Application of the stable isotope composition of SO4 to tracing anomalous TDS in Nose Creek, Southern Alberta, Canada

Nose Creek, a tributary of the Bow River, has a TDS load that is significantly higher than the Bow River or its other tributaries. Chemical and stable isotope analyses were used to elucidate the sources of TDS in Nose Creek. Oxygen and H isotopes indicate that water is added to Nose Creek by leaky municipal pipes, via groundwater infiltration, as the creek flows through the cities of Airdrie and Calgary. Upstream of Airdrie, the high delta(34)S Of dissolved SO4 (+175 parts per thousand), is consistent with derivation from the local sour gas industry. The SO4 concentration of Nose Creek doubles as the creek flows through agricultural land between Airdrie and Calgary, while the delta(34)S composition remains a consistent 5 parts per thousand. This is indicative of S derived from local soils. Within Calgary, SO4 is derived from oxidation of reduced forms of S in the till, related to the influx of municipal groundwater. (C) 1997 Elsevier Science Ltd.