Elemental analysis of the edible fruit of Carpobrotus dimidiatus (from Kwazulu-Natal,South Africa) and the influence of soil quality on its elemental uptake

Abstract

Carpobrotus dimidiatus is an indigenous South African medicinal plant species from the Aizoaceae family that bears edible fruit that is consumed for nutritional value. In this study, the elemental distribution in C. dimidiatus fruit and growth soil from fifteen sites in KwaZulu-Natal (South Africa) was determined along with soil pH, soil organic matter and cation exchange capacity, to assess for nutritional value and the effect of soil quality on elemental uptake. The results showed elemental concentrations in fruit to be in decreasing order of Ca (6235–32755?mg kg^?1) > Mg (2250–5262?mg kg^?1) > Fe?>?Mn?>?Zn (20.9–50.6?mg kg^?1) > Cu (3.83–20.6?mg kg^?1) > Pb?>?Cr?>?Cd?>?As?～?Co?～?Ni?～?Se and no potential health risk due to metal toxicity from average consumption. For sites that had high levels of Cd and Pb, bioaccumulation occurred from atmospheric deposition. Concentrations of elements in soil were found to be in decreasing order of Fe (1059–63747?mg kg^?1) > Ca (1048–41475?mg kg^?1) > Mg?>?Mn (9.76–174?mg kg^?1) > Cr (1.55–135?mg kg^?1) > Zn (0.76–58.2?mg kg^?1) > Se?>?Cu?>?Ni?>?Pb?>?Co?>?As?～?Cd with no evidence of heavy metal contamination. This study revealed that the plant inherently controlled uptake of essential elements according to physiological needs and that the concentrations of essential elements in the fruit could contribute positively to the diet.     

Diffusive gradient in thin FILMS (DGT) compared with soil solution and labile uranium fraction for predicting uranium bioavailability to ryegrass

The usefulness of uranium concentration in soil solution or recovered by selective extraction as unequivocal bioavailability indices for uranium uptake by plants is still unclear. The aim of the present study was to test if the uranium concentration measured by the diffusive gradient in thin films (DGT) technique is a relevant substitute for plant uranium availability in comparison to uranium concentration in the soil solution or uranium recovered by ammonium acetate. Ryegrass (Lolium perenne L. var. Melvina) is grown in greenhouse on a range of uranium spiked soils. The DGT-recovered uranium concentration (C_DGT) was correlated with uranium concentration in the soil solution or with uranium recovered by ammonium acetate extraction. Plant uptake was better predicted by the summed soil solution concentrations of UO₂²⁺, uranyl carbonate complexes and UO₂PO₄⁻. The DGT technique did not provide significant advantages over conventional methods to predict uranium uptake by plants.     

Interaction of DNA with aromatic hydrocarbons fraction in atmospheric particulates of Xigu District of Lanzhou, China

Voluminously epidemiological studies show that the relationships exist between the air pollution and human health and cancer. Aromatic hydrocarbons(AHs)in air form a large class of organic pollutants,which are widely in environment and many of them are known to be carcinogenic and/or mutagenic and contribute to ambient air pollution.In the past decades,bioassays mainly have been used to evaluate the toxicity of chemical mixtures in atmospheric particulates or aqueous environment.However,it is well known that the covalent complexes formed by carcinogens with DNA may be exert negative results in bioassay.So the main aim of this paper is to develop an evaluation method of toxicity effects of chemical mixtures in atmospheric particulates from chemical standpoint.In this study,the in vitro interaction of the AHs with DNA was investigated by absorption,fluorescence and resonance light scattering (RLS)spectroscopic techniques.The results showed that the AHs in the atmospheric particulates could combine with calf thymus DNA(ctDNA)and herring sperm DNA(hsDNA)without being activated or metabolized by organism,respectively.Intercalation may be present in the mechanism of interaction.The binding constants of the AHs with ctDNA and hsDNA were 2.5×10~2 and 2.0×10~3, respectively,which indicated that the interaction of the AHs with hsDNA is stronger than that with ctDNA.In addition,the relationships of dose-effect between the total mole concentration of chemical components and the ability of binding ctDNA and hsDNA were confirmed.This research made it possible to study the toxicity effects of chemical mixtures in atmospheric particulates by chemical method.It is believed that the composition and contents of unknown AHs and the interaction of DNA with AHs in atmospheric particulates of Xigu District of Lanzhou City,China are first reported in the past twenty years.     

