Samples from the wells GW2, GW3, and GW4 and the deep groundwater (deepGW) were taken by submerged pumps (Whale). the pumps were cleaned in the lab by pumping 0.01 M HNO3 for at least 30 min. Prior to the sampling, groundwater was pumped during 20-30 min to remove old water from the pipe. Samples for metal concentration determination by ICP-MS were taken directly at the outflow of the pump and filtered (0.45 mm, Acrodisc, Gelman Science) on the site into precleaned PE tubes (with added HNO3 to give a final concentration of 0.1 M). the filters had been soaked for a few days with 0.01 M HNO3. the first 10-20 mL of the filtrate was discarded. twelve samples from GW2 and GW3 were taken, four from GW4 and three from deepGW. pH and temperature were measured in the field. the samples for EDTA and metal speciation were transported to the lab for every 24 h, under exclusion of light to avoid photolysis of Fe(III)-EDTA.