Impact of forest fires on PAH levels in groundwater from mountain areas

Wildfires, both natural and manmade, are a major environmental hazard with significant short-term and long-term effects on human health and environment. Independently of fire type and intensity, the combustion process generates huge amounts of carbon dioxide and several groups of pollutants such as dioxins, dibenzofurans and polycyclic aromatic hydrocarbons (PAHs). Due to their potential adverse effects on humans and wildlife, PAHs are registered on European and American lists of priority pollutants that must be monitored in environment. Several PAHs compounds can increase the incidence of cancer, and are also referred to as endocrine disruptor compounds, with the most well-known marker being benzo[a]pyrene. Regarding water quality, PAHs were firstly considered priority hazardous substances (those presenting a significant risk to or via the aquatic environment) by the Decision no2455/2001/EC of the European Parliament and of the Council, which becomes Annex X of the Water Framework Directive (2000/60/EC). This list was then replaced by Annex II of the Directive 2008/105/EC, known as the Priority Substances Directive, subsequently reviewed by the Commission in 2012 (COM(2011) 876 final. PAHs are also mentioned in our drinking water legislation (DL306/07). Until now, there are still substantial knowledge gaps about the water quality impacts of forest fires concerning PAHs contamination, as well as the influence of the climatic conditions and the time elapsed since the last fire.