Recognizing the groundwater related to chronic kidney disease of unknown etiology by humic-like organic matter

Xianjiang Zeng,Wei He,Qiutong Shi,Jin Hur,Huaming Guo,Meththika Vithanage,Yaxin Zheng

doi:10.1038/s41545-022-00151-8

Abstract

Chronic kidney disease of unknown etiology (CKDu) becomes a health concern in developing countries. It is urgent to recognize CKDu-related groundwater in CKDu-prevalent areas. Here, spectral indices showed that DOM from CKDu groundwater was characterized by higher molecular weight, stronger exogenous feature, and greater degree of humification and unsaturation than from non-CKDu groundwater. Parallel factor analysis of fluorescence spectra showed that DOM from CKDu groundwater contained significantly more humic-like substances (C1%) and less protein-like substances than from non-CKDu groundwater. Furthermore, C1% was correlated with concentrations of inorganic chemicals associated with CKDu, indicating the feasibility of using C1% for probing CKDu groundwater. According to our self-developed method, both the non-CKDu probability of groundwater with C1% less than the recognizing threshold (RT, 28.8%) and the CKDu probability of groundwater with C1% larger than RT are 70.1%. This indicates that the C1%-based method is a feasible tool for recognizing CKDu groundwater.

Highlights

Chronic kidney disease affects ~15% of population worldwide and is one of the global public health problems[1]
A chronic kidney disease that is unrelated to the above-mentioned causes, namely chronic kidney disease of unknown etiology (CKDu), has been reported in Central America, India, Sri Lanka, and other places[3]
In Sri Lanka, the health of more than 400,000 people is threatened by CKDu, and the incidence of CKDu is as high as 15–23% in North Central Province[4,5]

Summary

Introduction

Chronic kidney disease affects ~15% of population worldwide and is one of the global public health problems[1]. Hypertension, diabetes, and chronic nephritis are usually the main causes of chronic kidney disease[2]. A chronic kidney disease that is unrelated to the above-mentioned causes, namely chronic kidney disease of unknown etiology (CKDu), has been reported in Central America, India, Sri Lanka, and other places[3]. In Sri Lanka, the health of more than 400,000 people is threatened by CKDu, and the incidence of CKDu is as high as 15–23% in North Central Province[4,5]. In CKDu-prevalent areas, the occurrence of CKDu is dependent on the quality of drinking groundwater for local residents, and the distributions of clean groundwater sources and CKDu-related groundwater sources were uneven[8]. The recognition of clean groundwater sources has become an urgent action taken for the residents in CKDu-prevalent areas in developing countries such as Sri Lanka[5]

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Methods

Results