The presence of contaminants in the waters of the Negro River arouses concern among the scientific community in Northern Patagonia. A new scientific study detected that the effects on the aquatic ecosystem are not seriously dangerous, but warn that red flags should not be ignored.
This is how he revealed it the report on the environmental status of the Río Negro carried out by researchers from the Argentine Institute of Oceanography, Conicet and the National University of Bahía Blanca and the National University of Río Negro (UNRN). The comparative analysis of the levels of hydrocarbons and pesticides was recently released by the scientific journal Environmental Pollutionfrom the international publisher Elsevier.
They did an analysis of water samples collected at 21 points in the region. A range of 600 kilometers was covered, from the confluence of the Limay and Neuquén rivers, to the mouth of the San Matías Gulf.
The researchers went with the primary objective of measuring the presence of hydrocarbon particles, specifically, polycyclic aromatic hydrocarbons (PAHs). These are organic compounds that are natural constituents of crude oil, but also appear in incomplete combustion or pyrolysis processes. The latter are the most toxic.
“We went site by site and sought to differentiate whether the hydrocarbons we found came from a spill or were generated by combustion, such as from an engine,” said Andrés Arias, a doctor in Biology, who works at the aforementioned Institute in Bahia. Blanca, in dialogue with Diary BLACK RIVER.
The results of the analysis were not as marked as they supposed. The presence of hydrocarbons generated by combustion prevailed over the indications of particles from spills.
“One of the objectives was to see if we could find crude oil, because we know that there is oil exploitation in the upper basin. We were only able to find oil fractions in the most densely populated areas, such as Neuquén or Cipolletti. However, the pattern was mixed, there were both combusted hydrocarbons and those that were not,” he specified.
The maximum levels of contaminants were found at the Neuquén, Fernández Oro, Allen, Regina and Isla La Paloma stations (located near the mouth of the river).. However, the presence of hydrocarbons occurs in a fairly uniform and homogeneous way.
“We are reporting a presence throughout the river, that is, there are no places with a large presence of carbides and places that do not. They are present throughout the river, with peaks in the urban conglomerate areas that have gas and oil extraction structures, ”he expanded.
As it was a study of particles and not on sedimentation, differences according to the season of the year were evident. The researchers estimate that it is due to a factor closely linked to the level of the flow, in turn, motivated by thaws.
More than 80% of the water samples obtained were within the objectives of the international standards that regulate the presence of hydrocarbons in water. The remaining 20% exceeded the permitted levels of Anthracene, Pyrene, Fluoranthene and Benzo-a-anthracene.which are chemical compounds from the combustion of automobiles and other sources derived from oil and gas.
What is the situation regarding agrochemicals
A second part of the study consisted of the analysis of organochlorine pesticides. This type of chemical compounds, used to combat pests in agriculture, are characterized by high efficacy and extreme toxicity.
“These pesticides have been banned since the 90’s in Argentina and since the 70’s worldwide. They were incorporated by the Stockholm Convention (international treaty that regulates the treatment of persistent organic pollutants) because they have the characteristic of lasting too long in the environment and in living beings”, Arias described.
The study revealed, to the researchers’ surprise, that the levels of pesticides present in the Río Negro are the same as those detected in a 2006 study.. Arias maintained that this finding may be due to the fact that they continue to be used illegally in the fruit growing industry.
“They are present in quantities similar to what Dr. Karina Miglioranza measured in 2006. Which is telling us that not only do they remain, but there is probably a recent entry of some of those chlorinated compounds. We know that they are still being manufactured on the black market and are still being used. It’s not that they use them because people are bad, but because they are effective,” she noted.
The compounds were found more abundantly at the Fernández Oro, Paso Córdoba, Pomona, Conesa, Isla La Paloma and Desagüe Patagones stations.
“We are seeing pesticides in many places. Even in the lower valley, which is not a farm site. Although we observe the main peaks in areas of great productive development”, she concluded.
What are the risks of the presence of hydrocarbons and pesticides in the Negro River
The environmental report of the Río Negro assured that the levels of hydrocarbons and pesticides found in the water do not present, under current conditions, a severe long-term risk for the ecosystem.
“Although there are some specific exceedances to the recommended values, it can be concluded that adverse effects on aquatic life due to chronic exposure to these compounds are not expected,” the letter specifies.
However, the authors caution that the effects of pollutants should not be underestimated, let alone ignored. In a context in which other factors also affect the survival of fauna and florasuch as the introduction of exotic species and the gradual destruction of natural habitats.
How the presence of hydrocarbons and pesticides in the Negro River could be reduced
The environmental report for the Río Negro was presented with the fundamental premise of leaving a record for the formulation of environmental policies by public control agencies.
However, according to the scientists from the Conicet and the UNRN, no major initiatives are needed to improve the current state of water contaminants. Effective controls are mainly needed when dumping waste from production and industry. As is the case with the collection campaigns for phytosanitary containers used in fruit growing.
“In a context in which 44% of the world‘s water reaches watercourses without treatment, be they rivers, lakes or seas, sometimes when one simply treats their urban waste, substantial improvements in the quality of the body can be achieved. receiver, without the need to make great strategies”, warned the researcher Pablo Arias.
