Intensive agriculture, livestock and domestic sewage degrade the water of the Guadiana | Environment

Official documents from Portugal and Spain do not ignore the problem: the degradation of the Guadiana water continues to prove to be an environmental constraint that is difficult to control. The warning arrives from Spain: about 50 kilometers from the Alqueva reservoir, the population of the Extremaduran city of Almendralejo, for more than a decade, has been denouncing the poor quality of the water that is captured at the confluence of the Machatel river with the Guadiana river, for consumption human.

The situation has given rise to frequent protests from the Platform against Contamination of Almendralejo (PCCA), an organization created to claim another source of supply that does not endanger the health of consumers. As a result of the survey they carried out on the state of the water in 2014, they highlighted its “poor quality” and proposed that the Guadiana Hydrographic Confederation (CHG) consider the tributary flowing into the Guadiana at the catchment site of “Type A2 (polluted water) and /or Type A3 (very polluted waters).”

This warning was confirmed by the Ministry of Ecological Transition and Demographic Challenge (Miterd) after the monitoring carried out during the elaboration of the Guadiana Hydrological Plan (PHG) on the Spanish side, for the 3rd Cycle referring to the period 2022-2027. Hydrographic plans are drawn up in planning cycles and are reviewed and updated every six years.

In the composition of the raw water collected in several places of the hydrographic network, the registered values ​​exceeded the maximum parameters in a set of polluting substances. In fact, the largest volume of microbiological pollution caused by discharges of domestic wastewater produced by almost 1.5 million residents in the territory delimited by the Guadiana basin, with an extension of 55,220 square kilometers, comes, in large part, from the regions of Badajoz , Mérida, Zafra and Ciudad Real.

In turn, the contamination resulting from agricultural and livestock holdings “originates in the regions of Las Vegas Altas and Vegas Baixas in the Alto Guadiana”, where the largest areas of irrigated crops are located. Annex 4 – Water Uses and Requirements – included in the Hydrological Plan for the Spanish part points out that the extension of the area allocated to irrigation reached 630,423 hectares between 2014 and 2018. The average consumption of water used in irrigation was estimated at 2055 cubic hectometers (hm3).

Toxic waters and heavy metals

The volume of water used in human activity, in agricultural and livestock holdings, between 2014 and 2018 was, on average, 946 cubic hectometers (hm3), a volume that, in large part, is debited to the hydrographic network and then concentrated in the course of the Guadiana River, a detail that explains the proliferation of exotic plants, the water hyacinth and the Mexican water lily. The first has affected the water intake that supplies Almendralejo.

The survey carried out for the PHG 2022-2027 “estimates” that of the 376 bodies of surface water in Spanish territory, 232 (61.7%) “are at high risk of not achieving good ecological status by 2027”. The document also highlights the presence of heavy metals with values ​​“above the limits established by Spanish legislation”: arsenic, mercury, barium, cadmium, chromium, nickel, iron, selenium, total ammonium, copper. And also phenols, phosphate, nitrogen, nitrate, pesticides, herbicides, insecticides, BOD and BOD5 (biochemical oxygen demand), suspended matter, etc.

The conflict between the population of Almendralejo and the managing entity of the Guadiana basin became more acute in January 2017, when the platform verified that the results of analyzes carried out on total coliforms and fecal streptococci had ceased to be published. Félix Lorenzo Donoso, president of the PCCA, explained to PÚBLICO that the microbiological parameters showed “alarming values ​​and that it would be reasonable to continue analyzing them” and make them available for public consultation.

The information made available by the CHG in 2015 (the last year in which the microbiological parameters were released) showed “exceedings” that were around 50,000 total coliform bacteria per colony forming units (CFU/100mL), when the maximum admissible value (VMA) points to for the 10,000 bacteria.

Complaint of water with “bad smell” and “bad taste”

The CHG was asked to explain the missing data on total coliforms and faecal streptococci. “The reason we were told is that there was a European Union directive that did not oblige us to carry out the respective analyses,” when it is proven that “the water contains a large amount of fecal matter”, explained the president of the PCCA. He left a note: to “clean and disinfect” water collected from the Guadiana river, it is necessary to “use an average of 830 kilos of reagents per day” before releasing it into the public network for the population of Almendralejo.

This data was extracted from the documentation provided by the Estremadura Health Service (SES) in compliance with a resolution by the Council for Transparency and Good Government, after the platform had initially turned to the Ombudsman to obtain information on the water supply to the population of the Spanish county.

And, among the clarifications provided to the Ombudsman (PJ) by the CHG, this entity recognizes: “Our agency is aware that in the Guadiana river basin corresponding to the section where the water intake that is supplied to the ETA from Almendralejo, there are urban agglomerations (47) that currently lack works and facilities to properly treat their wastewater.”

The provider continues: “The hydrographic confederation should investigate the state of the water, if it has received substantiated complaints.” And he adds: “It is true that untreated discharges are being carried out.”

