Did volatile halogenated gases from giant salt lakes at the end of the Permian Age lead to a mass extinction of species?
The largest mass extinction in the history of the earth could have been triggered off by giant salt lakes, whose emissions of halogenated gases changed the atmospheric composition so dramatically that vegetation was irretrievably damaged. At least that is what an international team of scientists have reported in the most recent edition of the "Proceedings of the Russian Academy of Sciences". At the Permian/Triassic boundary, 250 million years ago about 90 percent of the animal and plant species ashore became extinct. Previously it was thought that volcanic eruptions, the impacts of asteroids, or methane hydrate were instigating causes. The new theory is based on a comparison with today’s biochemical and atmospheric chemical processes. "Our calculations show that airborne pollutants from giant salt lakes like the Zechstein Sea must have had catastrophic effects at that time", states co-author Dr. Ludwig Weißflog from the Helmholtz-Center for Environmental Research (UFZ). Forecasts predict an increase in the surface areas of deserts and salt lakes due to climate change. That is why the researchers expect that the effects of these halogenated gases will equally increase.
The team of researchers from Russia, Austria, South Africa and Germany investigated whether a process that has been taking place since primordial times on earth could have led to global mass extinctions, particularly at the end of the Permian. The starting point for this theory was their discovery in the south of Russia and South Africa that microbial processes in present-day salt lakes naturally produce and emit highly volatile halocarbons such as chloroform, trichloroethene, and tetrachloroethene. They transcribed these findings to the Zechstein Sea, which about 250 million years ago in the Permian Age, was situated about where present day Central Europe is. The Zechstein Sea with a total surface area of around 600.000 km2 was almost as large as France is today. The hyper saline flat sea at that time was exposed to a predominantly dry continental desert climate and intensive solar radiation - like today’s salt seas. "Consequently, we assume that the climatic, geo-chemical and microbial conditions in the area of the Zechstein Sea were comparable with those of the present day salt seas that we investigated," Weißflog said.
In their current publication the authors explain the similarities between the complex processes of the CO2-cycle in the Permian Age as well as between global warming from that time and at present. Based on comparable calculations from halogenated gas emissions in the atmosphere from present-day salt seas in the south of Russia, the scientists calculated that from the Zechstein Sea alone an annual VHC emissions rate of at least 1.3 million tonnes of trichloroethene, 1.3 million tonnes of tetrachloroethene, 1.1 million tonnes of chloroform as well as 0.050 million tonnes of methyl chloroform can be assumed. By comparison, the annual global industrial emissions of trichloroethene and tetrachloroethene amount to only about 20 percent of that respectively, and only about 5 percent of the chloroform from the emissions calculated for the Zechstein Sea by the scientists. Incidentally, the industrial production of methyl chloroform, which depletes the ozone layer, has been banned since 1987 by regulation of the Montreal Protocol.
"Using steppe plant species we were able to prove that halogenated gases contribute to speeding up desertification: The combination of stress induced by dryness and the simultaneous chemical stressor `halogenated hydrocarbons´ disproportionately damages and destabilize the plants and speeds up the process of erosion," Dr. Karsten Kotte from the University of Heidelberg explained.
Based on both of these findings the researchers were able to form their new hypothesis: At the end of the Permian Age the emissions of halogenated gases from the Zechstein Sea and other salt seas were responsible in a complex chain of events for the world’s largest mass extinction in the history of the earth, in which about 90 percent of the animal and plant species of that time became extinct.
According to the forecast from the International Panel on Climate Change (IPCC), increasing temperatures and aridity due to climate change will also speed up desertification, increasing with it the number and surface area of salt seas, salt lagoons and salt marshlands. Moreover, this will then lead to an increase in naturally formed halogenated gases. The phytotoxic effects of these substances become intensified in conjunction with other atmospheric pollutants and at the same time increasing dryness and exponentiate the eco-toxicological consequences of climate change.
The new theory could be like a jigsaw piece that contributes to solving the puzzle of the largest mass extinction in the history of the earth. "The question as to whether the halogenated gases from the giant salt lakes alone were responsible for it or whether it was a combination of various factors with volcanic eruptions, the impact of asteroids, or methane hydrate equally playing their role still remains unanswered," Ludwig Weißflog said. What is fact however is that the effects of salt seas were previously underestimated. In their publication the researchers working with Dr. Ludwig Weißflog from the UFZ and Dr. Karsten Kotte from the University of Heidelberg want to prove that recent salt lakes and salt deserts of south-east Europe, Middle Asia, Australia, Africa, America can not only influence the regional but also the global climate. The new findings on the effects of these halogenated gases are important for revising climate models, which form the basis for climate forecasts.
Showing posts with label Logos. Show all posts
Showing posts with label Logos. Show all posts
Southern Africa’s freshwater species in firing line
Istanbul, Turkey, 19 March 2009 (IUCN) – Many freshwater fish, crabs, dragonflies, molluscs and aquatic plants are at risk of extinction in southern Africa if its rivers and lakes are not protected from developers, according to IUCN.
The study, released at the World Water Forum by the IUCN Species Programme in collaboration with the South African Institute for Aquatic Biodiversity, shows that seven percent of species are known to be regionally threatened or extinct. But this figure will skyrocket unless freshwater species conservation is considered in development planning.
These species provide food for local people and some of them, such as the mollucs, help purify the drinking water. The study shows that while 77 percent of species are not threatened with extinction, there is not enough information for the remaining 16 percent to determine their threat status.
“Here at the World Water Forum the trend is to think about water supply in terms of irrigation, hydropower and drinking water,” says William Darwall, Manager of IUCN’s Freshwater Biodiversity Unit. "People tend to forget about the species that live in the water but we can no longer afford to do this. We want developers to use the information on the IUCN Red List of Threatened Species to work out how they can minimize the impact on freshwater species when they develop water resources.”
The results from the assessment of 1,279 freshwater species in southern Africa show that the more developed a country is, the more species are threatened with extinction. Of the 94 species threatened in southern Africa, 78 of these are found in South Africa, the most developed country in the region.
“We are in a unique position in Africa to avoid an extinction disaster,” says Julia Marton-Lefèvre, IUCN Director General. “Most developers have not taken freshwater species into consideration because they simply don’t have the information they need. We hope this study will change that and show that Africa’s water resources can be developed without causing thousands of extinctions.”
Three hotspots of species diversity have been highlighted in the report, including the area where the upper Zambezi meets the Kwando and Chobe rivers above Victoria Falls, the Komati and Crocodile river tributaries of the Incomati system in Mpumalanga, South Africa, and the Mbuluzi river basin, also in Mpumalanga, South Africa, and in Swaziland.
