Simulating the influence of snow on the fate of organic compounds
Simulating the influence of snow on the fate of organic compounds
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DOI：
10.1021/es035105r
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发表时间：
2004-08-01
影响因子：
11.4
通讯作者：
Wania, F
中科院分区：
文献类型：
--
作者：
Daly, GL;Wania, F
为了研究降雪对不同环境介质中有机污染物浓度的影响，将积雪、季节性积雪和动态水量平衡纳入非稳态通用多媒体命运模型。雪对大块非极性有机蒸气和颗粒结合的有机化学品的有效清除可以降低冬季空气浓度，并使其融入积雪。积雪起到了临时蓄水池的作用，在冬季短暂的融化期间释放出累积的污染物，导致空气、水和土壤中的浓度暂时升高。这些峰值的强度随着积雪时间的延长而增加。足够挥发性的有机化学品(logK-OA和lt；9；例如，轻质多氯联苯)可以从积雪中挥发，导致大气中春季浓度达到最大值。在融雪过程中，相当易溶的化学物质的行为取决于它们对新形成的液态水相和迅速减少的冰面的相对亲和力--由它们的界面水分配系数(K-IW)定量表示。偏爱溶解相(低K-IW；例如五氯苯酚)的化学物质可能在第一个熔水组分中变得丰富，并在湖泊和河流中经历一个临时的浓度峰值。既不足以从积雪中蒸发的挥发性有机化学品，也不足以在融水中溶解的有机化学品(如多溴联苯醚)会吸附到积雪中的颗粒。这些颗粒在融雪期间释放时，可能受到足够的污染，构成了进入陆地环境的主要输入途径。由于冬季积雪的沉积量可能高于未被积雪覆盖的表面，从长远来看，这可能会导致土壤中持久性有机污染物的浓度更高。峰值暴露的潜在生态毒理学意义要求更好地了解雪在有机污染物命运中的作用。
Snow scavenging, a seasonal snowpack, and a dynamic water balance are incorporated in a non-steady-state generic multimedia fate model in order to investigate the effect of snow on the magnitude and temporal variability of organic contaminant concentrations in various environmental media. Efficient scavenging of large nonpolar organic vapors and particle-bound organic chemicals by snow can lead to reduced wintertime air concentrations and incorporation in the snowpack. The snow cover functions as a temporary storage reservoir that releases contaminants accumulating over the winter during a short melt period, resulting in temporarily elevated concentrations in air, water, and soil. The intensity of these peaks increases with the length of the snow accumulation period. Organic chemicals of sufficient volatility (log K-OA < 9; e.g., light polychlorinated biphenyls) can volatilize from the snowpack, resulting in springtime concentration maxima in the atmosphere. The behavior of fairly water-soluble chemicals during snowmelt depends on their relative affinity for the newly formed liquid water phase and the rapidly diminishing ice surface-quantitatively expressed by their interface-water partition coefficient (K-IW). Chemicals with a preference for the dissolved phase (low K-IW; e.g., pentachlorophenol) can become enriched in the first meltwater fractions and experience a temporary concentration peak in lakes and rivers. Organic chemicals that are neither volatile enough to evaporate from the snowpack nor sufficiently water soluble to dissolve in the meltwater (e.g., polybrominated diphenyl ethers) sorb to the particles in the snowpack. These particles may be sufficiently contaminated to constitute the major input route to the terrestrial environment upon release during snowmelt. Because wintertime deposition to the snowpack may be higher than to a non-snow covered surface, this can result in higher soil concentrations of persistent organic contaminants in the long term. The potential ecotoxicological significance of peak exposures demands a better understanding of the role of snow in the fate of organic contaminants.