Nitrates high in Malta’s three watercourses

The watercourses host a variety of animals, including the Maltese fresh water crab and the Maltese painted frog.

Wied Lunzjata. High levels of nitrates kill aquatic life
Wied Lunzjata. High levels of nitrates kill aquatic life

All three of Malta’s natural watercourses – Bahrija valley, Wied il-Luq in Buskett, and Wied Lunzjata in Gozo – have registered high nitrate levels in the range of between 110 and 200 milligrams per litre of water throughout the year, which is well over double the acceptable 50mg/l level for drinking water.

The highest level of nitrates (250 mg/l) was registered in Bahrija Valley.

High levels of nitrates cause ‘eutrophication’ – which cause algal blooms and the depletion of oxygen from the water, which may even cause death to aquatic life.

The watercourses host a variety of animals, including the Maltese fresh water crab and the Maltese painted frog.

Readings taken each month between February 2012 and January 2013 in all three watercourses showed levels above 100 mg/l except on two occasions. Potential sources of high nitrate levels include agricultural activities and water depletion through groundwater extraction. 

The studies, published on the MEPA website, were undertaken as part of the implementation of Malta’s Water Catchment Management Plan for 2009 and 2015.

Relatively low levels of nitrates were registered in Malta’s only two freshwater pools: Il-Qattara and l-Ghadira ta’ Sarraflu (both located in Gozo). This suggests a direct link between watercourses and groundwater.

Studies on the state of groundwater make it clear that very little improvement can be expected in the state of groundwater by 2021, despite Malta’s implementation of the EU’s nitrate directive.  

This is because studies show that groundwater takes as long as 40-60 years to percolate down to Malta and Gozo’s main aquifers, meaning that nitrates deposited in the 1980s could still be making their way down to the water table.