This study reports analyses of carbon and nitrogen content, and delta(15)N and delta(13)C in sediments of the Höggarnsfjärden Bay near Stockholm. Samples have been taken upstream, near, and downstream of a point source of processed leach water from a garbage dump. The surface sediment at the upstream and downstream sites has delta(15)N and delta(13)C close to the expected background of the area, even though a contribution from the leach water can be observed downstream of the point source. The sediment close to the outflow is strongly influenced by the carbon and nitrogen in the leach water.