广州市蔬菜地土壤-蔬菜中重金属Hg的含量及变化趋势

测定了95份土壤样品、94份水样以及292份蔬菜样品中汞的含量,探讨了广州市蔬菜地土壤-蔬菜中重金属Hg污染状况.发现蔬菜中的Hg含量与土壤中的Hg含量较为密切.广州市土壤、蔬菜中Hg的含量水平均比过去大幅度降低.蔬菜中Hg含量与其它城市比较,污染情况较轻,处于其它城市的中低水平.     

Mercury in some chemical fertilizers and the effect of calcium superphosphate on mercury uptake by corn seedlings(Zea mays L.)

Mercury (Hg) contents in ten chemical fertilizers were determined, and the effect of calcium superphosphate (CSP) on the uptake and translocation of Hg in corn seedlings was investigated by pot experiments. CSP was applied at the levels of 0, 66.7, and 133.4 mg P2O5/kg to Hg-treated (2 mg/kg) and untreated soils. CSP had the highest Hg content (5.1 mg/kg), followed by the NPK compound fertilizer 15-5-5 (15% N, 5% P2O5, 5% K2O) (1.2 mg/kg), then by nitrogen fertilizers (except for ammonia sulfate) and potassium fertilizers. Application of CSP did not obviously iuence the biomass of corn roots, but it significantly increased the biomass of corn shoots in Hg-treated soil. Application of CSP at the levels of 66.7 and 133.4 mg P2O5/kg did not obviously iuence the uptake of Hg by corn seedlings on soils without Hg treatment, but it decreased the Hg uptake of corn seedlings significantly on Hg-treated soils. The transfer coefficient of Hg in corn seedlings improved slightly on soils without Hg treatment, but decreased slightly on Hg-treated soils with the application of CSP. These results implied that CSP could ameliorate Hg toxicity to corn seedlings by inhibiting the uptake and the translocation of Hg in plants on Hg-polluted soils.     

重金属（Hg，As，Pb）污染对蚕豆根尖细胞微核的诱变研究

采用蚕豆根尖细胞微核检测技术,分别探讨不同浓度的HgCl2、As2O3、Pb（NO3）2对蚕豆根尖细胞微核率的影响。以蒸馏水处理作为阴性对照实验。结果表明不同浓度的HgCl2可使蚕豆根尖细胞微核率明显上升,说明HgCl2对蚕豆根尖具有明显的毒性效应——诱发突变（微核）。不同浓度As2O3可使蚕豆根尖细胞微核率明显上升。说明三氧化二砷（As2O3）对蚕豆根尖具有明显的毒性效应——诱发突变（微核）。蚕豆根尖微核率在铅离子浓度0—25mg／L范围内,随着硝酸铅处理浓度的升高而升高,说明硝酸铅是一种较强的诱变剂。     

巯基功能化沸石吸附Hg2+特征及固化/稳定化含汞废物研究

采用3-巯基丙基三甲氧基硅烷在天然斜发沸石表面进行自组装巯基改性,制得巯基功能化沸石.研究了吸附剂用量、pH值、温度、Hg2+浓度和吸附时间对巯基功能化沸石吸附Hg2+的影响,测定了巯基含量,并进一步研究了吸附机理.同时,探讨了巯基功能化沸石吸附剂作为稳定化剂固化/稳定化含汞危险废物的可行性.结果表明,巯基功能化沸石具有较高的巯基含量（1.91%±0.01%）,对Hg2+的吸附容量为87.72 mg·g-1,比天然沸石对Hg2+的吸附容量（8.06 mg·g-1）提高了近10倍.巯基功能化沸石吸附Hg2+的机制主要是表面的巯基与Hg2+的反应,其受pH值、温度的影响小于天然沸石.动力学实验结果表明,巯基功能化沸石吸附Hg2+以较快的速率进行,3h时基本达到吸附平衡.巯基功能化沸石做稳定化剂能够促进汞的稳定,与单独使用水泥相比固化体浸出汞浓度显著降低,含汞1000 mg·kg-1的模拟废物固化体浸出汞浓度低于国家标准.     

Hg稳定同位素地球化学研究进展

近年来汞(Hg)稳定同位素研究进展显著。Hg具有七种稳定同位素。以往研究不但报道了Hg同位素质量分馏,也报道了Hg同位素非质量分馏,使Hg成为目前唯一在自然界中具有同位素非质量分馏的重金属元素。本文阐述了Hg同位素的研究背景,总结了Hg同位素分析方法和引起Hg同位素分馏的生物化学过程,介绍了地球各圈层样品中Hg同位素组成的国内外最新研究现状。而最新发现的大气降雨中异常的、呈季节性变化的偶数Hg同位素非质量分馏(Δ200 Hg),更开辟了Hg同位素研究的新领域。不同于奇数Hg同位素非质量分馏,偶数Hg同位素非质量分馏还未经任何实验验证,其分馏机理也完全不清楚,亟待深入研究。Hg可能的"三维"同位素体系(质量分馏、奇数以及偶数Hg同位素非质量分馏)的研究和应用将有希望为进一步认识Hg环境过程、生物累积、大尺度迁移以及全球性的生物地球化学循环提供更加丰富的信息,具有重要的科学意义。     

