The Oswaldo Cruz Institute (IOC/Fiocruz) detected, for the first time in the world, the contamination of sharks by cocaine and its metabolite, benzoylecgonia. This data draws attention to the high quantity of the drug that is consumed in the city and discarded into the sea via sewage.
Conducted by the Environmental Health Assessment and Promotion Laboratory of IOC, the study identified the presence of cocaine in 13 animals of the species Rhizoprionodon lalandii, popularly known as “Brazilian fin-beaked shark”, “rola-rola dogfish” or “chicken dogfish”.
Species shark Rhizoprionodon lalandii being analyzed in the laboratory. Photo: Disclosure
The main metabolite of the substance, benzoylecgonine, resulting from the metabolization of cocaine in the body, was found in 12 of these animals.
The collections were carried out in the neighborhood of Recreio dos Bandeirantes, in the West Zone of Rio de Janeiro, between September 2021 and August 2023, as part of an effort to assess environmental health, with a focus on monitoring changes in the environment, whether occurring in naturally or through human interference – and its impacts on the various forms of marine life.
Specialists throughout Brazil are dedicated, for example, to analyzing the presence of viruses and bacteria in sewage to identify and measure the possible silent circulation of disease-causing microorganisms.
It is also common to study soil and water contamination by metals and pesticides, such as mercury, lead and arsenic, which directly affect the health of people, animals and the environment.
“In Brazil, studies have already detected contamination of water and a few aquatic beings by cocaine, such as mussels. Our analysis is the first to find the substance in sharks”, describes pharmacist Enrico Mendes Saggioro, one of the researchers behind the unprecedented finding, together with biologist Rachel Ann Hauser-Davis, both from the Environmental Health Assessment and Promotion Laboratory of the IOC.
According to Rachel, sharks play a crucial role in the marine ecosystem, as do rays. Because they are predators, they are central figures in the food chain and are considered sentinel species for detecting environmental damage, including different forms of contamination.
The Laboratory has been responsible for important environmental alerts, based on studies that identified the metal contamination in fish from the Rio Doce, in Espírito Santo, after the tragedy caused by the collapse of the Samarco mining company dam; is at cations e rays collected in Rio de Janeiro.
The most recent world drug report, published in 2024 by the United Nations Office on Drugs and Crime (UNODC), places Brazil among the largest global consumers of cocaine.
According to available studies, researchers believe that the main route for the drug to enter the marine environment is through the disposal of residues of the substance in sewage, which is released into the sea.
The lagoon complex in the Barra da Tijuca and Jacarepaguá region is known for its high level of pollution. Photograph: Green Eye Project
“Following this finding in the national territory, our research group decided to investigate whether the animals that our laboratory had collected for studies involving other contaminants were also contaminated by cocaine. The result is impressive. We found the substance in all 13 sharks analyzed and in only one of them, benzoylecgonine, which is the main metabolite of the drug, was not detected”, adds Enrico.
Following good research practice protocols and with due authorizations from the Biodiversity Authorization and Information System (Sisbio) and the National Genetic Heritage Management System (SisGen), researchers analyzed the muscle and liver of 13 sharks of the species Rhizoprionodon lalandii collected at Recreio dos Bandeirantes. Three were males and 10 were females.
Using specific techniques and reagents and cutting-edge equipment, the samples were analyzed at the Advanced Laboratory Section of Santa Catarina (SLAV/SC), a unit linked to the National Agricultural Laboratory of Rio Grande do Sul, which is part of the National Laboratory Network Agricultural officers from the Ministry of Agriculture, Livestock and Supply (MAPA). This stage was led by pharmacist and biochemist Rodrigo Barcellos Hoff, who works at SLAV/SC.
All muscle and liver samples tested positive for the presence of cocaine. Benzoylecgonine was detected in 12 muscle samples and 2 liver samples. The results were published in the scientific journal Science of The Total Environment.
The average concentration of cocaine in the animals was 3 times higher than the concentration of the metabolite. One hypothesis of the researchers to explain this data is the overexposure of animals to the substance.
Another finding that intrigued the experts was the higher concentration of cocaine in the muscles than in the liver of the animals analyzed.
Preparation of biological samples for laboratory analysis. Photo: Disclosure
“Just like in humans, the shark’s liver is a metabolizing organ. Everything that is ingested is transformed by the liver and then excreted. To our surprise, cocaine was found in higher concentrations in muscle, which is an accumulation tissue, which may signal the abundance of the substance in the marine environment. The sharks would be contaminating themselves in different ways, whether because they inhabit the region or feed on other contaminated animals”, highlights Enrico.
