Thursday, December 10, 2009

"Water quality in natural habitats" course for Jurong Junior College (4 Dec 09) - field trip to Ngee Ann Stream

Junior colleges are now getting into the act of water quality monitoring too. After all, this activity neatly ties up many disciplines such as geography, chemistry, physics and biology, allowing the students to appreciate how science works in the real world (which may not resemble anything like the theories in books).

Reality check - we were into the month of December within the period of the Northeast Monsoon. Rain was expected but expecting it did not make things any easier. Heck, this field trip was the wettest I have ever led since the rain started before, lasted during and ended after the whole trip.

Frankly, I was really relieved when I saw that the students were prepared for rain. To their credit, this was one of the best bunches of participants I ever had.

One common problem, whether raining or not, was someone's shoe(s) being totalled (i.e. sole came off) in the mud and rough terrain. See below for the end result. Thankfully, the hapless victim was resourceful enough to tie up the mess into a walkable vessel using a shoe lace.

True to rumours, the area adjacent to The Sterling (a condominium) was cleared bare. There goes the nice forest setting. This makes me wonder how long Ngee Ann Stream can endure before it is gone for good. The machines were still clearing up remnants of the forest. (More condos coming up?) The delineation between cleared area and vegetation is shown below (the stream is to the right).

Major obstacle. Because of the downpour, the canal was flooded to waist level with rapid flow. The bottom of this canal would have been 2 of my sampling stations. Worse, we need to walk along this canal to reach our rendezvous with our transport back to campus. In view of the risks, we took an alternative route back to the starting point and had to forgo trying our luck in the rapid waters of the last 2 sampling stations. People, if you want to conduct a field trip, it pays to know the area well. Also, think hard for alternative exits in case a quick evacuation is necessary.

Fast flowing waters leading to the canal.

Back in the comfort of air conditioning and soft cushions.

What was that odd smell in the air? Just students drying their mud soaked shoes.

Working on the analysis of water samples using testing kits.

My favourite tool for field trips - African walking stick from Cold Steel. Modelled on the walking stick used by Zulu tribesman but made of polypropylene rather than wood. Virtually indestructible and superbly useful - prod the ground ahead for concealed trenches, clear bushes out of the way, balance oneself uphill or downhill, reach out to participants who need to be pulled to safety and of course discipline the occasional recalcitrant participant who insists to do things the hard way... (just kidding for the last point)

Thursday, December 03, 2009

Water, energy and the environment

Water and energy. 2 high profile environmental issues. Both are very important to the proper functioning of society. Yet we seldom link one with the other. In many discussions on climate change, energy alone always steals the limelight since its generation invariably produces CO2, a major greenhouse gas. Has it ever occurred to you that water and energy are more intricately linked to the environment than you think?

I came across this thought provoking article from a Wayne Patterson of Atreides Capital posted in the Water Forum. It is reproduced here in its complete form. It is slightly lengthy so make sure you have some spare time before opening it up, say during working hours. Link

To spare you the agony of going through the full article (or perhaps to entice you to complete reading it), here are its highlights.

  1. Generation of energy requires water. Transportation, treatment, disposal of water requires energy
  2. Lack of energy means no cars, no computers, no internet, no factories. Lack of water means death.
  3. Fossil fuels are finite and so is water yet few people talk about water running out.
  4. (Best of all) In the race to mitigate the effects of climate change caused by the use of fossil fuels, much R&D, resources and brain power are focused on alternative forms of energy. Another consequence is the world's fixation on carbon footprint and carbon credits. But have you wondered about the water costs of alternative forms of energy? For example, solar panels and biofuels require vast amounts of water to produce, outpacing the water requirements of traditional power plants (which by the way are already water hogs). Perhaps we should come up with water footprint and water credits to reflect the true costs of different human activities and technologies.

Yucks! What is that thing in my water?

All right, hands up, those of you who have seen "oily" patches like those in the 2 photos below. Let's count: 1, 2, 3...

Yes, they seem to be rather common in Singapore, whether in mangroves, streams, canals or ponds. And they appear throughout the year.

What are they? Are they natural or man-made? What are the ecological implications? Are they an indicator of water quality?

(Photo of Sungei Buloh Wetland Reserve (SBWR) by Anuj Jain 2009)

(Photo of Sungei Buloh Wetland Reserve (SBWR) by Anuj Jain 2009)

From the looks of the above photos, these "oil" patches could be caused by either real oil or certain metals (especially iron and manganese). To differentiate between them, try using a stick to disturb the patch. If it breaks up into smaller angular patches, it is likely to be metals. If the patch does not break but instead appears to follow your swirling, oil is present.

Iron and manganese are usually from the surrounding soils so yes, I would consider this natural.

Oils can also be from natural sources especially if nearby vegetation contains oils and somehow get into the water (pine oil, anyone?). A submerged dead animal can also produce oil from its fats.

Oils can be anthropogenic though. Without performing a lab analysis, it is difficult to differentiate between oils of natural and anthropogenic origins.

Ecologically, natural patches are probably harmless. Anthropogenic oil CAN be a problem, depending on its exact nature. Is it cooking oil, petrol, diesel, fuel oil or grease?

Yes, the appearance of oil in water can be an indicator of poor water quality but for most purposes, water quality is measured by a suite of parameters that can be quantified e.g. DO, oil content

Compare to the photo below. Even though there is a hint of an "oily" sheen, its characteristic colour (orangey) and angular fragments identify it as probably iron oxide. No prizes for guessing that it is similar to rust.

(Photo of a stream near Choa Chu Park by Robin 2009)