The Albufera of Valencia receives up to 1.5 tons of pesticides per year, according to a study.

Valencia, Sep 16 (EFE).- A study by the University of Valencia (UV) warns that some 35 tons of pesticides are applied annually in the Albufera Natural Park (Valencia), of which seven are emitted by rice fields into the park's water and approximately 1.5 of them enter the lake.

This pioneering work, conducted by researchers from the Limnology group at the Cavanilles Institute of Biodiversity and Evolutionary Biology at UV, allows us to follow, step by step, the path that agricultural pesticides take in this natural park, from their application in rice fields to their arrival at the lake and the sea.

Pesticides are carried away by runoff and drainage water, and contaminate the natural park's aquatic ecosystems within hours of application, the University stated in a statement.

Researchers have modeled the environmental dispersal of eight pesticides applied over a ten-year period to the park's rice fields under realistic climate, agricultural management, and water circulation conditions.

About 35 tons of pesticides

The study, published in the journal Environmental Pollution, integrates a high-resolution hydrological model that simulates agricultural management in rice fields with a hydrological model implemented at a regional scale.

"The results of the study show that approximately 35 tons of pesticides are applied annually in the Albufera Natural Park, of which seven tons are emitted by rice fields into the park's water, and approximately 1.5 tons enter the lake," explained Pablo Amador, one of the researchers.

It is also concluded that 0.6 tons of pesticides are emitted through the inlets into the Mediterranean Sea, and that the most widely applied compound is the herbicide Bentazone, with 11 tons.

Pollution of ecosystems

The tool used by researchers at UV's Cavanilles Institute allows them to accurately represent the inflow and outflow pulses in the park's traditional irrigation system, in addition to tracking the transport of pollutants in water bodies on a daily basis.

The resolution achieved far exceeds that of conventional monitoring or environmental models published to date, according to the same sources.

"The model shows that pesticides used intensively in rice cultivation are carried away by runoff and drainage water, contaminating the aquatic ecosystems of the natural park within a few hours of application," Amador said.

In addition, the compounds with the greatest risk to the park's aquatic organisms are the fungicides Azoxystrobin and Difenoconazole, and the herbicide MCPA.

The south of the lake, more exposed

According to Andreu Rico, another of the researchers, "the areas with the highest risk of exposure are located in the south of the lake, where agricultural return waters with high pollutant loads converge."

The scientific study, in which the Instituto de Empresa University and Tragsatec also participated, also concludes that during the cultivation campaign, mixtures of up to five pesticides exceeding the risk threshold were simultaneously detected in the lake.

The maximum risk is reached in August, with levels that can cause chronic effects in up to 40% of the lake's aquatic species.

"This fact demonstrates that the pollution goes beyond the rice fields and affects the entire aquatic system of the natural park," Andreu Rico emphasized.