Degradation of sulfonamides antibiotics in lake water and sediment

Abstract

Degradation of three sulfonamides (SAs), namely sulfamethoxazole (SMX), sulfamethazine (SMZ), and sulfadimethoxine (SDM) in surface water and sediments collected from Taihu Lake and Dianchi Lake, China was investigated in this study. The surface water (5-10 cm) was collected from the east region of Taihu Lake, China. Two sets of degradation experiments were conducted in 3-L glass bottles containing 2 L of fresh lake water and 100 μg/L of individual SAs aerated by bubbling air at a rate of approximately 1.2 L/min, one of which was sterilized by the addition of NaN3 (0.1%). Sediment samples were taken from Taihu Lake and Dianchi Lake, China. For the sediment experiment, 5 g of sediment were weighed into a 50-mL glass tube, with 10 mg/kg of individual SAs. Different experimental conditions including the sediment types, sterilization, light exposure, and redox condition were also considered in the experiments. The three SAs degraded in lake water with half-lives (t 1/2) of 10.5-12.9 days, and the half-lives increased significantly to 31.9-49.8 days in the sterilized water. SMZ and SDM were degraded by abiotic processes in Taihu and Dianchi sediments, and the different experimental conditions and sediments characteristics had no significant effect on their declines. SMX, however, was mainly transformed by facultative anaerobes in Taihu and Dianchi sediments under anaerobic conditions, and the degradation rate of SMX in non-sterile sediment (t 1/2 of 9.6-16.7 days) were higher than in sterilized sediment (t 1/2 of 18.7-135.9 days). Under abiotic conditions, degradation of SMX in Dianchi sediment was faster than in Taihu sediment, probably due to the higher organic matter content and inorganic photosensitizers concentrations in Dianchi sediment. High initial SAs concentration inhibited the SAs degradation, which was likely related to the inhibition of microorganism activities by high SAs levels in sediments. Results from this study could provide information on the persistence of commonly used sulfanomides antibiotics in lake environment.

Elimination patterns of worldwide used sulfonamides and tetracyclines during anaerobic fermentation

“…Apparently, the matrix itself has an influence on the elimination which seems to exceed the impact of anaerobic or aerobic conditions. In sediment samples, no pronounced differences were found for sulfamethazine elimination under sterile and non-sterile anaerobic conditions (Zhang et al, 2013). The authors concluded that the elimination mainly occurred due to abiotic processes.…”

Impact of chlortetracycline and sulfapyridine antibiotics on soil enzyme activities

“…Indeed, Al-Ahmad et al (1999) observed weak biodegradability of sulfamethoxazole (SMX) on day 28 of incubation. The weak degradation of sulfonamides, therefore, could contribute to the inhibition of microorganism activity due to high primary concentrations of antibiotics (Zhang et al, 2013).…”

Photodegradation of sulfapyridine under simulated sunlight irradiation: Kinetics, mechanism and toxicity evolvement

“…Antibiotics are a class of commonly used PPCPs used as human and veterinary medicine. Due to their pseudo-persistent nature and potential to cause antibiotic resistant bacteria and genes (Baran et al, 2006;Zhang et al, 2013;Guo et al, 2013), it is imperative to study the fate and transport of antibiotics and their impacts in the natural environment (Ge et al, 2009(Ge et al, , 2010Guo et al, 2013).…”