via Allison Cekala
U.S. rivers are getting saltier, potentially compromising drinking water
By Roni Dengler
The bomb cyclone that hit the northeastern United States last week left roadways and vehicles caked in a white film of road salt and grime. Those salts might be washing into the region’s fresh waterways, a new study reveals. A 50-year-long analysis of hundreds of U.S. Geological Survey monitoring sites finds salts in freshwater rivers and streams are rising across much of the nation. That could mean compromised drinking water akin to the crisis that struck Flint, Michigan, in 2014 when the city switched its water source to the highly salted Flint River. But road salts and deicers, mostly made of the same stuff as table salt, are not the only culprits. Researchers discovered additional salt ions—potassium, magnesium, and calcium, among others—are also increasing in the country’s freshwater rivers. Water pH increased at 66% of sites, meaning many waterways are becoming more alkaline. Those changes varied by region. For example, in midwestern agricultural areas, potassium levels rose fastest, likely from fertilizer runoff, whereas salt numbers swelled most rapidly in the densely populated and humid Northeast. Such changes were largely missing in the arid West. Taken together, the “freshwater salinization syndrome” researchers describe today in the Proceedings of the National Academy of Sciences could be an issue for people with high blood pressure that require a low-sodium diet and patients who need kidney dialysis. And salt can make water more corrosive, which tends to leach more lead from pipes, as happened in Flint. The researchers say strategies such as replacing old water pipes, updating salt-spreading equipment, and using brine instead of granulated salts on roadways could help alleviate the problem.
from Scientific American
Freshwater Is Getting Saltier, Threatening People and Wildlife
Road de-icing, industrial activity and other culprits are pushing salt levels in rivers and streams to alarming levels
By Tim Vernimmen
Credit: Getty Images
Salts that de-ice roads, parking lots and sidewalks keep people safe in winter. But new research shows they are contributing to a sharp and widely rising problem across the U.S. At least a third of the rivers and streams in the country have gotten saltier in the past 25 years. And by 2100, more than half of them may contain at least 50 percent more salt than they used to. Increasing salinity will not just affect freshwater plants and animals but human lives as well—notably, by affecting drinking water.
Sujay Kaushal, a biogeochemist at the University of Maryland, College Park, recounts an experience he had when visiting relatives in New Jersey. When getting a drink from the tap, “I saw a white film on the glass.” After trying to scrub it off, he found, “it turned out to be a thin layer of salt crusting the glass”
When Kaushal, who studies how salt invades freshwater sources, sampled the local water supply he found not just an elevated level of the sodium chloride, widely used in winter to de-ice outdoor surfaces, but plenty of other salts such as sodium bicarbonate and magnesium chloride. He also found similar concentrations of these chemicals in most rivers along the east coast, including the Potomac, which provides drinking water for Washington, D.C. Where did all of it come from?
De-icing salts, Kaushal determined, are part of the problem, slowly corroding our infrastructure. Estimates put the cost of repairs at about $1,000 per ton of de-icing salt imposed on the environment. But he also found a link to acid rain, caused by the air pollution from burning fossil fuels in power plants and cars. “Decades of acid rain have dissolved not just portions of rock and soils but buildings and roads as well—all of which have added various salts to the water,” he says. Although the acidity of the rain is decreasing, it is still present. Meantime the amount of concrete and asphalt in the world have continued to expand.
Salts can free up other pollutants, too In his own house near Washington, D.C., Kaushal once had black water coming from the tap. “The salts in the water were leaching manganese—a neurotoxin—from the old pipes in the neighborhood,” he says.
A similar issue recently arose in Flint, Mich., where the decision to start drawing drinking water from a saltier local river mobilized lead from pipes into the water supply. Nationwide, salts are crusting the insides of home boilers and the cooling tanks of power plants. They are also coating the land where crops grow. And they are stressing plants and animals in freshwater ecosystems, in some cases until they disappear.
Land Use Is a Primary Culprit
In January 2018 Kaushal and his colleagues published the nationwide study that showed at least a third of U.S. streams and rivers have gotten saltier over 25 years. On December 3 a modeling analysis by freshwater scientist John Olson at California State University, Monterey Bay, confirmed these findings, which indicated the future looks briny, as well.
If salt use continues at the current rate, Olson’s group showed, salinization levels would likely rise at least 50 percent in half of U.S. streams by 2100. This could be a problem for drinking water, and it also would double the number of streams that are too salty for irrigation—from 3 to 6 percent. Effects of climate change were included in the study.
Of course Olson is concerned with salt’s effects on people. But he is also worried about ecosystems. One experiment in which he tracked the survival and growth of a dozen freshwater species in two Nevada streams of different salinity levels taught him some animals are very sensitive to the levels. “Because their body tissues have a higher salt concentration than the water around them, freshwater animals are adapted to pump out the water that keeps rushing in while trying to hold on to the salts,” Olson notes. But when the salt levels suddenly go up, the animals may get an overdose, adds entomologist John Jackson, who was not involved in Olson’s study.
Ancient Egyptians discovered Algol's variability 3,000 years before western astronomers
by De Gruyter
Credit: CC0 Public Domain
An ancient Egyptian papyrus, known as the Cairo Calendar, could be the oldest historical record of a star's brightness, providing a new perspective on the development of the Algol triple star system over thousands of years.
Known as the Calendar of Lucky and Unlucky Days, the Cairo Calendar, dated from 1244 – 1163 BC, assigns predictions and prognoses to every day of the Egyptian year. These prognoses indicate whether the day, or part of the day, is considered "good" or "bad" The calendar also contains information regarding the day's astronomical observations, such as the behaviour of astronomical objects, especially Algol.
