云南不同产地三七的重金属吸收累积特征研究

[目的]三七Panax notoginseng (Burk.) F. H. Chen是我国传统珍贵中草药植物,其在云南种植区域不断北移和扩大,重金属污染问题已引起广泛关注,但相关研究却非常有限。[方法]本研究采集了分布于云南三州七县27个三七样品,并采用湿法消解前处理方法,电感耦合等离子体质谱仪( ICP－MS) 测定其4种重金属元素Pb、Cd、As、Cu 的含量,揭示云南不同产地三七植物体内重金属的吸收富集特征及转运规律,并对不同产地三七的食用安全性进行人体健康评估。[结果]结果表明,参照《药用植物及制剂外经贸绿色行业标准》,三七块根中Pb、Cd、As、Cu的超标率为0%、62.96%、37.04%和0%,对应叶片中的超标率分别为37.04%、33.33%、48.15%、3.70%,应加强Cd、As的安全性关注。三七块根中Cd的富集系数最大,As和Cu相近,Pb最小。叶片中Pb、As、Cu富集系数变化较小,与三七块根相似,而Cd不同产地富集系数变异较大,最大的建水是最小的师宗的8.3倍。聚类分析表明不同地区的不同重金属的污染程度差异较大。不同产地三七Pb、Cd、Cr、Cu 对人体的摄入风险贡献依次为4.91%～10.00%、3.83～10.50%、7.34～23.28%、0.40～0.61%,所占比例较小。[结论]云南部分三七存在一定的重金属污染风险,本研究可为三七药材的规范化种植,安全评价及三七安全质量控制技术提供理论依据。     

Distribution of Cr,Ni and Co in soils and rocks of Neyriz area (Iran): the influence of ophiolitic formations

Neyriz area, on south of Neyriz ophiolite complex, is one of the most important areas in fruit production. However, no study has been yet performed to assess the contamination status of soils in this region. The objective of the present study was to explore soil pollution by Cr, Ni and Co. Three landforms (ophiolite hills, alluvial fan and playa) were selected along a transect. Seven pedons were excavated and soil and rock samples were obtained. The total concentration of Cr, Ni and Co, Enrichment Factor (EF) and Geo-accumulation index (I_geo) were determined. Results showed that soils over ophiolite hills and alluvial fan were extremely polluted by Cr and Ni (I_geo=3–6). The EF Index confirmed that heavy metals originated from ophiolite rocks in the region. Both indices showed a descending trend from ophiolite hills to playa that related to deposit transportation processes during landforms evolution. It was also observed a decreasing vertical trend in metal contents in the soils over alluvial fan which can be attributed to the long-time irrigation and plant uptake as affected by land use. Further investigation is needed to understand the contamination status of ground-water and orchards of the region to achieve sustainable management.     

高尔夫球场不同草坪土壤重金属的富集及分析-以东山球场为例

为探讨高尔球场草坪养护对土壤重金属含量的影响。系统采集了球场中球道、发球台、果岭耕作层及犁底层的土壤共20个样品,分析了三种草坪不同深度土壤中Cr,Ni,As,Cd,Hg,Pb,Cu的垂直含量和水平含量。结果显示:研究区域内,除了球道土壤中的As、Hg及果岭土壤中的Cd之外,其他地点的重金属基本上都是犁底层耕作层。球道、发球台、果岭的耕作层及犁底层重金属含量无显著差异。但从两个深度重金属的平均含量看,Cd,Pb,Cu的平均含量呈现球道发球台果岭;Hg,Ni的平均含量呈现发球台球道果岭;Cr的平均含量呈现果岭球道发球台;As的平均含量呈现球道果岭发球台。高尔夫球场草坪土壤中As、Pb两种重金属含量未超国家标准限值,但高出背景值。Cd,Hg及球道犁底层、果岭耕作层的Cr含量既超过国家标准限值又超过背景值,富集严重。球场草坪土壤中重金属的垂直分布主要受施用化肥及降雨量的影响,而不同草坪土壤重金属的含量则与球场施用化肥的品质有关。     

Impact of deposition on the enrichment of organic carbon in eroded sediment

A substantial part of eroded material can be deposited along the runoff pathway. This deposition process may alter the composition of the transported material. Topography- and vegetation-induced deposition processes were examined under laboratory conditions and at the hillslope and watershed scale. The laboratory experiments showed that the enrichment ratio of the specific surface area, ER_SSA, of the transported sediment followed an exponential increase with decreasing sediment delivery ratio, SDR, regardless of the type of deposition process. However, the increase in ER_SSA with decreasing SDR values was lower than expected. The upper limit of the ER_SSA was estimated to be 1.66, which is much lower than the calculated theoretical upper limit of 5.22. This difference can be attributed to the transport of the eroded material in micro-aggregated form. It was also found that the specific surface area, SSA, is a good predictor of organic carbon, OC. The observations on field plots confirmed the results of the laboratory experiments. Measurements at the watershed level indicated that the intensity of the erosion process had a more important influence on sediment enrichment, while the impact of deposition tended to be rather limited. However, sediment monitoring over a longer period is required to reveal the importance of the different erosion processes with regard to OC losses at the field and watershed level.     

