Environmental biogeochemical behaviors of rare earth elements in soil–plant systems

With the continual increase in the utilization of rare earth elements (REEs) for industrial and agricultural purposes in China, the research into the environmental biogeochemical behavior of REEs has become a pressing issue. The REEs’ content in soil and various parts of wheat under different conditions in soil–plant systems were measured by INAA and ICP-MS. The results showed four aspects. (1) The mean value of total REEs in soil of China was 176.8 mg kg⁻¹. The mean ratio of ΣLREE/ΣHREE in soils was 8.0 and cerium accounts for 42% of the total REEs. The content of REEs in wheat seed ranged between 10⁻¹¹ and 10⁻⁸ g g⁻¹, 3–4 orders of magnitude lower than that in soil. (2) The REEs contents in ryegrass, especially in roots, were significantly related to that of soil. The bioavailability of REEs in soil mainly depended on the exchangeable fraction of REEs, which was strongly affected by the physico–chemical properties of the soil. (3) Long-term foliage-dressing with Changle microfertilizer of REEs did not affect the contents and distribution patterns of REEs in soil. At the maturing stage of spring wheat, the REEs content was in the order of root > leaf >stem and crust. Compared with the control, foliage-dressing has a higher accumulation of REEs in root and leaf. However, no significant difference was found in stem and crust between the two treatments. (4) There was no significant accumulation with the soil-dressing method. When comparing controls in both foliage- and soil-dressing methods, no distinct residue of REEs in grains was found.     

贵州喀斯特山区植物营养元素含量特征

贵州喀斯特山区是我国乃至世界喀斯特分布面积最大的片区之一,由于其生态系统的脆弱性,加之人类活动的干扰,使得该区的植被退化较为严重。文章选择该区的12种主要植物作为研究对象,对其营养元素进行了研究。结果表明:>1000μg·g-1的元素有N、P、K、Ca、Mg、S,100～1000μg·g-1的元素有Fe、Mn、Al,10～100μg·g-1的元素有Zn、Sr,<10μg·g-1的元素为Cu、Mo,其中Mo含量最低,仅为0.17μg·g-1。这些元素中,Ca、P、K元素高于所报道的陆生植物的含量范围。元素含量特点是Ca>K>Mg型。N、P、K、Mg元素的频数分布为正态分布,Ca、Al、Fe、Mn、Cu、Zn、Sr、S元素为对数正态分布。变异系数大于100%的元素有Al、Fe、Mn、Sr,变异系数小于60%的元素有N、P、K、Ca、Mg、S、Cu,其中Ca的变异系数最小,仅为11.8%。不同生境下相同植物的营养元素含量有较大的差异,石灰土上植物的N、P、K、Ca、Mg、Al、Cu、Mo元素含量要高于黄壤上植物的。元素间的相关分析表明:P和K、P和Cu、Al和Fe、Al和Zn、Fe和Zn元素具有显著相关关系;N和P、P和Mg、K和Al、K和Cu、Ca和Sr、S和Mo元素具有一般相关关系。     

Influence of soil-applied coal combustion by-products on growth and elemental composition of annual ryegrass

The total annual production of coal combustion by-products in the USA is expected to exceed 150 million Mg by the year 2000. Agricultural utilisation may offer a partial solution to disposal problems, but the benefits and risks associated with using these materials must be assessed. Four coal combustion by-products, bed ash (BA) and fly ash (FA) from a fluidised-bed combustion furnace and stabilised scrubber sludge (SS) and a high gypsum content by-product (G) from flue gas desulphurisation processes were added to two soils at rates of 0, 20, 40 and 80 g kg-1. The growth and elemental composition of Gulf annual ryegrass (Lolium multiflorum L.) were evaluated in the treated soils. Adding FA, SS and G to both soils at application rates of up to 80 g kg-1 was not detrimental to the growth of ryegrass and resulted in higher yields than controls in some instances. Adding BA created a high alkalinity, high soluble-salt environment that initially inhibited seedling germination and significantly reduced (p<0.05) yields of dry matter, so it will probably need to be restricted to rates of lime requirement. Ryegrass concentrations of Cu, Zn, Ni, Pb, Cd and Cr were similar in control and treated soils, but levels of B, Se, As and Mo were raised in treatments. Based on low trace-element concentrations in ryegrass shoots and in soil solution, Se from FA application may be the only potential food-chain risk associated with application of the four coal combustion by-products used in this investigation.     

Arsenic and other toxic elemental contamination of groundwater, surface water and soil in Bangladesh and its possible effects on human health

The problems of contamination caused by arsenic (As) and other toxic metals in groundwater, surface water and soils in the Bengal basin of Bangladesh have been studied. Altogether 10 groundwater, seven surface water and 31 soil samples were collected from arsenic-affected areas and analysed chemically. The geologic and anthropogenic sources of As and other toxic metals are discussed in this paper. The chemical results show that the mean As concentrations in groundwater in the Char Ruppur (0.253mg As L^–1), Rajarampur (1.955mg As L^–1) and Shamta areas (0.996mg As L^–1) greatly exceed the WHO recommended value, which is 0.01mg As L^–1. The concentrations of As in groundwater are very high compared to those in surface water and in surface soil in the three (As-affected) areas studied. This indicates that the source of As in groundwater could be bedrock. The relatively high concentrations of Cr, Cu, Ni, Pb and Zn in surface water, compared to world typical value, are due to the solubility of metal ions, organometalic complexes, coprecipitation or co-existance with the colloidal clay fraction. In the soil, the elevated concentrations of As, Cr, Cu, Ni, Pb and Zn are due to their strong affinity to organic matter, hydrous oxides of Fe and Mn, and clay minerals.     

