Environmental Forensic Study and Remediation Feasibility in an Abandoned Industrial Site

An environmental forensic study was developed in a former industrial area in southern Spain. Previous information about the site revealed arsenic and hydrocarbons affection exceeding soil screening levels. A full characterisation of arsenic affection was thus performed. In this regard, the bioavailable fractions, arsenic speciation and grain-size distribution were determined. Two different polluted types of soils/fillers were identified. The first one is affected by non-bioavailability As(V) concentrations on the finer fraction, and the other one is affected by As(III) and As(V) with higher bioavailability than the other case, affecting all grain-size fractions homogeneously. Notably the textures are very heterogeneous within the site. On the other hand, hydrocarbons affection was also studied. Cuantitative and cualitative organic analyses revealed the presence of organic products with differing degree of degradation (naphthas). An additional microbiological study revealed regular microbial counts for a non-fertilized soil, and an edaphological characterization showed alkaline soils with low levels of nutrients and natural organic matter. The information gathered was used to evaluate remediation feasibility. Soil washing was selected as an interesting possibility for arsenic removal, although grain-size distribution must be studied carefully because of high variability. As regards as organics, bioremediation is a valuable option due to the suitable microbiology and the type of hydrocarbons found, together with the usual low costs of techniques such as landfarming or biopiles.