AMAZON RIVER, Brazil – Those who have visited the Amazon know the importance that the rivers have to the local communities, whose livelihoods depend on them. They provide drinking and cooking water, abundant fishing opportunities, and vital transportation routes for people and goods. Simply put, the rivers are the heart of life in the Amazon.
With that in mind, scientists from the Amazonas State University and Harvard embarked on a groundbreaking expedition to explore the health of two major Amazon River’s tributaries — the Negro and the Madeira.
Equipped with a floating laboratory, the researchers collected samples to carry out an unprecedented study on the water quality and mercury contamination along the rivers. Their goal is to create a Water Quality Index (WQI) for each of the largest rivers in Amazonas state, and to establish ongoing monitoring during the wet and dry seasons. The insights from this research aim to inform public policy and ensure the preservation of aquatic ecosystems, as well as the health and well-being of the communities that rely on them.
Joining the researchers on this 24-day river journey were Mongabay and Ambiental Media, capturing the vital work being done. Watch this video to discover more about their findings, the WQI initiative, and the mercury cycle in Amazonian rivers.
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Banner image: Mobile laboratory boat. Image ©Bruno Kelly.
Transcript
Notice: Transcripts are machine and human generated and lightly edited for accuracy. They may contain errors.
This isn’t an ordinary boat. It’s a mobile laboratory on a mission to better understand the very lifeblood of the Amazon: its rivers.
Scientists from Amazonas State University and Harvard are using the floating lab to carry out unprecedented research to help understand the water quality of two of the Amazon River’s main tributaries, the Negro and the Madeira, and using their findings to help preserve the aquatic ecosystems and the health of the communities who live here.
Mongabay and Ambiental Media joined the lab boat on two expeditions, a 24-day immersion on the rivers’ health.
The Amazon region needs a water quality index for each type of water that it has here. Any type of anomaly in the aquatic environment will have a direct relationship with public health not only for the riverine community but also for those in the city. We chose the Negro, and also because there is little research, unfortunately, on it. The entire Amazon is neglected.
The reason we chose the Madeira River is that I believe it is one of the most economically important rivers in Brazil. Apart from, obviously, the problem of gold mining in the Madeira River.
The Negro River runs 2,250 kilometers from its headwaters in Colombia to its meeting with the waters of the Solimões, where it forms the Amazon River. In the Brazilian portion, it is home to the largest river archipelagos in the world, riverine communities and small towns, conservation units and Indigenous lands. On this first expedition, the boat passes through three cities along more than 700 kilometers.
The research focuses on two main aspects: the mercury cycle along the river and creating a database for water quality to improve monitoring. We know that the pressure of urbanization is growing every day. And a monitoring system is necessary so that not only the technical and scientific team has this notion of the quality and state of the aquatic environment but also the general population. I was born in the Amazon, in the Middle Rio Negro. My family’s relationship with the Rio Negro has been passed down from generation to generation. Many people here don’t even know the quality of the river water. This is the first time I’ve participated in a trip made by researchers from both outside and here. It’s a source of pride for us, the Amazonians who study, the researchers from Amazonas State University. I think this is an innovation for the Amazon region.
The scientists use nine parameters to diagnose the state of the river, called the Water Quality Index or WQI. And they classify water quality as very bad, bad, acceptable, good, and excellent. If I want to create a water quality index for blackwater rivers, I need a place where there is no human interference whatsoever. And the Rio Negro simply gives us that. So that’s how important it is in our research work. It will be a reference.
We measure five parameters here on the boat. Of these five, four make up the WQI. They are dissolved oxygen, pH, water temperature, and turbidity.
There are people working in mining near Santa Isabel, and this directly affects mainly the riverine population, who depend on hunting and fishing. Everyone drinks water from the river. So it’s very important for us to know what we’re drinking.
We know that the riverine people depend directly on this natural environment, both for extractivism and for agriculture and fishing. And the quality of these environments is also part of the public health of those people who depend directly on this river.
The researchers’ work yielded positive results. The majority of the collection points in the Negro River were rated as “good” or “excellent.”
This allowed the Brazilian scientists to come up with an ideal WQI for this type of water body. But the river also faces problems, particularly where it runs close to cities and communities, due to lack of basic sanitation and direct dumping of sewage into the river. From these research projects, I can provide public managers with the necessary data to take the actions they need to resolve the problem or minimize the problem in the basins that are being monitored. So that’s our role.
The second part of the project focuses on an 800-km stretch of the Madeira River. But it is also a place with many challenges: A huge hydroelectric complex, illegal mining, deforestation, and the advance of agribusiness.
Unfortunately, the fish are disappearing with the devastation and the drought. And we are being affected, both fishermen and farmers. The climate has changed a lot compared to what we saw before. After the impact of building the dam in the upper part, it really affected us down here. Fish died in the lakes. We hear a lot about mercury in the water, which causes several types of diseases. There are a lot of gold miners in our region. So understanding what the impact is and what is happening, and what this can cause, for me, is what draws the most attention. And you also have a possibility of what can be done to mitigate these impacts. Today, the community lives mainly from family farming. Farming is one of the things that still supports the riverine dwellers … fishing is almost nonexistent for the fishermen on the riverbank.
Since 2014, when this dam was built, there has been a huge change in the amount of fish caught. So for this reason, people were moving from fishing to mining. We used to drink this water. Not anymore. No one drinks it anymore. We have to bring water from the city because it is no longer good enough to drink. These riverine people suffer a lot because they have no other resources.
We know that mercury itself has a major impact on human and animal health. Being able to understand and talk to people, getting closer to the people who are suffering this impact, is essential for mapping out the entire environmental issues involved. And perhaps even try to make people aware that some behaviors can be harmful to them.
Preliminary results show high levels of mercury in the Madeira water, but still within the safe limits established by the Brazilian health authorities.
In some predatory fish species, the Harvard researchers identified total mercury levels exceeding the recommended limit. And among the species most consumed by the local population, the mercury levels were within the limits, requiring the attention of public authorities.
The researchers emphasize the need for continuous monitoring, to understand the level of exposure of the population.
The results we have now obtained from the Madeira River will be the first step in building a water quality index for these rivers with these characteristics, which are very different from the Negro River.
The first results of the research on the Negro and Madeira rivers indicate that the rivers have been able to cope with many human-made problems, but for how long?
In their next expeditions, the scientists will continue monitoring the water to build the index, an essential tool to identify and solve the water quality problems of the largest tributaries of the Amazon River.