Comparing the data from the current study with others published on the topic, referring to the contamination of other species, the average level of cocaine identified in sharks was higher than that detected in other animals, according to the experts.
“As the next steps, we intend to collect and analyze samples of water and other animals from this and other regions of the coast of Rio de Janeiro”, says Rachel.
The West Zone is the fastest growing region in the city of Rio and also the most populous, with almost 3 million inhabitants, according to the 2022 demographic census.
The scientists explain that the species of shark analyzed does not have migratory characteristics and lives close to the coast. Thus, the likely location of contamination was the coastal area.ioca.
“It is necessary to carry out specific studies to determine the exact consequences of this contamination on animals. It is believed that there may be an impact on the growth, maturation and, potentially, the fecundity of sharks, since the liver plays a role in the development of embryos”, comments Rachel.
Recently, a study conducted by the Federal University of São Paulo and the Santa Cecília University, in São Paulo, showed high concentrations of cocaine in the water of Santos Bay and showed that the drug can cause problems in the cells and genetic material of mussels.
In relation to human health, Rachel and Enrico believe that specific research is needed to answer this question.
Area view of the Recreio dos Bandeirantes region, in Rio de Janeiro. Photo: Fwellisch
“Bathers’ contact with the water is sporadic and they also do not use sea water to eat or drink. Therefore, we believe that the risk to humans is minimal”, highlights Enrico.
“It is worth remembering that sharks are often sold irregularly under the popular name of dogfish. We have already found several toxic metals in dogfish and rays, which are also sold and consumed. Now, we detect cocaine in sharks. Pollution and contamination of the environment directly affect animals and nature, but they also impact, in one way or another, human life. One person’s health is linked to the other’s health”, ponders Rachel.
The research was carried out in partnership with the Sérgio Arouca National School of Public Health (ENSP/Fiocruz), Federal University of Santa Catarina, Federal University of Rio de Janeiro, Advanced Laboratory Sector in Santa Catarina (SLAV/SC), Instituto Museu Aquário Marinho do Rio de Janeiro (IMAM/AquaRio) and Cape Eleuthera Institute (Bahamas).
The work was funded by the Carlos Chagas Filho Research Support Foundation of the State of Rio de Janeiro (Faperj), the Brazilian Biodiversity Fund (FUNBIO) and the National Council for Scientific and Technological Development (CNPq).
The Oswaldo Cruz Institute (IOC/Fiocruz) detected, for the first time in the world, the contamination of sharks by cocaine and its metabolite, benzoylecgonia. This data draws attention to the high quantity of the drug that is consumed in the city and discarded into the sea via sewage.
Conducted by the Environmental Health Assessment and Promotion Laboratory of IOC, the study identified the presence of cocaine in 13 animals of the species Rhizoprionodon lalandii, popularly known as “Brazilian fin-beaked shark”, “rola-rola dogfish” or “chicken dogfish”.
Species shark Rhizoprionodon lalandii being analyzed in the laboratory. Photo: Disclosure
The main metabolite of the substance, benzoylecgonine, resulting from the metabolization of cocaine in the body, was found in 12 of these animals.
The collections were carried out in the neighborhood of Recreio dos Bandeirantes, in the West Zone of Rio de Janeiro, between September 2021 and August 2023, as part of an effort to assess environmental health, with a focus on monitoring changes in the environment, whether occurring in naturally or through human interference – and its impacts on the various forms of marine life.
Specialists throughout Brazil are dedicated, for example, to analyzing the presence of viruses and bacteria in sewage to identify and measure the possible silent circulation of disease-causing microorganisms.
It is also common to study soil and water contamination by metals and pesticides, such as mercury, lead and arsenic, which directly affect the health of people, animals and the environment.
“In Brazil, studies have already detected contamination of water and a few aquatic beings by cocaine, such as mussels. Our analysis is the first to find the substance in sharks”, describes pharmacist Enrico Mendes Saggioro, one of the researchers behind the unprecedented finding, together with biologist Rachel Ann Hauser-Davis, both from the Environmental Health Assessment and Promotion Laboratory of the IOC.
According to Rachel, sharks play a crucial role in the marine ecosystem, as do rays. Because they are predators, they are central figures in the food chain and are considered sentinel species for detecting environmental damage, including different forms of contamination.
The Laboratory has been responsible for important environmental alerts, based on studies that identified the metal contamination in fish from the Rio Doce, in Espírito Santo, after the tragedy caused by the collapse of the Samarco mining company dam; is at cations e rays collected in Rio de Janeiro.
The most recent world drug report, published in 2024 by the United Nations Office on Drugs and Crime (UNODC), places Brazil among the largest global consumers of cocaine.
