内蒙古草地生长季植被变化对气候因子的响应

基于MODIS NDVI数据,研究分析了2000-2010年内蒙古典型草原、草甸草原和荒漠草原生长季NDVI时空变化趋势,探讨不同类型草地生长季NDVI对温度、降水的响应。结果表明,内蒙古草地生长季NDVI整体年增长速率为0.735%,典型草原最为明显,年增长率达到1.063%;但是仍有31.807%的草地NDVI呈现下降趋势,其中典型草原、草甸草原和荒漠草原分别有8.664×10⁴、6.814×10⁴、2.841×10⁴ km²。除东北部草甸草原外,大部分草地生长季NDVI与降水量的相关性高于温度;草地生长季NDVI与温度和降水的相关系数均呈现出草甸草原>典型草原>荒漠草原的变化规律。内蒙古草地植被变化对温度和降水的响应具有滞后作用,且具有明显的经度地带性和纬度地带性特征,其滞后时间随着经度和纬度的增加逐渐减少。     

Can pollution tax rebates protect low-wage earners?

Pollution taxes are believed to burden low-income households that spend a greater than average share of income on pollution-intensive goods. Some proposals offset that effect by returning revenue to low-income workers via reduced labor tax. We build analytical general equilibrium models with both high-skilled and low-skilled labor, and we solve for the change in real net wage of each group. Decomposition shows the separate effects of the tax rebate, higher product prices, and the changes in relative wage rates. We also include numerical examples. Even though the pollution tax injures both types of labor, in most cases we find that returning all of the revenue to low-skilled workers is still not enough to offset higher product prices. Changes in relative wage rates may further hurt low-skilled labor. Protecting low-income workers is possible in this model only if they are defined as those below a relatively low wage threshold, but we discuss many possible elaborations of this model that could affect those results.     

Short-term effects of sucralose on Calanus finmarchicus and Calanus glacialis in Disko Bay,Greenland

The potential effects of sucralose on the Arctic copepods Calanus finmarchicus and Calanus glacialis were studied in Disko Bay, Greenland. Sucralose is a non-calorie sweetener and chlorine derivate of sucrose containing three chlorine atoms. Scandinavian screening studies of sucralose in 2007, revealed sucralose in all effluent samples. To investigate whether sucralose is harmful to the Arctic aquatic ecosystems, possible short-term effects were investigated on egg production, hatching rate, food intake and mortality of two species of Arctic copepods. The copepods were exposed to six different concentrations (0–50,000 ng · L^?1) of sucralose, which spans the range of concentrations found in the screening studies. Exposure led to no mortality among the copepods. Food intake by C. glacialis increased with increasing concentrations of sucralose. In C. finmarchicus, food intake did not differ with increasing concentrations. No effect of sucralose was observed on egg production of C. finmarchicus. Despite increased food intake with increasing concentrations of sucralose, C. glacialis did not increase its egg production. The results show that both species responded weakly to sucralose, but with C. glacialis being possibly slightly more sensitive to sucralose than C. finmarchicus.     

Excessive chromium may cause dietary toxicity in parsley (Petroselinum crispum)

A bibliographical review on the possible effects of radiofrequency radiation (RFR) from wireless telecommunications on living organisms and its impact on amphibians is presented. The technical characteristics of this new technology and the scientific discoveries that are of interest in the study of their effects on wild fauna and amphibians are described. Electromagnetic pollution (in the microwave and in the radiofrequency range) is a possible cause for deformations and decline of some amphibian populations. Keeping in mind that amphibians are reliable bio-indicators, it is of great importance to carry out studies on the effects of this new type of contamination. Finally, some methodologies that could be useful to determine the adverse health effects are proposed.     

A comparitive study between the coal-biomass briquette and raw coal in SO2 pollution and adverse effects in rabbits

This study was conducted to evaluate the adverse health effects on rabbits exposed to SO₂ emitted indoors from burning coals, and compare differences between coal-biomass briquette (B.B.) and raw coal (R.C.). Thirty-six male rabbits were divided equally into three groups at random, and then exposed to burning R.C., B.B., and the third without burning coal (Control) for 90 days. Data showed that the average concentration of SO₂ in 24?h in R.C. was 13.04?mg?m^?3, which was 5-fold greater than B.B. (2.68?mg?m^?3) and 31-fold higher than control (0.41?mg?m^?3). After 45 days, the numbers of rabbits, with increased frequency of Comet cell was highest in R.C. After 90 days, the % positive Comet cell was significant at 10.36% in R.C., 5.42% in B.B., and 1.73% in Control. There was a nonlinear dose–effect relationship between % positive Comet cell and the concentration of SO₂. The incidence of interstitial pneumonia was 6/12 in R.C. and 4/12 in B.B. showing severe squamous metaplasia with atypical hyperplasia in bronchial epithelia in R.C. animals. The results of study indicate that use of B.B. reduced the emission of SO₂; but the smoke emitted from burning coal still produced DNA damage.     

