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371.
372.
Assessing soil ecotoxicity of methyl tert-butyl ether using earthworm bioassay; closed soil microcosm test for volatile organic compounds 总被引:2,自引:0,他引:2
An YJ 《Environmental pollution (Barking, Essex : 1987)》2005,134(2):181-186
An earthworm bioassay was conducted to assess ecotoxicity in methyl tert-butyl ether (MTBE)-amended soils. Ecotoxicity of MTBE to earthworms was evaluated by a paper contact method, natural field soil test, and an OECD artificial soil test. All tests were conducted in closed systems to prevent volatilization of MTBE out of test units. Test earthworm species were Perionyx excavatus and Eisenia andrei. Mortality and abnormal morphology of earthworms exposed to different concentrations of MTBE were examined. MTBE was toxic to both earthworm species and the severity of response increased with increasing MTBE concentrations. Perionyx excavatus was more sensitive to MTBE than Eisenia andrei in filter papers and two different types of soils. MTBE toxicity was more severe in OECD artificial soils than in field soils, possibly due to the burrowing behavior of earthworms into artificial soils. The present study demonstrated that ecotoxicity of volatile organic compounds such as MTBE can be assessed using an earthworm bioassay in closed soil microcosm with short-term exposure duration. 相似文献
373.
Application of rare-earth elements in the agriculture of China and its environmental behavior in soil 总被引:2,自引:1,他引:2
Rare-earth elements (REEs) have been used in fertilizers in the agriculture of China for about 20 years. They have been shown to be beneficial elements for plants. For example, they have improved the yield and quality for several kinds of crops. This paper reviews the current literature on studies of REEs being used as fertilizers. Some studies have focused on the effects of REEs on metabolic nutrients, photosynthesis and stress resistance of plants. Other studies have shown that the environmental behaviors of REEs in soil are dominated by their low solubility. Fluorides, carbonates, phosphates and hydroxides may form neutral complexes containing REEs with a low solubility. The amount of extraneous REEs demonstrate the following relationship: residual > bound to organic matter > bound to Fe-Mn oxides > bound to carbonate > exchangeable and water soluble forms. The adsorption capacity of REEs depends on the clay type and the content of amorphous and manganese oxides, whereas the desorption of REEs is usually very low. At the end of the paper, authors discuss the needs for future environmental research on REEs, which would shed new light on the effects of REEs on agriculture, environment and human health. 相似文献
374.
Giuseppe Donati An Bollen Silvana M. Borgognini-Tarli Joerg U. Ganzhorn 《Behavioral ecology and sociobiology》2007,61(8):1237-1251
Animals show specific morphological, physiological and behavioural adaptations to diurnal or nocturnal activity. Cathemeral
species, i.e. animals with activities distributed over the 24-h period, have to compromise between these specific adaptations.
The driving evolutionary forces and the proximate costs and benefits of cathemerality are still poorly understood. Our goal
was to evaluate the role of predator avoidance, food availability and diet quality in shaping cathemeral activity of arboreal
mammals using a lemur species as an example. For this, two groups of collared lemurs, Eulemur collaris, were studied for 14 months in the littoral forest of southeastern Madagascar. Data on feeding behaviour were collected during
all-day and all-night follows by direct observation. A phenological transect containing 78 plant species was established and
monitored every 2 weeks to evaluate food availability during the study period. Characteristics of food items and animal nutritional
intake were determined via biochemical analyses. The ratio of diurnal to nocturnal feeding was used as response variable in
the analyses. The effects of abiotic environmental variables were removed statistically before the analyses of the biotic
variables. We found that diurnal feeding lasted longer during the hot–wet season (December–February), whereas nocturnal feeding
peaked during the hot–dry and cool–wet seasons (March–August). Although the lemurs foraged mostly in lower forest strata during
daylight and used emergent trees preferably at night, the variables which measured animal exposure to birds of prey failed
to predict the variation of the ratio of diurnal/nocturnal feeding. Ripe fruit availability and fiber intake are the two variables
which best predicted the annual variation of the lemur diurnality. The data indicate that feeding over the whole 24-h cycle
is advantageous during lean periods when animals have a fibre-rich, low-quality diet. 相似文献
375.
