The Estero de Domingo Rubio wetland, located near the Marismas del Odiel Natural Area in the Huelva estuary, is regionally, nationally and internationally protected thanks to its ecological value. However, its tributary rivers and the Ra de Huelva estuary pump manmade pollutants into it, which could affect its water quality and ecosystem.
Industrial activity, accumulations of dangerous waste, the expansion of farming, and excessive extraction of sand and gravel for the construction industry are the leading threats to the Estero de Domingo Rubio wetland, the tidal system of which plays a "crucial" role in transporting and dispersing pollutants.
The wetland is "periodically flooded with high levels of dissolved elements such as copper (Cu), arsenic (As), cadmium (Cd), cobalt (Co), chrome (Cr), nickel (Ni) and zinc (Zn), which come from the water entering the estuary, which is affected by pollution from the mining industry", Cinta Barba-Brioso, co-author of the study and a researcher at the University of Seville (US), tells SINC.
The study, which has recently been published in the Marine Pollution Bulletin, shows that the wetland's tidal channel also receives acid lixiviates (liquid pollutants) that come from the dumping of sulphurous waste, industrial waste outflow pipes, and abandoned chemical plants, which all contribute to its metallic "enrichment".
Barba-Brioso says: "Agriculture is another significant source of diffuse contamination in the wetland" with nitrates and phosphates entering through agricultural runoff. "Domingo Rubio also receives inflows of phosphates from the Huelva estuary from the phosphogypsum stacks on the right hand banks of the Tinto river", the researcher explains.
Agriculture also generates pesticide concentrations in the water that "generally exceed the vulnerability levels set for wetlands by the European Commission (CCEE)", she stresses. "This contamination by agrochemicals could
FECYT - Spanish Foundation for Science and Technology