Planned Mega-Dam Threatens Fish Populations and Food Security in Cambodia
By Sabrina Gyorvary
Auntie Punleu has spent most of her life on Koh Dambang, an island set in the middle of the Mekong River in Cambodia. A small, grandmotherly woman, she paints an idyllic picture of life there.
"We catch fish as our main food every day. We eat fish nearly six days a week," she said. With her gentle strength and keen knowledge of community affairs, people on the island look to her as a natural leader. "My children and grandchildren have enough food to eat every day and they are healthy. We do not need to spend money to buy fish. We do not need to beg people for them. They come naturally from the river."
The Mekong River is threatened by a mega-dam project in the Sambor District, one of 11 large hydropower dams planned for the river's lower mainstream.International Rivers
A few kilometers away, Uncle Songom, a resident of the quiet riverside village of Svay Chek, echoed Punleu: "My family have enough food and my children are healthy because of the Mekong River."
Punleu's story is replicated up and down the riverbanks. The livelihoods and cultures of 60 million people in the lower Mekong Basin are intimately connected with the Mekong River's natural cycles. Boasting one of the world's most diverse and productive inland fisheries, the Mekong supplies people in the region with approximately 80 percent of their protein needs. For families living on the margin, the river is an invaluable source of both protein and income.
But this vital lifeline is now at risk, and families like those of Punleu and Songom face an uncertain future. Regional governments are pushing forward a series of large-scale hydropower dam projects that are threatening the Mekong's abundant fisheries, and consequently the food supply of millions.
This past September saw the inauguration of the Lower Sesan 2 Dam, a project that fisheries experts warn will block fish migrations on two of the major tributaries of the Mekong River, the Sesan and Srepok rivers, causing a 9.3 percent drop in fish biomass for the entire river basin. The dam is also expected to flood 36,000 hectares, displacing about 5,000 people. The plans for these large-scale projects are typically conceived and approved in secret, and the communities who stand to lose the most are never consulted.
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Punleu's island is now facing inundation by one such project: the proposed Sambor Dam. The dam would be located on the Mekong River's mainstream at Sambor town, Kratie Province, Cambodia. This would be one of 11 large hydropower dams planned for the Mekong River's lower mainstream. (In total, some 200 dams are already built, under construction, or planned on the Mekong River system.)
The dams that clogged rivers in the American west in the twentieth century decimated salmon populations, blocking their access to traditional spawning grounds. Now it looks like the same sort of catastrophe is headed for the Mekong, but on an even larger scale. The Sambor Dam alone would block major fish migrations between Southern Laos and Cambodia's Tonle Sap Lake, destroy critical deep pool fish habitats, and interrupt the river's hydrological, sediment, and nutrient cycles, impacting the river's wider ecology.
Combined, the 11 dams on the lower Mekong would block the major fish migrations that are essential to the life cycle of around 70 percent of the Mekong River's commercial fish catch. This would result in a total estimated fishery loss of 26 to 42 percent, placing at risk the livelihoods and food security of millions of people.
This would be devastating to Cambodia food security. The country's per capita consumption of inland fish is among the highest in the world and its people depend on fish for nearly three-quarters of their protein intake. According to one estimate, Cambodian fishers pull between 289,000 to 431,000 tons from the Mekong every year.
And impacts would extend beyond those to fish. In addition to providing Cambodia's main source of protein, the Mekong supplies water for the cultivation of rice in an area where irrigated land is scarce. "We can grow rice even in the dry season by pumping water from the river to our rice paddies," Puleau explained. "The river is absolutely essential to us."
The Mekong River supplies water for the cultivation of rice, as well as for drinking and other household uses. International Rivers
The Mekong also serves as the community's only reliable source of water for drinking and household use. "The river is central to our daily lives," said Bunleap, a homemaker and mother of three on Pdau Island. "Not only do we bring water from the river to cultivate our rice fields and vegetable gardens, we also use it for cleaning, cooking and drinking."
