Increasing Arsenic Concentrations in Runoff from 12 Small Forested Catchments (Czech Republic, Central Europe): Patterns and Controls

The 40-year period of heavy industrialization in Central Europe (1950-1990) was accompanied by massive burning of arsenic-rich lignite in power plants. Absence of effective dust removal devices in power plants led to substantial accumulation of arsenic in ecosystems, mainly in forest soils. There are fears that retreating acidification in spruce die-back affected areas of southeastern Germany, northern Czech Republic and southern Poland (the Black Triangle) may lead to arsenic mobilization into drinking water, caused by competitive ligand exchange. We present monthly arsenic concentrations in surface runoff from 12 headwater catchments in the Czech Republic for a period of 13 years (1996-2008). The area covering 75,000 km2 was characterized by a north-south gradient of decreasing pollution. Acidification has been retreating since the late 1980s. Between 1996 and 2003, maximum arsenic concentrations in stream water did not change, and were < 1 ppm in the rural south and < 2 ppm in the industrial north of the country. During the subsequent two years, 2004-2005, maximum arsenic concentrations in runoff increased in 11 of the 12 catchments, reaching 60% of the drinking water limit (10 ppm). Starting in 2006, another major change occurred. Maximum arsenic concentrations returned to lower values at most sites. We discuss three possible causes of the recent arsenic concentration maximum in streams. We rule out retreating acidification and a pulse of high industrial emission rates as possible controls. The pH of stream water has not changed since 1996, and is still too low (<6.5) at most sites for an As¿OH- ligand exchange to become significant. Elevated arsenic concentrations in runoff in 2004-2005 may reflect climate change through changing hydrological conditions at some, but not all, sites. A wet year 2002 was followed by a dry year 2003 just before the high-arsenic period in runoff at 6 sites.

NOVAK Martin;  ERBANOVA Lucie;  FOTTOVA Daniela;  VOLDRICHOVA Petra;  PECHOVA Eva;  BLAHA Vladimir;  VESELOVSKY Frantisek;  KRACHLER Michael; 

2010-07-19

ELSEVIER SCIENCE BV

JRC57866

0048-9697,   

www.elsevi e r.com/locate/scitotenv,    https://publications.jrc.ec.europa.eu/repository/handle/JRC57866,   

10.1016/j.scitotenv.2010.04.016,