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A variety of mono- and di-chlorinated and brominated triphenylamines were identified in the sludge and contaminated soils affected by a toxic waste spill that occurred in the Los Frailes pyrite mine (SW Spain). A negative gradient of aromatic amine concentrations from 29 μg g−1 in the vicinity of the broken dam to 0.14 μg g−1 in contaminated soils collected 30 km to the south in the Guadiamar River valley was observed. Substituted carbazoles (e.g. 9-phenylcarbazole) were also identified as contaminating sludge, soils and the temporarily dammed water at Entremuros and the Guadalquivir River and its tributary, the Guadiamar River. Our results demonstrate that contaminated waters from the pyrite sludge spill reached the Guadalquivir Estuary. However, the more lipophilic compounds, such as the halogenated triphenylamines, were not recorded in water bodies because of their strong adsorption by soils during the weathering process. Conversely, the more hydrophilic benzothiazoles were widespread in surface waters, a finding attributable to their higher solubility than chlorinated aromatic amines. Although the source of the nitrogen organic compounds (NOCs) has not yet been identified, it would seem to be related to the pyrite tail spillage. For example, degradation of technical products used in ore processing or industrial waste dumped in the mine waste collection dam could be the source of these compounds. Given the widespread occurrence of 9-phenylcarbazole in the affected area, this compound is proposed as a specific molecular marker of the Aznalcollar spill. Furthermore, some of the NOCs were identified in the contaminated waters of the Guadiamar and Guadalquivir Rivers, providing evidence that these rivers were affected by the mining spill. Taking into account the field concentrations (water, sludge) and the spill volume, it can be concluded that the budget of aromatic amines is in the range of 27 t — of this, 32.6% was in the aqueous phase and the remaining 67.4% was in the soil. |
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