Journal Recommendation!

Dear fellow readers,

To further your knowledge on the wonderful topic of bioindicators in understanding environmental pollution I recommend everyone interested to read the journal “Ecological Indicators”. That journal contains plenty of information on the topic of bioindicators. As a blogger writing on the topic of bioindicators, I believe that I have an obligation to share with everyone this piece of information. You may check it out in the link below: 

https://www.sciencedirect.com/journal/ecological-indicators

In the meantime, take care and see you guys soon for more bite-sized information on bioindicators! 

Review thus far

Author’s message: So far in this blog we have discussed the basic definition of bioindicators and explored quite a few species of bioindicators based on basic information of species and their uses as bioindicators based on published research, news articles and even videos on these interesting species of organisms! What’s next for this blog? I have a few things in mind. Firstly I will attempt to cover every different kind of bioindicators. This means that I will have to discuss bioassays and sentinels. Next I will work on one or two blog posts which focuses more details on the conduct of the research rather than the species in the research and the “results” of pollutants on the bioindicator species in order to provide more insight into how the scientific research is carried out rather than the “theory” of the research. I’ll try to present certain unexpected bioindicator species too. Stay tuned for more!

Corals As Bioindicators: How Coral Reefs Tell The Tale Of Lead Pollution

This is my competition entry on the use of corals as bioindicators for reference for my next post and also for interested readers! 

Lead pollutants can be found in the unlikeliest of places. Encrypted within the skeletal structures of the corals residing in our coasts lies the history of lead pollution.

It was a December morning of 1921. Tomas Midgley and his team of researchers from the General Motors Research Laboratory were hard at work experimenting with mixing various compounds in fuel in their effort to increase the efficiency of engines. It was then, when a small amount of compound was administered into the fuel supply that the ear-splitting cacophony of the test engine was reduced into a smooth purr and the team erupted in cheers.

The organolead compound known as Tetraethyllead (C₂H₅)₄Pb was discovered to possess “anti-knocking” properties (the quality which enables more fuel to be compressed into the engine without running the risk of premature combustion) thereby increasing the efficiency of internal combustion engines.

Then, hailed as a “gift from God”, leaded petrol quickly rose to prominence in the automobile industry within the same decade where it continued its steady increase for the next half a century to become the primary source of lead pollution in the United States before its eventual decline when studies on lead revealed health and environmental detriments concerning its use.

However, the problem of lead remains in Asia. In many Asian countries, attempts to reduce the use of leaded petrol had taken place only decades after their Western counterparts while attempts to phase out the use of leaded petrol entirely has been slow to catch on, with parts of Asia such as Iraq and Afghanistan continuing its use of leaded petrol up till this very day.

Aside from leaded petrol, the increasing use of coal following the industrialisation of India and China quickly rose to contribute to large quantities of anthropogenic lead (lead from human activity) despite the reduction in the use of leaded petrol. Today, the concentration of lead within the waters of Asia far exceeds their non-Asiatic counterparts. Hence, due to health and environmental concerns, the concentration of lead within the Asia is closely monitored.

One such attempt to study the proliferation of anthropogenic lead lies in the study of coral reefs. When lead is released into the atmosphere from human activity it mixes with rainwater which is eventually transported via natural or man-made drainage basins into coastal waters. Corals in the coastal waters regularly utilises lead in seawater as the replacement for calcium found in the water to construct its skeletal structure, effectively recording the concentration (which can be deduced by the ratio of lead to calcium in the structure of the corals) and type of lead isotopes found in its environment as it grows.

In certain species of corals such as the Porite corals, its skeletal structure grows to produce distinct bands with each year similar to the growth of trees trunks, enabling the past concentration and distribution of isotopes recorded within its skeletal structure to be dated.

The isotopic distribution of lead within the corals reveals much about the lead pollution taking place in the region for two reasons.  Firstly, the composition of lead isotopes contained in man-made products differs from that of the natural source within the vicinity.

Secondly, because the isotopic ratios for different sources of lead is location specific, the composition of lead isotopes in man-made products from various countries is unique due to the different geographical sources in which the country obtains the lead from to manufacture its products.

By comparing the ratio of the different lead isotopes within the coral sample with the known ratio from the natural sources within the vicinity as well as with sources from man-made products in various countries, researchers can determine the extent that these different sources contribute to the problem of lead pollution within the location of study.

