UN Calls for Wastewater Focus

In my research, I focus on toxic chemicals that cannot be removed from wastewater treatment. And a lot of studies aim to develop advanced wastewater treatment technologies to remove more toxic chemicals in order to reduce loadings of toxic chemicals to the environment, which would affect ecosystems and in turn human health.

While developed countries such as Canada and the USA have over 90% of wastewater treated, sanitation of wastewater is still a big challenge faced by many low-income countries.  The global data indicate that only 20% of global wastewater is currently being treated. Wastewater in some developing countries is barely treated before released to the environment. Low-income countries possessing only 8 per cent of the required capacity to treat wastewater effectively. Such untreated wastewater is likely to contaminate water supplies and cause diseases. A UN-Water Analytical Brief, produced by the World Health Organization (WHO), the United Nations Environment Programme (UNEP) and UN-Habitat, on behalf of UN-Water, describes the damage being done to ecosystems and biodiversity as 'dire' and warns of the threat wastewater will increasingly pose to human health, economic activity, and water security if left unaddressed.

It is obvious that sustainable wastewater management will become a key task for the world to apply in the coming years.

UN and WHO officials pointed out  "Wastewater management has been neglected in the rush to commercialize drinking water production, a situation exacerbated by a fragmented water management system in many countries, and the use of different technologies that are often designed separately and retrofitted to existing systems."

"Around 70 per cent of industrial discharge in developing countries goes untreated. And eutrophication - from wastewater and agricultural run-off - has, according to recent estimates, reduced biodiversity in rivers, lakes and wetlands by about one-third globally."

"It is time to turn this environmental and human health challenge into an opportunity. Agriculture consumes 70 per cent of global water withdrawal, but agricultural irrigation from reclaimed wastewater is on the rise, and is being used to irrigate 20 to 45 million hectares worldwide. This is just a fraction of what is possible if policy and available technologies converge to ensure that wastewater and water quality are fully integrated into a more holistic water agenda as part of the post-2015 process,"

"To be successful and sustainable, wastewater management must be an integral part of the critical levers of urban planning and legislation resulting in productive, healthy and livable cities. The upcoming UN Conference on Housing and Sustainable Urban Development, Habitat III, will be an opportunity to underscore the importance of effective wastewater management and highlight the role of wastewater in the new urban agenda."

References and read more:
www.unwater.org/publications/publications-detail/en/c/275896/
http://www.unep.org/newscentre/Default.aspx?DocumentID=2818&ArticleID=11130&l=en#sthash.KH72aIVy.dpuf

Road salt and the environment

Before and after it snows, people often spread loads of salt all over the sidewalks and roads. I know the salt makes your winter shoes worn out more quickly. How does the salt the environment then?



Salt is applied on the roads in winter because the freezing point of salty water is lower than that of pure water. So scattering salt on ice or snow can help accelerate the melting process, opening up the roads to traffic that much sooner. It is estimated that over 50 kg of salt is used annually for every resident in the North America!

"Salt" can refer to any compound consisting of the cation from a base and the anion from an acid and which is readily dissociated in water. While sodium chloride (NaCl) is by far the most frequently used road salt in Canada, other inorganic salts used in Canada include calcium chloride (CaCl2), magnesium chloride (MgCl2) and potassium chloride (KCl). Sometimes sodium ferrocyanide (Na4Fe(CN)6·10H2O) is added as an anti-caking agent.
After it dissolves—and is split into sodium and chloride ions—it gets carried away via runoff and deposited into both surface water (streams, lakes and rivers) and the groundwater under our feet.

The biggest concern with road salt is how it affects water quality when the snow and ice melts, the salt is washed away into lakes and streams or seeped into groundwater supplies. ~70 % of the salt applied to roads stays within the region's watershed. Once it gets there, the chemicals is difficult and expensive to remove.  The salt from the roads can cause salty groundwater. That's a health issue for people on restricted-sodium diets and a taste problem for everyone else. When salt migrates into lakes and streams, it can harm aquatic plants and animals. A heavy influx of sodium and chloride ions will disrupt the ability of freshwater organisms to regulate how fluid passes in and out of their bodies. An estimated 40 percent of the country's urban streams have chloride levels that exceed safe guidelines for aquatic life, largely because of road salt. Changes in the salinity of a pond or lake can also affect the way the water mixes as the seasons change, leading to the formation of salty pockets near the bottom and biological dead zones. Salt applied on roads can also erode the soil, and damage trees and vegetation .

With urbanization and increasing number of roads, he mounting piles of salt dumped on the road may be getting to be a bigger problem than ever. In 2004, Canada categorized road salt as a toxin and placed new guidelines on its use.

While salt can cause such problems, we still have to rely on it because it's cheap and applying it on icy road can reduce risks such as traffic accident. Although there are alternative chemicals available but the alternatives are much more expensive and the alternatives may still cause environmental problems once largely used because toxicology tells us every chemical is toxic; the dose plays a role. and they often require municipalities to invest in new spreading equipment. So far, there are no better solutions to get ice off the roads—except, perhaps, the shovel.

As we still have to rely on salt to de-ice the road, more environmental friendly way we can do include (1) cutting back salt usage by pre-wetting the salt,  which allows for more controlled application and better sticking power.  (2) Applying salt just before a storm hits, so that the snow can't adhere to the ground (this relies on accurate weather forecast!) (3) Apply salt only when the pavement temperature is below freezing but above -21 degreeC because sodium chloride doesn't work below that temperature.

References and more information, check
http://www.ec.gc.ca/sels-salts/
http://www.hc-sc.gc.ca/ewh-semt/alt_formats/hecs-sesc/pdf/pubs/contaminants/psl2-lsp2/road_salt_sels_voirie/road_salt_sels_voirie-eng.pdf
http://www.smithsonianmag.com/science-nature/what-happens-to-all-the-salt-we-dump-on-the-roads-180948079/?no-ist
http://www.slate.com/articles/health_and_science/the_green_lantern/2010/02/salting_the_earth.html

Flame retardant-polybrominated diphenyl ethers

Polybrominated diphenyl ethers or PBDEs, are used as flame retardant in a wide array of products, including building materials, electronics, furnishings, motor vehicles, airplanes, plastics, polyurethane foams, and textiles. They are structurally akin to the PCBs and other polyhalogenated compounds, consisting of two halogenated aromatic rings.

PBDEs bioaccumulate in blood, breast milk, and fat tissues. Bioaccumulation is of particular concern in such instances, especially for personnel in recycling and repair plants of PBDE-containing products.

photo source: http://www.greenpeace.org/international/en/campaigns/detox/electronics/


People are also exposed to these chemicals in their domestic environment because of their prevalence in common household items.  PBDEs have been found in common foods such as salmon, ground beef, butter, and cheese and also in indoor dust, sewage sludge, and effluents from wastewater treatment plants.

There is also growing concern that PBDEs share the environmental long life and bioaccumulation properties of polychlorinated dibenzodioxins. With levels found in households, PBDEs could reduce fertility in humans. Because of their toxicity and persistence, the industrial production of some PBDEs is restricted under the Stockholm Convention, a treaty to control and phase out major persistent organic pollutants (POPs).

Despite of the regulations,  there is still huge amount of PBDEs in products in use.
A recent study has estimated 60% of the stock of PBDEs (most Deca-Mixture) in 2014 will remain in the use phase in 2020. Such estimation considers only the first use (no reuse and/or storage) of PBDE-containing products. Additional PBDEs will be in the use phase in the future via reuse of PBDE containing material.

For more information in PBDE stock and emissions, read this article recently published in Environmental Science & Technology