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Media coverage about the complicated situation relating to the current deterioration of the Mar Menor has this week focused on the topic of contamination of both the lagoon itself and the extensive body of water which lies beneath the Campo de Cartagena which is what’s known as a quaternary aquifer.

 

A quaternary aquifer lies between bedrock and the earth's surface and is a zone of saturated water.When water infiltrates into the ground it passes through (unsaturated)layers of earth, which are highly permeable filtering through to the saturated zone, which is full of water. The boundary between the saturated zone and the unsaturated zone is called the water table. The water table moves up and down depending on how much water is in the aquifer. As aquifers are directly connected to the surface, they are constantly re-filled via water seeping down through the soil, (or in this case, from the Mar Menor as well) so are prone to external contamination.

 

There are three aquifers below a vast area stretching inland from the Mar Menor and across into the Alicante province; the Carrascoy Triassic aquifer, the Victorias Triassic aguifer and the Campo de Cartagena aquifer, by far the largest which borders with the Mar Menor and has multiple layers, formed in successive geological periods.

 

In the case of the aquifer below the campo de Cartagena, the principal polluter is agricultural fertilisers which contain nitrates.These nitrates are contained within the run-off water which seeps through the topsoil layers and back into the aquifer, polluting the body of water which lies beneath the surface and which is in turn extracted legally by agriculturalists with licences to undertake irrigated farming.

 

Historically, there has been a significant problem with the agricultural sector illegally drilling wells, extracting the water, which is saline, desalinating it for agricultural use, tipping the brackish water which is the waste product generated by desalination into water run-offs (desalination generates 70% of usable water and 30% of salt and nitrate laden waste) which in turn either filter back down through the topsoil to the aquifer or run into the Mar Menor. The water generated is then used to irrigate crops, enriched with agricultural fertilisers containing nitrates. These then leach into the soil and into the aquifer. The scale of this activity is vast and the quantities of chemicals leaching into the aquifer has caused significant contamination.

 

Another problem has been the drilling of deep wells into the lower layers of the aquifer to reach the older water, which is not saline. As many wells have been badly drilled, and the chambers not sealed, saline water (containing nitrates) has seeped down from the upper levels to contaminate these deep water reserves, and the problem has been exacerbated by some agriculturalists tipping the saline brine generated by desalination back down into some of the deepest wells to get rid of it so that their illegal desalinating processes remain undetected.

 

Leaching of nitrates into the Mar Menor is believed to be the principal cause of the increased algal growth which can be clearly seen this summer and is likely to spread further as the weather warms up, but the other issue caused by the use of the nitrates is, as mentioned above, the contamination of the aquifer itself and this has been the principal topic of this week.

 

The nitrate concentration of the Campo de Cartagena quaternary aquifer is around 200 mgNO3 / l (milligrams of nitrates per litre). This level is well above the optimal values recommended by the scientific community, which are around 50 mgNO3 / l.

 

Spain is subject to legislation from the European Commission which aims to protect water bodies from nitrate pollution and any measurement exceeding 50 mgNO3 / l is a breach of Nitrates Directive 91/676/EEC.

 

Spain is currently subject to infringement proceedings for non-compliance with Nitrates Directive 91/676, because it exceeds that threshold in many bodies of water, including the aquifer beneath the Campo de Cartagena, infringement procedure No 2018/2250 initiated by the European Commission in 2018 explicitly stating that in the Region of Murcia, "additional or reinforced measures must be taken and additional measures are needed.

 

The Region of Murcia is obliged by European law to also draw up and apply Codes of Good Agricultural practices in areas which are vulnerable to nitrate contamination and this has been done in the region in both 1998 and 2003, but have not been enforced as per the legislation. Failure to do this is being laid at the feet of a former regional head of agriculture and water who is now being investigated as part of a criminal investigation against farmers who drilled illegal wells as well as other bodies deemed not to have complied with the European and Spanish legislation including the CHS and regional government (caso Topillo).This case is currently being investigated by the Court of Instruction number 2 in Murcia, by magistrate Ángel Garrote, and once investigations have been completed will recommend whether the public prosecution offices should initiate criminal charges against the many companies and individuals involved. It is highly complex.

In 2018 the Regional Government of Murcia passed the Law of Urgent Measures for the Mar Menor,part of which included the division of the Campo de Cartagena into three zones, level 1 being nearest to the lagoon and the area in which agricultural activity should be most restricted.Since then a process has been underway to identify the agriculturalists illegally extracting and irrigating, confirming with the CHS that they have no licences and then shut down their illegal desalination plants and return the land to its former status,ie in many cases, as non-irrigated land, starting with the urgent zone 1 parcels. These agriculturalists are all under criminal investigation within the caso Topillo, but it is only now that the regional government has finally been able to complete all of these processes and start shutting down the illegal activity.

 

The law is NOT attempting to shut down agriculture, but instead find mechanisms by which agricultural activity, recognised as being a major economic contributor to the area, can be compatible with the environment.