Effect of Cd++ on germination,growth and active principles of Datura metel L.∗

The effects of Cd⁺⁺ concentration increment in soil and/or in atmosphere, on germination, growth and alkaloid contents of Datura metel L. were investigated. We observed a significant reduction of growth following addition of Cd⁺⁺ in soil. Minor effects on growth were evident when the plants were sprayed with CdCl₂ solution (10mgCd⁺⁺/l).

Scanning electron microscope observation showed stomata widely open and conspicuous cuticular striations in the foliar epidermis of polluted plants.

GLC analysis of extracts evidenced a significant variation in active principle content among plants undergoing different treatments.     

Absorption and retention of polydimethylsiloxanes (silicones) in fish: Preliminary experiments†

Hydrophobicity and bioaccumulation potential of linear and cyclic polydimethylsiloxane (PDMS) oligomers were estimated by reversed‐phase liquid chromatography and feeding experiments with guppies (Poecilia reticulata). PDMS concentrations in fish were determined by capillary column gas chromatography and gas chromatography‐mass spectrometry. In contrast to polychlorinated biphenyls (PCBs), only very small amounts of PDMS were retained by the fish after six weeks feeding.     

铜与锌对香樟、广玉兰及榉树生理生化特性的复合影响

为了解土壤中铜（Cu）与锌（Zn）对不同乔木抗氧化系统的复合影响及植物生态修复土壤cu和Zn复合污染的生理生化基础,以香樟（Cinnamomumcamphora）、广玉兰（Magnolia grandiflora）和榉树（Zelkovaschneideriana）3种乔木为实验材料,采用土培盆栽方法,研究单-Cu2＋（75mg·L-1）溶液和单一Zn2＋（210mg·L-1）溶液及两者复合溶液污灌对香樟、广玉兰和榉树叶片丙二醛（MDA）含量、脯氨酸（Pro）含量、过氧化物酶（POD）活性和过氧化氢酶（CAT）活性的动态影响。结果表明,Zn2＋／t~用下3种乔木MDA含量升高,Cu2＋作用下MDA含量降低,Zn2＋和Cu2＋复合作用下3种乔木MDA含量低于Zn2＋作用,即210mg-L。Zn2＋对3种乔木生长的毒害作用比75mg·L。Cu2＋明显,两者复合作用使Zn2＋的伤害作用减轻。随胁迫时间延长,香樟POD和CAT活性增加,MDA含量和Pro含量减少。广玉兰细胞活性氧代谢失衡,POD活性和CAT活性急剧上升,第7天时分别达到1243．89％和300．00％（单一Cu2＋’）、149．22％和60．00％（单一Zn2＋）、653．96％和170．00％（Cu2＋和Zn2＋复合作用）。榉树无法承受高浓度Cu2＋和Zn2＋伤害而死亡。综合考虑,Zn2＋对3种乔木伤害严重,Cu2＋在诱导POD和CAT活性过程中与zn2＋存在拮抗作用,香樟对重金属Cu2＋和zn2＋的耐性最强。     

污染场地河道底泥浸出液对斑马鱼胚胎的毒性效应

为了评价某污染场地河道底泥对水生生物的毒性效应及其潜在生态风险,以斑马鱼(Brachydanio rerio)为受试生物,进行了河道底泥浸出液对斑马鱼胚胎的发育毒性实验。结果表明,5种底泥浸出液(A1、A2、A3、A4、A5)对斑马鱼胚胎的发育均有毒性效应,浸出液对斑马鱼胚胎的死亡率存在一定的剂量-效应关系,随着浸出液体积分数的增加,死亡率显著上升。浸出液对胚胎孵化抑制作用明显,随着浸出液体积分数的增加,孵化率显著下降。且能引起斑马鱼胚胎多种中毒症状,如水肿,鱼体弯曲,发育不全等异常现象,表明该段河道底泥存在潜在的生态风险。因此,在后期的污染场地河道整治中,需对河道底泥进行挖掘清理和无害化处理。