Dams upstream are already changing the river, and the area's residents are no longer able to count on the Mekong to meet their needs.
Just five years ago, Punleu's son-in-law could earn 300,000 Riel (US $75) per fishing trip. He made two to three trips per week. This income provided a critical safety net, helping the family cope with unexpected shocks such as hospital bills. Now her son-in-law earns only 100,000 Riel (US $25) per trip—his income has declined by two-thirds.
When asked about the reason for this sharp decline, Punleu said, "I suspect upstream dams could be one of the reasons." So far, seven megadams have been built on the upper Mekong in China, and construction is well underway on the Xayaburi and Don Sahong dams in neighboring Lao PDR. Despite these projects' profound impacts on the food security of Cambodia, they have proceeded with no transboundary environmental impact assessments, and no consultation with affected communities downstream. "I need more information regarding these dams' impacts," said Punleu.
Bunleap's family is also finding it harder to catch fish. Five years ago, the fish they caught for sale provided a crucial source of income. "Now we usually only catch enough fish to eat within our family, and sometimes, we don't even catch enough to eat," she said. "I don't know why. Now we sometimes have to buy fish to cook. My husband has had to change his career from fishing to work as a logger."
Punleu, too, is seeing more family members go off to the forest to log trees. She's saddened by this turn of events, and well aware of the unsustainability of this new enterprise. "What career will we have in our village when there are no more forests to log?" she asked. "In the future, if this decrease in fish continues, making a living will become more and more difficult, and my children's nutrition will suffer. This could really harm my children's health."
Punleu's fears are well founded. A 2013 report financed by Danida, Oxfam, and the World Wildlife Fund shows that the combined impact of mainstream dams and population growth could reduce consumption of fish in Cambodia from 49 kilograms per person per year to as little as two kilograms by 2030. This would have a profound impact on child nutrition in a country where nearly 40 percent of children under five are chronically malnourished, more than 28 percent are underweight, and roughly 11 percent are acutely malnourished.
Songom shares Punleu's concern. "If the fishing gets any worse, I'm scared that I won't be able to feed my family," he said. "I am worried that my children and grandchildren won't have enough food to eat every day, and that they'll get sick."
Five years ago, many people in Bunleap and Songom's villages caught fish not only for their daily meals, but also to make supplemental foods like prohok (fermented fish) that can be stored long-term. For many poorer Cambodians, prohok is the only affordable source of complete protein available year-round, and it's crucial to the country's most vulnerable communities.
Fish and fish products like prohok are critical sources of iron. Already in Cambodia, an estimated 70 percent of pregnant women and 74 percent of children under the age of five suffer from iron deficiencies. Iron shortages rob people of energy, ultimately perpetuating the cycle of poverty.
A decline in fish could also result in weakened muscles and bones associated with calcium deficiency; body-wasting and memory-loss associated with zinc deficiency; decreased resistance to disease from insufficient Vitamin A; and mental retardation caused by too little iodine.
Food security is a foundation on which other important forms of development are built, and wild-capture fisheries are a vital source of nutrients to rural families throughout the Mekong region. As such, protection of wild-capture fisheries should be central to poverty-reduction efforts.
Cambodia still has time to pull back from this path. The Cambodian government could embrace the innovative renewable and decentralized electricity technologies like wind and solar, which are now available and cost-competitive, and could help Cambodia avoid these large-scale and destructive mega-dam projects. By adopting national energy policies that encourage investment in these new energy technologies, the Mekong governments could start growing sustainable, modern economies without losing the many benefits that healthy rivers bring. Punleu, for one, would thank them.
All names have been changed to protect people's identities.
Sabrina Gyorvary is the Mekong Program Coordinator for the global river protection group International Rivers.
Reposted with permission from our media associate Earth Island Journal.
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By Brian Bienkowski
Fish exposed to endocrine-disrupting compounds pass on health problems to future generations, including deformities, reduced survival, and reproductive problems, according to a new study.