According to available studies, researchers believe that the main route for the drug to enter the marine environment is through the disposal of residues of the substance in sewage, which is released into the sea.
The lagoon complex in the Barra da Tijuca and Jacarepaguá region is known for its high level of pollution. Photograph: Green Eye Project
“Following this finding in the national territory, our research group decided to investigate whether the animals that our laboratory had collected for studies involving other contaminants were also contaminated by cocaine. The result is impressive. We found the substance in all 13 sharks analyzed and in only one of them, benzoylecgonine, which is the main metabolite of the drug, was not detected”, adds Enrico.
Following good research practice protocols and with due authorizations from the Biodiversity Authorization and Information System (Sisbio) and the National Genetic Heritage Management System (SisGen), researchers analyzed the muscle and liver of 13 sharks of the species Rhizoprionodon lalandii collected at Recreio dos Bandeirantes. Three were males and 10 were females.
Using specific techniques and reagents and cutting-edge equipment, the samples were analyzed at the Advanced Laboratory Section of Santa Catarina (SLAV/SC), a unit linked to the National Agricultural Laboratory of Rio Grande do Sul, which is part of the National Laboratory Network Agricultural officers from the Ministry of Agriculture, Livestock and Supply (MAPA). This stage was led by pharmacist and biochemist Rodrigo Barcellos Hoff, who works at SLAV/SC.
All muscle and liver samples tested positive for the presence of cocaine. Benzoylecgonine was detected in 12 muscle samples and 2 liver samples. The results were published in the scientific journal Science of The Total Environment.
The average concentration of cocaine in the animals was 3 times higher than the concentration of the metabolite. One hypothesis of the researchers to explain this data is the overexposure of animals to the substance.
Another finding that intrigued the experts was the higher concentration of cocaine in the muscles than in the liver of the animals analyzed.
Preparation of biological samples for laboratory analysis. Photo: Disclosure
“Just like in humans, the shark’s liver is a metabolizing organ. Everything that is ingested is transformed by the liver and then excreted. To our surprise, cocaine was found in higher concentrations in muscle, which is an accumulation tissue, which may signal the abundance of the substance in the marine environment. The sharks would be contaminating themselves in different ways, whether because they inhabit the region or feed on other contaminated animals”, highlights Enrico.
Comparing the data from the current study with others published on the topic, referring to the contamination of other species, the average level of cocaine identified in sharks was higher than that detected in other animals, according to the experts.
“As the next steps, we intend to collect and analyze samples of water and other animals from this and other regions of the coast of Rio de Janeiro”, says Rachel.
The West Zone is the fastest growing region in the city of Rio and also the most populous, with almost 3 million inhabitants, according to the 2022 demographic census.
The scientists explain that the species of shark analyzed does not have migratory characteristics and lives close to the coast. Thus, the likely location of contamination was the coastal area.ioca.
“It is necessary to carry out specific studies to determine the exact consequences of this contamination on animals. It is believed that there may be an impact on the growth, maturation and, potentially, the fecundity of sharks, since the liver plays a role in the development of embryos”, comments Rachel.
Recently, a study conducted by the Federal University of São Paulo and the Santa Cecília University, in São Paulo, showed high concentrations of cocaine in the water of Santos Bay and showed that the drug can cause problems in the cells and genetic material of mussels.
In relation to human health, Rachel and Enrico believe that specific research is needed to answer this question.
Area view of the Recreio dos Bandeirantes region, in Rio de Janeiro. Photo: Fwellisch
“Bathers’ contact with the water is sporadic and they also do not use sea water to eat or drink. Therefore, we believe that the risk to humans is minimal”, highlights Enrico.
“It is worth remembering that sharks are often sold irregularly under the popular name of dogfish. We have already found several toxic metals in dogfish and rays, which are also sold and consumed. Now, we detect cocaine in sharks. Pollution and contamination of the environment directly affect animals and nature, but they also impact, in one way or another, human life. One person’s health is linked to the other’s health”, ponders Rachel.
The research was carried out in partnership with the Sérgio Arouca National School of Public Health (ENSP/Fiocruz), Federal University of Santa Catarina, Federal University of Rio de Janeiro, Advanced Laboratory Sector in Santa Catarina (SLAV/SC), Instituto Museu Aquário Marinho do Rio de Janeiro (IMAM/AquaRio) and Cape Eleuthera Institute (Bahamas).
The work was funded by the Carlos Chagas Filho Research Support Foundation of the State of Rio de Janeiro (Faperj), the Brazilian Biodiversity Fund (FUNBIO) and the National Council for Scientific and Technological Development (CNPq).
The non-profit reproduction of the text is allowed as long as the source is cited (Comunicação / Instituto Oswaldo Cruz)
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