Sorption of heavy metals on organic and inorganic soil constituents

Sorption of heavy metals to organic matter and mineral soil constituents can hardly be separated experimentally. Here we studied the retention capacity of organic matter and minerals from soils in a long-term field experiment in which the organic carbon content had been altered, but the mineral phase had remained constant over time. The sorption of Cu, Cd and Zn showed a non-additive contribution of soil organic matter and minerals to the sorption capacity of soil. Sorption on organic matter exceeded mineral sorption from 6 to 13 times. This is the first time that sorption to soil organic matter is quantified in bulk soils.     

Movement and transformation of35S-labelled sulphate in the soil of a heavily polluted site in the Northern Czech Republic

Changes in chemistry and vertical distribution of³⁵S were investigated in column experiments using intact topsoil and repacked mineral soil horizons 1 to 20 weeks after tracer application (901 kBq³⁵S-SO₄ ^2– per column 6.5 cm in diameter). Horizons O, A, AE and Bvs of an Orthic Podzol were incubated at 20°C and wetted twice a week with 11 mm of natural throughfall precipitation (38.5 mg S0₄ ^2– L^–1-, pH 3.3). The top 35 cm of the soil contained 1,290 kg S ha^–1, or 18 times more than is the annual atmospheric S input (71.4 kg S ha^–1 yr^–1). Of this amount, 17.8 % was stored as inorganic sulphate S, 4.6 % as reduced inorganic S, and 77.6 % as organic S. In O + A and AE, free sulphate was the most abundant³⁵S form, while in Bvs the 35S activity of free and adsorbed sulphate was similar. The proportion of adsorbed sulphate increased with depth, averaging 23, 30 and 47 % of total inorganic sulphate³⁵S in O + A, AE and Bvs, respectively. Total specific activity of chemically transformed³⁵S (i.e., of reduced inorganic S and organic S) constituted 3.4, 3.8 and 105 % of inorganic sulphate³⁵S activity in O + A, AE and Bvs, respectively, in averaged weeks 2–4, and 7.5, 6.4 and 39.6 % in averaged weeks 11–13 in O+A, AE and Bvs, respectively. The turnover time of C-bonded³⁵S was shorter than that of ester sulphate³⁵S. An increase in FeS_2– ³⁵S with time indicated anaerobic conditions suitable for bacterial sulphate reduction. After 13 weeks, 68 % of the tracer was found deeper than 8 cm below soil surface.     

广东山地丘陵土壤的特性

广东山地丘陵面积约占总面积的70％,山地丘陵在广东经济发展中占有重要地位。本文根据长达5年的南方山区土壤资源考察及前人的研究成果,论述了广东山地丘陵土壤中有机质、全氮、颗粒组成、代换性能、矿质营养元素和土壤水分等的特点。建议根据山地土壤资源的优势和生态系统的脆弱性,实行保护性开发、建立良性人工生态系统,因地制宜,因土种植,合理施肥和实行人工灌溉等土壤水分的调控措施。     

Relative Importance of Reproductive Biology and Establishment Ecology for Persistence of a Rare Shrub in a Fragmented Landscape

Abstract:  Verticordia fimbrilepis (Turcz) ssp. fimbrilepis (Myrtaceae) is an endangered shrub that occurs in a number of populations varying in size and landscape context. We compared the importance of factors associated with its reproductive biology with that of factors influencing the regeneration niche in survival of small, isolated populations in contrasting habitat fragments. Small populations on road verges had equal or greater diversity of insect visitors to flowers, rates of pollination, and seed production compared with larger populations in conservation reserves. V. fimbrilepis seeds remained dormant in the soil for at least 30 months, and germination was stimulated by smoke. Plants were killed by fire, but mass recruitment from soil-stored seed reserves occurred in the first and second winters following fire. Our studies showed some seedling recruitment between fires, but this was strongly related to the availability of competition-free establishment sites. Whether this is enough to replace older plants as they die and thereby sustain stable populations is unknown and probably varies with the landscape. Environmental variation between fire episodes influenced population size. Drought increased mortality, but wetter years encouraged interfire recruitment. Most populations are declining and cannot recover without the occurrence of fire. In a fragmented agricultural landscape, fire suppression is the primary management practice. This may adversely affect rare species such as V. fimbrilepis and others with similar life histories that rely on a particular fire regime to persist. Population persistence is more likely to be related to stochastic environmental events than to factors associated with reproductive biology.     

Environmental prospection for PCDD/PCDF, PAH, PCB and heavy metals around the incinerator power plant of Reggio Emilia town (Northern Italy) and surrounding main roads

Samples of soil, sediment and pine needles from the Reggio Emilia area were analysed in order to estimate the environmental pollution caused by an MSWI. PCDD/PCDF, PCB, PAH and metals were analysed in the collected samples. The data obtained showed relatively low pollution levels. Indeed, the PCDD/PCDF and PCB data were comparable to the values usually found in the grazing areas of the European Union countries. Metal concentrations in soils and sediments may be related to local geological occurrences and to agricultural activities. PAH values are significantly lower than the limit values set by the Italian law.     

广东石灰岩山区土壤资源利用研究——以阳山县江英乡为例

本文以江英乡为例,阐明了广东石灰岩山区土壤资源的生态环境特点。针对这些特点,我们提出了顺应生态环境、充分发挥小气候优势、推广良种良法、调整农业结构、发展外向型绿色企业以及保水保土等一系列综合开发利用的措施,并在江英乡付诸实施。实践证明,这些措施具有明显的经济效益和社会效益,从而为广东石灰岩山区开发利用土壤资源、发展农业经济提供了参考依据。     

铜对砖红壤性水稻土微生物影响的初步研究

添加铜对砖红壤性水稻土微生物群体数量影响的盆栽试验研究表明,添加铜浓度与土壤微生物数量之间的关系未能呈现良好的相关性,微生物的变化晚季比早季稳定,建议以晚季微生物受抑制的添加浓度125mg kg~(-1)做为土壤微生物的毒性临界浓度。     

氢化物-原子荧光光谱法测定土壤中硒

通过对比实验选择了最佳的仪器测定条件、主要试剂的浓度及土壤的前处理方式。实验结果表明：采用HN03-HClO4酸体系在沙浴中对土壤进行消解，硒的检出限为0．02mg/kg；线性范围为0ug/L～200ug/L；平均回收率可达100％～103％。方法经土壤国家标准物质中硒的测定验证，结果与标准值相符。     

桂西北肯福环境移民示范区园地土壤肥力变化状况

果树业作为肯福环境移民示范区的一项长期的云集产业，在示范区移民的生产、生活中起着不可缺少的作用。为了解示范区园类用地（主要是宜果类用地）开发利用对土壤肥力变化的影响，以便更好地指导移民进行合理的综合性开发，特对开垦前（1996年上半年，此时移民也开始迁入）和开垦后第三年（1998年下半年）示范区的园类用地土壤养分变化进行了调查研究，分析了耕层土样的8个土壤养分指标，结果表明：示范区园类用地土壤肥力整体上基本保持不变，但表现出微弱的下降趋势；其中的长绿果树地土壤肥力略有下降，而落叶果树地土壤肥力有极微的上升趋势；不同的土壤养分元素含量变化又有差异。