Low Levels Lead to Generational Impacts<p>Researchers exposed inland silverside fish to bifenthrin, levonorgestrel, ethinylestradiol, and trenbolone to levels currently found in waterways.</p><p>"Our concentrations were actually on the low end" of what is found in the wild, DeCourten said, adding that it was low amounts of chemicals in parts per trillion.</p><p>Bifenthrin is a pesticide; levonorgestrel and ethinylestradiol are synthetic hormones used in birth controls; and trenbolone is a synthetic steroid often given to cattle to bulk them up.</p><p>Such endocrine-disruptors have already been linked to a variety of health problems in directly exposed fish including altered growth, reduced survival, lowered egg production, skewed sex ratios, and negative impacts to immune systems. But what remains less clear is how the exposure may impact future generations.</p><p>For their study, DeCourten and colleagues started the exposure when the fish were embryos and continued it for 21 days.</p><p>They then tracked effects on the exposed fish, and the next two generations.</p>
Inherited Problems<p>DeCourten said the altered DNA methylation is one of the plausible ways that future generations would experience health impacts from previous generations' exposure. Hormone-disrupting compounds have been shown to impact DNA methylation, which is an important marker of how an organism will develop.</p><p>"Methyl groups are added to specific sites on the genome, [the exposure] is not changing the genome itself, but rather how the genome is expressed," she said. "And that can be inherited throughout generations."</p><p>In addition, Brander said there are essentially different "tags" that exist on DNA molecules, which tell genes how to turn on and off. She said the exposure to different compounds may be "influencing which methyl tags get taken on or off as you proceed through generations."</p><p>The researchers said the study should prompt future toxics testing to consider impacts on future generations.</p><p>"The results … throw a wrench in the current approach to regulating chemicals, where it's often short-term testing looking at simple things like growth, survival, and maybe gene expression," Brander said.</p><p>"These findings are telling us we really at least need to consider" the next two generations, she added.</p>
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Consumers have long turned to vitamins and herbs to try to protect themselves from disease. This pandemic is no different — especially with headlines that scream "This supplement could save you from coronavirus."
Vitamin D<p><strong>What it is: </strong>Called "the sunshine vitamin" because the body makes it naturally in the presence of ultraviolet light, <a href="https://www.sciencenews.org/article/vitamin-d-supplements-lose-luster" target="_blank">Vitamin D is one of the most heavily studied</a> supplements (<em>SN: 1/27/19</em>). <a href="https://health.gov/our-work/food-nutrition/2015-2020-dietary-guidelines/guidelines/appendix-12/" target="_blank">Certain foods</a>, including fish and fortified milk products, are also high in the vitamin.</p><p><strong>Why it might help: </strong>Vitamin D is a hormone building block that helps strengthen the immune system.</p><p><strong>How it works for other infections:</strong> In 2017, the <em>British Medical Journal</em> published a meta-analysis that suggested a daily vitamin D supplement <a href="https://www.bmj.com/content/356/bmj.i6583" target="_blank">might help prevent respiratory infections</a>, particularly in people who are deficient in the vitamin.</p><p>But one key word here is <em>deficient. </em>That risk is highest during dark winters at high latitudes and among people with more color in their skin (melanin, a pigment that's higher in darker skin, inhibits the production of vitamin D).</p><p>"If you have enough vitamin D in your body, the evidence doesn't stack up to say that giving you more will make a real difference," says Susan Lanham-New, head of the Nutritional Sciences Department at the University of Surrey in England.</p><p>And taking too much can create new health problems, stressing certain internal organs and leading to a dangerously high calcium buildup in the blood. The recommended daily allowance for adults is 600 to 800 International Units per day, and the upper limit is considered to be 4,000 IUs per day.</p><p><strong>What we know about Vitamin D and COVID-19:</strong> Few studies have looked directly at whether vitamin D makes a difference in COVID.</p>
