Organic marker compounds in surface soils of crop fields from the San Joaquin Valley fugitive dust characterization study
Organic marker compounds in surface soils of crop fields from the San Joaquin Valley fugitive dust characterization study
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DOI：
10.1016/j.atmosenv.2007.06.030
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发表时间：
2007-12
影响因子：
5
通讯作者：
W. Rogge;P. Medeiros;B. Simoneit
中科院分区：
文献类型：
--
作者：
W. Rogge;P. Medeiros;B. Simoneit
收获后和农业活动期间干旱和休耕土地侵蚀产生的飘尘有时可能是空气中颗粒物的主要来源。为了评估源对给定站点的贡献，化学质量平衡（CMB）模型通常与有机和无机成分的源特定配置文件一起使用。然而，只有考虑到所有主要来源的排放概况，才能实现质量平衡闭合。虽然通过在元素、离子、EC和有机碳（OC）中添加单独的有机标记化合物，实现了更高程度的质量平衡闭合，但扬尘的主要来源概况尚不可用。因此，既不知道生活在农田扬尘源附近的人口的暴露情况，也不知道其化学成分。作物田的表层土壤富含来自地上和地下植物部分的植物碎屑;因此，表层土壤灰尘含有来自作物和土壤微生物群的天然有机化合物。在这里，来自种植棉花，红花，番茄，杏仁和葡萄的土壤表层已经分析了180多种有机化合物，包括天然脂质，杀虫剂，除草剂和多环芳烃（PAH）。这项研究的主要结果是，选择性的生物源性有机化合物是合适的标志物，从主要的农业作物领域在圣华金河谷扬尘。脂肪族同系物表现出典型的生物特征的epicuticular植物蜡，并因此指示扬尘排放和机械磨损的蜡突起从叶表面。其中α-和β-葡萄糖、蔗糖和海藻糖在表层土壤中的浓度最高，已被认为是耕地扬尘的一般标志物。同样，类固醇也强烈表明有粉尘飞扬。然而，三萜类化合物揭示了最明显的分布差异，所有类型的耕作土壤在这里检查，本身是强大的标志，允许区分作物栽培类型之间的扬尘。多环芳烃也存在于一些表层土壤中，以及持久性农药，例如，DDE、Fosfall和其他。
Fugitive dust from the erosion of arid and fallow land, after harvest and during agricultural activities, can at times be the dominant source of airborne particulate matter. In order to assess the source contributions to a given site, chemical mass balance (CMB) modeling is typically used together with source-specific profiles for organic and inorganic constituents. Yet, the mass balance closure can be achieved only if emission profiles for all major sources are considered. While a higher degree of mass balance closure has been achieved by adding individual organic marker compounds to elements, ions, EC, and organic carbon (OC), major source profiles for fugitive dust are not available. Consequently, neither the exposure of the population living near fugitive dust sources from farm land, nor its chemical composition is known. Surface soils from crop fields are enriched in plant detritus from both above and below ground plant parts; therefore, surface soil dust contains natural organic compounds from the crops and soil microbiota. Here, surface soils derived from fields growing cotton, safflower, tomato, almonds, and grapes have been analyzed for more than 180 organic compounds, including natural lipids, saccharides, pesticides, herbicides, and polycyclic aromatic hydrocarbon (PAH). The major result of this study is that selective biogenically derived organic compounds are suitable markers of fugitive dust from major agricultural crop fields in the San Joaquin Valley. Aliphatic homologs exhibit the typical biogenic signatures of epicuticular plant waxes and are therefore indicative of fugitive dust emissions and mechanical abrasion of wax protrusions from leaf surfaces. Saccharides, among which α- and β-glucose, sucrose, and mycose show the highest concentrations in surface soils, have been proposed to be generic markers for fugitive dust from cultivated land. Similarly, steroids are strongly indicative of fugitive dust. Yet, triterpenoids reveal the most pronounced distribution differences for all types of cultivated soils examined here and are by themselves powerful markers for fugitive dust that allow differentiation between the types of crops cultivated. PAHs are also found in some surface soils, as well as persistent pesticides, e.g., DDE, Fosfall, and others.