 

So the law also prohibits the use of highly soluble and potentially polluting fertilizers such as ammonium nitrate, calcium nitrate and urea, and will permit the use of desalination plants, as long as proper sytems are put in place to control the disposal of the nitrate and salt laden waters.

 

In 2019 the Ministry of Ecological Transition published a public consultation to update the catalogue of nitrate-polluted waters in Spain.

 

The latest report produced by the Ministry for Ecological Transition states that in the 2018/19 hydraulic year, 4,111 kilos of nitrates per DAY, a total of 1575 tons, entered the Mar Menor via agricultural run-off.

 

The aquifers are directly controlled and managed by the CHS, Confederación Hidrográfica del Segura, which itself answers to the Ministerio para la transición ecológica y el reto demográfico of the Spanish state and has carried out an extensive study relating to the aquifer which is currently on public display until 29th June.

 

 

This week the CHS has put out a document answering various points made in the media about the report and aquifer, saying that the aquifer is considered as being “unhealthy” if a single checkpoint exceeds the 50 mgNO3 / l level, as a body of water is rated for the worst value it presents in its official network.

 

There are 18 measuring stations monitoring the composition of the aquifer.

 

”The CHS says that, “both the Segura Hydrographic Confederation and the Ministry for Ecological Transition and the Demographic Challenge are undertaking precise actions to curb the deterioration of the groundwater mass of the Campo de Cartagena and to reverse the situation”.

 

The CHS wants to declare this body of water “at chemical risk”, a process that is already underway and the regional government has been aware of the nitrates problem in the aquifer for literally decades, having declared the aquifer “a vulnerable area to nitrate contamination of agricultural origin” as far back as 2001, yet continuing to allow the widescale continuance of nitrate-driven agriculture for almost 20 years, virtually unchecked.

 

This has started to change since the lagoon literally turned green in 2016 due to the high level of nitrates , bringing the matter to the attention of the wider public. Since then several protest platforms have been formed; pacto por el Mar Menor, SOS Mar Menor, and others, all calling for change and for measures to be taken to prevent the further degredation of the lagoon as well as prevent damaging agricultural practices.

This week the Pacto por el Mar Menor protest group published a study by the Polytechnic University of Valencia and the Institute of Water and Environment Engineering prepared by researcher Miguel Ángel Pérez Martín.

 

This study says that there must be an overall reduction in nitrogen pressure on the aquifer of 80% in order to reverse the current levels of pollution, which in turn would lead to a regeneration of the body of groundwater under the Cartagena region in a period of approximately 18 years.

 

Any reduction below that level would not be compatible with the recovery of the aquifer, although the researcher believes that limiting the use of nitrates in agricultural activity would even lead to significant reductions in the first and second year in terms of nitrate concentration as "the contributions of surface water during episodes of rain which generate water and sediment contain a significantly smaller amount of nitrogen" (ie, rainfall would dilute existing contamination).

 

At the moment this subject is highly topical as the regional government draft bill for the comprehensive protection of the Mar Menor has been prominent in the news, particularly relating to the proposal to create a strip of land around the shores of the Mar Menor which would be “nitrate free”, thus preventing the agricultural sector from using chemicals or artificial irrigation in this area.

 

The original proposal by the regional government was for this strip to be 500 metres wide, but this week the Ciudadanos party has decided to support an initiative first put forward by the PSOE party, that the strip be widened to 1500 metres.

 

This report adds its voice to that of other scientists who believe that the strip should be 1500 metres wide, arguing that by doing so an area of 1,400 hectares would be nitrate free, whereas limiting the strip width to 500 meters would only affect the control of 127 hectares. "Increasing the width of the strip from 500 to 1,500 meters means practically multiplying the area affected by the limitation by 10, which can contribute substantially to reducing the contribution of nutrients to the lagoon" and would avoid the eutrophication process, reports the scientist .

 

He also believes that "the maximum amount of total nitrogen use per hectare a year in the Campo de Cartagena area should be clearly and explicitly incorporated," into the new legislation, a figure that he believes should be 170 kgN / ha / year (kilograms of nitrogen per hectare and year).

 

The agricultural sector, meanwhile, is bitterly opposed to any such restrictions and this week has put forward its own list of 24 points which it would like to see amended in the proposed legislation, one of which is that the fringe of 500 metres of “nitrate free agriculture” be removed from the proposed legislation altogether, ie there be no restricted farming area at all.

 

They have commissioned their own study from the UPCT by Victoriano Martínez, professor of Agroforestry Engineering and director of the Transfer and Sustainability Chair at the Polytechnic University of Cartagena which concludes that agricultural activity along the shores of the Mar Menor is compatible with its conservation.

 

The Polytechnic study considers that the legislation points the finger at irrigation as the main pollutant via irrigated agriculture, but criticizes that it does not take into account or minimize other activities that have also played their part in the deterioration of the ecosystem. However, it does accept that irrigation has made "an important contribution to the environmental problems of the Mar Menor".

 

Which of course, has also contributed to the pollution of the aquifer, without which the agricultural sector could not survive.

Background information about this complex topic can be found by clicking here