Many of southern Africa’s coastal drainages have sites which contain species that only occur in that area, including the Kunene and Kwanza rivers on the west coast of Angola, and the Rovuma and Pungwe and Buzi systems on the east coast of Mozambique.
“If we really want to save these species we must protect the rivers and lakes by looking at river basins as a whole,” says Mark Smith, Head of IUCN’s Water Programme. “We can’t just look at the parts that interest us economically or as natural areas. For our plans to work, we must manage them together, using all the tools we have to meet the needs of people and nature for water.”
The results of this report will be combined with similar studies currently being conducted in the rest of Africa. Case studies will be used to develop a series of Good Practice Guidelines to help developers and governments take freshwater species into consideration when planning water projects in Africa.
The study, released at the World Water Forum by the IUCN Species Programme in collaboration with the South African Institute for Aquatic Biodiversity, shows that seven percent of species are known to be regionally threatened or extinct. But this figure will skyrocket unless freshwater species conservation is considered in development planning.
These species provide food for local people and some of them, such as the mollucs, help purify the drinking water. The study shows that while 77 percent of species are not threatened with extinction, there is not enough information for the remaining 16 percent to determine their threat status.
“Here at the World Water Forum the trend is to think about water supply in terms of irrigation, hydropower and drinking water,” says William Darwall, Manager of IUCN’s Freshwater Biodiversity Unit. "People tend to forget about the species that live in the water but we can no longer afford to do this. We want developers to use the information on the IUCN Red List of Threatened Species to work out how they can minimize the impact on freshwater species when they develop water resources.”
The results from the assessment of 1,279 freshwater species in southern Africa show that the more developed a country is, the more species are threatened with extinction. Of the 94 species threatened in southern Africa, 78 of these are found in South Africa, the most developed country in the region.
“We are in a unique position in Africa to avoid an extinction disaster,” says Julia Marton-Lefèvre, IUCN Director General. “Most developers have not taken freshwater species into consideration because they simply don’t have the information they need. We hope this study will change that and show that Africa’s water resources can be developed without causing thousands of extinctions.”
Three hotspots of species diversity have been highlighted in the report, including the area where the upper Zambezi meets the Kwando and Chobe rivers above Victoria Falls, the Komati and Crocodile river tributaries of the Incomati system in Mpumalanga, South Africa, and the Mbuluzi river basin, also in Mpumalanga, South Africa, and in Swaziland.
Many of southern Africa’s coastal drainages have sites which contain species that only occur in that area, including the Kunene and Kwanza rivers on the west coast of Angola, and the Rovuma and Pungwe and Buzi systems on the east coast of Mozambique.
“If we really want to save these species we must protect the rivers and lakes by looking at river basins as a whole,” says Mark Smith, Head of IUCN’s Water Programme. “We can’t just look at the parts that interest us economically or as natural areas. For our plans to work, we must manage them together, using all the tools we have to meet the needs of people and nature for water.”
The results of this report will be combined with similar studies currently being conducted in the rest of Africa. Case studies will be used to develop a series of Good Practice Guidelines to help developers and governments take freshwater species into consideration when planning water projects in Africa.
Protecting watersheds saves billions
Gland, Switzerland, 13 March 2009 (IUCN) – Protecting watersheds provides many of the world’s megacities with freshwater – and saves billions of dollars. This is the result of a new compilation of case studies by IUCN, published today ahead of the World Water Forum, held from 16-22 March in Istanbul, Turkey.
“Many of the world’s big cities have understood that protecting their catchment areas makes economic sense. Rather than chopping down the forests or draining their marshlands, they are keeping them healthy and saving billions of dollars by not having to pay for costly infrastructure to store water, clean it or bring it from elsewhere,” says Mark Smith, Head of IUCN’s Water Programme.
The Indonesian capital Jakarta gets its freshwater for free from some 60 rivers originating in the nearby Gunung Gede Pangrango National Park. The water is worth an estimated US$1.5 billion.
The Venezuelan capital Caracas relies on the rivers from Guatopo and Macarao National Parks for its freshwater provision. Today, those rivers continue to supply a constant flow of freshwater to the city’s 5 million inhabitants, consuming some 17 thousand litres of water per second.
Protecting freshwater sources also benefits nature. In and around South Africa’s Kruger National Park, better river management has helped improve water provision for some local rural communities – whilst at the same time preventing loss of aquatic life in the park.
“Kruger’s main five rivers have suffered from pollution and unsustainable water use upstream which led to some of them drying up completely. After implementing a large river-related programme with the agriculture, forestry and mining industries, we have seen an improvement in flows. Previously disappeared species have re-colonised, and fewer unnatural fish kills have occurred,” says Harry Biggs, Programme Integrator at South African National Parks and leader of IUCN’s World Commission on Protected Areas Freshwater Task Force.
During drier times, expensive arrangements like water transfers and trucking of water had to be made to meet basic needs of some rural communities living along rivers near the park, when they could no longer, as in the past, access water from rivers. For some of these communities, cleaner and more water is now available.
“Healthy river systems are essential to maintain the livelihoods of local communities. The objectives of sustainable development can only be achieved if nature continues to provide freshwater that everyone needs,” says David Sheppard, Head of IUCN’s Programme on Protected Areas.
“Many of the world’s big cities have understood that protecting their catchment areas makes economic sense. Rather than chopping down the forests or draining their marshlands, they are keeping them healthy and saving billions of dollars by not having to pay for costly infrastructure to store water, clean it or bring it from elsewhere,” says Mark Smith, Head of IUCN’s Water Programme.
The Indonesian capital Jakarta gets its freshwater for free from some 60 rivers originating in the nearby Gunung Gede Pangrango National Park. The water is worth an estimated US$1.5 billion.
The Venezuelan capital Caracas relies on the rivers from Guatopo and Macarao National Parks for its freshwater provision. Today, those rivers continue to supply a constant flow of freshwater to the city’s 5 million inhabitants, consuming some 17 thousand litres of water per second.
Protecting freshwater sources also benefits nature. In and around South Africa’s Kruger National Park, better river management has helped improve water provision for some local rural communities – whilst at the same time preventing loss of aquatic life in the park.
“Kruger’s main five rivers have suffered from pollution and unsustainable water use upstream which led to some of them drying up completely. After implementing a large river-related programme with the agriculture, forestry and mining industries, we have seen an improvement in flows. Previously disappeared species have re-colonised, and fewer unnatural fish kills have occurred,” says Harry Biggs, Programme Integrator at South African National Parks and leader of IUCN’s World Commission on Protected Areas Freshwater Task Force.
During drier times, expensive arrangements like water transfers and trucking of water had to be made to meet basic needs of some rural communities living along rivers near the park, when they could no longer, as in the past, access water from rivers. For some of these communities, cleaner and more water is now available.
