几种城市绿化树种叶片中铅砷铬镉汞元素的含量特征

2003年对昆明、思茅、丽江3个城市的16个绿化树种叶片中的铅、砷、铬、镉、汞5种重金属元素的含量进行了测定，并结合采集地的空气污染指数进行了相关分析。结果表明：麻栗坡含笑、山玉兰和杜英叶片中Pb的含量与空气污染指数间的相关性显著；石楠、云南拟单性木兰、山玉兰、冬樱花叶片中As的含量与空气污染指数间的相关性达显著或极显著水平；杜英、山玉兰、石楠、天竺桂、云南拟单性木兰叶片中Cr的含量与空气污染指数间的相关性均为显著和极显著；石楠、杜英、冬樱花叶片中Cd的含量与空气污染指数间有显著或极显著的正相关性；8个树种叶片中Hg的含量与污染指数间均没有显著的正相关性。而16个树种中，冬樱花叶片中5种重金属元素的总含量最大，为15．563mg／kg；总含量最低的树种是竹柏（0．692mg／kg）等，两者总含量的差异达14．871mg／kg。不同树种对环境中Pb、As、Cr、Cd、Hg等5种元素的吸收富集能力有较大的差异。16个树种叶片中Cd和Cr含量的相关系数为r0.05=0．582^＊，说明Cr与Cd之间有显著的互相促进作用；Cd与Hg元素含量的相关系数为r0.01=0．807^＊＊，也表明Cd与Hg间有十分显著的互相促进的作用。     

土壤中砷·汞·铅·镉·铬测定方法的研究

[目的]研究土壤中重金属元素砷、汞、铅、镉、铬的测定方法。[方法]微波消解样品,利用原子荧光分光光度法、原子吸收分光光度法对相关重金属元素进行测定,并与ICP-MS测定结果进行对比。[结果]采用3 ml HNO3＋1 ml HF的混合酸体系消解样品,样品消解完全,利用原子荧光分光光度法、原子吸收分光光度法测定,所得值与ICP-MS测定值相差不大,测定值均在标样的不确定度范围内,相对标准偏差均小于5%;土壤样品添加回收试验所得回收率均高于90%。[结论]利用微波消解结合原子荧光、原子吸收法测定土壤中重金属元素砷、汞、铅、镉、铬,方法简便、快速、准确,适用于土壤样品的测定。     

砷、镉胁迫对茶树生育的影响

采用室内水培法,分别研究了砷(As)、镉(Cd)单一胁迫对茶树新梢生育和光合作用的影响以及毒害症状,结果表明:随着砷胁迫浓度的升高,茶树发芽和新梢生长受到严重抑制;茶树的叶绿素含量、光合速率、气孔导度和蒸腾速率均随砷胁迫浓度的升高而降低,同时各胁迫处理的茶树均出现明显的受害症状。镉胁迫的茶树在处理80 d后出现轻微毒害症状,低浓度镉胁迫(≤3 mg/L)对新梢生长、叶绿素合成和光合作用有一定促进作用;当胁迫浓度≥4 mg/L时,则表现负面影响。砷胁迫的毒害作用强于镉胁迫。     

Cd、Pb、Ni、As单一污染对油麦菜叶绿素含量和抗氧化酶系统的影响

研究了Cd、Pb、Ni、As单一污染对油麦菜叶绿素含量和抗氧化酶系统的影响，结果表明油麦菜叶绿素含量低于对照，并且随着Cd、Pb、Ni、As处理浓度的增加呈先升后降的趋势；油麦菜抗氧化酶系统所受影响因重金属污染种类不同而不同，其中SOD的活性随着Cd、Pb单一污染浓度的增加呈下降趋势，而随着As、Ni污染浓度的增加呈先升后降的趋势；CAT和POD的活性随着As污染浓度的增加呈上升趋势，而随着Cd、Pb、Ni污染浓度的增加呈先升后降的趋势。     

Arsenic Accumulation in Two Vegetables Grown in Soils Amended with Arsenic-Bearing Chicken Manures

The use of organoarsenic roxarsone as a feed additive, which is widely used as a growth promoter in animal production, has caused concern over potential negative environmental impacts. A pot experiment was conducted to investigate the growth and arsenic (As) uptake of pakchoi cabbage and tomatoes grown in a gray Fluvo-aquic soil amended with 2% As-bearing chicken manures to which 50 mg kg^?1 and 80 mg kg^?1 roxarsone were added, respectively. Arsenic accumulation factors of pakchoi cabbage were significantly greater than those of shoots of tomato. The biomass, As content, and As accumulation factors of both vegetables showed significant differences with species. The correlations between As contents and biomass of the vegetables were positive in pakchoi cabbage and negative in tomato. Arsenic accumulation was apparent in pakchoi cabbage; therefore, crop species with a potential to accumulate As, such as pakchoi cabbage, should be avoided when fertilizing with As-polluted manures due to food safety concerns.     

