## 1 Introduction  
Sewage sludge contains a wide spectrum of organic and inorganic contaminants which are separated from the liquid phase in wastewater treatment. The main disposal routes are incineration, landfill, composting, and the use in construction depending on regional situations and local regulation. Agricultural use of sewage sludge can reduce the use of chemical fertilizers as well as mitigate problems resulting from unwise processing of the sludge [1]. Although agricultural use of sewage sludge reaches 50% in Denmark [2], only 15 % of the annual generation of sewage sludge was utilized for agricultural and gardening purposes in Japan, where rice cultivation is very active, according to a statistical survey by Japanese government in 2017. It is necessary to deliberate on various environmental impacts with rice cultivation to increase the use of biosolids [3]. One of the concerns against the use of wastewater byproducts for agricultural purposes is emerging contaminants contained in wastewater and sewage sludge. Pharmaceuticals and personal care products are frequently detected with a concentration range 10-10,000 ng/dry-g in primary sludge and in secondary sludge [4; 2; 5; 6]. Pharmaceuticals in treated and untreated wastewater are also of concern in wastewater reuse for agricultural purposes [7]. The concentrations of pharmaceuticals in soils irrigated with reclaimed wastewater was in the range from less than 1 ng/g to several hundred ng/g [8; 9]. Antibiotics and antibiotic resistance in microbial community are of emerging concern in the agricultural environment receiving sewage sludge and reclaimed wastewater [10; 11]. Due to ubiquitous presence of pharmaceuticals in agricultural soils receiving sewage sludge, the fate of pharmaceuticals in sewage sludge treatment processes before agricultural application has been investigated [5]. The effect of type of sludge treatment (aerobic or anaerobic) on the concentrations of residual pharmaceuticals in stabilized sludge was reported to be compound-dependent [12; 13], although the composting process has been shown to be effective for the degradation of various pharmaceuticals [14]. Taking all available information into account, it is anticipated that a considerable part of pharmaceuticals still remain in biosolids even after sludge treatment processes. Non-steroidal anti-inflammatory drugs (NSAIDs) are often focused as target compounds in environmental studies because of the high residual concentrations in sewage sludge in spite of their relatively water soluble nature [2]. A study on the degradation of pharmaceuticals in four US agricultural soils reported half-life times of 1-20 days for ibuprofen, naproxen, and diclofenac [15]. The removal of NSAIDs in need beds for sludge treatment was reported to be high, although complete separation of removal into adsorption, biodegradation and transformation to other compounds was difficult [16]. The fate of NSAIDs in plants and crops after taking up pharmaceuticals from reclaimed water and sewage sludge have been actively investigated [17]. Nonionic pharmaceuticals were concentrated on leaves at higher concentrations than ionic pharmaceuticals on the occasion of the irrigation of root vegetables with treated wastewater [18]. Limited information is available for the fate of xenobiotics in paddy fields except for agricultural chemicals [19]. Although several studies showed that the degradation of NSAIDs in agricultural soils can be expected to a certain extent [15], it is not clear whether the previous findings on the degradation can be applied to rice paddy fields, that are flooded in anaerobic condition. In addition, Asian soils have to be examined for the degradability of pharmaceuticals because the highest rice producers are Asian countries. The fate of pharmaceuticals in water-saturated different soils taken from various paddy fields was investigated in this study.