One World - An indication on the state of our environment (19)
Waters: nitrate and chloride levels at WSC abstraction boreholes
What is the status of groundwater with respect to nitrates and chlorides?
Nitrate levels exceeded the EU standard (50 milligrams per litre (mg/l)) at 9 out of 13 WSC groundwater abstraction boreholes in 2006, as in 2005.
Several perched aquifer systems in Malta and Gozo continued to exceed EU standards for nitrates as they are predominantly located in agricultural areas, while nitrate levels in the mean sea level aquifer (MSLA) system are variable and highly dependent on the human activities in the area.
The highest nitrate concentration in the MSLA system was recorded at the Speranza pumping station, where the concentration increased from 103mg/l in 2005 to 111mg/l in 2006.
While no limit value for chloride levels exists, the World Health Organisation (WHO) has indicated that values higher than 250mg/l of chlorides in water would be detectable by taste.[1]
The highest average highest chloride concentration recorded in 2006 was of 1,435 mg/l, at Ta' Kandja. Malta is currently in the process of setting a threshold value for chlorides in ground waters as per the obligations of the EU Groundwater Directive.[2]
Source: Malta Resources Authority
Environmental tip: Be aware of and support good agriculture practices and if you purchase from private water supplies do this only from licensed operators
[1] WHO (World Health Organisation) 2006. Guidelines for drinking-water quality [electronic resource]: incorporating first addendum. Vol. 1, Recommendations, 3rd edition, WHO, Geneva.
[2] 2006/118/EC.