Arsenic Concentrations in Groundwater,Soils, and Irrigated Rice in Southwestern Bangladesh

Arsenic (As) poisoning of groundwater in Bangladesh has become a major environmental and health issue. The extensive use of groundwater in irrigation of rice has resulted in elevated As in soils and crops. A study was undertaken to determine As concentrations in groundwater, soils, and crops in 16 districts of southwestern Bangladesh. Groundwater samples were collected from shallow-tube and hand-tube wells (STW and HTW) used for irrigation and drinking water. Soil and rice plants were sampled from the command area of the tube wells. Arsenic concentrations were determined using an atomic absorption spectrometer equipped with flow injection hydride generator. Groundwater samples contained <10 to 552 μg As L^?1. Arsenic concentrations in 59% of STW samples exceeded 50 μg As L^?1, the national standard for As in drinking water. Unlike groundwater, most of the surface water samples contained <10 μg As L^?1. Concentrations of As in the soils from the command area of the tube wells ranged from 4.5 to 68 mg kg^?1. More than 85% of the soils contained <20 mg As kg^?1. The mean As concentration in the rice grain samples was 0.23 mg kg^?1, which is much less than the maximum food hygiene standard. A positive relationship was observed between groundwater and soil As, implying that soil As level increases as a result of irrigation with contaminated water. However, irrigation water As did not show any relation with rice grain As. The findings suggest that surface water bodies are a safe source of irrigation water in the As-contaminated areas.     

沙棘果中重金属与农药残留的检测分析

对山西8个主产地沙棘果进行重金属和农药残留量检测,为沙棘资源的进一步开发利用提供参考依据。运用原子吸收分光光度法、原子荧光分光光度法和气相色谱法分别测定沙棘果中铅、砷、汞和六六六、滴滴涕的含量。结果看到,山西沙棘果重金属铅、砷、汞和农药残留六六六、滴滴涕的含量均极少,甚至未检出。表明山西沙棘果重金属和农药残留均未超标,符合药食用标准,并且优于国家相关标准。因此,山西沙棘果无论药用还是食用都是安全的。     

修复剂对烟草吸收污染土壤中砷的改良

采用盆栽试验,研究3种修复剂对减少烟草吸收土壤重金属As之改良效果。烟草生长在As含量为25mg/kg的污染植烟土壤上,通过添加3种土壤修复剂,测定烟草在不同生长时期不同部位的生物量及重金属As含量。结果表明:烟草体内As含量的分布为根>叶>茎,烟草由根部向地上部运转As能力不强;烟草体内不同部位在不同的生长时期As的含量也发生变化;3种修复剂均在不同程度上减少了烟草不同部位重金属As的含量,同时也改变了烟草中As的根吸收系数、初级转移系数和次级转移系数,增加了烟草的生物量,达到了提高烟草安全性和品质的目的。     

水稻糙米砷含量及其与土壤砷含量的关系

筛选低砷含量水稻品种或减少水稻对种植土壤中砷的吸收是控制稻米砷含量最直接有效的办法。本研究采用ICP-MS法测定21份水稻品种在3个试验点的糙米砷含量,结果表明:在3个土壤砷含量由低至高的试验点中,21份水稻品种糙米砷含量平均值也呈现出由低到高的趋势。分析水稻砷含量对不同种植环境的反应,多数品种对不同试验点环境表现的敏感性不一致,但有4个品种表现稳定,如明恢70都表现为迟钝型;明恢86表现为敏感型;明恢72和明恢81为中间型。分析浙优12号在15个栽培点中土壤砷含量、穗茎节砷含量、糙米砷含量的相关性表明,砷含量高低依次为土壤糙米穗茎节,土壤砷含量与糙米砷含量的相关性不显著;土壤砷含量与穗茎节砷含量存在不显著负相关;穗茎节砷含量与糙米砷含量之间呈极显著正相关。     

应用AFS—2201型双道原子荧光光谱法联合测定水产品中砷和汞

应用AFS-2201型双道原子荧光光谱法研究了联合测定水产品中砷和汞的技术；用HNO6－HClO4（4∶1）混合酸消化样品，待样品消化完全之后再加入5％硫脲－5％抗坏血酸混合改进剂，并以1.40％硼氢化钾（KBH4）为还原剂，在（1＋9）的硝酸介质中测定砷和汞，其砷和汞的最低检出量为AS：0．2ng／ml，Hg：0．06ng／ml。