Characterization of organic compounds in soil and water affected by pyritetailing spillage

A variety of mono- and di-chlorinated and brominated triphenylamines were i dentified in the sludge and contaminated soils affected by a toxic waste sp ill that occurred in the Los Frailes pyrite mine (SW Spain). A negative gra dient of aromatic amine concentrations from 29 mu g g(-1) in the vicinity o f the broken dam to 0.14 mu g g(-1) in contaminated soils collected 30 km t o the south in the Guadiamar River valley was observed. Substituted carbazo les (e.g. 9-phenylcarbazole) were also identified as contaminating sludge, soils and the temporarily dammed water at Entremuros and the Guadalquivir R iver and its tributary, the Guadiamar River. Our results demonstrate that c ontaminated waters from the pyrite sludge spill reached the Guadalquivir Es tuary. However, the more lipophilic compounds, such as the halogenated trip henylamines, were not recorded in water bodies because of their strong adso rption by soils during the weathering process. Conversely, the more hydroph ilic benzothiazoles were widespread in surface waters, a finding attributab le to their higher solubility than chlorinated aromatic amines. Although th e source of the nitrogen organic compounds (NOCs) has not yet been identifi ed, it would seem to be related to the pyrite tail spillage. For example, d egradation of technical products used in ore processing or industrial waste dumped in the mine waste collection dam could be the source of these compo unds. Given the widespread occurrence of 9-phenylcarbazole in the affected area, this compound is proposed as a specific molecular marker of the Aznal collar spill. Furthermore, some of the NOCs were identified in the contamin ated waters of the Guadiamar and Guadalquivir Rivers, providing evidence th at these rivers were affected by the mining spill. Taking into account the field concentrations (water, sludge) and the spill volume, it can be conclu ded that the budget of aromatic amines is in the range of 27 t - of this, 3 2.6% was in the aqueous phase and the remaining 67.4% was in the soil. (C) 1999 Elsevier Science B.V. All rights reserved.