Nitrate levels in more than three quarters of groundwater sources across the Maltese islands are above the acceptable level, according to a study by the Malta Resources Authority.
The analysis of 13 aquifers in Malta and Gozo showed just three had nitrate levels below the acceptable standard of 50mg per litre. These aquifers were all situated at sea level in the Miżieb area, Comino and Gozo.
Three aquifers - the Pwales and Mellieħa coastal aquifers and the perched aquifer in Żebbuġ, Gozo - had nitrate levels six times the set standard.
High nitrate levels have an economic impact because groundwater extracted by the Water Services Corporation would have to be blended with the more expensive reverse osmosis water to dilute the nitrates and render it safe for human consumption.
According to Resources Minister George Pullicino, the two main sources of nitrate contamination were agricultural practices that used too much fertiliser and the incorrect management of manure by the animal husbandry industry.
At a meeting for journalists to launch a six-week public con-sultation exercise on measures to reduce nitrate levels, Mr Pullicino said it would take about 40 years for nitrate levels in groundwater to drop below acceptable standards.
"We will be talking to all stakeholders, especially farmers and animal farm owners, to rope them in on the exercise. We have to introduce a registration system for fertiliser use, hold educational meetings on the correct use of fertiliser depending on the type of crop it is used for and the correct storage of manure so that contaminated rainwater will not leach into the ground," Mr Pullicino said, insisting other measures were also being considered.
A study conducted by the Agriculture Department showed farmers generally overused nitrate-rich fertiliser, with fields used for planting watermelons having the highest nitrate levels.
According to Neville Mercieca, an expert from the Department of Agriculture, farmers who plant watermelons could save up to €100 for every tumolo of land if they used the correct amount of fertiliser.
"Fertiliser is very costly and so it is also economically beneficial to farmers to use the correct amount," Mr Pullicino said. There was absolutely no danger to human health from the consumption of vegetables, he added, because crops only consumed the amount of nitrates they needed and any excess would remain in the soil eventually washing its way down into the aquifer.
Primarily, farmers use manure as organic fertiliser, however, they also use non-organic chemicals, which are spread out on the soil.
A public consultation document can be found on www.mrra.gov.mt and comments can be submitted via e-mail to info.mrra@gov.mt.