The release and transport of heavy metals(Ni,Cr,Cu and Pb) from Liangshui River sediments into the overlying water column during the resuspension event were determined using an annular flume with a velocity ranging from 0.15 to 0.35 m/s.It is shown that the suspended particulate matters(SPM) increased as much as nearly 25 times from 165 to 4220 mg/L as the velocity increased.Heavy metals showed an increase in dissolved phase as the velocity increased due to their desorption from the SPM.Acid-soluble heavy metals increased as the velocity increased,indicating that part of the heavy metals transformed from stable phase to labile phase during resuspension.Heavy metal concentrations in the SPM on volume normalization increased by approximately 2-6 times.However,on the mass weighted basis they decreased,approaching the bulk-sediment contents at high velocity,due to the "particle concentration effect".The distribution coefficients(K D) of heavy metals were higher at slower velocity during the sediment resuspension,which could be attributed to the decrease of fine particles(silt/clay fraction) during resuspension.
The vertical profiles of nonylphenol （NP） and nonylphenol ethoxylates （NPEOs） were investigated in a sediment core from the Beipaiming Channel, North China using high sensitive LC-MS and GC-MS metthods In this core, relatively high concentrations of NP and NPEOs occurred in the surface sediment （≤40 cm）, with the maximum value of NP and NPEOs reaching 3539 and 12735 mg/g, respectively, whereas, no NP or NPEOs were detected in deeper sediments （〉40 cm）. The high concentrations of NP and NPEOs in the surface layers suggested recent inputs in this area. NPEOs with short ethoxy chains （NPnEO, n=0-3） were dominant in the NPEO mixture with percentages from 54% to 78%, which were similar to the distribution of homolog NPEO in effluents from nearby sewage treatment plants （STPs）, indicating that the channel received the effluents from these STPs. The sewage treatment ratio was quite similar to that found in North America before the 1980s. Finally, the concentrations of NP and NPEOs were related to the total organic carbon （TOC） （p〈0.001）, suggesting that TOC was an important factor for vertical distribution of NPEOs and NP from the Beipaiming Channel.
