Anaerobic digestion in mesophilic and room temperature conditions: Digestion performance and soil-borne pathogen survival

Tomato plant waste(TPW) was used as the feedstock of a batch anaerobic reactor to evaluate the effect of anaerobic digestion on Ralstonia solanacearum and Phytophthora capsici survival. Batch experiments were carried out for TS(total solid) concentrations of 2%, 4% and 6% respectively, at mesophilic(37 ± 1°C) and room(20–25°C) temperatures. Results showed that higher digestion performance was achieved under mesophilic digestion temperature and lower TS concentration conditions. The biogas production ranged from 71 to 416 L/kg VS(volatile solids). The inactivation of anaerobic digestion tended to increase as digestion performance improved. The maximum log copies reduction of R. solanacearum and P. capsici detected by quantitative PCR(polymerase chain reaction) were 3.80 and 4.08 respectively in reactors with 4% TS concentration at mesophilic temperatures. However, both in mesophilic and room temperature conditions, the lowest reduction of R. solanacearum was found in the reactors with 6% TS concentration, which possessed the highest VFA(volatile fatty acid) concentration. These findings indicated that simple accumulation of VFAs failed to restrain R. solanacearum effectively, although the VFAs were considered poisonous. P. capsici was nearly completely dead under all conditions. Based on the digestion performance and the pathogen survival rate, a model was established to evaluate the digestate biosafety.     

有色冶金区土壤-蔬菜系统重金属污染特征及健康风险分析

采用对应采样方法研究大冶有色冶炼厂周围地区土壤、蔬菜中Cd、Cu、Pb和As的含量,并对蔬菜重金属污染状况、富集能力及健康风险进行了分析。结果表明,研究区土壤重金属污染严重,Cd、Cu、Pb和As平均含量分别达5.28、193.37、93.83和36.56 mg/kg,分别为湖北省对应元素土壤背景值的31.06、6.30、3.51和2.97倍,表现为以Cd为主的多种重金属共同污染。与《食品中污染物限量》(GB2762-2012)标准比较,蔬菜中Cd和Cu含量的样本超标率分别为68%和6%,而As、Pb的含量均不超标。蔬菜中重金属富集能力的排序为:CdCuAsPb,叶菜类蔬菜对Cd、Cu、Pb和As的富集系数均高于非叶菜类蔬菜。土壤和蔬菜重金属综合质量指数达10.07,为重度污染。研究区人群通过蔬菜摄入As、Cd的目标危险系数均大于1,存在As、Cd暴露的健康风险;成人和儿童食用蔬菜而摄入重金属的TTHQ分别为2.11~5.06和2.78~6.64,儿童比成人遭受的健康风险更大,并且距离冶炼厂越近,所遭受的健康风险越大。蔬菜中重金属的复合污染已使大冶有色冶炼厂周围居民面临潜在的健康风险。     

植物油烟组分的色质联机分析

将植物油烟采集在玻璃纤维滤筒中 ,用环己烷处理样品 ,样品经过净化处理 ,然后进行色质联机分析。对油烟化学成分的分析有助于人们研究油烟对人体健康的影响     

啤酒废水灌溉对6种蔬菜硝酸盐亚硝酸盐含量的影响

通过啤酒废水灌溉对６种蔬菜硝酸盐等的影响研究认为：啤酒废水灌溉对６种蔬菜灰分含量无明显影响；明显提高莴苣、马铃薯和甘蓝中维生素Ｃ的含量；提高韭菜、莴苣和甘蓝硝酸盐的含量；降低大葱硝酸盐的含量；可提高韭菜和马铃薯中亚硝酸盐的含量，而对于大葱、莴苣、小白菜和甘蓝中亚硝酸盐含量无明显影响     

重庆市无公害蔬菜基地环境和产品质量评价标准初探

通过对重庆市环境污染情况的调查分析 ,结合现行的国家相关环境质量标准和食品卫生标准 ,提出了适合重庆市无公害蔬菜基地建设的环境质量和产品质量评价标准体系 ,为建立规范化、标准化绿色蔬菜基地打下了基础     

上海城郊大棚蔬菜地土壤总硝化与反硝化作用研究

通过BaPS技术对上海城郊大棚蔬菜地土壤总硝化和反硝化作用速率进行了测定，利用因子分析对影响土壤硝化和反硝化的主要因素进行了分析，结果表明：各大棚蔬菜地土壤总硝化、反硝化速率差异性显著（〖WTBX〗p〖WTBZ〗<001），其中土壤总硝化速率为17758～45726 Nug/kg·h，土壤反硝化速率为23151～415 Nug/kg·h，土壤总硝化作用速率与与土壤容重呈显著性负相关（〖WTBX〗p〖WTBZ〗<005），与硝态氮含量呈极显著性正相关（〖WTBX〗p〖WTBZ〗<001），土壤反硝化作用与土壤含水量呈显著性正相关（〖WTBX〗p〖WTBZ〗<005），与土壤有机质、硝态氮呈极显著性正相关（〖WTBX〗p〖WTBZ〗<001）。土壤含水量、土壤有机质含量、土壤硝态氮含量、土壤容重是影响土壤总硝化和反硝化作用的主要因素，四项指标能概括所测定全部指标包含信息的80%以上；土壤硝化作用和反硝化作用对土壤N2O排放的贡献率分别为475%、525%，土壤硝化和反硝化作用均对大棚蔬菜地土壤氮损失产生影响     

