Investigating Water Toxicity in Central Valley
By Benjamin Sipes
“They already realize the water is contaminated,” explains Dr. Wilson Ramirez-Duarte, a post doctoral scholar at the University of California, Davis, “but they don’t know how serious the problem is.” The farmers of Central Valley, California are aware of agricultural contaminants affecting their water, but many do not know just how toxic the water is nor how their attempts to clean it are only making matters worse.
Those who are aware of the potentially toxic water still use the tap water to cook, while others boil the tap water before they drink it. Boiling water is a technique for water purification that dates back to ancient civilizations. However, many people do not understand that boiling water only kills bacteria and does nothing to remove other contaminants. In fact, it can makes the water more toxic.
“Everybody boils water and drinks it thinking it's good for them,” says Dr. Swee Teh, Professor of Anatomy, Physiology and Cell Biology at the University of California, Davis, “but they do not know that boiling the water may make the chemical more concentrated.” Even just cooking with the water can be dangerous. Cooking with contaminated water infuses the food with toxins in it.
There is not one specific contaminant that is in the Central Valley groundwater, but a multitude. Pesticides, herbicides, poisonous metals, and nitrates from fertilizer all pose high risks. Not only can each contaminant produce negative health effects, but contaminants may produce combined effects as well. Two toxins working together can have health implications far worse than either one separately.
If the presence of contaminants in the water was not bad enough, there are also reasons to believe that the water recently became even more toxic. The drought in past years reduced the availability of groundwater that supplies wells in the Central Valley. As the water evaporates from the drought, the contaminants remain trapped underground, increasing their concentration in the water left behind.
But the problems with the Central Valley groundwater do not end there. The groundwater recharge time, which is the time it takes for surface water to return to the water table, is decreasing. This issue is believed to be caused by increased drilling into the earth’s crust. This means that contaminants from agricultural runoff are entering drinking water faster than ever.
Dr. Swee Teh has spent much of his academic life studying the effects of endocrine disrupting compounds in fish. Based on his previous research, he and Dr. Ramirez-Duarte, his former graduate student and current post doctoral scholar, believe that using a fish species known as Medaka (Oryzias latipes) as an animal model may provide insight into Central Valley water toxicity including if health implications differ between men and women. In partnership with the Community Water Center (CWC), Dr. Teh is committed to both investigating the health impacts of Central Valley and raising awareness for this issue.
Before coming to UC Davis, neither Dr. Teh nor Dr. Ramirez-Duarte thought they would be studying the environment. “I come from Malaysia,” recalls Dr. Teh, “so my goal coming to the United States was my education.” Dr. Teh originally wanted to become a medical doctor. Similarly, Dr. Ramirez-Duarte came to the United States from Colombia where he studied Veterinary Medicine. Independently, they both became interested in health implications of the environment. They now use fish as an animal model to better understand environmental health.
Dr. Teh and Dr. Ramirez-Duarte consider themselves novices when it comes to community-engaged research. However, this in no way dampens Dr. Teh’s enthusiasm about the project. “I have always wanted to do this study because environmental health is so important to us,” he says.
The partnership between the CWC and Dr. Teh’s lab has been mutually beneficial. Dr. Teh sought to investigate the question of water safety but did not know how to start or where to test. The CWC, conversely, advocates for water health issues but needs scientists and university resources to investigate them. “The CWC has data showing some of the well water in different communities that are high in certain metals or contaminants,” says Dr. Teh. “We decided based on that information.”
Dr. Ramirez-Duarte traveled to meet the well owners, sample their water, and discuss the details of the project. “We talked with them about [data ownership],” says Dr. Ramirez-Duarte, who explained their agreement to keep specific test sites confidential in exchange for the lab’s ownership of the research. Dr. Teh stressed, however, that they will not publish results until they communicate them to the community.
Dr. Teh and Dr. Ramirez-Duarte use fish to investigate water toxicity. On the surface, fish may seem like an odd animal to relate to humans, but they can be very useful. There are fundamental biological processes that have stayed the same throughout the evolution of many animal species. Fish and humans share many of the same biochemical and metabolic processes, making them effective at testing the health implications for humans. Additionally, living in water makes it easy to see effects of toxins compared to other animal models.
