粤东凤凰山茶区土壤不同形态铅含量及其影响因素

Distribution Characteristics of Lead and Its Affecting Factors in the Tea Garden Soils of Fenghuang Mountain,East of Guangdong Province

通过对粤东凤凰山茶区12个大型茶园土壤和茶叶进行采样,采用连续提取法将茶园土壤Pb分为可交换态、碳酸盐结合态、铁锰氧化态、有机束缚态和残渣态,探讨茶园土壤Pb的5种化学形态分布与土壤理化性质、茶叶Pb含量的相关性关系。结果发现,土壤中Pb的5种化学形态分布的规律为残渣态>铁锰氧化态>交换态>有机束缚态>碳酸盐态。土壤有机质与可交换态Pb含量呈显著负相关,与碳酸盐结合态Pb呈极其显著负相关,而土壤pH值与土壤可交换态Pb呈显著负相关,与碳酸盐态Pb和有机束缚态Pb呈极其显著正相关。茶区12个茶园土壤样品的Pb生物有效性系数范围在0.029～0.113,平均值为0.061;Pb可迁移性系数范围在0.021～0.078,平均值为0.044。凤凰山茶叶Pb含量的范围在1.39～1.82 mg/kg之间,平均为1.56 mg/kg。茶叶中的Pb含量与土壤氧化物结合态Pb、有机束缚态Pb呈显著正相关,与土壤有机质呈极其显著正相关。

The fractionation of Pb in tea garden soils and the relationships between Pb fraction and soil properties,Pb contents in tea leaves were studied by collecting the tea garden soils from 12 tea gardens of Fenghuang mountain in east of Guangdong province.The results showed that the distribution of chemical fractions of Pb in the tea garden soils were decreased in the order： Residual-Pb〉Fe/Mn oxides-Pb〉exchangeable-Pb〉organic-Pb〉carbonate-Pb.Correlation analyses showed that soil organic matter was significantly negative correlated with ex-Pb and high significantly negative correlated with carb-Pb.Soil pH was high negative correlated with ex-Pb,significantly positive correlated with carb-Pb and or-Pb.The bioavailability characteristic of Pb in 60 soils of tea gardens was between 0.029 and 0.113,0.061 in average.The mobility characteristic of Pb in 60 soils of tea gardens was between 0.021 and 0.078,0.044 in average.In addition,results showed that the Pb contents in tea leaves were between 1.39 mg/kg and 1.82 mg/kg,1.56 mg/kg in average.What＇s more,the significantly positive correlation was found between the Pb contents in tea leaves and Fe/Mn-Pb and or-Pb,high significantly positive correlated with soil organic matter.