“Healthy river systems are essential to maintain the livelihoods of local communities. The objectives of sustainable development can only be achieved if nature continues to provide freshwater that everyone needs,” says David Sheppard, Head of IUCN’s Programme on Protected Areas.
Cheap Love Costs the Earth
Stark warning by University of Leicester researcher on high ecological price paid for cheap roses
Ecology and conservation biologist at the University of Leicester, Dr David Harper, who has conducted research for over 25 years at Lake Naivasha in Kenya, today warned that cut-price Valentine roses exported for sale in the UK were 'bleeding that country dry'.
Dr Harper, of the University's Department of Biology where he is a senior lecturer, claimed that cheap roses grown by companies that had no concern for the environment were having a devastating effect on the ecology of Lake Naivasha, the centre of Kenya's horticultural industry.
Instead, Dr Harper urged UK shoppers to buy Fair Trade roses, produced by companies that were conscientious and had a transparent supply chain.
Dr Harper said: "Roses that come cheap are grown by companies that have no concern for the environment, who cut corners and avoid legislation, who sell their flowers into the auction in Amsterdam so that all the buyer knows is the flowers "come from Holland". In reality, they have come from Kenya where the industry is literally draining that country dry."
However, some companies took a more responsible approach and sold direct to British supermarkets - many of them being "Fair Trade" certified.
"These companies want a sustainable future for the wildlife and the environment, as well as the people, where they grow their roses. Sadly, there are not enough of them,” said Dr Harper.
"At Lake Naivasha, the good companies make up about half of the total. That is not enough; together, the industry is sucking the lake dry. The country's legislation is strong, but its enforcement is weak so companies whose only interest is profit take advantage of that."
Dr Harper said the demand for the ten thousand tonnes of roses sold in the UK for Valentine's Day and for Mother's Day had contributed to the devastation of the ecosystem at the lake.
Almost half a million people now live around the shores of the lake, drawn there by the flower trade. The shanty towns that have emerged around the lake have no sanitation - water comes from the lake and sewage returns to it. This pressure from people is destroying the lake that supports their jobs, lives and their livelihoods.
David and his colleagues from other UK and Dutch universities first raised the alarm about the situation in 2002, just as the new Kenyan Water Act was passed.
Since then, the lake has continued to shrink.
Ecology and conservation biologist at the University of Leicester, Dr David Harper, who has conducted research for over 25 years at Lake Naivasha in Kenya, today warned that cut-price Valentine roses exported for sale in the UK were 'bleeding that country dry'.
Dr Harper, of the University's Department of Biology where he is a senior lecturer, claimed that cheap roses grown by companies that had no concern for the environment were having a devastating effect on the ecology of Lake Naivasha, the centre of Kenya's horticultural industry.
Instead, Dr Harper urged UK shoppers to buy Fair Trade roses, produced by companies that were conscientious and had a transparent supply chain.
Dr Harper said: "Roses that come cheap are grown by companies that have no concern for the environment, who cut corners and avoid legislation, who sell their flowers into the auction in Amsterdam so that all the buyer knows is the flowers "come from Holland". In reality, they have come from Kenya where the industry is literally draining that country dry."
However, some companies took a more responsible approach and sold direct to British supermarkets - many of them being "Fair Trade" certified.
"These companies want a sustainable future for the wildlife and the environment, as well as the people, where they grow their roses. Sadly, there are not enough of them,” said Dr Harper.
"At Lake Naivasha, the good companies make up about half of the total. That is not enough; together, the industry is sucking the lake dry. The country's legislation is strong, but its enforcement is weak so companies whose only interest is profit take advantage of that."
Dr Harper said the demand for the ten thousand tonnes of roses sold in the UK for Valentine's Day and for Mother's Day had contributed to the devastation of the ecosystem at the lake.
Almost half a million people now live around the shores of the lake, drawn there by the flower trade. The shanty towns that have emerged around the lake have no sanitation - water comes from the lake and sewage returns to it. This pressure from people is destroying the lake that supports their jobs, lives and their livelihoods.
David and his colleagues from other UK and Dutch universities first raised the alarm about the situation in 2002, just as the new Kenyan Water Act was passed.
Since then, the lake has continued to shrink.
Cropland Diversity Reduces Nitrogen Pollution
Biodiversity in crops decreases fertiliser damage to rivers and lakes
Researchers have identified a link between the diversity of crops grown in farmlands and the pollution they create in lakes and rivers. In Frontiers in Ecology and the Environment e-View paper, ecologists show that when the biodiversity of crops is high, less dissolved nitrogen is found exiting the surrounding watersheds.
Nitrogen from agricultural fertilisers leaches through soils to groundwater and runs off into rivers and lakes, increasing aquatic dissolved nitrate. Too much nitrate in the water can lead to prolific growth of aquatic algae, which can use up most of a water body's oxygen when they die and are decomposed, creating "dead zones" that cannot support life.
Whitney Broussard of the University of Louisiana at Lafayette and R. Eugene Turner of Louisiana State University at Baton Rouge compiled data from the past 100 years on watersheds varying in size from the Illinois Cache River basin (400 square miles) to the Mississippi River Basin (more than a million square miles). The researchers compared this watershed data with land-use practices since the early 1900s.
The results show that since the beginning of the last century, the average farm size in the United States has doubled and the number of farms has fallen by almost two-thirds. Broussard also says that a shift from farm animals and simple ploughs to the use of machines to till croplands has changed not only the culture but the environmental impact of farming.
"With the growing American farm, comes the necessity to use more industrialised means of farming," says Broussard. "Our agricultural practices have always impacted water quality, but over the past century the mechanisation of agriculture and the use of more potent fertilisers has caused a greater effect: the nitrogen leakage rate is higher."
Modern farms tend to produce fewer crop varieties; this lower crop biodiversity can negatively impact surrounding watersheds. According to the study, within a given area, a higher biodiversity of crops led to less dissolved nitrogen in surrounding water bodies. The explanation for this phenomenon, Broussard says, is difficult to discern.
"Diverse farms tend to have smaller fields with more edges, which can mean there's a greater buffering effect on nitrogen runoff by surrounding grasslands or woodlands," he says.
The researchers' results also showed that since 1906, the average aquatic nitrate concentration increased threefold in the entire US and tenfold in the Iowa, Des Moines, and Minnesota Rivers, all of which fall in heavily tilled agricultural areas.
In areas where farming is scarce or absent, however, the authors found no perceptible change in dissolved nitrogen concentrations since the early 1900s. Broussard thinks this indicates that the impacts might be reversible if policy changes included incentives for farmers to rotate more crops, decrease their field size, increase the edges of fields and sizes of buffering zones, and incorporate more native perennial grasses into farms and in between fields.