Lead concentration and composition speaks volumes about the history of the region. For example in Vietnam, the ratio of lead to calcium found within the corals increased from 14nmol/mol between 1870 and the mid-1950s to 22nmol/mol in the 1970s which coincides with the introduction of anthropogenic lead pollutants into the environment during the Vietnamese war. From 1959, the isotopic ratio of 206Pb/207Pb decreased from 1.190-1.194 to 1.178, coinciding with the increased presence of leaded petrol from American sources following America’s increasing participation in the Vietnam War. Subsequently, the concentration of lead in Vietnam from the 1970s was followed by a steady increase to 44nmol/mol in the 2000s which indicated an increase in the use of leaded petrol and coal following a series of industrialisation within its region after the war.

The historical development of lead use in other parts of the world can be similarly reconstructed with the study of the corals near its coasts. Of late, corals in Hong Kong, the Chagos Archipelago (South of India) and the countries of the United States, Brazil, Kuwait, Vietnam, Malaysia and Singapore are among those that have been examined for this purpose.

Lead pollution is a transnational problem because lead pollutants originating from one country can be transported by human activity such as illegal dumping or by nature such as wind and ocean currents to other countries. The use of corals for researchers to pin-point the geographical sources of lead contributing to the lead pollutant within the location of study (based on the isotopic distribution of lead within the corals) provide researchers with valuable information to deal with the problem.

For example in Vietnam, the isotopic ratio of 206/207Pb was 1.172 which was comparable to that of the Yangtze River delta (1.166-1.176) while significantly different from the lead isotopic ratios of coral samples obtained from countries south of Vietnam such as in Malaysia (1.127). This implies that the lead pollutants from neighbouring South China poses a greater threat to lead pollution in Vietnam as compared to those in neighbouring Malaysia and Indonesia.

In Asia, where historical and even modern industrial statistics are often difficult to come by, coral reefs provide a reliable and novel way to study the history and present state of lead pollution within the region. As developing economies continue to flex their ever increasing industrial prowess, the need to study and track the environmental consequence of increasing industrial activity in Asia provides yet another reason to preserve these complex underwater ecosystems living within our coastal waters.

Why Bioindicators? My experience in the Asian Scientist Writing Prize (Part One)

For my first series of blog posts, I would like to share my personal experience with the topic of environmental pollution because it was my personal experience which ultimately inspired me to focus on the topic of bioindicators. This would involve my participation in the recent 2017 Asian Scientist Writing Prize competition.  More information on the competition can be found here  https://www.asianscientist.com/2017/07/pr/asian-scientist-writing-prize-2017-winners/.

Back then to improve my chances in the competition I looked to the entries of past ASWP winners in order to gain some idea on the style plus level of content preferred by the Asian Scientist magazine. It was then that I encountered the piece titled “Once An Industry Wonder, Now A Silent Killer” by the previous grand prize winner of the ASWP on the pollutant known as Asbestos (Asbestos is a naturally occurring silicate mineral comprising of thin fibrous crystals used in products for its heat, electricity and sound resistance properties which was later found to be a health risk for its harm on respiratory and cardiovascular tracts).

Asbestos: Notice the fibrous strands. Natural History museum of London, obtained from: https://en.wikipedia.org/wiki/Asbestos

As the piece had pointed out, while the threat of Asbestos was eventually identified, this substance still poses a threat since it still lurks within our environment-particularly within Asia where it is ready to cause harm if it enters our bodies. This caused a change in my perspective. Firstly, I used to think that pollution was only something associated with unwanted chemical waste products expelled from the exhaust of machinery in our factories or vehicles rather than substances with beneficial qualities that were harnessed for use. Secondly, I was also under the impression that pollution was something that would kill us quickly that needs to be disposed out into the far-flung barren backwater regions of our environment rather than something much closer to us-potentially hidden within the very walls (quite literally!) of our houses or even lying silently in wait within our very bodies!

This led me to consider further the kinds of pollutants that might be lying in wait within the bodies of living organisms, its implications, the kinds of information we could obtain out of it and many more ideas which culminated in my interest in the topic of bioindicators which I would also use for my own competition entry.