Fish kill at Pais Ris: do you have a million bucks to spare?

Apparently, the recent fish kill at Pasir Ris (Dec 09) and Pulau Ubin (Jan 10) was not the only event concerning negative water quality in that area.

Other events include:

1. 2008, 2009 - Pasir Ris Beach was found unsuitable for swimming because of the high bacateria (Enterococcus) count
2. Dec 2006/ Jan 2007 - mass death of marine creatures in Chek Jawa due to drop in salinity caused by heavy rainfall
   (Update: a comment from "Death Note from Chek Jawa" recorded the salinity at 22ppt (parts per thousand). I believe this was  measured using a portable conductivity meter. I personally find measuring the salinity this way can be rather confusing to readers as the salinity is calculated by the meter based on the conductivity multiplied by a conversion factor. Unfortunately, this conversion factor can be quite different for different waters, ranging from 0.5 to 0.7. Hence, I personally find it more useful to report the salinity as the base measurement of electrical conductivity adjusted to 25oC.)

According to AVA, a monitoring programme has already been in place to test the water quality in the said area. Without elaboration from AVA about its programme, I shall not comment on its effectiveness but here are my suggestions for AVA/NEA for a price tag of (you got it!) a million bucks.

Since this Pasir Ris/ Pulau Ubin/ Changi is such a problematic area in terms of water quality, install a continuous monitoring system with maybe 3 to 5 monitoring stations to provide real time data for immediate response. The technology is there... you just need money. Even manpower is saved since staff only go down to the field for further investigation or to do sampling for a more detailed analysis.

1. 3 - 5 buoys containing water quality and metereological sensors, telemetry package, solar panels and batteries. See previous post. They should be strategically placed for maximum monitoring effectiveness - 1 at north of Pulau Tekong, 1 south of P. Tekong, 1 between P. Tekong and P. Ubin, 1 north of P. Punggol and 1 north of Pasir Ris Beach
2. One/two water quality sensor packages installed on each buoy. See previous post. They should be able to measure depth, dissolved oxygen (DO), turbidity, electrical conductivity (EC), temperature, pH, chlorophyll, nitrate, ammonia. I was told that each package can cost about S$15000.
3. Remote server (perhaps in the agency's HQ) with the capability to receive data via cellular signals from the buoys/sensors.
4. To handle these vast amount of water quality data, GIS (geographic information system) should be installed on a workstation linked to the remote server to document and analyse the data. See previous post. A GIS can also provide a visual display of the water quality with colour coding. Any unusual or out-of-spec event should trigger an alarm. 
5. Better still, install a modelling software to tie in with the GIS. Some free models can be found at USEPA. A properly calibrated model can make predictions and simulations on the water quality in the area to prepare for future events of similar or worse magnitude.
6. Qualified and trained manpower to use and maintain all the above goodies.

All the above may not even amount to $1M. I am sure this system will reduce the guesswork involved in future events e.g. whose fault? and probably allow for rapid remediation if required.

Some thoughts on the fish kill at Pasir Ris

I must admit I have not been following the news about the recent fish kill at Pasir Ris as close as I should have. But thanks to Ria, her blog posts quickly brought me up to speed on the sequence of events. Here are the links with further links inside the webpages.

1. Dead fish patrol: Pasir Ris
2. Any dead fish at Changi?

From all accounts, the situation appeared to be a classic case of eutrophication. Put simply, eutrophication is an excessive growth of algae (sometimes, the term plankton is used though they are not the same) caused by the introduction of nutrients into an ecosystem. Depending on the type of algae, the nutrients may be nitrate, phosphate, silica or others.

Without further information from AVA (or NEA which was strangely silent in this whole episode) about the kind of algae (or "plankton" as given in the media) in the seas off Pasir Ris, I can only surmise that nitrate and ammonia (which can degrade to nitrate) are the probably culprits. In general, seawater is limited by nitrogen so once a sudden excessive input of nitrogen (in the form of nitrate or ammonia) rushes in, the algae immediately makes the best of this bonanza to multiply.

