微波消解-ICAP法测定土壤中总铬含量的研究

采用微波消解仪对土壤样品进行前处理,用ICAP测定土壤中总铬含量。通过硝酸-氢氟酸以及硝酸-盐酸-过氧化氢体系消解液对土壤样品消解,优化试验选择出微波最佳消解条件和ICAP的工作参数。结果表明,发现用硝酸-氢氟酸体系消解液,在谱线283.56 nm、267.72 nm处用ICAP能够准确而稳定地测得土壤中总铬含量。     

海藻提取物（海藻肥）在蔬菜上的应用效果研究

通过对海藻提取物在蔬菜上的应用效果研究，结果表明：海藻提取物可提早蔬菜的采收期6-14d，前期产量提高10．8％-27．4％，总产量提高6．8％-19．2％，并明显改善品质；以2．0g／L的海藻提取物处理日光温室番茄植株，可使番茄最大节水率达到22．6％；用不同浓度的海藻提取物处理菠菜叶片，可降低菠菜硝酸盐含量66．3％-93．2％；以2．0g／L的海藻提取物对辣椒进行灌根处理，可使辣椒生育期施用化肥量节约20％。     

五台山草地自然保护区土壤中铬含量分布及影响因素的研究

通过对五台山草地自然保护区土壤铬元素的含量，分布及影响因素的研究，结果表明，五台山土壤中铬元素含量范围为４．０８～４１．２８ｍｇ／ｋｇ，平均含量为２１．５８ｍｇ／ｋｇ，低于我国土壤的平均水平，各主要土类铬含量顺序（山地）棕壤〉淋溶褐土〉山地草甸土〉亚高山草甸土〉褐土性土〉石灰性褐土。铬元素在土壤剖面中的分布是不一致的，有的呈均匀型，有的为表层聚集型，的有为底层富集型，在土壤理化性质中，影响五台山土     

海藻提取物(海藻肥)在蔬菜上的应用效果研究

通过对海藻提取物在蔬菜上的应用效果研究,结果表明:海藻提取物可提早蔬菜的采收期6~14 d,前期产量提高10.8%~27.4%,总产量提高6.8%~19.2%,并明显改善品质;以2.0 g/L的海藻提取物处理日光温室番茄植株,可使番茄最大节水率达到22.6%;用不同浓度的海藻提取物处理菠菜叶片,可降低菠菜硝酸盐含量66.3%~93.2%;以2.0 g/L的海藻提取物对辣椒进行灌根处理,可使辣椒生育期施用化肥量节约20%。     

碳酸钙改性滑石施加量对土壤重金属铬的形态影响研究

通过将碳酸钙与滑石按照摩尔比2∶1混合后,在马弗炉中1150℃焙烧2 h后得到改性滑石,然后利用XRD、FTIR和BET对其进行系统表征,最后通过土壤培育实验探讨碳酸钙改性滑石不同施加量(添加量分别为0%、0.5%、1%、2%、3%和4%)对土壤铬形态动态影响效应。结果表明:碳酸钙改性滑石主要物相组成为Ca2Mg(Si2O7)和少量的Ca3Mg(SiO4)2,疏松多孔,平均孔径为18.809 nm,通过FTIR可以观测到明显的特征峰Si-O-Si,改性滑石有效硅含量高达19.09%。施加该材料在土壤中可以通过形成硅酸盐络合物来改变土壤铬的形态,有助于降低土壤中重金属铬的可交换态含量,最大降低幅度能够达到60%以上,并且对碳酸盐结合态有着明显的降低效果,但对铁锰氧化物结合态的影响不大,对于有机物结合态含量同样有着降低的效果。在第60天的时候,施加量为0.5%时,土壤中铬的残渣态含量增加了15%。过量的施加该材料会导致土壤的pH变成强碱性,因此适当的施加该材料有助于改变重金属铬在土壤中的存在形态,有助于降低铬的生物有效性,从而可以治理重金属污染。     

