Supervisors info:
Νικόλαος Θωμαΐδης, Καθηγητής, Τμήμα Χημείας, ΕΚΠΑ
Summary:
The site of interest of this study is Asopos river which is located in Sterea Ellada, north of Athens, and passes through areas where 20% of total Greece industrial production takes place. The extensive installation of industries in the area near the river, and the uncontrolled disposal of industrial and agricultural wastes into the river, make the water quality of Asopos questionable.
Over the last decade, the development of high resolving power mass analyzers (HRMS) has contributed significantly to the expansion of environmental studies’ interest from the restricted determination of priority pollutants to the wide-scope screening of emerging contaminants (ECs). In light of their potential risk to human health and the aquatic environment, action is urgently required. In the ECs analysis field, there is a clear trend toward LC-HRMS as the majority of ECs are more polar and less volatile. However, many high usage ECs, as well as priority pollutants, are volatile and thermostable, therefore GC-HRMS methods should be developed. So far, less polar and more volatile compounds remain unexploited, pinpointing the need for the establishment of efficient GC-HRMS workflows in order to extend the chemical domain of the applied screening approaches in monitoring studies.
The aim of this study was the development of a novel methodology for the determination of GC-amenable priority pollutants and emerging contaminants in river water samples from Asopos. Since the chemical domain of the analysis includes compounds with a wide variety of physicochemical properties, a generic sample preparation protocol should be followed. Several sample preparation methods were tested, including different extraction techniques and initial sample volumes. Solid phase extraction with C18 cartridges was selected for the pre-concentration of the analytes and the clean-up of the river samples.
The characteristics of the developed GC-APCI method, were evaluated with spiked samples of a representative group of compounds, for which reference standards were available. The validation dataset included chemicals from different classes of GC-amenable compounds, like polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and plant protection products (PPPs).
River water samples were collected from 2 sampling points, one close to industrial and agricultural activities and one close to the estuaries of Asopos. Two portable autosamplers were used in order to collect 24-hour samples from the river for 7 consecutive days during November 2018. Also, Weather conditions and the color of the river were recorded for each sampling day.
The resulting extracts from the sample’s pretreatment were analyzed using gas chromatography coupled with an Atmospheric Pressure Chemical Ionization (APCI) source,with a hybrid quadrupole time of flight (GC-QTOF-MS).
Concerning the results of the current study, the number of the detected compounds and the total concentration of all analytes were significantly higher in the samples withdrawn close to the industrial and agricultural activities. Moreover the weather contitions maybe can affect the concentration and the transport of the analytes.The overall results will indicate the contamination degree of Asopos river basin due to the occurrence of GC-amenable priority pollutants and emerging contaminants.
Keywords:
Method Development, Priority pollutants, Emerging contaminants, River water, GC-APCI-QTOF
