Copper and zinc accumulation, fractionation and migration in vineyard soils from Santa Catarina State, Brazil

ABSTRACT The purpose of this study was to evaluate Cu and Zn migration and fractions in sandy soil of vineyards. In Urussanga (SC), Brazil, soil samples were collected from a 4-year-old and 15-yearold vineyard, and from a forested area. In the soils, the chemical characteristics of Cu and Zn were analyzed by the EDTA method, which determines the fraction available in soil; 3050B method of the USEPA for total concentrations, which represents the pseudo-soil contents in the soil; and chemical fractionation, which estimates soluble fraction, exchangeable fraction, fraction associated with clay minerals, fraction associated with organic matter and residual fraction. The results show that there is accumulation of Cu and Zn in sandy soils cultivated with grapevines and with frequent fungicide applications. These higher levels were found in soils with longer cultivation time (15 years old), but were restricted to the superficial layers of the soil. Most of the Cu was extracted by EDTA method, and it may be considered as available to plants. The EDTA also extracted a small part of Zn. Most of the Cu in the vineyard soils can be characterized by low geochemical mobility, but in the uppermost soil layers of the oldest vineyard, there was an increase in Cu content associated with soil organic matter. Most of the Zn in the vineyard soil was associated with minerals, which indicates low mobility and also low potential for toxicity to plants and microorganisms.

摘要 本研究旨在评估葡萄园砂质土壤中铜（Cu）与锌（Zn）的迁移行为及赋存形态。研究于巴西圣卡塔琳娜州乌鲁桑加（Urussanga）开展，分别从4年树龄、15年树龄的葡萄园以及一片林区采集土壤样本。针对土壤样品中的铜、锌化学特征，本研究采用三类分析方法：乙二胺四乙酸（EDTA）法用以测定土壤有效态组分；美国环境保护署（USEPA）的3050B法测定全量浓度，即土壤的准总含量；以及化学分级提取法，用以估算可溶态、交换态、黏土矿物结合态、有机质结合态及残留态五种组分。研究结果显示，在频繁施用杀菌剂的葡萄种植砂质土壤中，铜与锌发生了累积。累积量随种植年限增长而升高（15年树龄园区），且仅富集于土壤表层。多数铜可通过EDTA法提取，表明其对植物具有生物有效性。EDTA法仅可提取少量锌。葡萄园土壤中的多数铜表现出较低的地球化学迁移性，但在最老龄葡萄园的表层土壤中，与土壤有机质结合的铜含量有所升高。葡萄园土壤中的多数锌与矿物相结合，表明其迁移性较低，且对植物及微生物的毒性潜力也较低。