【摘要】 "黄土来自远源"是以往的观点,近源对黄土是否有影响需要研究。(1)以马兰黄土中元素平均含量为本底,通过比较同一地区(北京)不同时期(晚更新世、现代)沙尘暴降尘中化学元素含量的差异,发现:现代沙尘暴降尘中Cd、As、S的含量比马兰黄土高8倍以上,表明现代人类活动对沙尘暴降尘有较大影响,原因之一是煤的开采和大量使用,煤中含有大量的As、Cd、S。(2)通过比较同一时期(现代)不同地区沙尘暴降尘中化学元素含量的差异,发现:北京地区降尘中As、S含量较高,武威地区Zn含量较高,哈尔滨地区Fe,Pb,Cr含量较高,表明现代人类活动对不同地区沙尘暴降尘的影响不同。(3)现代条件下沙尘暴降尘中As、Cd、S、Zn、Pb等污染元素的含量与本底比有明显的增加,说明近源对黄土有影响,以往"黄土来自远源"的观点需要部分改变,现代人类活动在一定程度上改变了自然变化过程黄土的组成和性质,其负面影响程度有待深入研究。更多还原

【Abstract】 It was well known that loess came from far source.If loess was influenced by near source?(1)Average contents of elements in Malan loess were regarded as background,the contents of elements in settled dust of sand and dust storm in modern times in Beijing was compared with those in late Pleistocene(Malan loess)in Beijing.The contents of Cd、As、S in modern settled dust of sand and dust storm were 8 times higher than those in Malan loess.The results showed that settled dust of sand and dust storm was influenced by modern human activities.One of the reasons is that a vast amount of coal was mined and used.There were a lot of As、Cd、S in coal.(2)Among three areas,such as Beijing,Wuwei and Harbin,in the corresponding period(modern times),the contents of elements in settled dust of sand and dust storm in one area was compared with those in other two areas.The results showed that the contents of As、S in modern settled dust of sand and dust storm in Beijing were higher than those in other two areas,the content of Zn in Wuwei area was higher than that in other two areas,the contents of Fe,Pb,Cr in Harbin area were higher than those in other two areas.(3)The settled dust of sand and dust storm was influenced in different areas by modern human activities.The results showed that loess was influenced by near source.Viewpoint of that loess came from far source was partly changed.Characters of loess were partly changed by modern human activities.Degree of harmful influence is needed to study deeply.更多还原