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Writing / Irene Vega
Polycyclic aromatic hydrocarbons (PAHs) are a variety of hydrophobic organic compounds with two or more aromatic rings that are characterized by their resistance to degradation. These compounds originate mainly from the incomplete combustion of petroleum. Exposure or ingestion through contaminated food or water can trigger harmful effects that include mucosal irritation, respiratory failure, and decreases in platelets and leukocytes. In addition, the International Agency for Research on Cancer has classified them as a human carcinogen.
The Applied Microbial Ecology team at the Rey Juan Carlos University (URJC), composed of Dr. González-Benítez, Dr. Bautista and Dr. Molina, together with Dr. Corral-García from the University's Ecology department Autonomous University of Madrid (UAM) and the large team of Dr. Espinosa at the Private Technical University of Loja in Ecuador, has analyzed the contamination by PAHs of sludge from effluents from the Napo and Aguarico rivers. “We have detected significant concentrations of PAHs in river sediments, which could serve as a continuous source of water contamination over time, especially in turbulent flows. We have been able to date some of these compounds to be between 60-80 years old, which shows the persistence of these compounds in river systems,” explains Dr. González-Benítez, one of those responsible for these investigations.
If the sludge is contaminated, the river becomes a pollutant distribution network that does not differentiate between nature conservation reserves and oil exploitation areas. They are all connected through rivers and, as the hydrological dynamics of the basin are characterized by the permanent overflow of the rivers, all the surrounding waters and lands are equally affected. Therefore, the objective of this project has been to evaluate the health of the river bottoms and establish a connection with the health of the human populations in the area.
The results obtained reveal that around 30% of the territory has some level of contamination. “This pollution is not only a threat to the biodiversity of the ecosystem and to the ecosystem services that the Amazon rainforest offers, but it also seriously affects a large part of the population in the Napo River basin. In fact, we have recently been able to detect a significant association between the risk of exposure and the prevalence of anemia in men,” says Dr. Espinosa.
Cooperation between Spanish and Ecuadorian research institutions is helping to understand a complex phenomenon that generates dramatic impacts on biodiversity and the local population. To do this, it is necessary to strengthen horizontal relationships that enhance the capacities of the institutions.
This research further reinforces the idea of a single planetary health (ONE HEALTH). “We will hardly be able to protect human health if we do not protect the health of our ecosystems,” the researchers conclude.
Protected environment since 1998
The middle basin of the Napo River in the Amazon rainforest (Ecuador) is home to unique flora and fauna adapted to the overflow of its complex river system, highlighting the great diversity of birds. However, this area is also a historical and current oil exploitation area. The threat from pollution and other anthropogenic disturbances in the area led to the Limoncocha Lagoon and its surroundings being recognized by UNESCO as a Ramsar Wetland protection in 1998.