Whicker Jeffrey J, Pinder John E, Breshears David D
Los Alamos National Laboratory, Health Physics Measurements Group, Mail Stop J573, Los Alamos, NM 87545, USA.
J Environ Qual. 2006 Feb 2;35(2):468-78. doi: 10.2134/jeq2005.0112. Print 2006 Mar-Apr.
Assessments of contaminant-related human and ecological risk require estimation of transport rates, but few data exist on wind-driven transport rates in nonagricultural systems, particularly in response to ecosystem disturbances such as forest wildfire and also relative to water-driven transport. The Cerro Grande wildfire in May of 2000 burned across ponderosa pine (Pinus ponderosa Douglas ex P.&C. Lawson var. scopulorum Englem.) forest within Los Alamos National Laboratory in northern New Mexico, where contaminant transport and associated post-fire inhalation risks are of concern. In response, the objectives of this study were to measure and compare wind-driven horizontal and vertical dust fluxes, metrics of transport related to wind erosion, for 3 yr for sites differentially affected by the Cerro Grande wildfire: unburned, moderately burned (fire mostly confined to ground vegetation), and severely burned (crown fire). Wind-driven dust flux was significantly greater in both types of burned areas relative to unburned areas, by more than one order of magnitude initially and by two to three times 1 yr after the fire. Unexpectedly, the elevated dust fluxes did not decrease during the second and third years in burned areas, apparently because ongoing drought delayed post-fire recovery. Our estimates enable assessment of amplification in contaminant-related risks following a major type of disturbance-wildfire, which is expected to increase in intensity and frequency due to climate change. More generally, our results highlight the importance of considering wind- as well as water-driven transport and erosion, particularly following disturbance, for ecosystem biogeochemistry in general and human and ecological risk assessment in particular.
对与污染物相关的人类和生态风险进行评估需要估算迁移速率，但在非农业系统中，尤其是针对森林野火等生态系统干扰以及相对于水驱动迁移而言，关于风驱动迁移速率的数据很少。2000年5月的塞罗格兰德野火在新墨西哥州北部洛斯阿拉莫斯国家实验室范围内的黄松（Pinus ponderosa Douglas ex P.&C. Lawson var. scopulorum Englem.）森林中燃烧，在那里污染物迁移及相关的火灾后吸入风险备受关注。对此，本研究的目的是测量和比较受塞罗格兰德野火不同程度影响的地点（未燃烧、中度燃烧（火灾主要局限于地面植被）和重度燃烧（树冠火））3年内风驱动的水平和垂直沙尘通量，这是与风蚀相关的迁移指标。相对于未燃烧区域，两种燃烧区域的风驱动沙尘通量均显著更大，最初超过一个数量级，火灾后1年则大两到三倍。出乎意料的是，燃烧区域的沙尘通量在第二年和第三年并未下降，显然是因为持续干旱延缓了火灾后的恢复。我们的估算能够评估一种主要干扰类型——野火后与污染物相关风险的放大情况，由于气候变化，预计野火的强度和频率将会增加。更普遍地说，我们的结果凸显了考虑风驱动和水驱动的迁移及侵蚀的重要性，特别是在干扰之后，这对于一般的生态系统生物地球化学以及特别是人类和生态风险评估而言都很重要。