Some of these effects, Dr. Teh informs, can cause changes both in a person’s body as well as a woman’s egg cells or fetus. A growing embryo receives all of the contaminants that a mother consumes, having the potential for causing drastic changes in the child. There are even studies in fish that suggest these contaminants have residual effects on later generations too.
These endocrine disrupting effects in a fetus have a plethora of possible outcomes, including changing their sexual development. Because early life stages, both in utero and out, are so integral to development, “any changes during the early life stage could become permanent,” says Dr. Teh.
Endocrine functioning is one of the most significant factors Dr. Teh and Dr. Ramirez-Duarte are investigating. The endocrine system consists of hormones in the body like estrogen and testosterone. Many different hormones are involved in maintaining bodily functions and determining sexual development. Fish farms commonly use compounds that disrupt the endocrine system to their advantage, turning all their fish male.
“People use herbicides, pesticides, or metals, and some of them can have an endocrine disrupting effect,” explains Dr. Teh. “They can be changing hormonal induction into the fish by making them more female or more male.” Dr. Teh further describes that dioxins, a toxic compound used in some fertilizers, cause human cells to produce the wrong hormones in vitro, meaning out of the body. This shows that some of the chemicals that change a fish’s sex can potentially change a human’s too.
Some of the contaminants speculated to be in the water, namely nitrate from fertilizer, can induce production of carcinogens. These, too, can have a sexually dimorphic effect. Female livers produce two to three times as many cells as male livers. Each time a cell multiplies, it has a chance to undergo mutations in its DNA. The introduction of a carcinogen increases the likelihood for mutations that cause cancer. Past studies show that female fish introduced to carcinogens show two to three times higher likelihood of developing cancer.
To evaluate which toxic effects the water could be having, Dr. Ramirez-Duarte collected enough water to expose a group of fish for seven days. While collecting the water, they made sure to use clean glass bottles to ensure that any contaminants in the water were from the well. They divided their test fish into males and females, exposed them to the well water, and recorded their behavior.
So far, “we finished exposing the fish to the water, we ran all the experiments, and we collected the water samples to be analyzed for specific chemicals,” says Dr. Ramirez-Duarte. His next task is to “collect samples to analyze the genome of the fish to see which genes are expressed and which aren’t.”
Their experiments aim to understand which contaminants are in the water and whether the fish’s DNA is changing expression and disrupting endocrine functioning. DNA contains a blueprint for building everything in the body. Within each cell, the DNA is modified to only produce proteins specific for the needs of that cell. Dr. Teh and Dr. Ramirez-Duarte speculate that some of the water contaminants could change how the DNA is modified in cells, causing them to disrupt several processes, including endocrine functioning.
Dr. Teh and Dr. Ramirez-Duarte shared some preliminary results to their study, explaining that many of the fish were swimming abnormally. “Fish swimming erratically is critical to us,” says Dr. Teh. “In the wild, if fish swim erratically, they are killed because a predator is going to take them out.” So far, they cannot say which contaminants are in the water, but they do know that the water is not healthy for the fish.
At the conclusion of their study, Dr. Teh and Dr. Ramirez-Duarte plan to give presentations to the CWC and the EJCW, the primary stakeholders in this issue. From there, the goal is to educate the community about the possibly harmful effects of drinking or cooking with the water, especially boiled water. Many communities in the Central Valley speak primarily Spanish, making communication challenging, but Dr. Teh is planning to work closely with the CWC to make the information accessible.
Dr. Teh is also looking forward to featuring his work at UC Davis’s Environmental Health Science Academy Day, which aims to bring together many researchers and community activist organizations. He hopes that presenting information learned from the investigation at the Academy Day will help raise awareness of water toxicity in the Central Valley.