"There has been great progress made to reduce the footprint of agriculture, but there is still room for improvement," says Broussard. "The American farmer is caught in a mode of production that has tremendous momentum and cannot be changed on the farm – it's a policy question now."
Researchers have identified a link between the diversity of crops grown in farmlands and the pollution they create in lakes and rivers. In Frontiers in Ecology and the Environment e-View paper, ecologists show that when the biodiversity of crops is high, less dissolved nitrogen is found exiting the surrounding watersheds.
Nitrogen from agricultural fertilisers leaches through soils to groundwater and runs off into rivers and lakes, increasing aquatic dissolved nitrate. Too much nitrate in the water can lead to prolific growth of aquatic algae, which can use up most of a water body's oxygen when they die and are decomposed, creating "dead zones" that cannot support life.
Whitney Broussard of the University of Louisiana at Lafayette and R. Eugene Turner of Louisiana State University at Baton Rouge compiled data from the past 100 years on watersheds varying in size from the Illinois Cache River basin (400 square miles) to the Mississippi River Basin (more than a million square miles). The researchers compared this watershed data with land-use practices since the early 1900s.
The results show that since the beginning of the last century, the average farm size in the United States has doubled and the number of farms has fallen by almost two-thirds. Broussard also says that a shift from farm animals and simple ploughs to the use of machines to till croplands has changed not only the culture but the environmental impact of farming.
"With the growing American farm, comes the necessity to use more industrialised means of farming," says Broussard. "Our agricultural practices have always impacted water quality, but over the past century the mechanisation of agriculture and the use of more potent fertilisers has caused a greater effect: the nitrogen leakage rate is higher."
Modern farms tend to produce fewer crop varieties; this lower crop biodiversity can negatively impact surrounding watersheds. According to the study, within a given area, a higher biodiversity of crops led to less dissolved nitrogen in surrounding water bodies. The explanation for this phenomenon, Broussard says, is difficult to discern.
"Diverse farms tend to have smaller fields with more edges, which can mean there's a greater buffering effect on nitrogen runoff by surrounding grasslands or woodlands," he says.
The researchers' results also showed that since 1906, the average aquatic nitrate concentration increased threefold in the entire US and tenfold in the Iowa, Des Moines, and Minnesota Rivers, all of which fall in heavily tilled agricultural areas.
In areas where farming is scarce or absent, however, the authors found no perceptible change in dissolved nitrogen concentrations since the early 1900s. Broussard thinks this indicates that the impacts might be reversible if policy changes included incentives for farmers to rotate more crops, decrease their field size, increase the edges of fields and sizes of buffering zones, and incorporate more native perennial grasses into farms and in between fields.
"There has been great progress made to reduce the footprint of agriculture, but there is still room for improvement," says Broussard. "The American farmer is caught in a mode of production that has tremendous momentum and cannot be changed on the farm – it's a policy question now."
Research Finds Most Road Salt Is Making It Into The State's Lakes And Rivers
Smarter application could help lessen the environmental impact
Research at the University of Minnesota has revealed that road salt used throughout the winter is making the state's lakes and rivers saltier, which could affect aquatic life and drinking water. The research indicates that better training of snow plough drivers and more judicious use of road salt could help lessen the impact and save the state money.
The researchers studied 39 lakes, three major rivers, 10 tributaries and numerous observation wells, and the results are alarming. They found that approximately 70 per cent of the road salt being applied in the metro area is retained in our watershed. The university researchers recently reported their findings to the Local Road Research Board. Nearly 350,000 tons of sodium chloride, commonly referred to as road salt, are applied for de-icing in the Twin Cities metro area every year.
"Nobody has asked the question of where the salt ultimately goes after the winter season is over," said research team leader Stefan, a civil engineering professor at the university's St. Anthony Falls Laboratory. "Our study has been concerned with that question in particular."
Stefan's team tracked the movement of chloride applied by humans throughout the water system, distinguishing it from geological or natural origins. They found that the chloride concentrations (salinity) in 39 metro area lakes have increased over the past 22 years, following a similar trend in road salt purchases by the state of Minnesota. Both show a marked increase from 1984 to 2005, which if continued would double salinity in these lakes in about 50 years. Compare this with a near zero concentration in the 1950s, when road salt application began.
The effects could be severe. Continuous levels of chloride concentration (as low as 250 mg/L, the equivalent of one teaspoon of salt in five gallons of water) have been shown to be harmful to aquatic life and to affect the taste of drinking water. In 2008, the Minnesota Pollution Control Agency listed five metro area streams as already impaired by chloride. Increases in sodium and chloride have been shown to decrease the biodiversity in wetland areas, altering the development of wood frogs, decreasing the number and types of fish available, and increasing mortality rates of organisms that rely on an aquatic system. Increases in sodium and chloride have also been shown to increase mobilisation of heavy metals in the soil along major highways.
To help reduce the effects, researchers recommend more judicious use of road salt through increased training of snow plough drivers to get the most out of the road salt they apply. Applying sodium chloride to pavement temperatures below 15 degrees Fahrenheit is generally not effective. At higher temperatures, researchers suggest using only one to three cups of salt per 1000 square feet. These recommendations are working at the University of Minnesota. Since training began two years ago, the university has reduced use of road salt by 41 per cent and saved more than USD50,000 in the first year.
To watch a video with research team leader Heinz Stefan, go to http://www1.umn.edu/urelate/newsservice/Multimedia_Videos/road_salt.htm
Research at the University of Minnesota has revealed that road salt used throughout the winter is making the state's lakes and rivers saltier, which could affect aquatic life and drinking water. The research indicates that better training of snow plough drivers and more judicious use of road salt could help lessen the impact and save the state money.
The researchers studied 39 lakes, three major rivers, 10 tributaries and numerous observation wells, and the results are alarming. They found that approximately 70 per cent of the road salt being applied in the metro area is retained in our watershed. The university researchers recently reported their findings to the Local Road Research Board. Nearly 350,000 tons of sodium chloride, commonly referred to as road salt, are applied for de-icing in the Twin Cities metro area every year.
"Nobody has asked the question of where the salt ultimately goes after the winter season is over," said research team leader Stefan, a civil engineering professor at the university's St. Anthony Falls Laboratory. "Our study has been concerned with that question in particular."
Stefan's team tracked the movement of chloride applied by humans throughout the water system, distinguishing it from geological or natural origins. They found that the chloride concentrations (salinity) in 39 metro area lakes have increased over the past 22 years, following a similar trend in road salt purchases by the state of Minnesota. Both show a marked increase from 1984 to 2005, which if continued would double salinity in these lakes in about 50 years. Compare this with a near zero concentration in the 1950s, when road salt application began.
