Characteristics of heavy meatals and nutrients of core Huoshaohei sediments in Lianhuan lake

The sedimentary environment's change will be recorded in the sediments, which can be manifested by the variation of the sediments' physicochemical features. To study the trophic evolution and heavy metals pollution processes, the sedimentary geochemical properties of the core Huoshaohei (HSH) sediments, such as grain size, nutrients, heavy metals, etc, are analyzed. The nutrients in the sediments depended mainly on the lake internal circulation and the heavy metals were from natural geogenic sources before the 1940s, which were not influenced by human activities generally. And grain size was one of the key factors influencing heavy metals content in the sediments. The results indicate that the influence of human activities to HSH is little. And the grain size has become finer from 1960s, while the contents of TP, TOC and C/N ratio increase obviously after 1960s, indicating the eutrophication state of HSH Lake in this period. Meanwhile the increasing of heavy metals content, such as Fe, Mn, Ni, Cr and Sr, and their proportion of valid fractions in the sediments prove that they all result from human pollutants since the late 1960s.