青海省民和县-海石湾土壤Hg异常调查及其生态效应

通过对民和县-海石湾城区及其周边地区表层土壤Hg元素异常空间分布特征的分析,查明了大气降尘是当地Hg异常的最主要来源,此外生活、工业固废污染也是可能的原因;在垂向分布上,自上而下Hg元素大体呈上升趋势,显示表面Hg元素富集。对土壤中Hg形态进行特征分析,探讨了Hg的各形态与含量之间的相关性,结果显示:残渣态>强有机态>腐植酸态>铁锰氧化态>水溶态>碳酸盐态>离子交换态。异常区土壤Hg的累积并未造成小麦及玉米的重金属超标,未影响到其食用安全性,但是潜在威胁性存在。     

Relationships between humic substance-bound mercury contents and soil properties in subtropical zone

The bioavailability of humic substance-bound mercury （HS-Hg） has been established, while the distribution of HS-Hg in soils in relation to soil properties remains obscure. Path analysis and principal component analysis were employed in present study to investigate how soil factors influence the contents of HS-Hg in soils. Results showed that HS-Hg ranged from 0.0192 to 0.2051 mg/kg in soils. The two fractions existed in soils as humic acid-bound mercury （HA-Hg） 〉 fulvic acid-bound mercury （FA-Hg） and the ratio of HA-Hg/FA-Hg was 1.61 on the average. Soil organic carbon （OC） and HS favorably determined soil HS-Hg and the two fractions. The mercury source forming HS-Hg derived from soil total mercury and HS-Hg. FA-Hg and HA-Hg served as mercury source for each other. In acidic soils, FA-Hg and HA-Hg consistently rose with the increase of OC, and generally HA-Hg increased more dramatically. Soils with lower pH and lighter texture contained more HS-Hg, particularly fraction of FA-Hg. Among all influencing factors, organic material source showed the strongest effect, followed by other soil properties and soil mercury source.     

Simultaneous radioassays of bacterial production and mercury methylation in the periphyton of a tropical and a temperate wetland

Laboratory radioassays were made to study mercury (Hg) methylation together with bacterial production in the periphyton of two aquatic macrophytes, the submerged Myriophyllum spicatum, from a constructed wetland in Sweden and the floating Eichhornia crassipes, from a eutrophied tropical lake in Brazil. Time course incubations were made by addition of (203)HgCl(2) and the methylmercury formed was extracted at pre-defined time intervals. Bacterial production ((14)C-leucine incorporation) was measured at the same time intervals, with plants removed from parallel incubations made with and without addition of cold HgCl(2). For E. crassipes, higher methylmercury production was observed at elevated bacterial production, whereas for M. spicatum, the bacterial production was significantly lower, and Hg methylation was below the detection limit. The combined results confirm the importance of microbial processes for Hg methylation, although other factors are known to influence this process in complex ways. The addition of Hg did not significantly influence bacterial production, while the incubation temperatures used (25 and 35 degrees C) resulted in different methylation rates. Radiotracer techniques for measurements of bacterial production such as (14)C-leucine uptake can provide useful insights into the Hg cycle in aquatic environments, and our data suggest that they may be used as a proxy of mercury methylation potentials.     

施工扬尘环境下短时强降雨屋面径流中砷、汞、铅、镉、锌的污染特征研究

以南京北郊为例,测量分析了屋面径流中砷(As)、汞(Hg)、铅(Pb)、镉(Cd)和锌(Zn)5种元素的浓度、形态特征。结果表明:短时强降雨过程中这5种元素浓度在较大范围内无规则波动,且不同元素间浓度分布存在较大差异;Zn与Pb的平均浓度分别高于《地表水环境质量标准》(GB 3838—2002)的Ⅴ类和Ⅳ类标准限值,污染程度从大到小依次为ZnPbAsHgCd。元素形态分析表明,径流中除Hg外其他4种元素主要以颗粒态形式存在,各元素颗粒态占总形态的平均分数分别为:As,64.5%;Hg,43.7%;Pb,76.5%;Cd,54.6%;Zn,54.3%。     

Mercury contamination in vicinity of secondary copper smelters in Fuyang, Zhejiang Province, China: Levels and contamination in topsoils

In the present study, we aim to investigate the extent of soil contamination by Hg, particularly by anthropogenic Hg, and tentatively estimate the total Hg (Hg_T) accumulation in topsoils (0-15 cm) in Fuyang, Zhejiang Province—a secondary Cu smelter of China. The results show that the levels of soil Hg in the vicinity of the smelters have been substantially elevated following local smelting activities. The spatial distribution of soil Hg in this area reveals a rapid decrease as the distance from the smelter reaches 1.5 km, which is probably due to the quick deposition process of particulate Hg and reactive gaseous Hg emitted from the smelters. The total accumulation of Hg_T in the topsoils of the study area of 10.9 km² is approximately 365-561 kg and of which 346-543 kg might be contributed by anthropogenic emission alone with an annual emission of 17.3-27.2 kg Hg to the topsoils.