碱性矿化水灌溉的淋洗分数

耐盐碱试验表明,在生育期内,小麦耐盐能力强于玉米,而耐碱能力弱于玉米.利用0.5-3.5 g/L的碱性矿化水灌溉时,淋洗分数约为4.4%～7.5%.相应地,需要增加的补水量小麦地为3181～     

石油污染地下水有机污染组分特征及其环境指示效应

通过采集我国北方某污染场地地下水样品,用GC-MS扫描分析石油烃成分及含量,研究油田开采情况下石油烃污染物在地下水中的分布变化及其对环境的指示作用.结果表明,地下水中总石油烃(TPH)均值为4.75mg/L;组分包括烷烃、芳香烃、酯类、醛类以及醇类等有机化合物,烷烃类含量最高,占总油百分含量平均值为65.6%;沿着地下水流向烷烃和芳香烃所占百分含量减少,分别从70.05%和14.56%下降至57.72%和10.58%,而非烃类逐渐富集,其百分含量从15.39%增加至31.72%.由样品色谱参数可知:场地Pr/Ph值在0.73~1.27之间,表明地下水处于缺氧的还原环境;Pr/C17值在0.42~1.51之间;Ph/C18值在0.61~1.30之间,指示出较强的微生物作用;细菌数与非烃类含量、Pr/C17以及Ph/C18之间呈现出正线性相关性,Pr/C17和Ph/C18值越大微生物作用越强.不同季节对石油烃浓度变化也有一定影响.     

Cr(VI) reduction capability of humic acid extracted from the organic component of municipal solid waste

The capacity of humic acid extracted from organic waste (HAw) to reduce Cr(Ⅵ) was tested at pH 2.5,4 and 6 and compared with coal-derived humic acid (HAc).HAw was more effective than HAc in reducing Cr(Ⅵ).The kinetics of Cr(Ⅵ) reductions depended strongly on pH.The calculation of the apparent rate coefficients indicated that HAw was more efficient at reducing Cr(Ⅵ) than HAc,but was also more efficient than HAs from soil and peat.The reduction capability of HAs depends on the type of functional groups (i.e.,thiols and phenols) present,rather than the free radicals.HAw was more efficient at reducing Cr(Ⅵ) than HAc because more reactive phenols were present,i.e.,methoxy-and methyl-phenols.     

2015年南京市城区挥发性有机物组成特征及大气反应活性

采用GC-FID自动在线监测系统对南京市2015年环境大气中56种VOCs开展了为期1a的连续观测.结果表明,南京市城区大气VOCs小时平均体积分数为（17.49±11.35）×10^-9,其中4月最高（22.21×10^-9）,7月最低（12.39×10^-9）,日均体积分数变化特征不明显.烷烃、烯烃、芳香烃和乙炔占比分别为56.51%、11.06%、24.62%和7.81%,丙烷（15.26%）、乙烷（14.14%）、乙炔（7.81%）、甲苯（6.97%）、正丁烷（6.23%）、乙烯（5.23%）、异丁烷（4.34%）、丙烯（4.13%）、异戊烷（4.12%）和间/对-二甲苯（4.06%）是含量最丰富的VOCs物种.T/B（甲苯/苯）均值为2.02,表明南京市城区大气VOCs主要受机动车尤其是汽油车排放的影响.E/E（乙烷/乙炔）均值为2.24,表明观测站点区域大气老化程度较严重.利用·OH消耗速率（L^·OH）和臭氧生成潜势（OFP）评估了大气VOCs的反应活性.南京市城区大气VOCs冬春季大气反应活性较夏秋季强.芳香烃和烯烃的活性最高,对L^·OH和OFP的贡献依次为46.96%和41.58%、33.73%和39.86%,丙烯、乙烯和二甲苯等苯系物是活性最高的VOCs物种.     

两步连续提取法测定植物中重金属的形态

重金属在植物体内的迁移、转化很大程度上取决于它们的化学形态。文章提出了一种简化的两步连续提取法,根据元素在植物体内活动性的大小,将重金属依次分为乙醇提取态、盐酸提取态和残渣态。采用标准物质(茶叶)对连续提取方法的回收率和精密度进行验证。16次重复测定Cu、Pb、Zn、Cd、Fe和Mn六种重金属元素,3种形态含量之和占各元素总量的82%~116%之间,回收率满足形态分析的要求;各形态含量分析的相对标准偏差,除了Zn、Pb和Cd 3种元素的乙醇态和残渣态在32%~57%之间外,其余均小于20%,表明本方法具有较好的精密度,能满足分析要求。利用蔬菜基地采得的10份植物样品(黄瓜的根、茎、叶片和果实)考察了该方法对不同类型植物样分析的实际应用情况。结果表明,对于根、茎、叶和果实不同植物样品,各元素的3种形态之和占总量的84.6%~106%,回收率满足形态分析的要求。     

Steam Reforming of Bio-Oil Aqueous Fractions for Syngas Production and Energy

Abstract The biorefinery concept has been proposed as a route map to convert biomass into fuels and chemicals, maximizing economic and environmental benefits while minimizing pollution. A biorefinery strategy based on fast pyrolysis is proposed following a two-stage process, where biomass is first subjected to fast pyrolysis, optimized to collect up to 75% (per unit weight of biomass) of a liquid fraction called bio-oil. This bio-oil or its fractions can be upgraded in a second step to different chemicals, to a syngas and/or to energy. In particular, the catalytic steam reforming of the aqueous fraction of bio-oil obtained by fractionation with water is one of the most attractive possibilities for bio-oil upgrading, yielding a H2-rich syngas with low CO content. From the results obtained, it can be concluded that the best alternative for the catalytic steam reforming process is hydrogen production through further purification of the gas obtained.