铬铜复合污染下铬形态分布及与土壤酶活性的关系

采用土培盆栽实验和室内分析相结合的方法,研究了Cr单一和Cu-Cr复合污染条件下,外源施加的Cr在土壤中的形态变化及其对土壤酶活性的影响。结果表明：随外源Cr浓度的增加,土壤交换态Cr含量增多,残渣态占总量的百分比减少,铁锰氧化物结合态与有机结合态变化不大（碳酸盐结合态未检出）。Cu-Cr复合污染条件下,≤400mg·kg-1Cu能促进Cr从有机结合态向交换态及铁锰氧化物结合态转化（P〈0.05）,而高浓度Cu（800mg·kg-1）却抑制了这种转化的发生。与对照（CK）相比,重金属Cu、Cr单一及复合污染均对土壤脲酶、碱性磷酸酶和过氧化氢酶活性产生一定的抑制作用,且酶活性抑制率随外源金属浓度的增加而增大;3种供试酶相比较,Cr、Cu对土壤脲酶和碱性磷酸酶活性影响较大,对除C（r5mg·kg-1）处理的过氧化氢酶活性影响较小;低浓度C（r5mg·kg-1）对土壤过氧化氢酶活性有一定激活作用。土壤脲酶活性受土壤交换态Cr含量的影响较大;碱性磷酸酶活性与铁锰氧化物结合态Cr含量有关;铁锰氧化物结合态和有机物结合态Cr对土壤过氧化氢酶活性产生一定的影响。残渣态Cr含量与3种供试的土壤酶活性间无显著相关。     

Chromium Speciation in Water by Sorption on Calcite and Determination by Electrothermal Atomic Absorption Spectrometry

Abstract

A rapid, sensitive, and accurate method for the separation and speciative determination of chromium (Cr)(VI) and Cr(III) in water samples has been developed using sorption as the separation technique in conjunction with final determination by electrothermal atomic absorption spectroscopy (ETAAS). The present method, where granular calcite is used as selective sorbent, separates Cr(III) with retention values up to 99%, resulting in high accuracy determination of Cr(VI). Total Cr was likewise determined by ETAAS after an efficient reduction of Cr(VI) to Cr(III) using ascorbic acid as reducing agent, deriving Cr(III) concentration from the difference between total Cr and Cr(VI). The parameters of the separation technique, solution pH (4.5–5.5), solution flow rate through the calcite column (0.14–0.42 mL min^?1), and calcite column internal diameter (1.5–3.0 cm), were evaluated. Best results were achieved with pH of 5.5, flow rate of 0.42 mL min^?1, and column internal diameter of 1.5 cm. Optimum determination conditions were found using magnesium nitrate [Mg(NO₃)₂] as chemical modifier, pyrolysis, and atomization temperatures of 1400 and 2200°C, respectively. In such conditions, the detection limits (n=10) were 1.5 and 0.8 µg L^?1 for Cr(III) and Cr(VI), respectively.     

不同钝化剂组合对土壤铬铜赋存形态及在水稻中积累的影响

为了筛选出能有效抑制水稻各部位吸收积累Cr和Cu的有机和无机材料钝化剂组合,选取水稻土以盆栽试验研究了15种钝化剂组合对土壤Cr和Cu赋存形态及水稻各部位吸收积累Cr和Cu的影响。结果表明:15种钝化剂组合施用使土壤pH上升0.25～1.04,土壤阳离子交换量增加2.65%～50.96%,土壤有机质含量增加0.22%～17.20%,土壤可交换态Cr含量降低35.21%～55.63%;除生石灰+钝化剂4+鸡粪组合使土壤可还原态显著增加外,其他组合的土壤可还原态Cr无显著变化;土壤可氧化态和残渣态Cr均无明显变化;土壤可交换态Cu含量降低6.66%～33.42%;土壤可还原态和可氧化态Cu无明显变化;土壤残渣态Cu增加0.32%～5.04%,其中钝化剂3、生石灰+钝化剂1+鸡粪、生石灰+钝化剂4+鸡粪3个组合能显著增加土壤残渣态含量。根系对Cr和Cu的富集能力最大,15种钝化剂组合可使水稻根系、秸秆、稻壳和糙米中Cr含量分别下降4.59%～49.41%,39.84%～76.87%,7.14%～31.60%,17.32%～67.10%,水稻根系、秸秆、稻壳和糙米中Cu含量分别下降10.57%～48.41%,7.99%～52.53%,21.12%～45.11%,14.39%～66.92%。15种钝化剂组合均可降低糙米中Cr和Cu的含量,其中以生石灰+钝化剂2+鸡粪的效果最佳。     