吸附—催化氧化—絮凝法联合处理造纸废水 总被引:14,自引:0,他引:14
采用吸附-催化氧化-絮凝法联合处理造纸废水,讨论了废水通过炉渣柱的滤速,在絮凝过程中Al2(SO4)3的加入量及催化氧化反应中溶液的pH值,铁屑的加入量,H2O2的加入量等主要因素对废水中COD去除率的影响,结果表明,COD,SS主要污染物去除率达97.0%和95.3%,各项指标超过一级排放标准,水质可以完全回收利用,为造纸废水的处理提供了新的技术方案。 相似文献
376.
通过^141Ce^3 同位素示踪法,研究了不同温度(19℃,30℃,40℃)和土壤饱和含水量(25%,37%,50%)条件下Ce^3 在四种土壤中的扩散。通过Fick第二定律推导的扩散系数计算公式,求得Ce^3 在不同条件下不同土壤中的扩散系数,结果表明:Ce^3 在土壤中的扩散系数因土壤类型、温度、土壤水分含量的不同而存在明显的差异。Ce^3 在四种土壤中的扩散系数与温度呈正比,随温度的升高(19℃→40℃),扩散系数逐渐增大;土壤水分含量在一定数量下(小于饱和土壤含水量),扩散系数与土壤水分含量呈明显相关;在相同条件下,Ce^3 在四种土壤中扩散系数的大小顺序为:马肝土>黄土>潮土>黑土。 相似文献
377.
单甲脒在大鼠体内的吸收,代谢和排出的研究 总被引:1,自引:0,他引:1
大鼠经口灌喂单甲脒后,通过测定实验动物不同时间的血、尿及内脏中单甲脒和代谢产物2,4-二甲基苯胺的含量,研究了单甲脒在大鼠体内的呼收、代谢和排出的变化规律。单甲脒经消化道被迅速吸收,48h内90%在肝脏代谢转化。72h内90%以代谢产物的形式随尿液排出体外。 相似文献
378.
本文研究了大鼠肝脏中单甲脒及其代谢产物2,4-二甲基苯胺残留量的气相色谱分析方法。肝脏匀浆用1mol.1^-1hHC1加热回流提取,等分为A,B两份,A份溶液调pH至13后用石油醚萃取定容;B份加两倍体积的10mol.1^-1NaOH溶解后用石油醚萃取定容。分别经七氟丁酸酐衍生化,用带电子捕获检测器的气相色谱仪测定2,4-二甲基苯胺的含量,最后计算单甲脒的残留量。该方法对2,4-二甲基苯胺的最低检 相似文献
379.
An KG 《Journal of environmental biology / Academy of Environmental Biology, India》2003,24(3):229-239
Long-term nutrient contents and nutrient ratios indicated that phosphorus was a potential limiting element for algal growth. In situ experiments of nutrient enrichment bioassay supported the evidence of P-limitation. However, regression analyses of log10-transformed chlorophyll-a (CHL) against TP (R2 values < 0.25) showed that seasonal CHL was not closely related to flux of phosphorus during all seasons. Also, two dimensional graphical approach of Trophic State Index (TSI) showed that most values of TSI (CHL) -TSI (TP) and TSI (CHL) -TSI (SD) were less than zero, indicating factors other than phosphorus limited algal biomass (CHL -TP < 0), and that non-algal particles dominated light attenuation (CHL -SD < 0). The weak empirical relations and trophic deviations were explained well by the experiment of NEB-II that was conduced during a period of high inorganic turbidity. Overall results suggest that phosphorus is the primary element regulating the system productivity, but the system also were highly influenced by rapid flushing and high inorganic turbidity. 相似文献
380.
IntroductionRecentfindingsfrommercuryresearchindicatethatthemajorsourcetolakesisatmosphericdeposition(Sorensen ,1990 ;Glass,1990 ) ,andthatsignificantsourcestotheatmospherearefossilfuelcombustionandincinerationofmunicipalsolidwasteandsludge(Glass,1991;White ,1992 ;C… 相似文献