大棚土壤和番茄中Cd含量及其生物有效性

为研究杨凌区大棚土壤和番茄Cd含量及其生物有效性,在该区主要大棚蔬菜产业带采集土壤和番茄样品,对土壤中总量和有效态Cd含量以及上述土壤中生长的番茄中Cd含量进行了测定。结果表明,李台乡大棚土壤Cd含量最高,平均值为0.278 mg/kg。与杨凌土壤背景值(0.108 mg/kg)相比,大棚Cd含量表现出明显的Cd累积效应,但仍低于温室土壤环境质量评价指标限值。有效态Cd含量占Cd总量的百分数分别为14.7、23.9和29.6%。土壤总量和有效态Cd含量之间呈极显著的正相关性。Cd在番茄体内含量为叶片>果实。按照国家Cd食品卫生限量标准(GB2526-2005)限量值,杨凌区大棚番茄果实均无超标样本。番茄对Cd的富集能力受到土壤有效态Cd含量的影响,并随有效态Cd含量的增加而增加。土壤有效态Cd含量与番茄叶片Cd含量之间达到极显著正相关。土壤Cd总量、有效态Cd含量与番茄果实Cd含量未表现出明显的正相关性;番茄叶片Cd含量与果实Cd含量之间表现出弱的正相关性。杨凌区大棚土壤Cd累积明显,大棚种植番茄适应当地土壤环境条件。

Content and Bioavailability of Cd in Soil and Tomato of Greenhouse

To assess the bioavailability posed by Cd content in soil and tomato of Yangling greenhouse.The results could be used to guide vegetable safety evaluation.According to the main greenhouse vegetable industry belt gather soil and tomato sample.The Cd content of greenhouse soil and leaf and fruit of tomato were investigated with measurement of the total content and available content of Cd,and their correlation coefficient were also measured.Total Cd content is the highest in Litaixiang,is 0.278 mg/kg.Compared to the background value of Yangling(0.108 mg/kg),display obvious Cd cumulative effect,but still was lower than the environmental quality evaluation standard for farmland of greenhouse vegetables production limits.Litaixiang,Wuquanzhen and Yangcunxiang's Cd available content state the percentage of the total Cd were 14.7,23.9 and 29.6%.There exist significantly positive correlations between the total and available Cd content.Cd content in tomato: leaf > fruit.According to state maximum levels of Cd in foods(GB2526-2005),the vegetables haven't exceeded standard samples.The significantly positive correlations were found between available Cd content and Cd content in tomato leaf.The correlations are not much positive between the above data for fruits and the total Cd and available Cd content;the Cd content in leaf and the Cd content in fruit have little positive correlation.Cd accumulated obviously in greenhouse soil of Yangling,planting tomatoes suited to the local soil conditions.