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1.
对广西某一遗留砒霜厂的场地进行砷(As)污染状况的调查,并对场地的废渣进行浸出毒性的测定,同时对该场地表层土壤As进行了风险评估,结果表明:该场地的土壤pH值为1.40~6.60,场地的表层土壤(0~0.5 m)的As污染情况严重,全量最高值达到144 000.00 mg/kg,超过了《土壤环境质量农用地土壤污染风险管控标准(试行)》(GB 15618—2018)的其他农用地土壤As污染风险筛选值的3 599倍。随着土壤深度的增加,土壤中As含量明显降低,但当土壤深度4.0 m,土壤中As污染指数大于1,仍处于污染状态。场地内部分废渣属于危险废物,急需处理。对场地表层土壤进行风险评估,土壤As致癌风险指数为1.72×10~(-2),非致癌危险商为5.50×10~2,远远超过可接受的水平(10~(-6)和1)。对周边的人体和环境造成了极高的健康风险。  相似文献   

2.
为研究垃圾场区域重金属积累对周边土壤的污染及人体健康影响,以广州市某垃圾场为例,采用单因子评价及健康风险模型方法进行评估。测得了其中41个采样点As、Cd、Cr、Cu、Hg、Ni、Pb、Zn的丰度;讨论了重金属含量与成土母质相关性、重金属间元素聚类分析组合特征,并统计了风险筛选点和管制点;进而圈定了地球化学异常;进行了重金属污染环境评价和人体健康的风险评估,分别评价了单元素及重金属整体对成年男性、女性和儿童的致癌风险、非致癌风险。结果表明,土壤清洁率达到87.8%,存在5个As元素1个Pb元素污染管制点,初步判断重金属来源于成土母质和外来输入。健康风险评估表明,土壤重金属对三类人群都存在明显的致癌风险,对儿童存在明显的潜在非致癌风险,风险主要来自As、Cr。  相似文献   

3.
对宿州煤矿区大气降尘中Hg和As的含量特征及赋存形态进行分析,并利用健康风险评价模型,评估其在多暴露途径下对人体的健康风险。结果表明:宿州煤矿区大气降尘中Hg和As的平均含量分别为土壤背景值的19.91和1.54倍,前者为偏重污染,后者介于无污染至轻度污染;降尘中Hg和As均以残渣态形式为主,生物可利用程度较低,但Hg元素具有较高的潜在生物危害性;As经手口摄入分别是引发大气降尘重金属非致癌健康风险的主要元素和暴露途径,儿童的非致癌风险(0.903)高于成人(0.122),但均低于美国EPA的风险限值1.0;降尘中As通过呼吸吸入途径不具有致癌风险。  相似文献   

4.
污染场地土壤修复是一项复杂工程,为检验土壤修复效果,依据《污染场地修复验收技术规范》,对福州XX化工厂进行场地修复效果评价.土壤样品检测结果表明,原来超标的Pb、Hg的含量均明显低于修复目标值,坑底采样的4个样品中,Cd和As的含量也低于修复目标值,场地修复效果显著.但是,侧壁采样的15个样品中,Cd和As的含量仍存在超标现象.采用人体健康.风险评价方法对两种目标污染物进行健康风险评价,结果显示,Cd和As的非致癌风险指数对儿童和成人都大于1,As的致癌风险指数对儿童和成人都大于1×10-6.场地还存在潜在健康风险,在投入使用前需要进行进一步修复.  相似文献   

5.
调查贵州省龙井洞和白龙洞裸灶螽部分环境因子,对2个洞穴的裸灶螽、土壤和水中重金属(Cu、Cr、Ni、Zn、Hg和As)含量进行测定,研究两洞穴裸灶螽的富集系数,对两洞穴土壤中重金属的污染指数及生态风险进行评价,结果表明:两洞穴有光带、弱光带和黑暗带土壤中重金属Cu、Cr、Ni、Zn、Hg及As的平均含量超过我国土壤背景值;两洞穴裸灶螽对Cu和Zn明显富集;龙井洞土壤中6种重金属潜在生态风险处于较高生态危害水平,且潜在生态风险系数大小排列为Hg>As>Cu>Ni>Zn>Cr;白龙洞土壤中6种重金属潜在生态风险处于高生态危害水平,且潜在生态风险系数大小排列为Hg>As>Cu>Ni>Zn>Cr,其中Hg是两洞穴最主要的生态风险因子.  相似文献   

