重庆市菜园土壤与蔬菜硝酸盐和亚硝酸盐含量及相关性研究

Nitrate and Nitrite Contents and Correlations of Vegetables with Soil in Chongqing

研究重庆4个农贸市场市售3大类19种蔬菜73个样品中硝酸盐含量及重庆市13个主要蔬菜基地土壤和蔬菜的硝酸盐、亚硝酸盐含量及相关性。结果表明,重庆市售蔬菜不同种类及同种蔬菜不同部位的硝酸盐含量差异显著。大小顺序为叶菜类(X=1 619.73 mg/kg)>茄果类(X=1 327.67 mg/kg)>葱蒜类(X=1 078.39 mg/kg);莴苣叶(X=1 567.91 mg/kg)>莴苣茎(X=1 871.62 mg/kg)。叶菜类全部超过了一级标准,污染指数高达9.09,污染程度最为严重;茄果类和葱蒜类超过一级标准的样本占81.3%和87.5%,污染指数分别高达8.85和6.56。重庆市13个主要蔬菜基地不同蔬菜以及同种蔬菜不同部位的硝酸盐含量差异也显著,大小顺序为萝卜叶(X=745.97 mg/kg)>莴苣茎(X=730.88 mg/kg)>莴苣叶(X=693.32 mg/kg)>白菜(X=617.63 mg/kg)>萝卜根(X=575.74 mg/kg)。土壤中NO3--N含量差异也显著,大小顺序为种植莴苣的土壤(X=75.24 mg/kg)>种植白菜的土壤(X=47.05 mg/kg)>种植萝卜的土壤(X=33.42 mg/kg)。蔬菜可食部分的硝酸盐与土壤中的NO3--N含量呈极显著正相关关系,线性方程y=407.872+4.796x。供试重庆市13个主要蔬菜基地土壤及蔬菜可食部分的NO2--N含量均较低且差异不显著,蔬菜中的亚硝酸盐含量和土壤中的NO2--N含量也无显著相关性。

Nitrate contents of 73 samples of 19 species of vegetables from three categories collected from four farmers' markets in Chongqing municipality were investigated. The contents of nitrate and nitrite in vegetables from 13 major vegetable planting bases in Chongqing were analyzed and correlated with those of soil samples from these planting bases. The results showed that significant differences in nitrate contents were observed among different vegetable species and different parts of the same species,and the decreasing order was leaf vegetables(X = 1 619.73 mg/kg) > solanaceous vegetables(X = 1 327.67 mg/kg) > allium vegetables(X = 1 078.39 mg/kg); and lettuce leaves(X = 1 567.91 mg/kg) >lettuce stems(X = 1 871.62 mg/kg). The content of nitrate in all leaf vegetables exceeded level I standard,showing a pollution index up to 9.09. About 81.3% of solanaceous vegetables and 87.5% of allium vegetables exceeded level I standard,and pollution index was up to 8.85 and 6.56,respectively. Significant differences in nitrate nitrogen were found among different vegetable species and among different parts of the same species from 13 vegetable planting bases,and the descending order was radish leaves(X = 745.97 mg/kg) > lettuce stems(X = 730.88 mg/kg) > lettuce leaves(693.32 mg/kg) > cabbages(X = 617.63 mg/kg) >radish roots(X = 575.74 mg/kg). Significant differences in nitrate nitrogen were also observed in soils from the vegetable bases,and the decreasing order was lettuce-growing soil(X = 75.24 mg/kg) > cabbage-growing soil(X = 47.05 mg/kg) >radish-growing soil(X = 33.42 mg/kg). Significant linear correlation of nitrate contents was found between vegetables and soils(y = 407.872 + 4.769x). The contents of nitrite in vegetables and soils from 13 vegetable bases were low,without showing significant differences. Moreover,no significant correlation of nitrite contents was found between vegetables and soils.