The effects could be severe. Continuous levels of chloride concentration (as low as 250 mg/L, the equivalent of one teaspoon of salt in five gallons of water) have been shown to be harmful to aquatic life and to affect the taste of drinking water. In 2008, the Minnesota Pollution Control Agency listed five metro area streams as already impaired by chloride. Increases in sodium and chloride have been shown to decrease the biodiversity in wetland areas, altering the development of wood frogs, decreasing the number and types of fish available, and increasing mortality rates of organisms that rely on an aquatic system. Increases in sodium and chloride have also been shown to increase mobilisation of heavy metals in the soil along major highways.
To help reduce the effects, researchers recommend more judicious use of road salt through increased training of snow plough drivers to get the most out of the road salt they apply. Applying sodium chloride to pavement temperatures below 15 degrees Fahrenheit is generally not effective. At higher temperatures, researchers suggest using only one to three cups of salt per 1000 square feet. These recommendations are working at the University of Minnesota. Since training began two years ago, the university has reduced use of road salt by 41 per cent and saved more than USD50,000 in the first year.
To watch a video with research team leader Heinz Stefan, go to http://www1.umn.edu/urelate/newsservice/Multimedia_Videos/road_salt.htm
Federal Agencies and Industry Work Together to Restore New Jersey’s Passaic River
NOAA and the US Fish & Wildlife Service have signed agreements with 23 companies to cooperatively assess the lower 17 miles of the Passaic River and develop and implement a restoration plan to restore damaged habitat.
“It’s a first, for New Jersey, that such a diverse group of companies came together with federal agencies to restore natural resources,” said John H. Dunnigan, NOAA's assistant administrator of the National Ocean Service. “These agreements provide the framework to cooperatively assess injury to, and initiate restoration of, natural resources for the Passaic, from Dundee Dam to Newark Bay.”
"This is the first significant step for federal trustees to work together with these 23 companies. Other potentially responsible parties will have opportunities to join discussions in the future,” said Regional Director Marvin E. Moriarty of the US Fish and Wildlife Service's Northeast Region. "We will be seeking common understandings of fish and wildlife injuries, of lost recreational services, and of early restoration options that will ultimately benefit fish, wildlife, and residents of the local communities along the 17 mile Lower Passaic River below Dundee Dam."
The highly industrialised and urbanised region surrounding the Lower Passaic River has a long history of degraded water quality, sediment contamination, loss of wetlands, and abandoned or underused properties along its shores. Dioxins, polychlorinated biphenyls, and other contaminants in this ecosystem have impaired fish, shellfish, and wildlife, as well as their habitats and human use of these resources.
These agreements provide USD600,000 for payment of a portion of NOAA and DOI/USFWS past assessment costs, as well as up to USD1 million for future efforts.
As a principal trustee for the public’s coastal natural resources, NOAA’s Damage Assessment, Remediation, and Restoration Program restores habitats and communities that have been harmed by oil spills, hazardous substance releases, and ship groundings. Through the program, NOAA works with other agencies, industry, and communities to protect and restore these coastal and marine resources. Since its inception in 1992, the program has successfully protected natural resources at more than 500 waste sites. As of 2008, the program had settled almost 200 natural resource damage assessment cases, generating almost USD450 million for restoration projects.
The DOI/USFWS is a principal trustee under the federal Superfund law for the public’s natural resources, including DOI-managed lands, as well as migratory birds, threatened and endangered species, inter-jurisdictional fishes and certain marine mammals. When hazardous substances enter the environment, fish, wildlife, and other natural resources can be injured. The Department of the Interior, along with State, Tribal and other federal partners, act as “trustees” for these resources. DOI/USFWS works to identify the natural resources injured, determines the extent of the injuries, recovers damages from those responsible, and carries out restoration activities, through its Natural Resource Damage Assessment and Restoration Program.
NOAA understands and predicts changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and conserves and manages our coastal and marine resources.
“It’s a first, for New Jersey, that such a diverse group of companies came together with federal agencies to restore natural resources,” said John H. Dunnigan, NOAA's assistant administrator of the National Ocean Service. “These agreements provide the framework to cooperatively assess injury to, and initiate restoration of, natural resources for the Passaic, from Dundee Dam to Newark Bay.”
"This is the first significant step for federal trustees to work together with these 23 companies. Other potentially responsible parties will have opportunities to join discussions in the future,” said Regional Director Marvin E. Moriarty of the US Fish and Wildlife Service's Northeast Region. "We will be seeking common understandings of fish and wildlife injuries, of lost recreational services, and of early restoration options that will ultimately benefit fish, wildlife, and residents of the local communities along the 17 mile Lower Passaic River below Dundee Dam."
The highly industrialised and urbanised region surrounding the Lower Passaic River has a long history of degraded water quality, sediment contamination, loss of wetlands, and abandoned or underused properties along its shores. Dioxins, polychlorinated biphenyls, and other contaminants in this ecosystem have impaired fish, shellfish, and wildlife, as well as their habitats and human use of these resources.
These agreements provide USD600,000 for payment of a portion of NOAA and DOI/USFWS past assessment costs, as well as up to USD1 million for future efforts.
As a principal trustee for the public’s coastal natural resources, NOAA’s Damage Assessment, Remediation, and Restoration Program restores habitats and communities that have been harmed by oil spills, hazardous substance releases, and ship groundings. Through the program, NOAA works with other agencies, industry, and communities to protect and restore these coastal and marine resources. Since its inception in 1992, the program has successfully protected natural resources at more than 500 waste sites. As of 2008, the program had settled almost 200 natural resource damage assessment cases, generating almost USD450 million for restoration projects.
The DOI/USFWS is a principal trustee under the federal Superfund law for the public’s natural resources, including DOI-managed lands, as well as migratory birds, threatened and endangered species, inter-jurisdictional fishes and certain marine mammals. When hazardous substances enter the environment, fish, wildlife, and other natural resources can be injured. The Department of the Interior, along with State, Tribal and other federal partners, act as “trustees” for these resources. DOI/USFWS works to identify the natural resources injured, determines the extent of the injuries, recovers damages from those responsible, and carries out restoration activities, through its Natural Resource Damage Assessment and Restoration Program.
NOAA understands and predicts changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and conserves and manages our coastal and marine resources.
Hypertension and Cholesterol Medications Found in River St. Lawrence
A study conducted by Université de Montréal researchers on downstream and upstream water from the Montreal wastewater treatment plant has revealed the presence of chemotherapy products and certain hypertension and cholesterol medications.
Bezafibrate (cholesterol reducing medication), enalapril (hypertension medication), methotrexate and cyclophosphamide (two products used in the treatment of certain cancers) have all been detected in wastewater entering the Montreal treatment station. However, only bezafibrate and enalapril have been detected in the treated water leaving the wastewater treatment plant and in the surface water of the St. Lawrence River, where the treated wastewater is released.
