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241.
Concentrations of metals were determined in four species of anchovy (Coilia sp.) from the Yangtze River, Taihu Lake, and Hongze Lake in Jiangsu Province, China. Concentrations of Cr in anchovy fish muscle ranged from 2.6 × 10−2 to 5.0 mg/kg ww, and Coilia nasus taihuensis in Jiaoshan, Taihu Lake contained the highest concentrations of Cr, which was almost 111-fold higher than the mean value at other locations. Concentrations of Pb ranged from 1.5 × 10−2 to 1.3 × 10−1 mg/kg ww. Comparisons of concentrations of lead (Pb) among the four species indicated that anadromous species contained higher concentrations of Pb than did freshwater species. However, concentrations of Pb in C. nasus from the Nanjing and Haimen locations in the Yangtze River were not significant higher than those of two freshwater species: C. nasus taihuensis from Taihu Lake and C. brachygnathus from Hongze Lake (Duncan’s test, α = 0.05). While concentrations of Cd and Zn ranged from 7.0 × 10−4 to 3.6 × 10−3 mg/kg ww and 3.4 to 4.8 mg/kg ww, respectively, there were no significant differences in concentrations among the eight locations. The only concentration of the metals studied that exceeded the Chinese National Standard was Cr in Coilia from Jiaoshan, Taihu Lake, which was 2.5-fold higher than the standard. These results indicate that people who consume the genus Coilia are not at risk due to concentrations of metals, except Cr in C. nasus taihuensis from Jiaoshan in Taihu Lake. Concentrations of all of the metals studied except for Cr were similar to or less than those of metals in most other areas in the world.  相似文献   
242.
利用盆载试验研究了黑麦草(Lolium multiflorum L.)对2,4,6-三氯酚(TCP)污染土壤的修复作用及其植物毒性影响.结果表明,培养75 d后土壤中TCP的可提取态质量分数随着时间延长逐渐减少,黑麦草加快了土壤中可提取态TCP质量分数的下降.在TCP浓度为1,10,100 mg·kg-1的处理中,种植黑麦草的降解率分别是92.5%、78.2%、55.6%,无植物处理的降解率分别为56.3%、49.2%、37.5%.植物毒性试验结果发现,Lactuca sativa种子的根生长试验可以判断土壤毒性的变化,土壤毒性随着处理时间的延长,毒性降低,说明了植物修复的作用.TCP污染土壤的水提取液也存在毒性,TCP污染土壤有污染地下水和地表水的可能.Lactuca sativa的发芽率不能反映土壤的毒性变化规律,不宜作为评价TCP污染土壤的毒性指标.可见,种植黑麦草具有强化TCP污染土壤的修复作用,可通过促进黑麦草生长,增强土壤微生物活性,提高黑麦草修复TCP污染土壤的能力.  相似文献   
243.
通过现场处理 ,对垃圾渗滤液的曝气 -絮凝处理进行了研究。结果表明该方法对渗滤液的色度、COD、总磷去除率达 80 %以上 ,对氨氮去除率达 60 %以上。在此基础上提出了最优综合控制指标  相似文献   
244.
丁辉 《安全》2000,21(6):5-7
自从1955年在罗马召开了首届世界职业安全与卫生大会以来,世界范围内的职业安全与卫生已越来越引起人们高度的重视,国际劳工组织(ILO)和国际社会保障协会(ISSA)对每一次大会都十分关注。20世纪末的最后一届大会在巴西召开,大会讨论了国际社会共同关注的问题和人类未来将遇到的挑战,即人类共同生存的环境与安全如何更美好。 大会的主题是:"安全、卫生与环境--全球的挑战"。 权威人士认为世纪之交之际是国与国之间相互依存这样一种从未有过的历史时刻,讨论职业安全卫生与环境极为重要。当前,经济全球化和竞争的加剧提出对生命质量新的条件因素和对生命质量提高的新挑战,经济全球化造成新的风险,也使各国相互交流经验成为可能。  相似文献   
245.
论聚烯烃裂解反应中的油化效果增强效应   总被引:1,自引:0,他引:1  
在废旧聚烯烃的裂解反应中,聚丙烯的存在,可以提高轻油馏份的收率,增强反应的油化效果,本文称之为聚烯烃裂解反应的增强效应。本文讨论了增强效应产生的机理,可为废旧塑料裂解油化技术的研究和开发提供参考。  相似文献   
246.
散射光下铁(Ⅲ)-丙酮酸盐配合物还原铬(Ⅵ)的研究   总被引:1,自引:0,他引:1  
研究了在散射光下铁(Ⅲ)-丙酮酸盐配合物对铬(Ⅵ)的光还原反应;考察了溶液pH、铁(Ⅲ)、丙酮酸钠、铬(Ⅵ)浓度对反应的影响;分析了铬(Ⅵ)光还原反应的动力学。实验结果表明:铁(Ⅲ)-丙酮酸盐配合物体系能在较弱的散射光下还原铬(Ⅵ)。在铬(Ⅵ)浓度为19.2μmol/L、铁(Ⅲ)浓度为10.0μmol/L、丙酮酸钠浓度为240μmol/L、pH为3.0、光照240min的条件下,铬(Ⅵ)的还原率达到99.7%。从表观动力学方程的反应级数看,铁(Ⅲ)的级数(0.83)最高,铁(Ⅲ)浓度是影响铬(Ⅵ)光还原反廊速率的主要因素.铁(Ⅱ)是铬(Ⅵ)光还原的主要还原剂。  相似文献   
247.