Distribution and Speciation of Chromium and Cadmium in an Organic and Inorganic Fertilized Chernozem

Fertilizers are widely applied in agricultural practice to improve crop yield and quality. However, they can also alter the behavior of soil pollutants. A field experiment was conducted on a chernozem in Heilongjiang Province, China. Various proportions of inorganic nitrogen (N), phosphorus (P), and organic (manure) fertilizers were applied. Soil samples were collected four times over 2 years, and the total concentrations and speciation of chromium (Cr) and cadmium (Cd) were analyzed. Inorganic fertilizer addition had little effect on the total concentration of Cr and Cd, while organic fertilizer addition reduced the total concentrations of both Cr and Cd. Inorganic fertilizers increased the concentration of Cr in the exchangeable form, but decreased that of the residual form (P < 0.05). Addition of inorganic or organic fertilizer alone decreased concentrations of exchangeable Cd (P < 0.05), but the combination of inorganic and organic fertilizers had the opposite effect. High concentration of total Cd exceeding the upper limits of the Environmental Quality Standard for Soils proposed by the Ministry of Environmental Protection of China could result in an environmental risk, and fertilizer application could lower that risk. Results of risk assessment code calculated as the percentage of the sum of metal concentrations in the exchangeable and carbonate-associated form in total metal concentration showed that Cr and Cd risks were lowered when organic fertilizer was applied alone or in combination with inorganic fertilizers. Our study highlighted that organic fertilizer should be applied alone or in combination with inorganic fertilizers to lower the environmental risks of Cr and Cd pollution in the chernozem.     

剩余污泥厌氧消化过程重金属形态转化及生物有效性分析

为研究污泥厌氧消化过程中物理化学性质的变化对典型重金属形态转化的影响,对其农用的可行性及生物有效性进行评估,对取自某城市污水处理厂的剩余污泥进行了序批式厌氧消化实验,在试验过程中测定了污泥理化学性质,采用Tessier分步提取法提取了污泥样品中的典型重金属,并采用电感耦合等离子发射光谱仪（ICP-OES）测定各形态重金属含量及总量。结果表明,厌氧消化过程中重金属的形态发生了显著变化,由不稳定态向比较稳定的残渣态和有机结合态转变,某些重金属形态与污泥理化性质如pH、碱度、VS/TS及氨氮显著相关。厌氧消化可以有效地降低污泥中重金属的潜在迁移能力和生物有效性,经厌氧消化后污泥可以更好地进行土地利用。     

包头市铜厂周边土壤中重金属垂直分布特征与形态分析

为了解包头市铜厂周边地区土壤剖面中重金属污染状况,采用火焰原子吸收分光光度法和Tessier连续提取法,对土壤中6种重金属（Cu,Zn,Mn,Ni,Pb和Cd）的垂直分布特征、形态及潜在生物可利用性进行了分析。结果表明:研究区土壤剖面各层土壤中6种重金属含量均超过内蒙古土壤背景值,Cu,Pb和Cd为主要污染物。随采样深度的增加,Cu,Zn,Pb和Mn的含量呈现下降趋势,且由相关性系数可知重金属Cu,Zn和Pb可能有相同人为或自然污染源;土壤剖面中6种重金属均主要以残渣态存在,含量均在50%以上,对生物危害较小;潜在生物可利用性分析结果为:Cu（32.61%） > Mn（31.85%） > Ni（24.90%） > Zn（16.60%） > Cd（15.23%） > Pb（14.87%）,Cu和Mn的潜在生物可利用性较大,其次为Ni,Zn,Cd和Pb潜在生物可利用性较小。     

