Uncontrolled landfill sites are one of the main sources of underground and surface water contamination. The absence of monitoring leads to the leakage of leachates into the environment, thereby severely contaminating the aquifers of the area. That is what happened in Sardas landfill located close to Sabiñanigo (Huesca, Spain). It is an old uncontrolled landfill that has been dumping huge quantities of urban, agriculture and industrial wastes since the 70s. Among all the waste residues in Sardas, the most toxic are the leachates of chloro-alkyl industry and the organochlorides generated by the pesticides industry. Inquinosa produced lindane from 1975 to 1988 and formulated lindane products until 1992.