The monitoring results of electromagnetic radiation of 110-kV high-voltage lines in one urban location in Chongqing P.R. China

To understand electromagnetic radiation field strength and its influencing factors of certain 110-kV high-voltage lines in one urban area of Chongqing by measuring 110-kV high-voltage line’s electromagnetic radiation level. According to the methodology as determined by the National Hygienic Standards, we selected certain adjacent residential buildings, high-voltage lines along a specific street and selected different distances around its vertical projection point as monitoring points. The levels of electromagnetic radiations were measured respectively. In this investigation within the frequency of 5–1,000 Hz both the electric field strength and magnetic field strength of each monitoring sites were lower than the public exposure standards as determined by the International Commission on Non-Ionizing Radiation Protection. However, the electrical field strength on the roof adjacent to the high-voltage lines was significantly higher than that as measured on the other floors in the same buildings (p < 0.05). The electromagnetic radiation measurements of different monitoring points, under the same high-voltage lines, showed the location which is nearer the high-voltage line maintain a consistently higher level of radiation than the more distant locations (p < 0.05). Electromagnetic radiation generated by high-voltage lines decreases proportionally to the distance from the lines. The buildings can to some extent shield (or absorb) the electric fields generated by high-voltage lines nearby. The electromagnetic radiation intensity near high-voltage lines may be mitigated or intensified by the manner in which the high-voltage lines are set up, and it merits attention for the potential impact on human health.     

A Complementarity Approach for an Environmental–Economic Game with Coupling Emission Constraints

We consider an environmental–economic game where players face not only Cournot competition but also coupling environmental and individual capacity constraints. Under the complementarity problem framework, we study the existence of the (normalized) Nash equilibrium, computability of the equilibria, and the closed form expressions of the optimal weights. We also report numerical results of two examples as well as the insights gained from them.     

Residues and dissipation of trifloxystrobin and its metabolite in tomatoes and soil

A simple residue analytical method using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure for the determination of trifloxystrobin and its metabolite trifloxystrobin acid (CGA321113) in tomato and soil was developed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The limits of detection were 0.0005 mg/kg for trifloxystrobin and 0.001 mg/kg for trifloxystrobin acid, respectively. The average recoveries in tomato and soil ranged from 73–99 % for trifloxystrobin and 75–109 % for trifloxystrobin acid, with relative standard deviations below 15 %. The method was then used to study the dissipation and residues in tomato and soil. The dissipation half-lives of trifloxystrobin in tomato were 2.9 days (Beijing) and 5.4 days (Shandong), while in soil were 1.9 days (Beijing) and 3.0 days (Shandong), respectively. The final results showed that the major residue compound was trifloxystrobin in tomato whereas it was its metabolite, trifloxystrobin acid, in soil. The final residues of total trifloxystrobin (including trifloxystrobin acid) were below the EU maximum residue limit of 0.5 mg kg^?1 in tomato 3 days after the treatment.     

Mechanism of ofloxacin fluorescence quenching and its interaction with sequentially extracted dissolved organic matter from lake sediment of Dianchi,China

The wide use and occurrence of antibiotics in water environments have caused wide concerns. Ofloxacin (OFL) was selected as a target antibiotic, and the interaction between OFL and sequential extracted dissolved organic matter (DOM) from the sediment of Dianchi, a hypertrophic lake in Southwest China, was explored using fluorescence quenching technology. The method of fuorescence quenching was used to characterize the interaction between OFL and sequentially extracted DOM. The result indicated that static and dynamic quenching both existed in the interaction. The interaction in the background water (0.01 mol/L NaCl and 200 mg/L NaN₃) became increasingly weak with the further extraction of DOM. A low non-linear factor N value (0.53～0.63) of Freundlich model was observed, indicating a non-linear interaction between OFL and DOM. Elemental characterization and infrared spectrum analysis showed an enhanced OFL-DOM binding with the decrease in humic acid (HA) polarity. The effect of ion strength was tested in the OFL-DOM interaction to show the impact of usually existing metal ions in water environment on the OFL behavior. The result showed that K⁺ had little influence, but Cu²⁺ had a significant promotion (p?相似文献   

Field trials to evaluate effects of continuously planted transgenic insect-resistant cottons on soil invertebrates