通过正交实验研究了用盐酸、硫酸、褐铁矿和硅酸钠制备聚硅氯化硫酸铁(PSFCS)絮凝剂的工艺条件。实验结果表明,浸取时间为2.5~3 h,浸取温度为110℃,硫酸浓度为6 mol/L,盐酸浓度为3 mol/L,质量液固比为4∶1,铁的浸出率可达95.7%~96.3%。溶液中加入少量聚乙烯醇作稳定剂,亚硝酸钠作氧化催化剂。PSFCS的合成条件:Fe/Si摩尔比为2,硅酸活化pH值为2,硅酸活化时间是30~40 min,陈化时间是2~2.5 h。与聚合硫酸铁(PFS)和聚合氯化铝(PAC)比较了处理印染废水的效果,表明PSFCS具有良好的絮凝性能,COD和浊度的去除率分别可达81.4%和96.1%。  相似文献   
248.
BACKGROUND: The Yangtze Delta is one of the most developed regions in China and includes Shanghai, eight cities in Jiangsu province and eight cities in Zhejiang province. Meat consumption in this region has increased with economic growth, and most of the consumed meat is produced locally. The water quality of surface waters has deteriorated in recent years. An example was the huge blue-green algae bloom in Tai Lake in late May 2007, which affected millions of people's daily drinking water. However, animal husbandry is considered to be one of the main pollution sources. METHODS: Pollutants (NH3-N, total phosphorus (TP), and total nitrogen (TN)) excreted by livestock and poultry, and the resultant COD (chemical oxygen demand) and BOD (biochemical oxygen demand), were estimated using two different methods based on different data sets. RESULTS: The number of livestock and poultry has remained stable in the Yangtze Delta over the four years from 1999 to 2002, with the average number of pigs, cattle, sheep and poultry being 21.1 M, 0.4 M, 7.7 M and 597.6 M, respectively. Pollutants in livestock and poultry excreta estimated by Method I were: 0.12 Mt NH3-N, 0.11 Mt TP and 0.29 Mt TN, resulting in COD and BOD of 1.34 Mt and 1.30 Mt, respectively, while the estimations based on Method II were: 0.18 Mt NH3-N, 0.15 Mt TP and 0.40 Mt TN, resulting in COD and BOD of 1.95 Mt and 1.80 Mt, respectively. DISCUSSION: Pollutants excreted annually by livestock and poultry in the Yangtze Delta are estimated to be: 0.17 Mt NH3-N, 0.16 Mt TP and 0.42 Mt TN, giving rise to a COD of 1.86 Mt and a BOD of 1.72 Mt. Approximately 25% of this pollution was estimated to enter water bodies, which means that the annual pollutant load is 43,700 t NH3-N, 39,400 tTP, 104,600t TN with a COD of 465,000 tand a BOD of 430,100 t. Pollutants from animal husbandry were similar in magnitude to those from industrial wastewater. Pigs produced the most pollution, followed by poultry, cattle and sheep. The pollution load from animal husbandry in the Yangtze Delta is about twice the average level of the whole of China. CONCLUSIONS: Domestic wastewater was the main pollution source in the Yangtze Delta, followed by pollution from raising livestock and poultry and from industrial wastewater. The pollution load in Shanghai and Jiaxing were the greatest, followed by 7 cities of Jiangsu province (except Suzhou) and other cities of Zhejiang province and Suzhou. Pigs and poultry produced about 90% of the total pollutants from animal husbandry. RECOMMENDATIONS AND PERSPECTIVES: The local governments, especially in Shanghai and Jiaxing, should focus their attention on the pollution produced by livestock and poulrry. Controlling pollution from pigs and poultry will have the greatest impact in this region. Control of pollution will be facilitated by the development of large-scale livestock and poultry farming units and a shift away from small scale husbandry.  相似文献   
249.
双酚A(bisphenol,BPA)的内分泌干扰性导致许多国家出台了管控措施,双酚F(bisphenol F,BPF)作为其替代物被大量使用,并广泛存在于水体和食品中,导致人群和野生动物长期处于其慢性暴露过程中,可能会威胁人类和生态健康.以斑马鱼胚胎为研究模型,将其暴露于不同浓度的BPF中至受精后144 h(hours...  相似文献   
250.
基因工程菌在厌氧膜生物反应器中对偶氮染料废水的脱色   总被引:1,自引:0,他引:1  
印染和染料废水色度大,COD高,可生化性差.采用基因工程菌Escherichia coli JM109(pGEX-AZR)在厌氧膜生物反应器中,对模拟偶氮染料废水进行脱色研究.结果表明,系统对酸性红B有很好的脱色能力,且启动期短,脱色效率高,脱色率稳定在95%以上,对COD的去除率能达到68%.系统运行过程中,反应器内生物量稳定在0.4 g/L.EPS与生物量变化趋势一致,先升高后降低;pH值在运行初期由6.5降至6.2,后维持在6.6左右.系统运行27 d后进行第一次膜清洗,膜通量恢复为初始值的92%,系统运行周期约为26 d.  相似文献   
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