Monitoring of cadmium pollution by carrot

从冲绳以外的46个县的232个城镇和村庄采集了373个胡萝卜样本。根据地理特征和植被，将46个县分为北海道、东北、关东、北海、东海、近海、四国、中部和九州9个省，用日立Z9000无焰原子吸收光谱仪在228.8 nm波长处测定溶液中的镉。根据同一批样品10次重复分析的变异系数，CD评价的可信度为7.4%。在每10个胡萝卜样品(0.1g)中加入0.04μg的Cd进行回收试验。平均回收率为103%。由于373个胡萝卜样品中Cd含量的频率分布偏左，进行了对数变换。Cd的几何平均值和几何标准偏差分别为24.4 ng/g湿重和2.2 ng/g湿重。计算了日本9个省的胡萝卜样品中Cd含量的GMS和GSD。采用瑞安方法进行多重比较。中部胡萝卜中Cd含量最高(36.7 ng/g)，东北胡萝卜次之(36.1 ng/g)。Kinki胡萝卜中Cd含量最低(15.8 ng/g)。中部胡萝卜和东北胡萝卜的Cd含量显著高于东北胡萝卜和东北胡萝卜(p&lt；0.05)。20个样品中水稻和胡萝卜中Cd的相关系数为0.492(p&lt；0.05)，胡萝卜是监测Cd污染的理想指示性食物。

373 carrot samples were collected from 232 cities, towns and villages in 46 prefectures other than Okinawa. According to geographical features and vegetation, the 46 prefectures were divided into 9 provinces : Hokkaido, Tohoku, Kanto, Hokuriku, Tokai, Kinki, Shikoku, Chugoku and Kyushu.Cadmium (Cd) in the solutions was measured by a flameless atomic absorption spectrophotometer (AAS) (Hitachi Z9000) at a wavelength of 228.8 nm. The reliability of Cd assessment was 7.4%, in terms of the coefficient of variation of 10 repeated analyses of the same sample lot. A recovery test was conducted by adding 0.04μg of Cd to each ten carrot sample (0.1 gram). The recovery rate was 103% on average.As the frequency distribution of Cd content in the 373 carrot samples was skewed to the left, a logarithmic transformation was made. Geometric mean (GM) and the geometric standard deviation (GSD) of Cd were 24.4 ng/g wet weight and 2.2, respectively. The range was 2.1 to 179.1 ng/g wet weight.GMs and GSDs of the Cd contents of carrot samples from 9 provinces in Japan are calculated. Multiple comparison by the Ryan's method was conducted. Cd was highest (36.7 ng/g) in carrots from Chugoku, followed Tohoku (36.1 ng/g). Cd was lowest (15.8 ng/g) in carrots from Kinki. Cd contents of carrots from Chugoku and Tohoku were significantly higher than those of carrots from Hkuriku and Kinki (p<.05).Cd contents of carrots by soil type are also calculated. The highest Cd level was in the soil type Fluvisol (171.9 ng/g), and the lowest (50.1 ng/g) was in Cambisol.The correlation coefficient of Cd in rice and Cd in carrot using 20 samples was 0.492 (p<.05).The authors conclude that carrots are an ideal indicator food for monitoring of Cd pollution in other countries of the worlds as opposed to rice.