title: Investigation of the heavy metal contamination of the sediments from the yellow river wetland nature reserve of zhengzhou, china.
abstract: BACKGROUND
  Heavy metal pollution in the sediment of the Yellow River draws wide attention in the recent years. The Yellow River Wetland Nature Reserve of Zhengzhou is one of the major wetlands of the river and located at the beginning of the lower reach. In this article, we aimed to investigate the degree and the sources of the metal pollution in the reserve.
  
  
  METHODS
  Metals as Cu, Pb, Cr, Cd and Mn in the sediment were monitored using flame atomic absorption spectrometry. The index of geo-accumulation (I(geo)) and the modified degree of contamination (mC(d)) were developed to evaluate individual metal pollution and overall enrichment impact of the elements.
  
  
  RESULTS
  Compared with sediment quality guidelines, the effect of Cr and Pb are more serious than others. I(geo) values show Pb pollution are moderate at the Xinzhai, Langchenggang and Nansutan sites, and mC(d) analysis indicate the whole contamination at the Wantan, Langchenggang and Nansutan sites was low. Principal component analysis indicated that the first factor was Cu, Mn and Cd, mainly from soil erosion and the irrational use of phosphate fertilizers; the second Pb from fossil fuel burning; and the third Cr from weathering process.
  
  
  CONCLUSIONS
  We conclude that Pb contamination is serious in the reserve, and the main sources of the metal are crude oil consumption and coal combustion of the brick kilns around. We also draw a conclusion that it is vital to evaluate contamination degree with both individual elements and overall average.
authors.affiliation: Institute of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Cheng
authors.forename: W
authors.initials: W
authors.lastname: Wang
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.lastname: Wang
authors.forename: Z
authors.initials: Z
authors.lastname: Zhao
keywords: China; Heavy metal pollution; Sediment; The Yellow River; Wetland