With an issue such as water quality, researchers need to work in close conjunction with community educators. Contaminated water can have effects that span multiple generations, affecting people in ways that are currently unforeseeable. More research is crucial to understanding what is in the water and how we can stop further contamination. “Hopefully we can provide the community some answers about how water affects the fish,” says Dr. Teh, “so they can relate that to human health.”
Those who are aware of the potentially toxic water still use the tap water to cook, while others boil the tap water before they drink it. Boiling water is a technique for water purification that dates back to ancient civilizations. However, many people do not understand that boiling water only kills bacteria and does nothing to remove other contaminants. In fact, it can makes the water more toxic.
“Everybody boils water and drinks it thinking it's good for them,” says Dr. Swee Teh, Professor of Anatomy, Physiology and Cell Biology at the University of California, Davis, “but they do not know that boiling the water may make the chemical more concentrated.” Even just cooking with the water can be dangerous. Cooking with contaminated water infuses the food with toxins in it.
There is not one specific contaminant that is in the Central Valley groundwater, but a multitude. Pesticides, herbicides, poisonous metals, and nitrates from fertilizer all pose high risks. Not only can each contaminant produce negative health effects, but contaminants may produce combined effects as well. Two toxins working together can have health implications far worse than either one separately.
If the presence of contaminants in the water was not bad enough, there are also reasons to believe that the water recently became even more toxic. The drought in past years reduced the availability of groundwater that supplies wells in the Central Valley. As the water evaporates from the drought, the contaminants remain trapped underground, increasing their concentration in the water left behind.
But the problems with the Central Valley groundwater do not end there. The groundwater recharge time, which is the time it takes for surface water to return to the water table, is decreasing. This issue is believed to be caused by increased drilling into the earth’s crust. This means that contaminants from agricultural runoff are entering drinking water faster than ever.
Dr. Swee Teh has spent much of his academic life studying the effects of endocrine disrupting compounds in fish. Based on his previous research, he and Dr. Ramirez-Duarte, his former graduate student and current post doctoral scholar, believe that using a fish species known as Medaka (Oryzias latipes) as an animal model may provide insight into Central Valley water toxicity including if health implications differ between men and women. In partnership with the Community Water Center (CWC), Dr. Teh is committed to both investigating the health impacts of Central Valley and raising awareness for this issue.
Before coming to UC Davis, neither Dr. Teh nor Dr. Ramirez-Duarte thought they would be studying the environment. “I come from Malaysia,” recalls Dr. Teh, “so my goal coming to the United States was my education.” Dr. Teh originally wanted to become a medical doctor. Similarly, Dr. Ramirez-Duarte came to the United States from Colombia where he studied Veterinary Medicine. Independently, they both became interested in health implications of the environment. They now use fish as an animal model to better understand environmental health.
Dr. Teh and Dr. Ramirez-Duarte consider themselves novices when it comes to community-engaged research. However, this in no way dampens Dr. Teh’s enthusiasm about the project. “I have always wanted to do this study because environmental health is so important to us,” he says.
The partnership between the CWC and Dr. Teh’s lab has been mutually beneficial. Dr. Teh sought to investigate the question of water safety but did not know how to start or where to test. The CWC, conversely, advocates for water health issues but needs scientists and university resources to investigate them. “The CWC has data showing some of the well water in different communities that are high in certain metals or contaminants,” says Dr. Teh. “We decided based on that information.”
Dr. Ramirez-Duarte traveled to meet the well owners, sample their water, and discuss the details of the project. “We talked with them about [data ownership],” says Dr. Ramirez-Duarte, who explained their agreement to keep specific test sites confidential in exchange for the lab’s ownership of the research. Dr. Teh stressed, however, that they will not publish results until they communicate them to the community.
Dr. Teh and Dr. Ramirez-Duarte use fish to investigate water toxicity. On the surface, fish may seem like an odd animal to relate to humans, but they can be very useful. There are fundamental biological processes that have stayed the same throughout the evolution of many animal species. Fish and humans share many of the same biochemical and metabolic processes, making them effective at testing the health implications for humans. Additionally, living in water makes it easy to see effects of toxins compared to other animal models.
