It's Getting Hot In Here...

Thermal pollution is the rise or fall in the temperature of a natural body of water caused by human influence, such as the degradation of water quality that changes ambient water temperature. The earth has a natural thermal cycle, but excessive temperature increases can be considered a rare type of pollution with long term effects. The phenomena is usually associated with the rise in natural water temperatures, but cooler water being released from dams and reservoirs into warmer streams and rivers are also responsible for this type of pollution.

A common cause of thermal pollution is the use of water as a coolant by power plants like Powergen and industrial manufacturers. When water used as a coolant is returned to the natural environment at a higher temperature the change in temperature impacts organisms in several different ways.

The above picture shows an urban community, specifically that of Belmont (Freetown). You may be wondering “Huh? What does that have to do with thermal pollution?” You’ll be surprised to know how much of an impact urbanization/urban sprawl has on this type of pollution. I'll give you a hint... It's BIG. During warm weather, urban and peri-urban runoff can have significant thermal impacts on small streams as well as the drains that flow through the capital, as storm water passes over hot parking lots, roads and sidewalks. Since the waterways in and around the Port of Spain Corporation have been altered by man to become concrete drains, in addition to runoff from the surrounding communities being heated by the aforementioned areas, they’re also heated by their main travelling medium as well during the day; the concrete channels. This also nullifies the stream shading effect that mountains, trees and other objects played in cooling the water earlier in the river’s youthful stage.

We can see how closely the effects of thermal pollution link with water pollution. When the water temperature increases, the oxygen levels in the water decrease thereby harming a plethora of aquatic animals and organisms in the process. The rise in temperature may also lead to a rise in the metabolisms of many of these creatures, causing them to eat more than they usually would in a shorter time period. This means more resources would be used up even faster than usual, some organisms would adapt better than others and the food chain would be skewed. Primary producers are affected by warm water because higher water temperature increases plant growth rates, resulting in a shorter lifespan and species overpopulation. This can cause an algae bloom which reduces oxygen levels. Temperature changes of even one to two degrees Celsius can cause significant changes in organism metabolism and other adverse cellular biology effects. Principal adverse changes can include rendering cell walls less permeable to necessary osmosis, coagulation of cell proteins, and alteration of enzyme metabolism. These cellular level effects can adversely affect mortality and reproduction.

There are several means of reducing impacts of warm water thermal discharges including use of cooling ponds, cooling towers, stormwater management facilities that absorb runoff or direct it into groundwater, e.g. bioretention systems and infiltration basins, and also productive use of the heated water for a secondary industrial process or space heating. But with our not-so-very-clever use of urban planning in the capital as many believe, would we have space for such tangible solutions?

References:

EPA. 1999. Preliminary Data Summary of Urban Storm Water Best Management 

 Practices. Washington DC: Office of Water. Accessed May 18, 

 2014. http://water.epa.gov/scitech/wastetech/guide/stormwater/upload/2006_10_31_gu  ide_stormwater_usw_a.pdf

The Encyclopedia of the Earth. "Thermal Pollution". Accessed May 18, 

    2014. http://www.eoearth.org/view/article/156599/

Love to Know. "Types of Pollution" Accessed May 18 2014. 

    http://greenliving.lovetoknow.com/Types_of_Pollution

TNAU Agritech Portal. "Environment and Pollution: Thermal Pollution" Accessed May 18, 

    2014. http://agritech.tnau.ac.in/environment/envi_pollution_intro%20-%20thermal.html