粉煤灰中重金属Pb/Cr/Cu在土壤——小白菜中的迁移与形态转化

以两种粒径粉煤灰与莱西棕壤按不同比例混匀后连续进行了四批次小白菜生长周期试验,采用欧共体标准物质局提出的三步提取法(简称BCR法)研究施灰土壤中铅(Pb)、铬(Cr)和铜(Cu)四种化学形态的转化特征,并通过计算小白菜对重金属的富集系数和转移系数,分析土壤重金属在小白菜中的迁移特性与生物利用率。结果表明:在小白菜种植的整个周期,各处理施灰土壤中Pb、Cr和Cu均以残渣态为主,含量随种植批次增加而减少;Pb、Cr的可提取态含量占15%以上,乙酸溶解态含量随种植批次增加而增加,Cu的可提取态含量占55%以上,乙酸溶解态含量随种植批次增加而减少。小白菜对三种重金属的富集能力表现为:CuCrPb,且均小于临界值1,因此,相较Pb和Cr,Cu的生物利用性更强。小白菜由根部向地上可食部分转移系数大于1,转移能力表现为:CrCuPb,因此Cr在小白菜中迁移能力更强。     

重金属Cd在小麦中的富集特征

［目的］为促进粮食安全生产。［方法］以小麦为受试植物,采用盆栽试验,研究重金属Cd在小麦中的富集特征。［结果］大部分Cd富集在小麦根部,幼苗期重金属分布为：根〉叶;拔节期分布为：根〉茎〉叶片;抽穗期分布为：根〉茎〉叶片〉颖壳;成熟期分布为：根〉茎〉叶片〉籽实〉颖壳。［结论］在不同生长时期小麦不同部位中重金属Cd的含量有很大差异。     

近1000年来浙江慈溪表层土壤重金属元素Hg污染评价

采用富集因子法评价了浙江慈溪地区不同成土时间表层土壤元素Hg的污染程度。结果表明,该地区成土过程中土壤重金属元素Hg污染程度一直增加,其中：成土前200年元素Hg污染程度缓慢增加,随后急剧上升,近1000年时污染程度最高;表层土壤元素Hg质量是自然积累和人为污染叠加的结果,近1000年表层土壤元素Hg人为污染量最多,约占Hg其总质量的83％。     

菜豆组培快繁技术研究

以双丰3号菜豆为试验材料,比较了种子消毒方法,筛选了快繁最佳增殖培养基、生根培养基及移栽基质。结果表明,25%次氯酸钠浸泡20 min对菜豆种子消毒效果最好;最佳增殖培养基为MSB5+6-BA 5.0 mg/L,14 d获得再生芽为9.2个/外植体;最佳生根培养基为1/2 MSB5+IBA 0.1 mg/L,生根率达95.3%;最佳移栽基质为草炭：蘑菇渣=1：1,移栽成活率为97%。     

多重丰容对圈养小熊猫个体刻板行为的影响

小熊猫(Ailurus fulgens)是亚洲特有的濒危动物。由于圈养小熊猫活动空间受限、环境单调等因素,时常有刻板行为表现。本研究依据小熊猫自然行为特性及动物福利要求,以环境、食物、气味等因素进行多重丰容,观察频繁出现刻板行为的2只圈养小熊猫个体的行为修正效果。应用聚集动物取样法,从9:00到17:00,全事件记录并观察小熊猫行为。观察发现,受试小熊猫主要表现摇晃与踱步两种刻板行为。通过丰容前与三个阶段的丰容后刻板行为发生率比较,丰容后的刻板行为均显著低于丰容前,而探究行为和修饰行为有所增加。由此可见,多重丰容可以减少圈养小熊猫刻板行为的发生,促进自然行为的表达。     

Enrichment of logging gaps with moabi (Baillonella toxisperma Pierre) in a Central African rain forest

Studies of regeneration in African rain forests suggest that without silvicultural treatments, natural succession in logging gaps may not result in the establishment of timber species. In this paper we present the results of an experimental enrichment planting with moabi (Baillonella toxisperma Pierre), a valuable and important timber species harvested in Central Africa. Although forest gaps are generally considered as favourable for the regeneration of this species, a survey conducted in a forest concession in south-eastern Cameroon provided an estimate of only 12.7 seedlings ha⁻¹, suggesting that the species was, in fact, poorly represented in logging gaps within the study area. To further investigate the dynamics of the moabi in logging gaps, 795 seeds were sown in 15 logging gaps and 410 nursery-raised seedlings were planted in 15 other gaps. A biannual monitoring program over a 30-month period showed a lower survival rate for seedlings from sowing (75.9%) compared to that of nursery-raised seedlings (95.3%). Planted seedlings reached an average of 229.3 cm tall whereas seedlings from sowing were 167.5 cm tall, with the observed difference roughly corresponding to the average height of the nursery-raised seedlings at the time they were introduced to the logging gaps. After 30 months, the diameters of planted seedlings (16.8 mm) were also greater than those of the directly sown individuals (12.5 mm). Forest gap characteristics significantly influenced the growth of the plants. Factors accounting for the differences were total solar radiation, the soil content of coarse sand, the topographic position of the gap, the vegetation cover and the density of Macaranga spp. Whilst total solar radiation had a positive influence on growth, the remaining factors had impacted growth negatively. A streamlined technique was tested by planting 7 seedlings in 250 gaps. Without additional site maintenance, 29.3% of the moabi seedlings emerged naturally from the competing vegetation after 24 months. With biannual maintenance some 89.4% of seedlings became successfully established. Clearance operations had no significant influence on the height of plants whilst plant diameter was greater in cleared gaps. The total cost of the enrichment technique was 5.5 EUR per gap without maintenance and 7.5 EUR per gap with a single maintenance measure. Whilst long-term monitoring is needed, this study suggests a high survival rate of moabi introduced in logging gaps, and a growth rate 10 times higher than previously reported under canopy cover. These findings, combined with the low costs of the enrichment technique, support the use of silvicultural measures in logging gaps to restore the forest.