This study was conducted due to the sharp rise in drug consumption over the past few years. In 1999, according to a study by IMS Health Global Services, world drug consumption amounted to USD342 billion. In 2006 that figure doubled to USD643 billion. A significant proportion of the drugs consumed are excreted by the human body in urine and end up in municipal wastewater. Chemotherapy products, such as methotrexate, are excreted by the body practically unchanged (80 to 90 per cent in their initial form).
Chemotherapy for fish?
The pharmaceutical compounds studied were chosen because of the large quantities prescribed by physicians. "Methotrexate and cyclophosphamide are two products very often used to treat cancer and are more likely to be found in water," says Sébastien Sauvé, a professor of environmental chemistry at the Université de Montréal. "Even though they treat cancer, these two products are highly toxic. This is why we wanted to know the extent to which the fauna and flora of the St. Lawrence are exposed to them."
Method and quantities
Professor Sauvé's team validated a rapid detection method for pharmaceutical compounds under study in the raw and treated wastewater of the Montreal wastewater treatment plant.
The quantities of bezafibrate and enalapril detected in the raw wastewater, treated wastewater and surface water at the treatment station outlet are respectively 50 nanograms per litre, 35 ng L and 8 ng L for bezafibrate and 280 ng L, 240 ng L and 39ng L for enalapril.
"All in all, these quantities are minimal, yet we don't yet know their effects on the fauna and flora of the St. Lawrence," Professor Sauvé explains. "It is possible that some species are sensitive to them. Other ecotoxicological studies will be necessary. As for the chemotherapy products detected in the raw wastewater but not in the treated wastewater, one question remains: did we not detect them because the treatment process succeeded in eliminating them or because our detection method is not yet sophisticated enough to detect them?"
A new threat to the aquatic environment
The release locations of wastewaters treated by the treatment stations are the main source of drug dispersion into the environment. Because of their high polarity and their acid-base character, some of the pharmaceutical compounds studied have the potential to be transported and dispersed widely in the aquatic environment. In Montreal, the wastewater treatment station treats a water volume representing 50 per cent of the water treated in Quebec and has a capacity of about 7.6 million cubic metres per day, making it the largest physicochemical treatment station in the Americas. This is why it is important to develop a simple, rapid, precise and inexpensive method, Professor Sauvé points out.
Bezafibrate (cholesterol reducing medication), enalapril (hypertension medication), methotrexate and cyclophosphamide (two products used in the treatment of certain cancers) have all been detected in wastewater entering the Montreal treatment station. However, only bezafibrate and enalapril have been detected in the treated water leaving the wastewater treatment plant and in the surface water of the St. Lawrence River, where the treated wastewater is released.
This study was conducted due to the sharp rise in drug consumption over the past few years. In 1999, according to a study by IMS Health Global Services, world drug consumption amounted to USD342 billion. In 2006 that figure doubled to USD643 billion. A significant proportion of the drugs consumed are excreted by the human body in urine and end up in municipal wastewater. Chemotherapy products, such as methotrexate, are excreted by the body practically unchanged (80 to 90 per cent in their initial form).
Chemotherapy for fish?
The pharmaceutical compounds studied were chosen because of the large quantities prescribed by physicians. "Methotrexate and cyclophosphamide are two products very often used to treat cancer and are more likely to be found in water," says Sébastien Sauvé, a professor of environmental chemistry at the Université de Montréal. "Even though they treat cancer, these two products are highly toxic. This is why we wanted to know the extent to which the fauna and flora of the St. Lawrence are exposed to them."
Method and quantities
Professor Sauvé's team validated a rapid detection method for pharmaceutical compounds under study in the raw and treated wastewater of the Montreal wastewater treatment plant.
The quantities of bezafibrate and enalapril detected in the raw wastewater, treated wastewater and surface water at the treatment station outlet are respectively 50 nanograms per litre, 35 ng L and 8 ng L for bezafibrate and 280 ng L, 240 ng L and 39ng L for enalapril.
"All in all, these quantities are minimal, yet we don't yet know their effects on the fauna and flora of the St. Lawrence," Professor Sauvé explains. "It is possible that some species are sensitive to them. Other ecotoxicological studies will be necessary. As for the chemotherapy products detected in the raw wastewater but not in the treated wastewater, one question remains: did we not detect them because the treatment process succeeded in eliminating them or because our detection method is not yet sophisticated enough to detect them?"
A new threat to the aquatic environment
The release locations of wastewaters treated by the treatment stations are the main source of drug dispersion into the environment. Because of their high polarity and their acid-base character, some of the pharmaceutical compounds studied have the potential to be transported and dispersed widely in the aquatic environment. In Montreal, the wastewater treatment station treats a water volume representing 50 per cent of the water treated in Quebec and has a capacity of about 7.6 million cubic metres per day, making it the largest physicochemical treatment station in the Americas. This is why it is important to develop a simple, rapid, precise and inexpensive method, Professor Sauvé points out.
Nile Delta Fishery Growth: Thanks to Run-Off of Sewage, Fertilisers
Considered pollutants in the West, discharges help to feed millions in Egypt
While many of the world's fisheries are in serious decline, the coastal Mediterranean fishery off the Nile Delta has expanded dramatically since the 1980s.
The surprising cause of this expansion, which followed a collapse of the fishery after completion of the Aswan High Dam in 1965, is run-off of fertilisers and sewage discharges in the region, according to a researcher at the University of Rhode Island Graduate School of Oceanography.
Autumn Oczkowski, a URI doctoral student, used stable isotopes of nitrogen to demonstrate that 60 to 100 per cent of the current fishery production is supported by nutrients from fertiliser and sewage.
"This is really a story about how people unintentionally impact ecosystems," Oczkowski said.
Historically, the Nile would flood the delta every fall, irrigate nearby agricultural land, and flow out to the Mediterranean, carrying with it nutrients to support a large and productive fishery. Construction of the dam stopped the flooding, and the fishery collapsed.
"That's when fertiliser consumption in the country skyrocketed," said Oczkowski. "The Egyptians were fertilising the land, and then fertilising the sea with the run-off. It also corresponded with a population boom and the expansion of the public water and sewer systems."
As a result, landings of fish in coastal and offshore waters are more than three times pre-dam levels. While increased fishing effort in recent years may have played some role in the recovery, Oczkowski's findings indicate that anthropogenic nutrient sources have now more than replaced the fertility carried by the historical flooding.
Oczkowski and colleagues from URI, the U.S. Environmental Protection Agency, and the University of Alexandria collected more than 600 fish in 2006 and 2007 from four regions that received run-off from the delta and two areas not affected by the Nile drainage. Stable isotopes of nitrogen in each fish were measured and compared.
