒草和接骨草是耐砷植物.模拟试验证实在炼砷废墟和高砷尾砂上种植这些植物可减少砷的迁移,且不致引起二次污染.1998年对铁屎坪土法炼砷废墟进行治理,经一年多跟踪观察,周边水体中砷含量从原来的约0.048 mg/L下降到0.001 06 mg/L.结果表明用植被治理尾砂的砷污染是一种价廉、有效的方法. 相似文献
358.
淡水绿藻的光合碳酸氢盐利用探讨 总被引:3,自引:0,他引:3
为了探讨藻类对碳酸氢盐的利用,采用pH漂移实验技术,辅以氧测定技术和抑制剂的抑制实验,研究了斜生栅藻(Scenedesmus obliquus)和蛋白核小球藻(Chlorella pyrenoidosa)的光合无机碳摄取速率(PCU)和净光合速率(NPS).结果表明,PCU对pH的曲线上存在明显的转折点(简写为pHTP),在pH超过PHTP后存在第2个PCU峰,求此峰的平均值并以PCUsc表示,可以作为表征藻类碳酸氢盐利用的参数.蛋白核小球藻和斜生栅藻的PCUBC值分别为269.41和175.98μmol·g-1·h-1它们的平均NPS(pH为4.8~11.0)分别为477.5和495.9ttmol·g-1·h-1.随着碳酸酐酶抑制剂AZ(acetazolamide)浓度的增加,PCUBC减小;当AZ达到1.2mmol·L-1时,蛋白核小球藻的PCUBC减小到0.随AZ浓度增加,蛋白核小球藻PCUBC减小的速度比斜生栅藻的快.AZ和阴离子交换抑制剂DIDS(4,4'-diisothiocyanatoetilbene-2,2'-disuffonic acid)对蛋白核小球藻的PCU和NPS的抑制作用大于斜生删藻.AZ和DIDS对2株藻的PCU的抑制均大于对它们NPS的抑制.2株藻具有高的PCUBC值,都是强碳酸氢盐利用者. 相似文献
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360.
水分管理和外源硒对水稻吸收累积铅的影响 总被引:1,自引:0,他引:1
通过盆栽试验,研究了不同水分管理和外源亚硒酸盐的添加对水稻根际铅的动态变化和水稻吸收累积铅的影响.结果表明,淹水显著增加了根表铁膜对铅的吸附和根系对铅的吸收,淹水下苗期和成熟期水稻根系铅含量分别是非淹水处理时的4.2~8.5和1.4~1.5倍;淹水降低了地上部的铅分配,在苗期和成熟期分别降低85.9%~86.7%和51.8%~74.0%.加硒降低了土壤溶液、苗期水稻根系和地上部的铅含量以及成熟期水稻根表铁膜、根系和茎中的铅含量.与对照相比,淹水和非淹水下加硒处理使苗期水稻根系铅含量分别降低了5.4%~24.3%和2.7%~61.7%,使成熟期水稻根系铅含量分别降低了56.1%~64.1%和53.8%~63.2%.水稻籽粒中的铅含量在不同处理间无显著差异.因此,水分管理和外源硒的添加显著影响了水稻根系对铅的吸收,而对水稻籽粒对铅的累积无显著影响. 相似文献