TABLE 1.

Geochemistry of the north and deep central sediment cores obtained from lignite mine Lake 77

Sediment zoneDepth (cm)pHAmt (mM) of:
Fe(II)Fe(III)
DissolvedaHCl extractedbDissolvedHCl extracted
North I0-12.84.517.4NDc211.7
North II1-42.97.313.1ND87.5
North III4-10.53.715.111.9NDND
North IV10.5-20.55.312.530.6NDND
Deep I0∼12.71.57.0ND81.0
Deep II1∼42.94.611.9ND129.7
Deep III4∼10.53.25.913.8ND10.9
Deep IV10.5∼20.54.14.216.3NDND
  • a Fe measured in the supernatant after centrifugation.

  • b Fe measured after preextraction of sediment in 0.5 M HCl.

  • c ND, not detected.