She found that the isotope signatures in the fish reflected two distinct sources of nitrogen: anthropogenic nitrogen from fertilisers and sewage in the fish caught in coastal and offshore areas of the delta, and nitrogen values consistent with the middle of the Mediterranean in fish caught in waters that were not affected by the delta drainage.
These results have raised questions among many scientists about the value of anthropogenic sources of nutrients to ecosystems.
"We're programmed in the West to think of nutrient enrichment of coastal systems as bad," Oczkowski said. "Here in Rhode Island we've spent hundreds of millions of dollars to upgrade sewage plants to reduce nutrient loading into Narragansett Bay. And it's a major issue in the Chesapeake Bay and in the Gulf of Mexico, where run-off of fertilisers from the country's breadbasket into the Mississippi River has caused a dead zone in the Gulf.
"But the Egyptians don't think it's a bad thing. For them, it's producing tons of fish and feeding millions of hungry people. It's forcing us to reconsider whether we can say that nutrient inputs are always a bad thing."
While many of the world's fisheries are in serious decline, the coastal Mediterranean fishery off the Nile Delta has expanded dramatically since the 1980s.
The surprising cause of this expansion, which followed a collapse of the fishery after completion of the Aswan High Dam in 1965, is run-off of fertilisers and sewage discharges in the region, according to a researcher at the University of Rhode Island Graduate School of Oceanography.
Autumn Oczkowski, a URI doctoral student, used stable isotopes of nitrogen to demonstrate that 60 to 100 per cent of the current fishery production is supported by nutrients from fertiliser and sewage.
"This is really a story about how people unintentionally impact ecosystems," Oczkowski said.
Historically, the Nile would flood the delta every fall, irrigate nearby agricultural land, and flow out to the Mediterranean, carrying with it nutrients to support a large and productive fishery. Construction of the dam stopped the flooding, and the fishery collapsed.
"That's when fertiliser consumption in the country skyrocketed," said Oczkowski. "The Egyptians were fertilising the land, and then fertilising the sea with the run-off. It also corresponded with a population boom and the expansion of the public water and sewer systems."
As a result, landings of fish in coastal and offshore waters are more than three times pre-dam levels. While increased fishing effort in recent years may have played some role in the recovery, Oczkowski's findings indicate that anthropogenic nutrient sources have now more than replaced the fertility carried by the historical flooding.
Oczkowski and colleagues from URI, the U.S. Environmental Protection Agency, and the University of Alexandria collected more than 600 fish in 2006 and 2007 from four regions that received run-off from the delta and two areas not affected by the Nile drainage. Stable isotopes of nitrogen in each fish were measured and compared.
She found that the isotope signatures in the fish reflected two distinct sources of nitrogen: anthropogenic nitrogen from fertilisers and sewage in the fish caught in coastal and offshore areas of the delta, and nitrogen values consistent with the middle of the Mediterranean in fish caught in waters that were not affected by the delta drainage.
These results have raised questions among many scientists about the value of anthropogenic sources of nutrients to ecosystems.
"We're programmed in the West to think of nutrient enrichment of coastal systems as bad," Oczkowski said. "Here in Rhode Island we've spent hundreds of millions of dollars to upgrade sewage plants to reduce nutrient loading into Narragansett Bay. And it's a major issue in the Chesapeake Bay and in the Gulf of Mexico, where run-off of fertilisers from the country's breadbasket into the Mississippi River has caused a dead zone in the Gulf.
"But the Egyptians don't think it's a bad thing. For them, it's producing tons of fish and feeding millions of hungry people. It's forcing us to reconsider whether we can say that nutrient inputs are always a bad thing."
Fighting Schistosomiasis
Scientists are looking to outer space for help in their attempt to prevent new outbreaks of the tropical disease schistosomiasis in southern China
Once the Three Gorges Dam is fully operational, researchers plan to use satellite data from space to determine whether changing water conditions in Poyang Lake, China's largest freshwater lake, create favourable conditions for the snails associated with the chronic disease that can damage internal organs and impair growth and cognitive development in children.
Adult and juvenile snails living in stagnant tropical freshwater lakes and ponds serve as hosts during part of the life cycle of schistosomes, the family of parasite species that cause schistosomiasis infections in warm climates around the world.
The scientists hope to combine data on changing water levels with biological information about the snails' behaviour. This should help inform public health officials on ways to reduce schistosomiasis infection in the Poyang Lake region between the Three Gorges Dam and Shanghai.
"Really, the only prevention is to not touch the water," said Motomu Ibaraki, an associate professor of earth sciences at Ohio State University and the leader of the research project. "What we hope we can do is point to the most dangerous areas for schistosomiasis transmission based on predictions we can calculate about the snail habitat."
Ibaraki described the research at the American Geophysical Union annual meeting in San Francisco. The project represents an emerging field, combining the expertise of specialists in hydrology and infectious diseases to tackle public health problems, he said.
Schistosomiasis is the second-most prevalent tropical disease after malaria, affecting 200 million people worldwide, according to the National Institutes of Health. People are infected through contact with water contaminated with the parasite. The parasite burrows into human skin within seconds, eventually matures to adulthood and settles in various areas of the body.
Over time, the infection can lead to a variety of health complications, such as bladder cancer, kidney and liver damage, and blood infections. No vaccine is available to prevent the illness, and medications to treat it generally are not effective at breaking the disease cycle, especially in poor, developing areas of the world.
After infecting humans, the adult worms lay eggs, which are released into water sources through human waste, perpetuating the cycle of contamination. Tiny worms hatch from the eggs in the water, and use snails as an intermediate host until they're large enough to float freely in the water.
The researchers travelled to the Poyang Lake region during the last two years to collect field data that they fed into a geographic information system documenting water levels, vegetation characteristics and air temperatures that, when combined, identify areas favourable for the host snails to thrive.
For future measurements, all Poyang Lake water level data will come from the European Space Agency's ENVISAT satellite, which measures the water level of the lake every 35 days. The radar readings have been calibrated to compare to baseline levels recorded in the field data.
The satellite work is led by C.K. Shum, a professor of earth sciences at Ohio State who specializes in the use of radar altimetry to measure water levels by satellite. The measurements are made by bouncing radio signals off of surfaces and measuring how long the signals take to return.
Others on the research team led by Daniel Janies, associate professor of biomedical informatics, will conduct DNA analyses of the snail species involved to better understand their behaviour, their origin and their preferred habitat.
Trying to kill the snails with molluscicides has been considered, but isn't practical in a body of water the size of Poyang Lake, Ibaraki said. The lake's surface area ranges from about 386 square miles during dry seasons to more than four times that -- 1,700 square miles -- during rainy periods. Adult snails number in the billions, and are about the size of a pinky fingertip.
