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181.
为了及时掌握炼化废水的BOD5值,因此对COD与BOD5之间的相关性进行了探讨试验;COD与BOD5的测定采用国家标准方法,连续20d,用最小二乘法计算COD与BOD5的相关关系式;通过相关式由COD值可求出当天相应的BOD5值,为及时调整污水处理设施提供依据。 相似文献
182.
Respiratory Suspended Particulate (RSP) Concentration and its Implications to Roadside Workers: A Case Study of Hong Kong 总被引:1,自引:0,他引:1
The adsorption behaviour of Diphenylamine (DPAM), napthylamine ( NAM), napthylamine ( NAM)and aniline on pyrolusite and activated carbon has been studied.Pyrolusite shows remarkable sorption capacity for DPAM and NAM as compared to aniline; (the adsorption followed theorder:Activated Carbon: DPAM = NAM > AnilinePyrolusite: DPAM: NAM > NAM> Aniline)The maximum adsorption of NAM occurred in theconcentration range 4–20 g mL-1 on pyrolusite (95%)and 4–50 g mL-1 on activated carbon (100%). Theeffect of various doses of activated carbon on the adsorption of NAM confirm Langmuir and Freundlich isotherms where asFreundlich isotherm is obeyed by pyrolusite. The adsorption of NAM on both the absorbents is not affected in presence ofDPAM over a wide range of their initial concentrations (20–60g mL-1). The desorption studies of NAM onpyrolusite was carried out by batch as well as column processes.Excellent results were obtained when a mixture of n-hexane andisopropanol (91:1) was used as eluent. 相似文献
183.
Total contents of metals in soil and sediments on the Tibetan Plateau of China have been widely analyzed, but existing information is insufficient to effectively evaluate metal ecological risk because of a lack of metal bioavailability data. In this study, distribution, potential risk, mobility and bioavailability of metals in sediments of Lake Yamdrok Basin in Tibet of China were explored by combined use of total digestion, sequential extraction and the diffusive gradient in thin-films (DGT). Average concentrations of Cr, Ni, Cu, Zn, As, Cd and Pb in surface sediments were 31.25, 30.31, 22.00, 45.04, 31.32, 0.13 and 13.39 mg/kg, respectively. Higher levels of metals were found near the inflowing rivers. Residual form was dominant in Cr, Ni, Zn, Cd and Pb, and reducible form was dominant in As and Cd. Metals in surface sediments showed a low enrichment degree overall, but Cd and As had higher ecological risk levels than the other metals. Furthermore, there was a larger average proportion of exchangeable form of As (20.4%) and Cd (9.0%) than the other metals (1.7%-3.3%), implying their higher mobility and release risk. Average DGT-labile concentrations of Cr, Ni, Cu, Zn, As, Cd and Pb were 0.5, 4.5, 0.7, 25.1, 60.0, 0.22 and 1.0 µg/L, respectively. The DGT-labile As was significantly correlated with extractable As forms (p< 0.01), suggesting that extractable As in sediments acts as a “mobile pool” for bioavailable As. These results suggest potential risks of As and Cd, especially As, deserve further attention in Lake Yamdrok Basin. 相似文献
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中国是世界上地震活动强烈的国家之一,全球三分之一的大陆地震发生在中国,全国每个省、自治区、直辖市历史上都发生过5级以上破坏性地震,除浙江和贵州外,其他省、自治区、直辖市都发生过6级以上强烈地震,有40%左右的国土,60%的50万以上人口的城市位于Ⅶ度和Ⅶ度以上的地震高烈度区。我国的地震具有分布广、强度大、频度高和震源浅 相似文献
186.
沉水植物的恢复是水生态修复的关键,但在光照、溶解氧以及水力条件等满足的情况下,不同性质的底质会影响沉水植物的生长。以菹草(Potrmogeton crispus)为研究对象,通过向过适宜营养条件下的底泥中添加原底泥30%、70%、100%体积量的沙,以改变底质的物理性质,在30 d内测定菹草的过氧化物酶(POD)、过氧化氢酶(CAT)、植物叶绿素、植物干物率、植物根系活力的变化情况。结果表明,几种处理试验组中,掺加原底泥体积70%沙组的CAT活性响应得较慢,在第20天时才达最大;全底泥和掺加原底泥体积30%沙的2个试验组10 d后POD活性持续上升,而掺加原底泥体积70%和100%组对POD的响应则几乎停止;各试验组植物叶绿素整体呈现下降趋势,但掺加原底泥体积100%沙组中植物叶绿素最高。植物干物率在20 d后都呈现下降的趋势。研究表明,若只通过加沙改变河道底质性质,则加原底泥体积70%~100%的沙对菹草的生长相对最有利。 相似文献
187.
Natural radionuclides, such as (210)Po and (210)Pb were measured in the water samples collected from six stations at Kuala Selangor, Malaysia. Results for (210)Po and (210)Pb in dissolved and particulate phases have showed the difference in distribution and chemical behavior. The fluctuation activities of (210)Po and (210)Pb depend on wave action, geology and degree of fresh water input occurring at study areas and probably due to different sampling dates. The distribution coefficient, K(d), values of (210)Po and (210)Pb ranged from 2.0 x 10(3)lg(-1) to 265.15 x 10(5)lg(-1), and from 3.0 x 10(3)lg(-1) to 558.16 x 10(5)lg(-1), respectively. High K(d) values of (210)Po and (210)Pb indicated that a strong adsorption of (210)Po and (210)Pb onto suspended particles, and the sinking of both nuclides on the seabed at study locations were controlled by the characteristics of suspended particles. 相似文献
188.
中国电子垃圾现状及环境管理对策分析 总被引:4,自引:1,他引:3
20世纪以来,随着电子信息等高科技产业迅猛发展,电子技术不断升级,电子产品寿命周期越来越短,电子垃圾的产生量迅速增大。另一方面,国内电子废物的飞速增长和国外电子废物的大量涌入,成为中国环境安全重大隐患。电子垃圾成分复杂且其污染物众多,对电子垃圾的不恰当处理势必造成了严重的环境污染。本文就中国电子垃圾现状、相应的国内外管理对策进行了分析,并针对中国电子垃圾处理现状,从可持续性发展的环保战略高度,对如何改善电子废弃物管理现状、提高废弃物循环利用率、减少电子废弃物产生、降低电子废弃物的危害等进行建议性分析。 相似文献
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