EDTA in environments subjected to disposal of dairy effluent from processing plants

Abstract

The presence of Ethylenediaminetetraacetic acid (EDTA) in environments related to the disposal of dairy effluent has been investigated. An HPLC-UV analytical method was used to determine concentrations of EDTA in soil, surface and ground waters. Method detection limits were 1.5 mg/kg (dry weight) for soil, 1 µg/L for surface water and 2 µg/L for groundwater. A quasi one-dimensional vertical mixing model and a numerical simulation of the hydrodynamic processes (the 3DD hydrodynamic model) were applied to simulate the dispersion of EDTA discharged from a large-scale dairy factory into a relatively small river. Based on the modelling results, large volumes of dairy wastewater discharged into the local river had no significant effects on the concentration of EDTA. Analytical results of EDTA in soil and groundwater indicated that there was no concern about the irrigation of dairy sludge onto pasture land. EDTA was, however, detectable in the soil and groundwater, and heavy metals appear to be transported into the groundwater with EDTA chelates in the pasture area irrigated by the dairy wastewater over periods of time.