Going to the local lake is one of life’s pleasures. Having a nice family picnic while gazing out on the sparkling brown water…..hold your horses. Brown water? We may have been raised on blue water but brown is more natural.
In remote parts of the UK, southern Scandinavia and eastern North America the lakes and streams have been being stained brown over the last twenty or so years. The root cause of this discolouration is dissolved organic matter.
There has been a reduction of the level of acid rain which is leading to a colour change in local waters. The brownish tinge is actually closer to the shades that are great grandparents parents would have noticed as they relaxed by the pond.
Don Monteith, Senior Research Fellow at the UCL Environmental Change Research Centre, says: “A huge amount of carbon is stored in the form of organic deposits in soils, and particularly in the peatlands that surround many of our remote surface waters. In the past two decades an increasing amount of this carbon has been dissolving into our rivers and lakes, turning the water brown.
Before you get too gleeful though researchers are still checking the situation out. There still may be toxic levels of environmental pathways of heavy metals like aluminium and mercury which are closely tied to dissolved organic carbon. It’s still too early to know how the organic matters increasing levels will affect those toxic compounds.
This is not an effect of global warming for a change. John Stoddard of the EPA stated that chemistry records from over 500 sites across the Northern hemisphere has found this is a result of the lessening of the acid rain
that has leveled off from the higher levels of the 1970’s. As acidity and pollutant concentrations in the soil fall, carbon becomes more soluble, which means more of it moves into our lakes and rivers and more can be exported to the oceans.
Chris Evans, from the UK Centre for Ecology and Hydrology, adds: “The suggestion that waters are returning to more natural conditions may be of little consolation to water supply companies as they are faced with the increasingly difficult - and expensive — task of removing the colour from drinking water using treatment facilities that were designed to deal with the lower concentrations experienced in previous years.”
UK, USA, Canada, Norway, Sweden and Finland all helped support the study. This study is the largest of its kind and the data that the scientists have recorded shows the main source of high quality information about our head water systems.
Some of the study sites though may not have the funding to continue much longs. This is true even in the UK.
The full research was published in the science journal Nature on November 22. To read the journal article you must be a paying member.
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