Attica’s soil has been swamped with nitrates

Contamination of the region’s ground water due to fertilizers and seawater has doubled in just a decade, say the experts

By Anna Sabatakaki - Kathimerini

Attica's underground water reserves have been judged as unfit to drink, mostly because of their high concentrations of nitrate. Since the city's water supply comes from the Mornos dam, there is no cause for immediate concern. However, this ground water is used for irrigating crops and so at some stage it does end up on our plates.

According to a recent study by a group led by Dr Philippos Harmanidis, a hydro-geologist at the Institute for Geological and Mining Exploration, ground-water pollution in Attica has doubled in the past decade.

In many areas, such as the Mesogeia Plain and Western Attica, the level of nitrates is above the maximum permissible, mainly because of the fertilizers and pesticides used in farming. The situation is worse on the Thriassio Plain, where industries have released heavy metals into the ground water.

According to the IGME study, high levels of nitrates are the main factor in the quality deterioration of the water in areas with intensive farming activity such as the Marathon and Mesogeia plains, where nitrate levels of 200 mg/1(ppm) are being recorded [compared to the maximum of 50 mg/1(ppm)].

There are also very high concentrates of chloride due to salination. According to Harmanidis, during the drought of the 1990s the drilling of new bores resulted in a lowering of the water table to below sea level, permitting seawater to infiltrate the ground water. This saline, nitrate-rich water is what irrigates the Mesogeia Plain farms. Harmanidis believes salination is at its highest in Palaia Fokaia, Lavrio, Schinias and the Bay of Faliro.

Although the permissible chloride content of water is 50 mg/1(ppm), even where drilling potential is just 20 cubic meters of water per hour, chloride pollution is at levels of 200 mg/1. Where the potential is 35-70 m2/hour, levels of 1,000-25,000 mg per liter are encountered.

In many of these areas, only the lowest concentrations of nitrates are 50 mg/1.

«The basin reaching from Kalivia to Markopoulo, Koropi, Paiania, Gerakas, Pallini and Spata has greatly deteriorated with extreme concentrations of nitrates. The water is classified as among the hardest,» said Harmanidis.

In the municipality of Athens, nitrate concentrations are as high as 86 mg per liter.

Ground water in western Attica, particularly the Thriassio Plain, has large concentrations of heavy metals.

«On the Thriassio Plain (Elefsina, Mandra, Aspropyrgos), intensive industrialization has resulted in infiltration of heavy metals into the ground water on a massive scale,» according to IGME hydro-geologist Nikos Siemos. «In certain areas there are increased levels of cadmium, zinc, iron, manganese and other metals,» he said.

The soil here has been overfarmed, and so there are increased levels of nitrates from fertilizers and pesticides, as well as salination from intensive drilling of groundwater. On the Thriassio Plain, nitrates are over 150mg/l; concentrations of chlorides are up to 3,000 mg/l. In the Megara area, there are also high concentrations of nitrates, but salination is as much of a problem as on the Thriassio and the coast toward Pachi. Salination of ground water has even been observed in the foothills of Mt Parnitha and Mt Kithaironas from infiltration of seawater.

For the Olympics, 48 deep (100- to 1,300-meter) bores were drilled near 12 Games venues, the Pedio tou Areos park and the National Gardens. Experts say the quality of the water is good enough to drink.

Nitrates: Nitrate pollution is chiefly due to the unrestricted use of nitrate fertilizers in farming, but also from human and animal waste (cesspits, cemeteries and urban waste). Large concentrations of nitrates are created by intensive agriculture. If drinking water contains nitrates, it can cause cancer of the bladder and ovaries.

Chlorides: Typical of pollution by seawater, chlorides appear in coastal ground water. Poor management of ground water in Attica has permitted the infiltration of seawater into the water table. Chlorides affect water quality and damage the soil, causing desalination.

Heavy metals: Lead, mercury, copper, cadmium, chromium, boron, manganese and strontium, among others, appear in the ground water in western Attica because of heavy industrialization. By entering the food chain they can cause all kinds of cancers. According to surveys by the European Commission, heavy metals are already apparent in Greek animal products.