By: Pablo Corso
The level of pesticides in fish, such as herbicides, is a worldwide problem. The muscle tissue of the edible tarpon (Prochilodus lineatus) from the Argentine province of Santa Fe is contaminated with “highest levels of polar (water soluble) herbicides in the world”, assures an article that will appear soon in the journal Science of the Total Environment.
Fish from the Salado River, a tributary of the Paraná (the largest South American river after the Amazon), showed traces of nine insecticides, herbicides and fungicides applied to transgenic soybean, corn and cotton crops that are abundant in that watershed.
Although the effects on fish and humans are not yet fully determined, the authors warn of the need for extreme precautionary measures in one of the most important waterways in the country, which supplies food both locally and for export. “There is an urgent need to increase the distance between pesticide-dependent GM crops and aquatic ecosystems, as well as to better address environmental risks.”. Rafael Lajmanovich, responsible for the research team, specified to SciDev.Net that this distance should be at least 1,000 meters.
The researchers analyzed river sediments, muscles and viscera from 16 tarpon acquired from fishermen along 100 kilometers of high agricultural productivity.
In muscle tissue were foundvery high concentrations” of the insecticide cypermethrin (up to 204 micrograms per kilogram); the fungicide pyraclostrobin (50 μg/kg); of glyphosate herbicides (187 μg/kg), together with its degradation acid AMPA (3116 μg/kg) and ammonium glufosinate (677 μg/kg).
Prior to this work, the highest levels of glyphosate recorded in fish were “less than 10 ug/k” and “there was not” information about the presence of glufosinate, Lajmanovich said in an e-mail.
Urgent gap between spraying and aquatic ecosystems
“Increasing the gap between pesticide-dependent GM crops and aquatic ecosystems is an urgent need, as is improving the approach to environmental risks”.
Published in: “Cocktails of pesticide residues in fish Prochilodus lineatus from the Salado River (South America): first record of high concentrations of polar herbicides”.
A study on the effects of polar herbicides published in 2021 detected maximum levels of AMPA of 300 ug/k in muscle tissue and 650 ug/k in the liver of Hoplosternum littorale fish (better known as cascarudos) from the same province, he specified. another email Andrea Rossi, one of the authors. Although there is no evidence of cellular damage or neurotoxic effects, alterations were found in the hematological parameters of the sampled specimens.
Acute exposure to the amounts found on this occasion, however, could generate “multiple” effects, both in fish and in humans, which would include genotoxicity (ability to cause genetic damage) and hormonal dysregulation, associated with the appearance of tumors, malformations, dysfunctions of the reproductive system, neurotoxicity or immune problems, explains Lajmanovich.
Between 2019 and 2022, the same researcher ―titular professor at the Department of Ecotoxicology at the National University of the Litoral― issued similar warnings about the combined effects of glyphosate with arsenic and microplastics.
The authors acknowledge that the high solubility of pesticides makes determining the levels of contaminants “problematic”, although this very solubility causes their toxicity to increase in aquatic environments, where fish membranes facilitate absorption.
High levels of hydrocarbons in tarpon
In this sense, Doctor of Natural Sciences Eric Speranza – who 14 years ago found high levels of hydrocarbons in the fat of tarpon near the city of Buenos Aires – is satisfied over the phone that it was possible to measure glyphosate and glufosinate in fish muscle tissue.
“This shows the impact of soybean farming”, warns the researcher from the Laboratory of Environmental Chemistry and Biogeochemistry at the Argentine universities of La Plata and Arturo Jauretche.
Yes well “the presence of the herbicide does not necessarily mean that the fish is affected”, also suggests the convenience of avoiding its consumption until further studies determine with greater precision the effects of pesticides on fish, although it clarifies that it is, for now, a decision of each consumer.
Regarding a possible provincial ban on fishing, Speranza is cautious, since it is a measure that “requires taking into account economic and social factors, such as the people who make a living from this activity”.
Sources from the National Service of Agro-Food Health and Quality – in charge of controlling the safety of food of animal and plant origin in Argentina – told SciDev.Net that the report “relative importance was given”, as they have objections to its methodology, for example, regarding the number of specimens analyzed.
Herbicide residues on tarpon and other fish
The agency currently does not measure pesticide levels in fish; maximum residue limits (MRL) are established for vegetables only. Even so, they suggest that the values found do not represent a risk to human health. In the case of consumer soy, for example, the MRL for glyphosate is 5,000 μg/kg.
However, the authors of the article insist that “Contamination of the Salado River by pesticides poses a detrimental threat to the viability of fish populations and other aquatic organisms and a major risk to consumers.”
Clear regulation on agrochemicals should establish tolerable limits for these substances, they propose, which would allow a better approach to the situation.
Several attempts by SciDev.Net to obtain an official statement regarding the Santa Fe government’s future measures have been unsuccessful as of this information’s closing.
> Link to article abstract in Science of the Total Environment
This article was produced by the Latin American and Caribbean edition of SciDev.Net BioSource: https://www.scidev.net/america-latina/news/pez-argentino-con-niveles-de-herbicidas-mas-altos-del-mundo/?utm_source=SciDev.Net&utm_medium=email&utm_campaign=13825406_2023-03-13 %20Weekly%20Email%20Digest%20-%20América%20Latin%20y%20el%20Caribbean%20Template.%20For%20no%20topic%20preferences&dm_i=1SCG,88BR2,B0L58T,XS7QJ,1