HISTORIC METAL MINING INPUTS TO TEES RIVER SEDIMENT

Historic metal mining has greatly influenced sediment delivery and met al contamination in the Tees River Basin. Investigations of metal-cont aminated overbank river sediment show that sediment-borne metal concen trations decrease downstream of mining areas. Metalliferous mineralogy also changes: sulphides and carbonates are abundant in the upstream p art of the basin, and both decline and disappear downstream where iron oxyhydroxides dominate. Mineral compositional and textural informatio n can be used to trace sources of mining-related contaminated sediment . Sulphides, carbonates, and oxyhydroxides which pseudomorph ore depos it minerals, are interpreted to be derived from outcropping ore bodies and mine-waste tips. The relative abundance of these grains suggests that the ore bodies and mine-waste tips are still important sources of metal pollutants. This is corroborated by morphological mapping and c oring of Tees floodplain sequences, which also suggests that metal-con taminated alluvium downstream has experienced limited re-working. (C) 1997 Elsevier Science B.V.