Water levels and vegetation in Poyang Lake are expected to change after the Three Gorges Dam project is completed upstream, but whether these changes will create better or worse conditions for the snails remains unknown, Ibaraki said. The Three Gorges Dam on the Yangtze River is the largest hydro-electric project in the world, intended to combine the generation of clean power with downstream flood control, and enable shipping in China's interior.
Those most in danger of schistosomiasis infection in the Poyang Lake region tend to be fishermen, Ibaraki said. The lake is a major source for the fish industry in the area, which is rural and very poor. In addition, a high infection rate of schistosomiasis is reported in the region.
"There are huge signs there that tell people not to go into the lake. People know about the dangers of infection, but they have to touch the water to some extent. It's part of their lifestyle," Ibaraki said.
The researchers plan to share the maps and numerical analyses of snail habitat trends with public health officials in China. They also hope to eventually apply the data-fusion techniques to other areas of the world affected by schistosomiasis. The disease is also a public health problem in southern and sub-Saharan Africa, parts of South America, several Caribbean counties, and portions of the Middle East and Southeast Asia.
Schistosomiasis
Schistosomiasis, or bilharzia, is a parasitic disease caused by trematode flatworms of the genus Schistosoma. Larval forms of the parasites, which are released by freshwater snails, penetrate the skin of people in the water.
In the body, the larvae develop into adult schistosomes, which live in the blood vessels. The females release eggs, some of which are passed out of the body in the urine or faeces. Others are trapped in body tissues, causing an immune reaction.
In urinary schistosomiasis, there is progressive damage to the bladder, urethras and kidneys. In intestinal schistosomiasis, there is progressive enlargement of the liver and spleen, intestinal damage, and hypertension of the abdominal blood vessels.
Control of schistosomiasis is based on drug treatment, snail control, improved sanitation and health education.
–WHO
Once the Three Gorges Dam is fully operational, researchers plan to use satellite data from space to determine whether changing water conditions in Poyang Lake, China's largest freshwater lake, create favourable conditions for the snails associated with the chronic disease that can damage internal organs and impair growth and cognitive development in children.
Adult and juvenile snails living in stagnant tropical freshwater lakes and ponds serve as hosts during part of the life cycle of schistosomes, the family of parasite species that cause schistosomiasis infections in warm climates around the world.
The scientists hope to combine data on changing water levels with biological information about the snails' behaviour. This should help inform public health officials on ways to reduce schistosomiasis infection in the Poyang Lake region between the Three Gorges Dam and Shanghai.
"Really, the only prevention is to not touch the water," said Motomu Ibaraki, an associate professor of earth sciences at Ohio State University and the leader of the research project. "What we hope we can do is point to the most dangerous areas for schistosomiasis transmission based on predictions we can calculate about the snail habitat."
Ibaraki described the research at the American Geophysical Union annual meeting in San Francisco. The project represents an emerging field, combining the expertise of specialists in hydrology and infectious diseases to tackle public health problems, he said.
Schistosomiasis is the second-most prevalent tropical disease after malaria, affecting 200 million people worldwide, according to the National Institutes of Health. People are infected through contact with water contaminated with the parasite. The parasite burrows into human skin within seconds, eventually matures to adulthood and settles in various areas of the body.
Over time, the infection can lead to a variety of health complications, such as bladder cancer, kidney and liver damage, and blood infections. No vaccine is available to prevent the illness, and medications to treat it generally are not effective at breaking the disease cycle, especially in poor, developing areas of the world.
After infecting humans, the adult worms lay eggs, which are released into water sources through human waste, perpetuating the cycle of contamination. Tiny worms hatch from the eggs in the water, and use snails as an intermediate host until they're large enough to float freely in the water.
The researchers travelled to the Poyang Lake region during the last two years to collect field data that they fed into a geographic information system documenting water levels, vegetation characteristics and air temperatures that, when combined, identify areas favourable for the host snails to thrive.
For future measurements, all Poyang Lake water level data will come from the European Space Agency's ENVISAT satellite, which measures the water level of the lake every 35 days. The radar readings have been calibrated to compare to baseline levels recorded in the field data.
The satellite work is led by C.K. Shum, a professor of earth sciences at Ohio State who specializes in the use of radar altimetry to measure water levels by satellite. The measurements are made by bouncing radio signals off of surfaces and measuring how long the signals take to return.
Others on the research team led by Daniel Janies, associate professor of biomedical informatics, will conduct DNA analyses of the snail species involved to better understand their behaviour, their origin and their preferred habitat.
Trying to kill the snails with molluscicides has been considered, but isn't practical in a body of water the size of Poyang Lake, Ibaraki said. The lake's surface area ranges from about 386 square miles during dry seasons to more than four times that -- 1,700 square miles -- during rainy periods. Adult snails number in the billions, and are about the size of a pinky fingertip.
Water levels and vegetation in Poyang Lake are expected to change after the Three Gorges Dam project is completed upstream, but whether these changes will create better or worse conditions for the snails remains unknown, Ibaraki said. The Three Gorges Dam on the Yangtze River is the largest hydro-electric project in the world, intended to combine the generation of clean power with downstream flood control, and enable shipping in China's interior.
Those most in danger of schistosomiasis infection in the Poyang Lake region tend to be fishermen, Ibaraki said. The lake is a major source for the fish industry in the area, which is rural and very poor. In addition, a high infection rate of schistosomiasis is reported in the region.
"There are huge signs there that tell people not to go into the lake. People know about the dangers of infection, but they have to touch the water to some extent. It's part of their lifestyle," Ibaraki said.
The researchers plan to share the maps and numerical analyses of snail habitat trends with public health officials in China. They also hope to eventually apply the data-fusion techniques to other areas of the world affected by schistosomiasis. The disease is also a public health problem in southern and sub-Saharan Africa, parts of South America, several Caribbean counties, and portions of the Middle East and Southeast Asia.
Schistosomiasis
Schistosomiasis, or bilharzia, is a parasitic disease caused by trematode flatworms of the genus Schistosoma. Larval forms of the parasites, which are released by freshwater snails, penetrate the skin of people in the water.
In the body, the larvae develop into adult schistosomes, which live in the blood vessels. The females release eggs, some of which are passed out of the body in the urine or faeces. Others are trapped in body tissues, causing an immune reaction.
In urinary schistosomiasis, there is progressive damage to the bladder, urethras and kidneys. In intestinal schistosomiasis, there is progressive enlargement of the liver and spleen, intestinal damage, and hypertension of the abdominal blood vessels.
Control of schistosomiasis is based on drug treatment, snail control, improved sanitation and health education.
–WHO
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