北京市区公路旁尘土中铂族元素的化学形态

用ICP-MS 法检测北京市区公路旁尘土中铂、铑和钯各种形态的含量及总含量.结果表明,北京市区采样点公路旁土壤中铂,铑和钯的总量分别为154.23 ng·g-1,62.77 ng·g-1和 77.97 ng·g-1,其中非残留态的百分比含量为铑(37.82%) ＞钯(27.45%) ＞铂(26.87%);在自然条件作用下可进入地下水和可被植物吸收部分的百分比为铑(29.14%)＞钯(23.87%)＞＞铂(7.92%).     

雷州无瓣海桑群落7种元素的生物累积和循环

在雷州市附城镇岚北人工生态恢复的 7a生无瓣海桑群落生物量调查的基础上 ,对所采集的无瓣海桑进行了植物体各组分样品的灰分和元素含量测定与循环分析 ,结果表明 :无瓣海桑植物体不同组分的灰分含量范围为 2 .2 7%～ 2 6 .4 1% ,以细根的含量最高 ,枯枝的含量最低 .植物体各组分中 7种元素质量分数范围分别为K 0 .11%～ 1.5 6 % ,Na0 .11%～ 1.6 6 % ,Ca 0 .2 0 %～ 2 .6 6 % ,Mg 0 .15 %～ 1.5 9% ,Fe 0 .0 4× 10 -3 ～ 9.6 4× 10 -3 ,Zn 0 .0 5× 10 -4～ 1.0 3× 10 -4,Cu0 .16× 10 -5～ 1.5 0× 10 -5.其加权平均的富集系数为 0 .0 5～ 9.70 ,其中Ca >K >Cu >Na >Mg>Zn >Fe .群落现存生物量中的累积储量分别为K 10 9.76gm-2 ,Ca 138.89gm-2 ,Na 86 .5 7gm-2 ,Mg 81.0 7gm-2 ,Fe 13.139gm-2 ,Zn 0 .4 83gm-2 ,Cu 0 .10 8gm-2 .群落 2 0 0 1年的元素存留累积储量分别为Ca4 1.6 8gm-2 ,K 37.2 4gm-2 ,Mg 2 7.33gm-2 ,Na2 5 .5 6gm-2 ,Fe 4 .2 75gm-2 ,Zn 0 .188gm-2 ,Cu 0 .0 39gm-2 .2 0 0 1年归还量分别为Ca 2 8.5 9gm-2 ,K 16 .83gm-2 ,Mg 12 .0 7gm-2 ,Na 11.5 8gm-2 ,Fe 0 .916gm-2 ,Zn 0 .14 1gm-2 ,Cu 0 .0 2 6gm-2 .年吸收量分别为Ca 70 .2 7gm-2 ,K 5 4 .0 7gm-2 ,Mg 39.4 0gm-2 ,Na 37.1     

岷江水系河水与沉积物中稀土,稀有元素背景值及其特征初探

报告了岷江水系河水及沉积物中８种稀土元素（Ｌａ，Ｃｅ，Ｎｄ，Ｓｍ，Ｅｕ，Ｔｂ，Ｙｂ，Ｌｕ）及８种稀有元素（Ｒｂ，Ｃｓ，Ｓｒ，Ｂａ，Ｓｂ，Ｔｈ，Ｓｃ，Ｕ）的背景值及其特征，并对元素的排列顺序及元素间的相关关系进行了初步探索，还列出了１６种元素在原水同积物中的相关矩阵及相互间的相关回归方程。     

长江口和黄河口沉积物非残渣态中元素的相关性

研究了长江口、黄河口表层沉积物中元素可提高取量间的相关性、元素可提取量与粒度组成之间的关系。通过对两个区域不同类型的大量沉积物的研究结果表明：用１ｍｏｌ／ＬＨＣｌ或０．５ｍｏｌ／ＬＨＣｌ＋Ｈ２Ｏ２提取沉积物，元素Ｃｕ、Ｚｎ、Ｐｂ、Ｃｏ、Ｌｉ、Ｎｉ、Ｆｅ、Ｋ、Ａｌ的提取量之间存在显著的正相关关系；元素Ｚｎ、Ｃｕ、Ｐｂ、Ｃｏ、Ｌｉ、Ｎｉ、Ｆｅ、Ｋ、Ａｌ的可提取量与沉积物中粘土含量呈显著的正相关关系；与     

锌及其它重金属元素在土壤中迁移性的调控

实验表明,使用不同处理溶液按不同顺序淋洗土壤,造成土壤中Zn、Cu、Fe、Mn、Ni等重金属元素迁移性不同,因而对作物生长及重金属元素对作物的有效性产生了明显影响.     

路用煤矸石环境影响评价

煤矸石可用于道路路基和基层，但在应用的同时需对环境造成的影响进行评价。文中根据国标《土壤环境质量标准》和《地下水质量标准》的有关指标，通过对宁夏地区的3种煤矸石中的重金属含量进行检验分析。评价煤矸石用做路用材料时可能对环境造成的影响。