Impacts on soil invertebrates are an important aspect of environmental risk assessment and post-release monitoring of transgenic insect-resistant plants. The purpose of this study was to research and survey the effects of transgenic insect-resistant cottons that had been planted over 10 years on the abundance and community structure of soil invertebrates under field conditions. During 3 consecutive years (2006-2008), eight common taxa (orders) of soil invertebrates belonging to the phylum Arthropoda were investigated in two different transgenic cotton fields and one non-transgenic cotton field (control). Each year, soil samples were taken at four different growth stages of cotton (seedling, budding, boll forming and boll opening). Animals were extracted from the samples using the improved Tullgren method, counted and determined to the order level. The diversity of the soil fauna communities in the different fields was compared using the Simpson's, Shannon's diversity indices and evenness index. The results showed a significant sampling time variation in the abundance of soil invertebrates monitored in the different fields. However, no difference in soil invertebrate abundance was found between the transgenic cotton fields and the control field. Both sampling time and cotton treatment had a significant effect on the Simpson's, Shannon's diversity indices and evenness index. They were higher in the transgenic fields than the control field at the growth stages of cotton. Long-term cultivation of transgenic insect-resistant cottons had no significant effect on the abundance of soil invertebrates. Collembola, Acarina and Araneae could act as the indicators of soil invertebrate in this region to monitor the environmental impacts of transgenic plants in the future.     

示波极谱法测定大气总悬浮微粒中微量锌

在乙二胺 (en)介质中 (p H1 1 .5～ 1 2 .3 ) ,Zn(en) 2 +3在单扫描示波极谱仪上于 -1 .42 V(vs.SCE)处产生一灵敏的络合物吸附波 ,锌含量在 0 .0 0 6～ 0 .3 5 μg/ml范围内 ,浓度与峰电流呈线性关系。检测限为 0 .0 0 3 μg/ml。加标回收率为92 %～ 1 0 3 % ,相对标准偏差小于 4.1 %。该方法准确、简便、选择性好 ,可用于 TSP中微量锌的测定。     

还原-光度法测定空气中二氧化硫

在 pH 5 0～ 6 2、甲醛 -邻苯二甲酸氢钾介质和沸水浴中 ,微量二氧化硫能迅速还原三价铁为二价铁 ,使生成的邻菲口罗啉 -铁 (Ⅱ )铬合物量增加 ,导致溶液颜色变深 ,据此测定二氧化硫的含量。方法测定范围为 0mg/L～1 4mg/L ,检测限为 0 4mg/L。用于测定空气中二氧化硫 ,获得了满意的结果     

Regional differences and sources of organochlorine pesticides in soils surrounding chemical industrial parks

Concentrations of organochlorine pesticides (OCPs; dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB)) were investigated in 105 soil samples collected in vicinity of the chemical industrial parks in Tianjin, China. OCP concentrations significantly varied in the study area, high HCH and DDT levels were found close to the chemical industrial parks. The intensity of agricultural activity and distance from the potential OCP emitters have important influences on the OCP residue distributions. Principal component analysis indicates that HCH pollution is a mix of historical technical HCH and current lindane pollution and DDT pollution input is only due to technical DDT sources. The significant correlations of OCP compounds reveal that HCHs, DDTs and HCB could have some similar sources of origin.     

HPLC-FLD测定水中联苯胺的方法研究

探讨了利用液相色谱分离,荧光检测器测定地表水中联苯胺的可行性。前处理方法对比验证了液液萃取法和固相萃取法。水样在碱性条件下(pH=11~12)进行提取,当提取体积为1.0 L时,液液萃取液相色谱荧光法检测,方法检出限为1.4 ng/L,定量下限为5.5 ng/L;固相萃取液相色谱荧光法检测,方法检出限为0.9 ng/L,定量下限为3.6 ng/L。分别对地表水、生活废水、工业废水3种不同水体进行基体加标试验,加标浓度为10.0、40.0、80.0 ng/L。结果显示,对于3种不同基体和不同加标浓度的水样,两种方法均有较好的准确性和重现性,方法回收率为80%~120%,相对标准偏差均小于20%,满足《地表水环境质量标准》(GB 3838—2002)中对联苯胺的监测需求。     

方法标准验证实验数据中离群值的识别

对方法标准验证实验中测量数据进行合格性审核,对于后续方法精密度计算是一个重要环节。文献中识别离群值的Grubbs法、Dixon法等经典方法有时不能满足要求。探讨了用稳健统计法识别离群值的可行性。基于2套文献数据和XRF方法标准验证实验精密度测量数据,对Grubbs法、Dixon法、Mandel h检验法、质控指标法和稳健统计法(四分位法、迭代法、合格数据范围判定法)进行了比较。结果表明:稳健统计法可有效识别离群值。但四分位法存在过度"检出"现象。综合考虑多种方法识别结果有利于提高离群值判定结论的可靠性。对于个别难以判断的情形,可借助质控指标、技术要求以及数据是否剔除对实验室间标准偏差的影响进行取舍。