In: N.E. Peters, R.J. Allan, V.V. Tsirkunov (eds); Hydrological, Chemical and Biological Processes of Transformation and Transport of Contaminants in Aquatic Environments, Proceedings of the Rostov-on-Don Symposium; May 1993, IAHS Publ. No. 219, IAHS Press, Wallingford, UK [1993]