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Friday, 18 April 2014

Tasik Chini Fieldwork - Environmental Forensic (part one)

Prof. Dr. Mohamad Pauzi who is also our deputy dean of Graduate, Research and Development. I remembered that I met him once during the orientation week that we found that he had went to many many places before including the Antarctic.
This was the most comfortable fieldwork we had as it was in the air-conditioned chalet! The extraction of organic contaminants from leaves is part of the Environmental Forensic Science too! There is another reason why we should plant more trees especially in urban area - the process of phytoextration carried out by the trees allows the trees to take up the surrounding pollutants at no cost at all! We do not have to pay for the filter paper, or the bulky sampler. What we need to do is just to pick some leaves (larger and older is better) and extract the content to be tested in the laboratory. The leaves have a layer of wax (similar to alkane like paraffin) on the upper surface which protects the leaves from physical injuries and formic acid of insects. That is the platform where contaminants landed and trapped in the leaves.

As we know there are pollutants suspended in the air. The lighter compounds will travel in the air to places far far away carried by wind while the larger compound will eventually drop on the ground due to gravity. Wet deposition happens during rain when rain water washes the contaminants onto the ground while dry deposition happens without the present of water. Hydrophobic polar compounds which are lighter will land on the leaves while the heavier non-polar ones will land on ground. We used to learn that the long-chained hydrocarbon is non-polar but the polar here means that it is relatively polar among the organic compounds.

Work in progress. It's not sambal belacan ok? Hahaha...
Firstly we should sample leaves from different trees around the area so that we can get a composition of leaves that can represent the amount of organic contaminant in that area. We should avoid touching the upper surface of the leaves which contain the 'evidence' that we need. Of course, glove is a must. Then, we grind all the leaves together by adding methanol (a chemical whose composition similar to the wax on the leaves) using mortar and pastel to get a green sticky paste called emulsion. The emulsion is then being transferred into a vial which is then being wrapped in aluminium foil to block out any sunlight which might cause photodegradation to the sample collected. Everything in the mortar should be transferred into the vial by rinsing with methanol. The vial is finally sent to the laboratory to go through a series of process to remove the methanol, chlorophyll etc. to obtain the weight of the contaminants. We calculate the amount of contaminants by dividing the weight of the contaminants with the total weight of the leaves.

Ready to be sent to the laboratory!
Can you see how interesting Environmental Forensic is??? I really wish I can share everything I learnt with you guys so that you can have a picture about what we (future) environmental scientists do so that there is no misconception and public will not see environmental studies as something insignificant. It's time to change our mindset and advance towards a better future (sounds like a typical motivation essay, hahahaha...)

P/S: Ok, finally here is the part one. =P

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