天津污灌区内气态汞的污染特征及在叶菜类蔬菜中的富集

污灌区土壤相当于一个巨大的汞(Hg)源向水体和大气释放汞,挥发的气态汞可以通过植物叶片的气孔进入植物体内,严重威胁着当地农产品安全及人类健康.天津污灌区是汞污染的重灾区之一,本研究选取天津污灌区内某稻田(污灌约30a)、菜田(污灌约15 a)和污灌区边缘某草地(无污灌史,对照)作为监测地点,以5种常见叶菜(菠菜、苋菜、油菜、生菜、韭菜)作为生物监测实验对象,考察污灌区内产地土壤、大气汞的浓度及其在叶菜中的富集特征.结果表明:1经过长期污灌,稻田和菜田土壤汞含量已显著高于区域土壤汞背景含量和土壤环境质量标准一级标准,但未超过二级.对照草地土壤汞含量在背景含量与一级标准之间.稻田和菜地大气环境已受到较为严重的汞污染,气态总汞均值分别为71.3 ng·m-3和39.2ng·m-3,远高于北半球大气总汞含量的背景水平(1.5~2.0 ng·m-3),对照草地总汞含量平均为9.4 ng·m-3.2叶菜汞含量与污灌区气态汞含量对数之间呈现极显著的线性关系,5种叶菜对污灌区气态汞的敏感程度依次为菠菜>苋菜>韭菜>油菜>生菜.菠菜和苋菜Hg含量的中位值及平均值均超出食品卫生限量标准,其中菠菜的中位值及均值在20μg·kg-1以上,其余3种叶菜中位值及均值在限量值标准以下.3污灌区内叶菜Hg来源主要通过叶片吸收气态汞进入植株体内,而非颗粒态汞.研究表明在污灌地区种植叶菜,不仅需要考虑土壤污染的因素,也需要考虑气态汞暴露的风险.     

基于地统计学和GIS的土壤和蔬菜重金属的环境质量评价

以浙江省上虞市东关镇为例,利用地统计学与GIS技术相结合的方法揭示了该地区土壤与蔬菜重金属含量的空间分布特征,并评价其重金属的环境质量状况,在参照评价标准的基础上,绘制了土壤与蔬菜重金属的空间分布图,并对其成因进行了探讨.结果表明:东关镇大部分田块存在着重金属分布不均的情况;Cu、Zn的含量偏低,Pb、Cd含量偏高;全镇土壤和蔬菜重金属含量的空间变异很大,土壤重金属的全量与有效态含量之间存在显著的正相关,空间分布存在一定相似形,与蔬菜的空间分布则存在很大的区别,蔬菜重金属含量与土壤重金属的含量有一定的相关性,基本都未达到显著水平;小青菜中Zn和Cu的含量未超标,Pb、Cd则超标.     

3种水生蔬菜对稀土元素钷的吸收与富集

应用放射性核素示踪技术 ,研究了 3种水生蔬菜 (慈姑、荸荠和水芹菜 )对稀土元素钷 (14 7Pm)的吸收与富集。结果表明 :(1 ) 3种水生蔬菜对14 7Pm均有较强的吸收与富集能力。其中 ,水芹菜随生长时间的延长 ,吸收14 7Pm的量明显增加 ,50、80、1 1 0d时全样的吸收系数分别为 0 98± 0 1 9、0 92± 0 3 8和 1 1 4± 0 1 8;(2 ) 3种蔬菜的食用器官 (水芹菜的主茎 ,慈姑和荸荠的球茎 )对14 7Pm具有明显的富集性 ,吸收系数分别为 1 2 9± 0 2 8、2 0 9± 0 0 3和 1 55± 0 55     

Emission and Performance Characteristics of a 2 Litre Toyota Diesel Van Operating on Esterified Waste Cooking Oil and Mineral Diesel Fuel

Exhaust emission and performance characteristics were evaluated in a Toyota van, powered by a 21 indirect injection (IDI) naturally aspirated diesel engine, operating on vegetable based waste cooking oil methyl ester (WCOME).Tests were performed on a chassis dynamometer and the data were compared with previous results conducted on the same vehicle using mineral diesel fuel. The data obtained includes smoke opacity, carbon monoxide (CO), carbon dioxide (CO₂), oxygen (O₂), nitrogen dioxide (NO₂), nitric oxide (NO), sulfur dioxide (SO₂) and brake power. Engine lubricating oil samples were also taken. Results from this study indicated a difference of approximately 9% in brake power between the two fuels. WCOME developed a significant lower smoke opacity level and reduced CO, CO₂, SO₂ emissions. However, O₂, NO₂ and NO levels were higher with the vegetable oil based fuel. Power values were comparable for both fuels. Lubricating oil analysis gave little change of viscosity and wear metal concentrations after 2887km were: Silicon 35ppm, Chromium 3.3ppm, Iron 33.8ppm, Copper 14.1ppm and lead 78.6ppm.