Transport of sulfadiazine and sulfamethoxazole in homogenous soil column systems

Abstract

Veterinary antibiotics can enter the soil and then may be transported to groundwater via leaching. The sorption behaviour of antibiotics may be influenced by changes in the pH of leachates and the weather conditions. The main aim of this study is to investigate the transport of sulfadiazine and sulfamethoxazole to groundwater. Glass columns with an inner diameter 20 cm and a height of 70 cm were used for experiments. Leachate samples from laboratory and field soil columns were collected 91 and 129 days after treatment, respectively. The study compounds were extracted from the leachate samples by solid phase extraction and analysed by HPLC-PDA system. The ranges of pH of leachate samples from the laboratory and field soil columns were 6.42–8.20 and 6.95–8.10, respectively. There was no leachate sample from the laboratory soil column where sulfadiazine or sulfamethoxazole could be detected. The peak concentrations of sulfadiazine and sulfamethoxazole detected in leachate samples from field soil column were 610.88 and 672.94 μg/L 11 days after treatment, respectively. Sulfadiazine and sulfamethoxazole were still detected in leachate samples 129 days after treatment at concentrations of 1.80 and 1.42 μg/L, respectively. There were two main differences between laboratory and field soil columns. These were pH of leachate samples and irrigation conditions that irrigation carried out with 0.01 M CaCl2 in laboratory soil column and took place under natural rainfall conditions in field soil column. The mentioned differences may be reason for undetection of the antibiotics in laboratory soil column.