Nitrate is commonly found in fertilisers (yes, it is good for plants too!) and sewage (an decomposition product of ammonia). The question is: who was releasing these fertilisers or sewage? One suggestion was the incidental heavy rains have washed fertilisers or sewage into the sea. Of course, the question remains: where did these fertilisers and sewage come from?

Algae grows fast but they die fast too. Dead algae is major bad news as they decompose, using up dissolved oxygen (DO) in the water. Since many marine organims can only breathe DO, they are in trouble. However, marine organisms are not created equally. Some are more hardy than others since they need less DO to survive.

Wouldn't oxygen from the air replenish the loss of DO in seawater? Yes, it would but the rate of replenishment lags far behind the rate of DO usage in decompostion. Imagine lots and lots of algae dying and taking up DO. Atmospheric oxygen wouldn't have a chance!

Figure: Eutrophication at Botanic Garden (Nov 08). The greenish water is a dead giveaway.
Monitoring by AVA
According to AVA, regular monitoring was in place even before the recent fish kill event (Straits Times Forum 11 Jan 10). When the fish kill occurred, its staff was monitoring daily.

It will be great if AVA can reveal more about its regular monitoring programme - how regular? where are the monitoring stations? What kind of data are collected? For its daily monitoring during the fish kill episode, in addition to the above questions, can AVA reveal the following - what kind of algae was detected in the bloom? Was there a spike in the nutrient levels? What kind of nutrients? What is the trend for DO during the monitoring period?

What about NEA? It has many water sampling stations along the coast. Can their data shed any light on the fish kill? For that matter, NEA has never elaborated on its monitoring programme either i.e. kind of data collected, frequency of collection. Its water quality results have never been in the public domain (except for bits and pieces in its annual report.) (That goes the same for PUB. Have you ever tried requesting for a copy of the analysis report of the tap water that goes to your house?)

Figure: NEA sampling stations in both inland and coastal waters (taken from NEA website a few years back as it no longer could be found currently)

For some reason, water quality data are considered confidential in Singapore. Do such data constitute an issue of national security? Or are the agencies concerned about a vulnerability in their legal position?

Check out the extensive data placed online by the Environmental Protection Department (EPD) of Hong Kong.

Or the data compiled by USGS (U.S. Geological Survey) for the USA.

Water trends in the next decade

As we come to the close of the first decade of the new millenium, it is time to do a bit of crystal ball gazing to find out what are in store for the next ten years.

1. Watershed and water quality management using GIS (geographic information system) and other tools
If you are not familiar with GIS (or confuse it with Genome Institute of Singapore), it is a computer database that incorporates geographical information (e.g. locations of petrol kiosks, water quality data) into a digital map. A good example of GIS is Google Earth though there are many other packages (both commercial and freeware) in the market.


With the aid of cheap GPS devices and telemetry, water quality sensors can be placed in strategic locations in a waterbody to provide continuous monitoring of the water quality. Data collected from these sensors can be transmitted via cellular/wireless/radio (aka telemetry) back to a remote server. These vast amount of data will need computing software such as GIS for interpretation into sensible and useful information. A polluting event can signal an immediate alert as monitoring is now continuous and no longer periodic (e.g. once a month). Manpower is also saved in such an arrangement as you do not need staff to go to the field regularly to take measurements. Staff are only mobilised to perform a more detailed investigation when an alert comes in from the remote sensors.

Figure: YSI buoy containing water quality and metereological sensors, telemetry package, solar panels and batteries (http://www.ysi.com/productsdetail.php?Buoys-Floating-Platforms-46)

One limitation of such a system is only certain parameters can be measured by sensors e.g. depth, dissolved oxygen (DO), turbidity, electrical conductivity (EC), temperature, pH, oxygen reduction potential (ORP), blue-green algae, chlorophyll, chloride, nitrate, ammonia. In general, these systems cannot measure phospate, bacterial count, heavy metals, pesticides, volatile organic carbon (VOC) etc. all of which exert significant impact on the water quality. (I am however sure that somewhere, somehow, someone is trying to develop continuous monitoring for these parameters.)

