Vegetable Oil Spills - Pollution Or Over-Cautiousness?

Vegetable oil spills are relatively uncommon compared to those of mineral oil in the marine environment. Evidence from the spillages that have occurred indicate that they can cause the death of animals in the vicinity through suffocation, inhibition of feeding and other non-specific toxic effects. Smothering of the intertidal area may lead to the development of anoxic conditions with associated changes in species diversity. Polymerisation appears to be a key process in determining the persistence of these oils in the intertidal region. Experiments have indicated that indigenous bacteria are capable of degrading the oil until it polymerises and work is being directed towards determining mechanisms to aid in the degradation process. in conclusion, vegetable oils are pollutants although the risk to the marine environment is small but that does not mean we should not be prepared for such events.     

Co-processing of DVDs and CDs with vegetable cooking oil by thermal degradation

Waste DVDs and CDs were thermally degraded at 450°C by a semibatch process. In total, 40–50 wt% was converted into liquid product that consisted of phenol derivatives (∼75 wt%), bisphenol (∼10 wt%) and its derivatives, and small amounts of aromatic hydrocarbons such as benzene, toluene, ethylbenzene, dimethylbenzene, methylethylbenzene, diethylbenzene, and methylisopropyl benzene. Degradation of the polycarbonate support from DVDs and CDs was enhanced by coprocessing with vegetable cooking oil, the degradation of which gave a homologue series of hydrocarbons and organic acids with up to 25 and 18 atoms of carbon, respectively. Silver from the reflective coating on DVDs and CDs remained in the solid residue, its concentration increasing about 2.5 times compared to that of the original disks.     

沈阳市农业污染现状的初步调查

区域化、规模化和集约化的生产方式促进了沈阳市蔬菜生产和畜牧业的快速发展 ,但是也带来了一些污染问题。调查表明 ,蔬菜的硝酸盐污染状况非常严重 ,多数叶菜类蔬菜的硝酸盐含量超标 ,其中 ,茼蒿菜的硝酸盐含量高达6687.9/ mg·kg- 1 ,超标近 9倍 ;由畜牧业生产各个环节引起的环境污染问题也日趋严峻。畜牧业生产专业村镇的空气和地下水污染严重 ,已对沈阳市及其周边地区小城镇的生态环境建设构成严重影响。     

云南寻定几种农作物籽粒中重金属的比较研究

通过对四种农作物（玉米、小麦、水箱、蚕豆）籽粒中八种重金属元素（Ｃｕ、Ｚｎ、Ｐｂ、Ｃｄ、Ｃｒ、Ｎｉ、Ａｓ、Ｈｇ）的调查研究。结果表明，四种农作物籽粒中重金属元素量与土壤重金属含量呈正相关，籽粒中重金属的吸收系数大致为Ｃｄ〉Ｚｎ〉Ｃｕ〈Ｐｂ，玉米籽粒Ｃｄ〈Ｚｎ、Ｃｕ，可能由于元素间的交互作用，Ｃｕ、Ｚｎ、Ｐｂ、Ｃｄ含量均处于较高水平，由于不同农作物和物的生物学特性之间的差异，Ｃｒ，Ｎｉ、Ａｓ、Ｈｇ在     

酸沉降区作物对汞的积累及其影响因素的研究

介绍了重庆市近郊的蔬菜含汞量随时距发电厂越近而浓度越高的趋势，蔬菜所生长的土壤及其附近的地下水含汞量，亦与蔬菜有类似的情况，但不同作物吸收汞的能力各异，不同来源的汞在作物在内的分布也不相同，来在大气的汞，大都集中地上部，来自土壤则大都聚积于根，土壤粘粒类型的差异，也对作物吸汞能力及汞在材料体内的分布有明显的影响，土壤肥力不单影响植物吸收土壤汞，而且制约作物吸收大气汞。     

宁波市蔬菜污染状况及防治对策

通过对宁波市蔬菜基地的蔬菜中有害物残留和累积状况的调查发现，菜区土壤及蔬菜都不同程度地受到了硝酸盐，重金属等有这物质的污染，其污染程度随物质类型、性质及数量而不同。如蔬菜中硝酸盐含量平均达８１７ｍｇ／ｋｇ，亚硝酸盐平均为０．８２ｍｇ／ｋｇ，平均超标率分别为４７．６％和２８．６％；重金属中铜，镉、铬的超标率都在６０％以上。这种状况对人体健康含有潜在的威胁。必需有效地控制和加以防治，文章最后提出了一些     

银川地区菜田土壤和蔬菜中有害元素含量及污染程度评价

对银川地区菜地土壤和蔬菜中有害元素进行调查并作出初步评价.表明该地区菜田土壤中氟、铅、汞有一定程度污染,镉污染也已露头;一定比例的蔬菜中,受到轻污染的元素有:铜、锌、铅、镉、砷和氟;汞在28.3％～53.2％的大白菜和青萝卜中受到中度及重度污染.     