Zinc<p><strong>What it is: </strong>Zinc, a mineral found in cells all over the body, is found naturally in certain meats, beans and oysters.</p><p><strong>Why it might help: </strong>It plays several supportive roles in the immune system, which is why zinc lozenges are always hot sellers in cold and flu season. Zinc also helps with cell division and growth.</p><p><strong>How it works for other infections: </strong><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6457799/" target="_blank" rel="noopener noreferrer">Studies of using zinc for colds</a> — which are frequently caused by coronaviruses — suggest that using a supplement right after symptoms start might make them go away quicker. That said, a clinical trial from researchers in Finland and the United Kingdom, published in January in <em>BMJ Open</em> <a href="https://bmjopen.bmj.com/content/10/1/e031662" target="_blank" rel="noopener noreferrer">did not find any value for zinc lozenges</a> for the treatment of colds. Some researchers have theorized that inconsistencies in data for colds may be explained by varying amounts of zinc released in different lozenges.</p><p><strong>What we know about zinc and COVID-19:</strong> The mineral is promising enough that it was added to some early studies of hydroxychloroquine, a drug tested early in the pandemic. (Studies have since shown that <a href="https://www.sciencenews.org/article/covid-19-coronavirus-hydroxychloroquine-no-evidence-treatment" target="_blank">hydroxychloroquine can't prevent or treat COVID-19</a> (<em>SN: 8/2/20</em>).)</p>
Vitamin C<p><strong>What it is: </strong>Also called L-ascorbic acid, vitamin C has a long list of roles in the body. It's found naturally in fruits and vegetables, especially citrus, peppers and tomatoes.</p><p><strong>Why it might help:</strong> It's a potent antioxidant that's important for a healthy immune system and preventing inflammation.</p><p><strong>How it works for other infections: </strong>Thomas cautions that the data on vitamin C are often contradictory. One review from Chinese researchers, published in February in the <em>Journal of Medical Virolog</em>y, looked at <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/jmv.25707" target="_blank">what is already known about vitamin C</a> and other supplements that might have a role in COVID-19 treatment. Among other encouraging signs, human studies find a lower incidence of pneumonia among people taking vitamin C, "suggesting that vitamin C might prevent the susceptibility to lower respiratory tract infections under certain conditions."</p><p>But for preventing colds, a 2013 Cochrane review of 29 studies <a href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD000980.pub4/full" target="_blank" rel="noopener noreferrer">didn't support the idea</a> that vitamin C supplements could help in the general population. However, the authors wrote, given that vitamin C is cheap and safe, "it may be worthwhile for common cold patients to test on an individual basis whether therapeutic vitamin C is beneficial."</p><p><strong>What we know about Vitamin C and COVID-19: </strong>About a dozen studies are under way or planned to examine whether vitamin C added to coronavirus treatment helps with symptoms or survival, including Thomas' study at the Cleveland Clinic.</p><p>In a review published online in July in <em>Nutrition</em>, researchers from KU Leuven in Belgium concluded that the <a href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD000980.pub4/full" target="_blank" rel="noopener noreferrer">vitamin may help prevent infection</a> and tamp down the dangerous inflammatory reaction that can cause severe symptoms, based on what is known about how the nutrient works in the body.</p><p>Melissa Badowski, a pharmacist who specializes in viral infections at the University of Illinois at Chicago College of Pharmacy and colleague Sarah Michienzi published an extensive look at all supplements that might be useful in the coronavirus epidemic. There's <a href="https://www.drugsincontext.com/can-vitamins-and-or-supplements-provide-hope-against-coronavirus/" target="_blank" rel="noopener noreferrer">still not enough evidence to know whether they are helpful</a>, the pair concluded in July in <em>Drugs in Context</em>. "It's not really clear if it's going to benefit patients," Badowski says.</p><p>And while supplements are generally safe, she adds that nothing is risk free. The best way to avoid infection, she says, is still to follow the advice of epidemiologists and public health experts: "Wash your hands, wear a mask, stay six feet apart."</p>
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