镉在土壤-辣椒体系的迁移富集规律

Migration and Enrichment of Cadmium in Soil-pepper System

喀斯特碳酸盐岩区具有典型的重金属地质高背景特征,土壤镉(Cadmium)污染严重,存在镉的食物链风险。辣椒(Capsicum frutescens L.)是贵州省的特色农产品,镉在土壤-辣椒体系的迁移富集规律值得探讨。选择贵州地带性土壤黄壤(Yellow earth)与石灰(岩)土(Limestone soil),朝天椒、线椒及杂交椒3种类型辣椒进行盆栽试验,研究不同镉浓度水平下镉的迁移富集规律,结果显示:辣椒果实镉与土壤总镉和有效态镉呈极显著正相关,相关系数分别是0.80和0. 76,果实镉含量为0.01 mg·kg-1至0.30 mg·kg-1,以国家食品安全标准限值(GB 2762-2017)辣椒限值(0.05 mg·kg-1)进行评价,超标率为38.89%;黄壤中朝天椒根、茎、叶、果实各部位镉含量范围是0.21~17.10 mg·kg-1,线椒0.11~33.71 mg·kg-1,杂交椒0.17~8.58 mg·kg-1,石灰(岩)土中朝天椒0.17~2.03 mg·kg-1,线椒0.14~2.81 mg·kg-1,杂交椒0.22~2.31 mg·kg-1,三种类型辣椒间没有表现出明显的差异,黄壤上辣椒镉表现为根>茎、叶>果实,石灰(岩)土上为根、叶>茎、果实;在相同土壤镉浓度下黄壤中辣椒镉含量普遍高于石灰(岩)土,镉在石灰(岩)土-辣椒体系的富集系数和迁移系数分别是黄壤-辣椒体系的0.35~0.56倍和1.33~3.89倍,石灰(岩)土上辣椒镉表现为低富集,高转运,在黄壤上表现为高富集,低转运,具有更高的食物链风险。

In Karst carbonate rock area, heavy metals is with high geochemical background value, soil Cadmium pollution is serious, it could bring about environmental and ecological risks. Pepper is a special agricultural prod-uct of Guizhou Province, in order to explore the characteristics of migration and enrichment of Cd in the soil-pep-per system,2 of the zonal soil, the yellow earth and limestone soil with 3 Cd concentration, and 3different type of pepper ( hot pepper, line pepper and hybrid pepper) were selected to study. The results showed that there was a significant positive correlation between pepper Cd, total Cd and available Cd in soil, the correlation coefficients were 0.80 and 0.76, Cd content of pepper was 0.01 mg ?kg-1 to 0.30 mg* kg-1, it exceeded the standard rate of 38.89%, which evaluated by the national food safety standard ( GB 2762-2017);In yellow earth, Cd in the roots, stems, leaves and fruits of hot pepper was 0.21 ?17.10 mg? kg.1,line pepper was 0.11 ?33.71 mg*kg_ 1, hybrid pepper was 0.17 ~ 8.58 mg'kg"1, in limestone soil, hot pepper was 0.17 ~ 2.03 mg* kg"1, line pepper was 0.14?2.81 mg*kg_1, hybrid pepper was 0.22?2.31 mg*kg_1,there was no significant difference among 3 types of peppers, pepper Cd in yellow earth showed root > stem, leaf > fruit, in limestone soil showed root,leaf > stem, fruit;pepper Cd in yellow earth was generally higher than that in limestone soil, the enrichment and migra- tion coefficient of Cd in limestone soil-pepper system were 0.35 ?0.56 times and 1.33 ?3.89 times than its in yellow earth-pepper system, pepper Cd in limestone soil showed low enrichment, high migration characteristics, on the contrary, pepper Cd in yellow earth expressed high enrichment, low migration law, pepper Cd in yellow earth could bring much higher food chain risk.