6.
以海口市周边农村土壤样品为研究对象,运用单因子指数、综合污染指数和潜在生态指数法对土壤重金属含量进行分析评价.结果表明,单因子指数小于1,土壤环境为未受污染;综合污染指数为CuCrCdZnHgPbAs,只有Cu和Cr受到轻度污染,其他元素均未超过警戒线;潜在生态危害指数小于40,风险系数为28.318,远小于150,为低微风险状态.土壤环境状况总体良好.  相似文献   

7.
沈抚污灌区农田土壤生态健康风险评价   总被引:1,自引:0,他引:1  
本文以沈抚污灌区农田土壤中6种污染重金属Cd、Hg、As、Pb、Cu和Cr的实测含量作为基础数据进行研究,利用Hakanson潜在生态风险评价法与美国环保署(USEPA)推荐的健康风险评价法对污灌区农田土壤进行生态及健康风险评价。结果表明,该研究区域Cd、Hg、Pb、Cu、Cr含量均超过了辽宁土壤背景值,且有逐年上升的趋势,其中Hg和Cd污染较严重,超过了国家土壤环境二级标准;虽然土壤样品中90%多因子潜在生态风险处于中度危害水平,但是不同污灌方式对风险指数也有一定影响,以污灌至采样年地区风险值较高;单因子潜在风险中,以Cd和Hg危害程度较为严重,且也表现出由于污灌而使重金属浓度增加的趋势,土壤样品中分别有60%和100%生态风险指数处于较重危害水平以上。健康风险评价中,研究区域各点6种重金属HQ和HI值均小于1,理论上不存在非致癌健康风险;Cr、Cd和As的CR值和TCR值均超过了USEPA提出的土壤治理标准,存在较高的致癌风险。  相似文献   

8.
《河南科学》2016,(4):577-580
利用美国环保署推荐的人体健康风险评价模型对洛南钼矿开采区域地表水的Pb、As、Cd、Mo污染状况做出一个健康风险评价.结果表明:钼矿开采区域地表水中的非致癌物质Pb和Mo非致癌风险值均低于美国环保署推荐的最大可接受水平,对居民的威胁可忽略.致癌物质As和Cd的致癌风险值也未超过美国环保署推荐的最大可接受风险水平,但As饮水途径的致癌风险值和美国环保署推荐的最大可接受风险持平,有必要采取措施防止地表水中的As含量继续升高.  相似文献   

9.
采集西安市101所小学及幼儿园灰尘样品,利用X-Ray荧光光谱仪测定了灰尘中重金属的含量,且采取美国EPA健康评价法对灰尘重金属对人体的健康危害进行了评价.结果显示,灰尘中Co、Cr、Cu、Pb、Zn的含量均显著超过陕西土壤背景值,而大部分样品中As、Mn、Ni和V的含量接近或稍高于陕西土壤背景值.灰尘重金属对儿童的健康风险评价结果表明,非致癌风险依次为Pb>Cr>As>Mn>V>Co>Cu>Ni>Zn,致癌风险为Cr>Co>As>Ni.重金属暴露量呼吸摄入量<皮肤接触量<手-口摄入量.风险值均低于风险阈值,不存在健康危害.  相似文献   

10.
为充分摸清某涂料企业遗留生产场地的污染情况,评估其按最新规划用地开发后对周边环境和人体健康的风险,开展了该生产场地的污染调查和风险评估工作. 场地调查结果表明,生产场地主要存在重金属污染,关注污染物为As、Cr、Cu、Zn、Pb,未发现有机污染物,地下水符合地下水质量标准. 风险评估结果表明,土壤中As、Cr通过所有途径的致癌风险和危害商分别大于可接受风险水平10-6和1,Cu、Zn通过所有途径的危害商均小于1. As、Cr的致癌危害及非致癌危害均对人体健康有潜在的健康风险,Cu、Zn的非致癌危害不会对人体健康造成危害. 最后,确定了场地污染物的土壤清理目标值为As 50 mg/kg、Cr 400 mg/kg、Cu 300 mg/kg、Zn 500 mg/kg和Pb 280 mg/kg,建议对污染的土壤采取修复措施,确保土壤质量满足规划用地要求.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

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