title: Heavy metals in navel orange orchards of Xinfeng County and their transfer from soils to navel oranges.
abstract: This study investigated heavy metal concentrations in soils and navel oranges of Xinfeng County, a well-known navel orange producing area of China. The results showed that the average concentrations of lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As) and mercury (Hg) in orchard soils all increased compared to the regional background values, especially for Cd, which increased by 422%. When compared to the Chinese Environmental Quality Standard for soil (GB15618-1995), Pb, Cr and Hg concentrations in all orchard soil samples were below the limit standards, but Cd concentrations in 24 soil samples (21%) and As concentrations in 8 soil samples (7%) exceeded the limit standards. However, concentrations of all heavy metals in navel orange pulps were within the National Food Safety Standard of China (GB 2762-2012). Dietary risk assessment also showed that the exposure to these five heavy metals by consumption of navel oranges could hardly pose adverse health effects on adults and children. Since the range and degree of soil Cd pollution was widest and the most severe of all, Cd was taken as an example to reveal the transfer characteristics of heavy metals in soil-navel orange system. Cd concentrations in different organs of navel orange trees decreased in the following order: root>leaf>peel>pulp. That navel oranges planted in the Cd contaminated soils were within the national food safety standard was mainly due to the low transfer factor for Cd from soil to pulp (TFpulp). Further studies showed that TFpulp was significantly negatively correlated with soil pH, organic carbon (OC) and cation exchange capacity (CEC). Based on these soil properties, a prediction equation for TFpulp was established, which indicated that the risk for Cd concentration of navel orange pulp exceeding the national food limit is generally low, when soil Cd concentration is below 7.30 mg/kg. If appropriate actions are taken to increase soil pH, OC and CEC, Cd concentrations in navel orange pulps could be further reduced.
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Jinjin
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Changfeng
authors.initials: C
authors.lastname: Ding
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Li
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Taolin
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China; Jiangxi Key Laboratory of Ecological Research of Red Soil, Ecological Experimental Station of Red Soil, Chinese Academy of Sciences, Yingtan 335211, PR China. Electronic address: xxwang@issas.ac.cn.
authors.forename: Xingxiang
authors.initials: X
authors.lastname: Wang
mesh_terms: D000328:Adult; D001151:Arsenic / Q000032:analysis* / Q000378:metabolism; D002244:Carbon / Q000032:analysis; D002648:Child; D002681:China; D032084:Citrus sinensis / Q000378:metabolism; D005506:Food Contamination / Q000032:analysis; D005638:Fruit / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy / Q000032:analysis* / Q000378:metabolism; D018570:Risk Assessment; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis* / Q000378:metabolism
chemical_list: D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D002244:Carbon; D001151:Arsenic
keywords: Cadmium; Food safety; Fruit trees; Prediction equation; Transfer characteristic