Can Contaminated Irrigation Water Drive Pharmaceutical Uptake and Transformation in Rice Paddy? Unveiling Pathways, Natural Attenuation Mechanisms, and Health Risk Assessments

Article Type

Research Article

Publication Title

ACS Es and T Water

Abstract

Contaminant uptake by crops and its subsequent transmission to humans via ingestion are a pressing environmental concern. The objective of this study is to delineate the uptake of emerging contaminants such as pharmaceuticals in food crops in a densely populated area. We executed a field experiment to investigate the fate of the pharmaceuticals carbamazepine (CAR) and sulfamethoxazole (SMX) in rice paddies irrigated with contaminant-spiked water. We experimented on designated field plots using three different dosages: low (500 μg), medium (1000 μg), and high (5000 μg). Using contaminant-spiked water enhanced straw yield while not affecting grain yield. Both pharmaceuticals were detected in soil and plant tissues, with CAR uptake 3-fold higher than SMX. Contaminants were primarily attenuated in soil, root, or shoot, resulting in minimal grain accumulation: 0.25–1% (CAR) and 0.1–0.6% (SMX). CAR-irrigated rice grains showed HQ > 0.1 and contained carcinogenic metabolites (10,11-epoxy carbamazepine, 9-acridine-carboxaldehyde, and acridine), while SMX metabolites exhibited lower toxicity. Notable shifts in microbial composition were observed in contaminated plant and soil samples. This study highlights concerns regarding the long-term human and soil health risks from using pharmaceutical-contaminated irrigation water due to toxic metabolite formation and shift in soil and plant microbial communities.

First Page

7182

Last Page

7193

DOI

10.1021/acsestwater.5c00443

Publication Date

12-12-2025

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