EDTA: a marker of anthropogenic pollution in the Suquía River basin

VALDÉS, M.E; MONFERRÁN. M.V; BISTONI, M.A.; WUNDERLIN, D.A

Berlin

Congreso; VI SETAC Word Congress, SETAC Europe 22nd Annual meeting; 2012

SETAC

Aminopolycarboxylates, such as ethylenediaminetetraacetic acid (EDTA) have been extensively used as chelating agents in many industrial and domestic applications for years. EDTA is released to the aquatic environment mainly via runoffs of sewage treatment plants. Due to high consumption and slow biodegradability, EDTA has been found in surface waters of different industrialized countries. Our main goal was determining the presence of EDTA as a marker of anthropogenic influence along the Suquia river basin (Córdoba-Argentina). To verify the pollution we also measured concentration of metals (Li, Be, B, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, Ba, Tl, Pb and Bi), pH, conductivity and dissolved oxygen (DO) at eight monitoring stations with different pollution degree from the upper to the lower river basin. Sampling was carried out during 2011, considering both dry and wet seasons. EDTA was analyzed by HPLC coupled to ESI-HRMS (QTOF), while metals were assayed by ICP-MS. EDTA was found in at least 3 locations. Amounts of EDTA varied along the basin, showing absence of EDTA in the high basin, trace amounts in the middle basin, while the highest values were observed at the lower basin. So far, it is possible to differentiate 3 areas in accordance with anthropogenic inputs: a quasi pristine area in the upper basin, a medium polluted zone surrounded by small cities in the medium basin, and a high impacted area, downstream the sewage discharge of the main city (Cordoba). Some metals (Be, Cr, Co, Ni, Se, Mo, Ag, Cd, Tl and Bi) were below LOD throughout the basin. Conductivity, DO and other metals (Li, K, Ca, Mg, Ga, Sr, Ba) showed a pattern coincident with EDTA concentration, with increased values as anthropogenic influence rose. Additionally, concentrations of Al, Mn, Fe, Cu and Zn increased progressively after Córdoba sewage discharge. Concentrations were generally higher during the dry season. Our current results demonstrate that EDTA can be used as an efficient marker of anthropogenic pollution, in addition to metals and other water qualities parameters