AWWA WQTC65796

On Friday, September 1, 2006, a toxic spill took place in Caldas de Reis, Pontevedra. A wide variety of chemical compounds were spilled as a result of a fire in the Brenntag factory located there. The spill, which consisted mainly of volatile organic compounds, ferric chloride, alumina sulfate, and a colorant, probably malachite green, contaminated about 4 kilometers of the Umia River until the Regional Executive of Galicia decided to raise a series of docks to temporarily dam the river. This caused various problems. First, as the spill took place on a Friday, it was hard to find a laboratory that could rapidly analyze the spill composition and conduct monitoring. Second, a decision had to be made quickly about how to contain the river and keep the spill from entering the water supply of the Arousa region where about 200,000 people live. Third, the spill had to be kept from reaching the shellfish beds of the Ria of Arousa. This paper examines all the decisions that were made in the first days after the spill, which were influenced by the need to ensure water supplies to the population affected. A water treatment system was improvised in the river using treatment ponds to eliminate the contaminants. Stopping the flow of the river had the following consequences: algal blooms; microcystins in drinking water; construction of a by-pass pipeline from a point upstream to the spill to a point below the last dock (15 km in 7 days); an effort that coincided with the grape harvest in a major winemaking area; difficulties in supplying water to different population centers; and others. Includes table, figures.