珠江三角洲地区典型菜地土壤与蔬菜重金属分布特征研究

通过对珠江三角洲地区的广州市、佛山市、江门市和惠州市典型菜地土壤和蔬菜中重金属（Pb、Cr、Cd、As和Hg）含量及其土壤中有效态（Pb、Cr、Cd）含量的调查,分析蔬菜重金属污染状况与土壤重金属含量的相关性,探讨了土壤重金属含量、有效态含量与土壤理化性质的相关性。结果表明,菜地土壤主要受Pb、Cd、Hg污染。Pb、Cd主要以轻度污染为主;而Hg污染在广州市菜地土壤以轻度污染和重度污染为主,佛山市菜地土壤以中度污染和重度污染为主,江门市和惠州市菜地土壤以轻度污染为主。蔬菜主要受Pb、Cd、Hg污染,少数蔬菜受到Cr污染,但并未检测出蔬菜受As污染。蔬菜中重金属含量与土壤中Pb、Cr、Cd的总量、有效态含量之间呈显著正相关关系,与土壤中As、Hg的总量无显著相关性。土壤中Pb、Cr含量与土壤有机质含量、黏粒含量、粉粒含量均达到显著相关。土壤中有效Pb与有效锰含量呈显著负相关关系,土壤中有效Cr含量与土壤粘粒含量、有效铁含量呈极显著正相关关系。     

Mercury contamination and health risk to crops around the zinc smelting plant in Huludao City,northeastern China

The Huludao zinc plant in Liaoning province, northeast China was the largest in Asia, and its smelting activities had seriously contaminated soil, water and atmosphere in the surrounding area. For the first time, we investigated the total mercury (THg) content in maize, soybean, broomcorn, 22 vegetables, and the soil around their roots from eight sampling plots near the Huludao zinc plant. THg contents of the seeds of maize, soybean, and broomcorn are 0.008, 0.006, and 0.057 mg kg⁻¹, respectively, with the broomcorn being the highest, exceeding the maximum level of contaminant in food (GB2762-2005) by 4.7 times. The edible parts of vegetables are also contaminated with a range of mercury contents of 0.001–0.147 mg kg⁻¹ (dry weight). THg contents in plant tissue decrease in the order of leaves > root > stalk > grain. Using correlation analysis, we show that mercury in the roots of these plants is mainly derived from soil, and the uptake of gaseous mercury is the predominant path by which the mercury accumulated in the foliage. The average and maximum mercury daily intake (DI) of adult around the Huludao zinc plant via consuming vegetables are 0.015 and 0.051 μg/kg/d, respectively, and those of children are 0.02 and 0.07 μg/kg/d, respectively. The average and maximum weekly intakes of total mercury for adult are 2.1 and 7.1%, respectively, of the provisional tolerable weekly intake (PTWI), and 2.8 and 9.7%, respectively, of the PTWI for children.     

The fate of exogenous iodine in pot soil cultivated with vegetables

A pot experiment was conducted to explore a more effective approach to enhancing vegetable uptake of soil iodine, with the ultimate goal of using agricultural fortification as a measure to prevent iodine deficiency disorders in local communities. Two types of iodine fertilizers were added separately to pot soil samples at various dosages. The fortified soil in each of the flower pots was seeded with one of four test crops (pakchoi, celery, pepper, and radish) in an effort to examine the effect of vegetable cultivation. The fate and residual levels of the exogenous iodine in the fortified soil samples were then monitored and quantified. The data showed that the soil iodine contents decreased with time (and hence with plant growth as well). At the second cutting, iodine from the inorganic form (KI) as the exogenous source was reduced to approximately 50% (41.6–61.0%) of the applied dose, whereas that in soil fortified with the seaweed fertilizer was down to approximately 60% (53.9–71.5%). The abilities of the edible portion of the four vegetables in accumulating the soil iodine were as follows: pakchoi > celery > radish > pepper. On the whole, iodine residues were found less in soil cultivated with vegetables. Vegetable cultivation appeared to have enhanced the soil content of the water-soluble form of iodine somewhat, especially in soil fortified with the inorganic forms. There also appeared to be a significant negative correlation between the residual iodine and its dissolution rate in soil. Overall, the results of the present study pointed toward the direction that the seaweed fertilizer tends to be a (more) preferred source of agricultural fortification in promoting human iodine nutrition.