The speciation of inorganic arsenic in soil and vegetables irrigated with treated municipal wastewater.

Mari Ataee,Negar Noori,Nazir Fattahi,Toraj Ahmadi-Jouibari

doi:10.1039/c9ra08031g

Abstract

In this research, an environmental friendly, green and efficient sample preparation method using vortex-assisted microextraction based on a deep eutectic solvent (VAME-DES) followed by graphite furnace atomic absorption spectrometry (GFAAS) was developed for the preconcentration and determination of As(iii)/As(v) and total inorganic arsenic in soil and vegetables irrigated with treated municipal wastewater from Tehran and Kermanshah, Iran. In the proposed method, a novel DES, characterized by its low density, was prepared by mixing choline chloride and citric acid monohydrate at a molar ratio of 1 : 1. Under optimal conditions, the proposed method enabled the achievement of a good enrichment factor of 175. The calibration graph was linear in the range of 0.3–100 μg kg−1 and the limit of detection (LOD) was 0.10 μg kg−1. The repeatability and reproducibility of the method based on seven replicate measurements of 50 μg kg−1 As(iii) in analysed samples were 4.2% and 6.5, respectively. The relative recoveries from soil and vegetables that were spiked with different levels of As(iii) and As(v) were 94.2–104.3 and 91.0–107.0%, respectively. The main advantage of the proposed method is the use of a non-toxic and non-volatile DES instead of volatile organic solvents. The accuracy of the proposed procedure was also assessed by the speciation of arsenic in two standard reference materials (GBW10014 cabbage and GBW10015 spinach). The extraction methodology is simple, rapid, cheap and green, since only small amounts of non-toxic solvents are necessary.

Highlights

In countries located in arid and semi-arid regions of the world, one of the most important problems facing agriculture as a major consumer of water resources is nding new and reliable water sources for irrigation
A new deep eutectic solvents (DESs) was applied to the extraction and preconcentration of As(III) and As(V) species in soil and vegetables irrigated with treated municipal wastewater from Tehran and Kermanshah, Iran prior to their analysis by modi ed tube graphite furnace atomic absorption spectrometry (GFAAS)
These results showed that the matrices of the analyzed real soil and vegetables have little effect on ME-DES followed by GFAAS for determination of inorganic arsenic species

Summary

Introduction

In countries located in arid and semi-arid regions of the world, one of the most important problems facing agriculture as a major consumer of water resources is nding new and reliable water sources for irrigation. The use of treated sewage for irrigation is a valuable way to increase the existing water resources, the quality and conditions of this water pose challenges to agriculture.[2] Longterm use of sewage in land irrigation o en results in increased levels of heavy, toxic and unnecessary metals in the. The presence of arsenic in food and water has been considered a major risk factor by researchers. It exists in organic and inorganic forms both naturally and arising from human activities in the environment.[6] Arsenic exposure can have adverse effects on human health and other organisms and can cause various side effects including skin changes, respiratory problems, cardiovascular disease, digestive system problems, genotoxicity and mutagenic and carcinogenic effects.[7] Arsenic in nature has four oxidation modes including As(0), As(III), As(V) and As(ÀIII). As(V) and As(III) are classi ed as group I carcinogens

Methods

Results

Conclusion