Polyphosphate Speciation for Soil and Fertilizer Analysis

Abstract

Ammonium polyphosphate fertilizers provide an analytical challenge because they contain mixed phosphorus (P) species in solution as orthophosphate, pyrophosphate, and tripolyphosphate species. The conventional technique for the determination of polyphosphate concentration in solution is measuring the difference between total digested P and initial orthophosphate with colorimetry. Online colorimetry was compared with ion chromatography as a method for the speciation and quantification of the chemical species of P supplied in polyphosphate fertilizers.

Ion chromatography was able to speciate all of the P species supplied in polyphosphate fertilizer, whereas colorimetry detected only P in solution as orthophosphate and, by the difference between the measurement of digested and undigested samples, total condensed P species. Ion chromatography had a detection limit of 0.02 mg P L^?1 for orthophosphate, 0.03 mg P L^?1 for pyrophosphate, and 0.05 mg P L^?1 for tripolyphosphate. The detection limit for orthophosphate measured by colorimetry was the same as that measured by chromatography, but the working range of concentrations was considerably greater for chromatography—from 0.02 to 200 mg P L^?1 compared with 0.02 to 2 mg P L^?1.     

小麦植株对重金属铬吸收累积的研究

为研究重金属Cr在小麦植株吸收、积累规律,为Cr污染修复与防治提供一定的依据。试验以矮抗58为供试品种,采用大田种植和盆栽试验,测定小麦不同生育期、不同部位的Cr含量,研究小麦植株中Cr吸收和累积的动态变化。结果表明,小麦植株中Cr含量较多的部位为根,而籽粒中含量较低。Cr的吸收速率以灌浆中末期最快,其次是返青一拔节期,出苗期至分蘖期最慢。并通过测定土壤Cr含量、成熟期籽粒Cr含量等建立回归方程,以此预测籽粒中Cr的含量。     

尾矿库尾砂及周边农田土壤重金属形态分布及其生物有效性

采用BCR（community bureau of reference）连续提取法对大宝山矿山槽对坑尾矿库尾砂和周边农田土壤重金属Cd、Pb、Cu和Zn的形态分布及其生物有效性进行了分析。结果表明,尾砂中Cd、Pb、Cu和Zn残渣态占绝对优势,占其总量的百分数均在85%以上。农田土壤中Cd、Cu和Zn都以残渣态为主,分别占其总量的60%、60%和90%以上,Pb以残渣态和可还原态为主,占其总量的93.44%。农田土壤重金属有效性较尾砂大,尾砂和农田土壤重金属生物有效性均以Pb为最高。     

蔬菜根际环境钒的形态变化及植物有效性

通过盆栽试验和Tessier连续提取法,研究了蔬菜根际和非根际土壤中钒的形态分布与植物有效性。结果表明,钒在根际和非根际土壤中主要以残渣态和铁锰氧化物结合态存在,钒的含量随其形态不同而变化：当土壤中钒添加量从25mg·kg^-1增加到200mg·kg^-1时,根际土壤交换态钒的百分率增加了9．89％,碳酸盐结合态钒增加了9．38％,铁锰氧化物结合态钒增加了9．99％,残渣态钒的百分率下降了33．6％。土壤添加的钒量增加时,钒的迁移能力增强,使蔬菜的生物量显著降低,蔬菜对钒的吸收作用增强：钒添加量从0增至200mg·kg^-1时,蔬菜鲜质量降低了41．65％,而蔬菜中85％以上的钒积累在根部。根际土壤中碳酸盐结合态钒含量对植物的根、茎叶中钒含量有显著影响,碳酸盐结合态钒与蔬菜鲜质量呈显著负相关。