Citizens are periodically confronted with “deficiencies in the quality of the drinking water that is supplied to the population, due to its bad smell and bad taste”, despite being treated, adds the platform.

Glyphosate herbicide detected in 315 samples

Arguments were still being made about the lack of monitoring of microbiological parameters, when a new controversy arose: in 2013, analyzes carried out at the catchment site that supplies Almendralejo registered an amount of 0.05 micrograms per liter of water in the river of the herbicide glyphosate. But in 2018 the value rose to 0.27 micrograms per litre, when the VMA forces it to be set at 0.1 micrograms per litre. The CHG also stopped making reference to this herbicide in 2021, 2022 and 2023.

Annex 9 of the PHG that the Spanish Government recently approved emphasizes: “Glyphosate was found in 315 samples taken in the hydrographic basin from the Guadiana [e a presença da substância] affects 30.52% of water lines.” For its part, the environmental organization Ecologistas em Acção reveals that the sale of this herbicide in Spain between 2011-2019 “surpassed 82.5 million kilos”.

Reacting to a series of questions posed by PÚBLICO, Félix Danoso leaves a warning: “It is clear that the heavy rains that occurred in December took with them the phytosanitary products used in the intensive agriculture of Las Vegas Altas del Guadiana.” The floods removed the river bed, causing the contaminated sludge to dissolve in the water, “carrying a greater amount of contaminants and causing their accumulation in sedimentation sites, which are usually the reservoirs (reservoirs of dams) that retain water” , observes the President of the Platform. The Alqueva reservoir concentrates the inflows coming from Spain.

The panorama observed in the hydrographic network in Spanish territory with the degradation of surface water quality ends up extending to the 11,611 square kilometers of the hydrographic basin that runs through the Alentejo and Algarve regions, where 230,000 people live.

APA concerned about water coming from Spain

During the public consultation of the Hydrological Project of the Spanish Guadiana Basin for the period that will take place between 2021-2027 that PÚBLICO read, the Portuguese Environment Agency (APA) prepared an opinion that demonstrates the concern of the Portuguese authorities about water quality coming from Spain. The affluent flows carry “high concentrations of nutrients and organic matter resulting from human activities, such as agriculture, livestock and discharges of wastewater, urban and industrial”. And microbiological pollution “is characterized by the presence of high amounts of microorganisms in water bodies, from domestic, urban and livestock wastewater discharges, as well as runoff from contaminated soils”.

According to the classification carried out by the Spanish authorities, 14 of the 27 transboundary water bodies “are at a high risk of not achieving good ecological status”. “The greatest concern is concentrated on the Mures stream (Alqueva), on the Ardila river and on the Caia river”, stresses the APA opinion.

The presence of these microorganisms constitutes a “risk factor for health, so they can restrict the potential uses of water, namely in water intended for public supply or recreation with direct contact”, concludes the APA in the opinion it addressed to the Spanish authorities. In Alqueva, five river beaches were installed and the large reservoir guarantees public water supply to 200,000 people.

In Portuguese territory…

The problem is that the situation in the Guadiana hydrographic basin in Portuguese territory is not better, as can be subtracted from the consultation of the Hydrographic Region Management Plan (PGRH) which covers 32 municipalities in Alentejo and Algarve.

In 2021, at the end of the 2nd cycle, of the 268 bodies of surface water existing in the Guadiana basin in Portuguese territory, 103 were in a “good” state (38%) and 158 (59%) were in a state below “good”due to organic and nutrient pollution.

In short, it appears that in the Guadiana Hydrographic Region (RH7) there was a slight improvement in the state “good” of water bodies that went from 38% to 40%, an increase that, even so, is 32 percentage points away from the environmental objective established for 2021.

This result is not unrelated to the non-compliance with the planning prepared for the period of validity of the PGRH, between 2016 and 2021. 107 intervention measures were defined in the hydrographic network, but at the end of 2019 the financial execution rate was around 36%, “ which represents a meager financial effort”, observes the management plan.

The “great optimism” placed in the physical and financial programming of the measures in the PGRH was followed by difficulties that “did not allow their implementation within the planned deadlines, with deadlines slipping”. And many measures programmed for the 2nd cycle were transferred to the 3rd cycle.

The blockade in interventions translates into the final conclusion of the PGRH: the state of water bodies “worsened between 2016 and 2021”. With regard to rivers and reservoirs, “most have a global status of “less than good”, corresponding, respectively, to around 59% of rivers and 60% of reservoirs”. A “significant increase” in the rejected loads of nitrogen and phosphorus by the agricultural and livestock sector is foreseeable, points out the document.

The environmental objective of the Water Framework Directive, and consequently of the Water Law, was to have achieved in 2015 the “good” state of all bodies of water, “which has been and is far from happening”, refers the PGRH with a final conclusion. “It is also urgent to start the Interministerial Commission for Water Coordination, which was created when the National Water Plan was approved”, in 2016.

PÚBLICO sent several questions to the Guadiana Hydrographic Confederation, to the Municipality of Almendralejo and to the APA; however, it did not receive a response to the requested clarifications.