Assessment of the lead and zinc contents in natural soils and tailing ponds from the Cartagena-La Unión mining district, SE Spain

1. Martínez-Martínez, S.
2. Acosta, J.A.
3. Cano, A.F.
4. Carmona, D.M.
5. Zornoza, R.
6. Cerda, C.