Contamination in wastewater and reservoirs found in Balearic Islands

by Lorraine Williamson
polluted wastewater

PALMA – On Mallorca, Menorca, and Ibiza, there is nitrate contamination in the wastewater at 23 locations and 8 hydrographic basins. This would concern the contamination of nitrates from agricultural sources. 

As such, the Ministry of Agriculture, Fisheries, and Food launched an investigation to identify the sources of this nitrate contamination. Consequently, the polluted areas are now classified as vulnerable zones. It is expected an agricultural source will be identified due to nitrogen fertilisation, storage, application of manure, and domestic wastewater. 

In detail, 21 masses of groundwater in Mallorca and two in Menorca have been contaminated. Furthermore, as for the hydrographic basins, there are five mountain streams in Mallorca, two in Menorca, and one in Ibiza. 

Sources of pollution 

An estimate is made for each sensitive area and the sources of pollution are quantified as accurately as possible. These are nitrogen fertilisation, domestic wastewater, storage and application of manure, etc. 

The research is being conducted by the Edaphology group of the Universitat de les Illes Balears (UIB). Futhermore, the samples will be analysed by a lab in Valladolid. 

Cogesa Expats

The general director of Agriculture, Livestock and Rural Development, Fernando Fernández said that the agricultural sector itself has requested an investigation into the origin of the pollution. This is because “it is the first person interested in complying with environmental regulations”. 

 The researchers want to quantify and map the agricultural and livestock population per area for which crop or cultivation system it is intended for and how the specific irrigation management and fertilisation of the soil are shaped in order to carry out the corresponding nitrogen balances. 

The study will also quantify the livestock load of each sensitive area, referring to the characteristics of livestock farming and manure management. Also, the estimated infiltration of domestic wastewater from isolated single-family homes in sensitive areas. And lastly, quantify the irrigation with recovered wastewater and its content in different forms of nitrogen to calculate the inputs through this route. 

Water samples are also collected from 48 wells selected by the Directorate-General for Agriculture and High Nitrate Water Resources. These samples are from areas vulnerable to nitrate pollution of agricultural origin and 12 water samples from treatment plants in the same areas. 

The ministry recalled the pollution of water by nitrates has been recognised by the European Union for about 30 years. The first vulnerable zone in the Balearic Islands was declared in 2000, that of the sub-basin Sa Pobla. 

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