Some of these effects, Dr. Teh informs, can cause changes both in a person’s body as well as a woman’s egg cells or fetus. A growing embryo receives all of the contaminants that a mother consumes, having the potential for causing drastic changes in the child. There are even studies in fish that suggest these contaminants have residual effects on later generations too.
These endocrine disrupting effects in a fetus have a plethora of possible outcomes, including changing their sexual development. Because early life stages, both in utero and out, are so integral to development, “any changes during the early life stage could become permanent,” says Dr. Teh.
Endocrine functioning is one of the most significant factors Dr. Teh and Dr. Ramirez-Duarte are investigating. The endocrine system consists of hormones in the body like estrogen and testosterone. Many different hormones are involved in maintaining bodily functions and determining sexual development. Fish farms commonly use compounds that disrupt the endocrine system to their advantage, turning all their fish male.
“People use herbicides, pesticides, or metals, and some of them can have an endocrine disrupting effect,” explains Dr. Teh. “They can be changing hormonal induction into the fish by making them more female or more male.” Dr. Teh further describes that dioxins, a toxic compound used in some fertilizers, cause human cells to produce the wrong hormones in vitro, meaning out of the body. This shows that some of the chemicals that change a fish’s sex can potentially change a human’s too.
Some of the contaminants speculated to be in the water, namely nitrate from fertilizer, can induce production of carcinogens. These, too, can have a sexually dimorphic effect. Female livers produce two to three times as many cells as male livers. Each time a cell multiplies, it has a chance to undergo mutations in its DNA. The introduction of a carcinogen increases the likelihood for mutations that cause cancer. Past studies show that female fish introduced to carcinogens show two to three times higher likelihood of developing cancer.
To evaluate which toxic effects the water could be having, Dr. Ramirez-Duarte collected enough water to expose a group of fish for seven days. While collecting the water, they made sure to use clean glass bottles to ensure that any contaminants in the water were from the well. They divided their test fish into males and females, exposed them to the well water, and recorded their behavior.
So far, “we finished exposing the fish to the water, we ran all the experiments, and we collected the water samples to be analyzed for specific chemicals,” says Dr. Ramirez-Duarte. His next task is to “collect samples to analyze the genome of the fish to see which genes are expressed and which aren’t.”
Their experiments aim to understand which contaminants are in the water and whether the fish’s DNA is changing expression and disrupting endocrine functioning. DNA contains a blueprint for building everything in the body. Within each cell, the DNA is modified to only produce proteins specific for the needs of that cell. Dr. Teh and Dr. Ramirez-Duarte speculate that some of the water contaminants could change how the DNA is modified in cells, causing them to disrupt several processes, including endocrine functioning.
Dr. Teh and Dr. Ramirez-Duarte shared some preliminary results to their study, explaining that many of the fish were swimming abnormally. “Fish swimming erratically is critical to us,” says Dr. Teh. “In the wild, if fish swim erratically, they are killed because a predator is going to take them out.” So far, they cannot say which contaminants are in the water, but they do know that the water is not healthy for the fish.
At the conclusion of their study, Dr. Teh and Dr. Ramirez-Duarte plan to give presentations to the CWC and the EJCW, the primary stakeholders in this issue. From there, the goal is to educate the community about the possibly harmful effects of drinking or cooking with the water, especially boiled water. Many communities in the Central Valley speak primarily Spanish, making communication challenging, but Dr. Teh is planning to work closely with the CWC to make the information accessible.
Dr. Teh is also looking forward to featuring his work at UC Davis’s Environmental Health Science Academy Day, which aims to bring together many researchers and community activist organizations. He hopes that presenting information learned from the investigation at the Academy Day will help raise awareness of water toxicity in the Central Valley.
With an issue such as water quality, researchers need to work in close conjunction with community educators. Contaminated water can have effects that span multiple generations, affecting people in ways that are currently unforeseeable. More research is crucial to understanding what is in the water and how we can stop further contamination. “Hopefully we can provide the community some answers about how water affects the fish,” says Dr. Teh, “so they can relate that to human health.”