Aerobic and Anaerobic Biological Degradation of Pharmaceutically Active Compounds in Rice Paddy Soils

Abstract

One of the concerns against the use of sewage sludge for agricultural purposes is emerging contaminants contained in sewage sludge. Most of the studies on biological degradation of pharmaceutically active compounds in agricultural land were carried out with water-unsaturated soils under relatively aerobic conditions. In this study, the degradation of pharmaceuticals mainly including non-steroidal anti-inflammatory drugs (NSAIDs) was investigated in Asian rice paddy soils that are flooded in anaerobic condition. The experimental results showed that the concentrations of the target pharmaceuticals excluding the exception of naproxen were poorly decreased in anaerobic condition. On the other hand, the microbial communities of the soils contained the aerobic degraders of clofibric acid and diclofenac, which are generally persistent in biological wastewater treatment. The higher degradation rates in aerobic condition suggest the possibility of enhanced degradation of pharmaceuticals by supplying oxygen with plowing anaerobic rice fields or with drying the field in off-season for farming.

Amended Vegetation Filters as Nature-Based Solutions for the Treatment of Pharmaceuticals: Infiltration Experiments Coupled to Reactive Transport Modelling

“…This phenomenon may account for the observed sorption onto the soil. Although ketoprofen has been reported as susceptible to degradation by fungi and bacteria under aerobic conditions [87][88][89], data quantifying such a process during infiltration through woodchips are not available in the literature. Therefore, the value fitted by our model cannot be quantitatively compared with published references.…”