Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Science , Peking University , Beijing 100871 , China.
Department of Marine Sciences , University of Connecticut , 1080 Shennecossett Rd. , Groton , Connecticut 06340 , United States.
Environ Sci Technol. 2019 Apr 16;53(8):4206-4214. doi: 10.1021/acs.est.8b06143. Epub 2019 Mar 28.
Soil erosion, which has been recently shown to significantly perturb carbon cycling, occurs naturally but can be either enhanced or reduced by human activities. However, the impacts of soil erosion on terrestrial contaminant cycles remain unclear. Here, we select eight trace elements, i.e., arsenic, cadmium, chromium, copper, nickel, lead, zinc, and mercury, to examine the erosional impacts of the elements' fate and transport across China. By synthesizing the detailed distribution of soil erosion fluxes, soil element inventories, and diverse modeling methods, we reveal that while human activities have reduced the lateral transport of these elements in the Loess Plateau (Central North China, a 56% decline in the past two decades with a range of 46% to 110%) due to soil conservation projects, they have increased these transport fluxes in China's major karst regions (Southwest China, a 84% increase with a range of 55% to 150%) because of severe rocky desertification. These fluxes have completely overwhelmed the soil conservation efforts in the Loess Plateau. Fluxes of these elements into aquatic environments from Southwest China reached 46% of the total input in China in 2010. These fluxes were higher than the inputs from point sources in the region by a factor of 50 because of impacts of excessive agricultural cultivation and geographical and climatic factors. These findings indicate the enormous perturbation of terrestrial contaminant cycles caused by soil erosion in karst regions and demonstrate the need for long-term sustainable management of soil erosion and contaminant discharge to protect fragile terrestrial ecosystems.
土壤侵蚀最近被证明会显著扰乱碳循环，它是自然发生的，但也可以被人类活动增强或减少。然而，土壤侵蚀对陆地污染物循环的影响仍不清楚。在这里，我们选择了砷、镉、铬、铜、镍、铅、锌和汞这 8 种微量元素，来检验这些元素在我国的迁移和归宿的侵蚀影响。通过综合详细的土壤侵蚀通量分布、土壤元素储量和多种建模方法，我们揭示了人类活动通过土壤保持项目减少了这些元素在黄土高原（中国中北部）的侧向迁移（在过去二十年中减少了 56%，范围在 46%到 110%之间），但由于严重的石漠化，在中国主要喀斯特地区增加了这些迁移通量（中国西南部，增加了 84%，范围在 55%到 150%之间）。这些通量完全超过了黄土高原的土壤保持努力。这些元素从西南地区进入水生环境的通量在 2010 年达到了中国总输入量的 46%。这些通量比该地区点源输入高出 50 倍，这是由于过度的农业种植以及地理和气候因素的影响。这些发现表明，喀斯特地区土壤侵蚀对陆地污染物循环造成了巨大的干扰，并表明需要对土壤侵蚀和污染物排放进行长期可持续管理，以保护脆弱的陆地生态系统。