Figure: YSI water quality sensor package which can be installed on board YSI buoys. (http://www.ysi.com/productsdetail.php?6600V2-1)
A parallel development in water quality monitoring is the use of remote sensing (aerial e.g. spectrographic imager; or satellite e.g. high-resolution imager) to gauge water quality in a watershed. These data can similarly be processed in a GIS. As you probably have guessed, remote sensing suffers the same weakness as telemetric monitoring - it can only assess a few parameters - turbidity, temperature, chlorophyll content etc., and in most cases less than those of telemetric monitoring.

Here is an example of remote sensing of coastal water quality by NOAA (National Oceanic and Atmospheric Administration). http://www.csc.noaa.gov/crs/cwq/demo.html


2. Integration of energy and water


In the first place, water and energy are intimately linked. See http://waterqualityinsingapore.blogspot.com/2009/12/water-energy-and-environment.html

With the current emphasis on climate change mitigation, there is a trend towards greening everything by reducing energy usage, including water/wastewater treatment since much energy is needed to process water/wastewater e.g. desalination - reverse osmosis requires high pressures (and high energy input), distillation of seawater is an even bigger energy hog.

Solar energy will be increasingly tapped to power the treatment plant. This is in addition to other energy conservation measures such as green building design. Low technology options include creation of wetlands and reforestation in the plant's vicinity to sequester carbon dioxide. Colocation of power plant and desalination plant is increasingly being explored A power plant typically generates an obscene amount of warm cooling water (originally extracted from the sea) which discharges back into the sea. In colocation, the desalination can receive the warm seawater discharge as its feed, hence lowering the osmotic pressure to be overcome in reverse osmosis.

3. And in Singapore... increasing use of bugs (macroinvertebrates) for biological monitoring of water quality
Even though little has so far been publicised about this issue but the truth is lots of research is currently being carried out to use bugs for an integrated approach to water quality monitoring. In simple terms, the type and quantity of bugs in the water tell you about how good the water is. Obviously, work has to be done to develop useful sampling protocols and biotic indices relevant to this part of the world. Yes, I know USEPA (http://www.epa.gov/bioiweb1/html/rbps.html) and UK (http://schools.ceh.ac.uk/advanced/freshpoll/pf-freshpoll3.htm) have very well established protocols and indices in place but are they applicable to Singapore or even Southeast Asia?

The strongest advantage of biological monitoring of bugs are:

1. You do not need to test each and every chemical to check for pollution. Most chemical pollutants are inherently harmful to bugs so the type of bug community you get will indicate their presence.
2. Unlike conventional monitoring of physical and chemical parameters, monitoring the bugs will reveal a pollution event has occurred, even though traces of the chemical pollutant have long since disappeared. Bugs will continue to display the effects of the pollutant for some time.

A major weakness...
Bug hunting is fun. Bug counting is NOT. Bringing a sediment sample back to the lab for sorting and counting of bugs can make one buggy. It is tedious and time consuming, causing the sorter/counter to enter a zombie-like state if done in excess.

Figure: Collection of bugs that is sure to thrill any student from primary to tertiary level.

Here are links to some of my bug hunting activities:
http://waterqualityinsingapore.blogspot.com/2009/03/myth-busted-and-new-believer-is-born-10.html
http://waterqualityinsingapore.blogspot.com/2008/12/finally-some-decent-bugs.html
http://waterqualityinsingapore.blogspot.com/2008/11/bug-hunting-in-singapore-polytechnic-sp.html

The above list is by no means comprehensive or exhaustive. They are what come to my mind based on my context and my experiences.

You may also read my interview on this topic in Straits Times (9 Jan 10).