Now researchers say that the astronomical symbolism discovered in the two most Ancient Egyptian myths suggest similar clues could be found in other ancient Egyptian texts.
The article, "Algol as Horus in the Cairo Calendar: the possible means and the motives of the observations," by Sebastian Porceddu, Lauri Jetsu, Tapio Markkanen, Joonas Lyytinen, Perttu Kajatkari, Jyri Lehtinen, and Jaana Toivari-Viitala published in De Gruyter's journal Open Astronomy, looks at how the legends of the Egyptian deities Horus and Set were used in the calendar. The deities describe the behavior of astronomical objects, specifically, the naked eye observations of the variable three-star system Algol.
However, next to nothing is known about who recorded Algol's period into the Cairo Calendar, nor how. The authors show how the ancient Egyptian scribes present celestial phenomena as the activity of gods, which reveals why Algol received the title of Horus.
The study presents ten arguments which show that the ancient Egyptian scribes, known as the "hour-watchers" had the possible means and motives to record the period of Algol in the Cairo Calendar.
"The discovery of Algol's variability would have to be dated to thousands of years earlier than has been previously known. The star would have been a part of ancient Egyptian mythology as a form of the god Horus," said study author Sebastian Porceddu from the University of Helsinki.
Some smart ideas to make toilets fit for purpose in Africa’s cities
Authors: Mooyoung Han, Shervin Hashemi
(Disclosure statement: Mooyoung Han receives funding from Korea Research Foundation. He is affiliated with Water and Sanitation Appropriate Technology(WASAT) center at Seoul National University. Shervin Hashemi is affiliated with Department of Civil and Environmental Engineering, Seoul National University.)
Every flush by a typical toilet sends about 6 to 16 litres of fresh water to wastewater treatment centres. lchumpitaz/Shutterstock
About 23% of people living in Sub-Saharan Africa don’t have access to toilets while 31% with toilets use one’s that aren’t connected to a formal sanitation system. This means that more than half the people in sub-Saharan Africa live without proper sanitation – that’s about 570 million people.
One of the problems is that existing toilets aren’t a good fit for parts of sub-Saharan Africa because many areas lack water and there are often no proper plumbing or facilities to treat wastewater.
But there are solutions – toilets that are designed differently. We have come up with some innovative designs overcome the two biggest challenges – excessive use of water, and the fact that urine and faeces aren’t considered as resources.
The designs we suggest have a number of key features. Primarily, they use no water and store and treat urine and faeces separately. They include innovative technologies that reduce water and energy consumption – both vital steps if we’re going to start building smarter, greener cities.
Problems with current designs
Every flush by a typical toilet sends about six to 16 litres of fresh water to wastewater treatment centres. That’s a lot of water. The average total water consumption per person in Africa is about 20 litres a day.
On top of this, the treatment of waste uses up a huge amount of energy – about three to 15 kWh. This energy is being used to provide fresh water from different sources – like dams – for the flushing process and to treat the produced wastewater. It’s a huge amount of energy given the fact that we need only about 2kWh to charge a smart phone over a whole year.
The process of treating wastewater, so that it can be recycled and reused, is expensive because urine and faeces are mixed at the source. This makes treatment lengthy, expensive and power intensive. It’s also bad because there are valuable elements in human waste – like nitrogen and phosphorous – that aren’t being extracted and reused.
The cost of a more innovative toilet system can be higher than others – like pit latrines – but it really depends on the raw construction materials like concrete and wood. Tanks and other parts can also be made through locally available materials – like jerrycans. But once it’s built, the operation and maintenance process is easy and can be done by local labours.
Separate waste: Our main idea, when it comes to improving toilets, is to view urine and faeces as a resource instead of waste. Nutrients from human waste – which can be used as a fertiliser to grow crops – can be removed during the treatment process through better management and technology.
To take advantage of this, the urine must be separated from the faeces. There are many toilets around the world that already do this. In some Asian countries, like Korea, Japan and Vietnam, it’s a traditional mechanism.
These toilets look similar to normal ones but there are two different inlets that store the waste in different tanks. Here they can be treated to remove smell and increase their fertility.
It’s a highly efficient process which doesn’t need complicated infrastructure and reduces the time needed for the treatment of waste. The system saves a huge amount of water and energy, which is beneficial to many local governments that are already under pressure.
Waterless: For most existing toilets, water is essential for flushing and draining. But it’s possible to have a waterless toilet. Again, the toilet must collect the urine separately from the faeces. Instead of flushing, the faeces and urine are separated from the source using urine-diverting dry toilets. These toilets are available in both sitting or squatting models and take advantage of the anatomy of the human body, which excretes urine and faeces separately. The urine is kept separate and drained via a basin with a small hole near the front of the toilet bowl or squatting pan, while faeces fall through a larger drop-hole at the rear.
Enhance waste: When waste is separated and collected into tanks, microbes can be added to them which ‘nitrify’ the waste – making it a better fertiliser – and control any bad smells from the toilet.
Community support: If these toilets are used communally they can bring huge social and economic benefits for communities. While common toilet systems are expensive to maintain, and pit latrines can be public health hazards, these systems are safe and can provide an excellent source of fertiliser for groups that grow their own food, or produce food for markets.
As African cities grow and develop, and pressure on natural resources and infrastructure – like sewerage – increase, these systems offer a sustainable and more hygienic way forward.