Roasted, fried, grilled or boiled. Regardless of the method of preparation, the fish has a guaranteed space on the table of the population of Roraima. However, the healthy and traditional habit is threatened by illegal mining in the Yanomami Indigenous Land.
Second study researchers from Fundação Oswaldo Cruz (Fiocruz), Instituto Socioambiental (ISA), Instituto Evandro Chagas and Universidade Federal de Roraima (UFRR), fish collected at three out of four points in the Rio Branco Basin had mercury concentrations greater than or equal to the limit established by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO).
According to study, for some species of carnivorous fish, such as the young, the contamination is already so high that there is practically no safe level for its consumption, regardless of the amount ingested. Consumption remains possible for species such as matrinxã, aracu, jaraqui, pacu, jandiá and others. However, for children and women of childbearing age, these species should be consumed in moderation to avoid health risks.
The health risk assessment analysis, based on a methodology proposed by the WHO, collected fish samples between February 27 and March 6, 2021 and revealed high levels of contamination in a stretch of the Rio Branco in the city of Boa Vista (25,5 %), Baixo Rio Branco (45%), Rio Mucajaí (53%) and Rio Uraricoera (57%).
“The high rates of contamination observed are probably due to the numerous illegal gold mines installed in the channels of the Mucajaí and Uraricoera rivers”, the researchers point out.
Know which fish can be eaten
! ️ Very high risk carnivorous fish: baby, beard, coronataí, piracatinga and pirandirá | consume a maximum of one serving of 50 grams, once a month.
❗High risk carnivorous fish: sea bream, mandubé, lyre, hake, black piranha and peacock bass | consumption should not exceed 200 grams per week.
✅ Medium and low risk non-carnivorous fish: curimatã, jaraqui, matrinxã and pacú | have no restrictions and can be consumed in portions of up to 300 grams per day.
* It is recommended to avoid consumption of carnivorous fish throughout pregnancy (barba flata, coronataí, cub, piracatinga and pirandirá)
At Uraricoera, the closest point to the Yanomami Indigenous Land, for every 10 fish collected, six had mercury levels above the limits stipulated by the WHO. In Rio Branco, at the height of the capital, Boa Vista, for every 10 fish collected, approximately two were not safe for consumption.
In other words, even far from the Yanomami Indigenous Land, and although in a smaller proportion, the inhabitants of Boa Vista are not free from the impacts of mercury used in illegal mining.
As explained by technical note, with data on the level of contamination in fish, a calculation of the risk of consumption among different population groups in Roraima was then carried out, which consisted of five steps.
The first established the division into population strata – urban and non-urban – and their respective average weights, determining the levels of mercury in fish and estimating the amount ingested daily by each population under study.
The health risks resulting from the consumption of fish contaminated by mercury were estimated for women of childbearing age (10 to 49 years), adult men (over 18 years), children aged 5 to 12 years and 2 to 4 years.
The second stage considered the estimate of the average amount of mercury ingested daily by the investigated strata, based on the amount of fish consumed. In the third step, the risk ratio was calculated, estimated by dividing the daily intake of mercury in each group, analyzed in the previous step, by the safe dose established by the FAO/WHO bodies.
Then, hypothetical exposure scenarios were constructed to assess the impact of different consumption patterns on the health of the groups. Finally, a set of guidelines was established in order to identify a Maximum Safe Consumption of Fish (CMS) pattern, based on the analyzes carried out, in order to avoid problems arising from mercury contamination.
In calculating the risk ratio, three patterns of fish consumption were defined for the analysis of health risk: low, with up to 50 grams of fish per day, moderate, with up to 100 grams of fish per day and high, with 200 grams of fish per day.
The conclusion is that there are no safe amounts of fish consumption for almost all groups analyzed - except men with consumption less than 50 grams daily.
The researchers further noted: "Comparing the estimated risk ratios for urban and non-urban populations, we found that both are equally at risk of becoming ill from ingesting methylmercury-contaminated fish."
Health impacts of mercury
Although fish is a protein of high nutritional quality, indicated in diets with low cholesterol and healthier, the contamination of fish from Roraima by mercury represents a warning sign, defend the researchers.
According to study, 45% of the mercury used in illegal gold mining is dumped into rivers and streams in the Amazon, without any treatment or care. Mercury released indiscriminately into the environment can remain for up to one hundred years in different environmental compartments and can cause various diseases in people and animals.
In children, problems can start in pregnancy. If the levels of contamination are very high, there may be miscarriages or the diagnosis of cerebral palsy, deformities and congenital malformations. Minors can also develop limitations in speech and mobility. Most of the time, the injuries are irreversible, causing impacts in adult life.
Recent Studies carried out with indigenous people of the Munduruku people who live in the Middle Tapajós region, in the state of Pará, reveal neurological and psychological alterations in adults and delays in the development of children associated with the consumption of fish contaminated by mercury.
The harmful effect of mercury on health has also been proven among the Yanomami. Second study from Fiocruz with support from ISA, in the community of Aracaçá, in the Waikás region, on the banks of the Uraricoera River, where there is a strong presence of prospectors, 92% of the people examined were contaminated by mercury.
“In summary, the presence of mining in indigenous lands, associated with the indiscriminate use of mercury, unlike what many politicians and businessmen say, does not bring wealth and development to communities. On the contrary, it leaves a legacy of ills and environmental problems that contributes to perpetuating the cycle of poverty, misery and inequality in the Amazon”, write the authors.
Impacts for the fishermen of Roraima
The reality verified by study generates direct impacts on the activities of artisanal fishing communities in Roraima. Without having any relationship with illegal mining, they end up being harmed by criminal activity when their main livelihood, fish, is contaminated by high concentrations of mercury, as revealed by the survey conducted by the researchers.
"This causes damage to fishermen and risks to the health of the entire population that eats fish from the rivers of Roraima", says Ciro Campos, a researcher at ISA. contaminated, there are others, also widely consumed, such as matrinxã, pacu and jaraqui, which "are still healthy".
In the list of recommendations made at the end of the technical note, the researchers guide the elaboration of financial protection mechanisms for the fishing sector, in order to prevent artisanal fishermen from being economically impacted by the restriction on the consumption of several species of contaminated fish.
According to the authors, it is important to apply the polluter pays principle: who should be responsible for the economic losses are the individuals and legal entities that invest and promote illegal mining in the region, and not the local population.