Soil properties and agronomic factors affecting cadmium concentrations in cacao beans: A nationwide survey in Ecuador
Soil properties and agronomic factors affecting cadmium concentrations in cacao beans: A nationwide survey in Ecuador
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DOI：
10.1016/j.scitotenv.2018.08.292
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发表时间：
2019-02-01
影响因子：
9.8
通讯作者：
Montalvo, Daniela
中科院分区：
文献类型：
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作者：
Arguello, David;Chavez, Eduardo;Montalvo, Daniela
最近巧克力中的镉（Cd）法规威胁到美国西南部可可生产的可持续性。可可豆中的镉污染尚未在国家一级进行评估。在厄瓜多尔进行了一项全国性调查，以确定可可豆中Cd的空间分布以及所涉及的土壤和农艺因素。在560个地点收集了成对的土壤和植物样本（豆荚和叶子）。通过为农民准备的调查表获得了有关农艺做法的资料。土壤总镉平均为0.44 mg kg(-1)，这是典型的年轻和无污染土壤。去皮豆中Cd的平均浓度为0.90 mg kg(-1)， 45%的样品超过了0.60 mg kg（-1）的阈值。在7个省的一些地区确定了豆cd热点。多因素回归分析表明，大豆Cd浓度随土壤总Cd的增加和土壤pH、草酸可提取锰（Mn-ox）和有机碳（OC）的降低而增加（R-2 = 0.65），表明Cd在土壤中的溶解度主要影响Cd的吸收。随着果园树龄从4年增加到40年，豆Cd浓度降低了1.4倍。大豆Cd浓度受基因型（CCN-51 vs. Nacional）、修剪或施肥的影响不一致。由此得出结论，厄瓜多尔大豆Cd浓度较高与其在幼嫩土壤上种植的高Cd吸收能力有关，而不是与Cd贫化风化土壤有关。缓解战略应考虑采用修正措施来改变这种土壤性质，以降低土壤镉的可用性。采用遗传缓解策略来减少大豆Cd是有可能的，但这需要进行适当的调查。(C) 2018 Elsevier B.V.版权所有
Recent cadmium (Cd) regulation in chocolate threatens the sustainability of cacao production in Southwest America. Cadmium contamination in cacao beans has not been assessed at a country level. A nationwide survey was conducted in Ecuador to identify the spatial distribution of Cd in cacao beans, as well as soil and agronomic factors involved. Paired soil and plant samples (pods and leaves) were collected at 560 locations. Information on agronomic practices was obtained through a prepared questionnaire for farmers. Total soil Cd averaged 0.44 mg kg(-1) which is typical for young and non-polluted soils. Mean Cd concentration in peeled beans was 0.90 mg kg(-1) and 45% of samples exceeded the 0.60 mg kg(-1) threshold. Bean Cd hotspots were identified in some areas in seven provinces. Multivariate regression analysis showed that bean Cd concentrations increased with increasing total soil Cd and with decreasing soil pH, oxalate-extractable manganese (Mn-ox) and organic carbon (OC) (R-2 = 0.65), suggesting that Cd solubility in soil mainly affects Cd uptake. Bean Cd concentration decreased a factor of 1.4 as the age of the orchard increased from 4 to 40 years. Bean Cd concentration was inconsistently affected by genotype (CCN-51 vs. Nacional), pruning or application of fertilizers. It is concluded that the relatively larger bean Cd concentrations in Ecuador are related to the high Cd uptake capacity of the plants combined with their cultivation on young soils, instead of Cd depleted weathered soils. Mitigation strategies should consider the application of amendments to modify such soil properties to lower soil Cd availability. There is scope for genetic mitigation strategy to reduce bean Cd, but this needs to be properly investigated. (C) 2018 Elsevier B.V. All rights reserved.