Re ECF Project: 2009-25

Project Title: Artificial Sweetener as an Emerging Contaminant: Its occurrence and transformation products in Hong Kong waters

Applicant: Dr. Kelvin Sze-yin LEUNG of Hong Kong Baptist University

Total Approved Grant: $409,720

Duration: 01/01/2012 to 30/09/2012

Project Status/Remarks: Completed

Scope:
The objectives of the project are:

  • to develop and validate sensitive liquid chromatography- quadrupole time-of-flight mass spectrometric (LC/Q-TOF) methods for the determination of four sweeteners namely sucralose, acesulfame, saccharin and cyclamate; and
  • to investigate the occurrence of four sweeteners and their transformation products in HK waters.

Summary of the Findings/Outcomes:
This project presents the primary occurrence data of Artificial Sweetener (AS) in Asian coastal waters. Although AS seems not to pose a direct and immediate effect on health or other life forms in a short period of time, the consequences of chronic exposure over a long period of time are still unknown. The effect of AS on environment especially its accumulation in water body has already emerged in many countries. For this reason, a mass spectrometric analytical method for the determination of AS in sea water and sludge was developed. The procedure combining SPE extraction and UPLC-MS analysis provided good recovery and sensitivity for the analysis of AS in two analytical matrices. Acesulfame, saccharin, cyclamate, sucralose were detected at concentrations of μg L-1 level in sea water samples in both summer and winter. UPLC-MS method was proven to be a suitable approach for AS analysis in water, allowing the detection limits at low ng L-1 levels. Highest level was detected for acesulfame in surface sea water. One particularly significant finding of the current study is the presence of four AS in all the sampling locations from east to west, representing the sea areas of Hong Kong. Since AS have been confirmed with highly persistence in aquatic systems, these systems could be affected by the persistent properties in relation to their bioaccumulation, high water solubility and low adsorbability to solids. Thus, AS could play a potential tracer role and act as an indicator of human activities. To date, there are rare data on their migration mechanisms, 39 degradation behaviors and potential environmental risks of AS, prompt research investigations on these areas are demanded.