What are Groundwater Contaminants & How to Reduce Them

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Water.

It’s probably one of the simplest things in our day-to-day lives. Yet it is also one of the most important. The human body is nearly 70% water and without it, we wouldn’t last very long. Of all the water on Earth, only about 3% is drinkable fresh water, and of that only about 1.2% is accessible for human consumption.

Some of the accessible water that we depend upon for survival is groundwater. This is water stored in natural pools underground called aquifers. Nearly 50% of the population of the United States gets their drinking water from a groundwater aquifer.

Given this, ensuring that the groundwater we have available remains clean and free of contaminants is a top priority. However, it can be much harder to detect and clean than many of us realize. Addressing groundwater contamination and working towards reducing it is one of the most important aspects of preserving our ability to survive on this planet.

Understanding Groundwater

Where does our groundwater come from? It might seem like a relatively simple question, but the groundwater supply that we currently enjoy comes from thousands of years of natural processes. In essence, groundwater accumulates as water slowly makes its way through the soil, and it only stops when it reaches a solid material that it cannot pass through. As more and more water accumulates and is pooled up by the impassible layer, aquifers form.

There are several professionals that study different facets of this process. They range from hydrologists who specifically study the movement of water in a given system to geologists who study different components of rocks. Someone who specifically specializes in groundwater collection and management might be considered a hydrogeologist because they study the interplay between water and rocks (along with the many other materials water passes through).

There is a lot that goes into being a successful hydrogeologist. Professionals may work towards solving difficult problems such as:

●     Can the aquifer support more development and housing in a certain area?

●     Will we lose surface water if certain changes are made?

●     Is waste water mixing with drinking water?

●     What chemicals are currently in the water? Do they come from natural sources or are they from an anthropogenic source?

●     How much water reclamation can be expected in the aquifer in a given year? What about during a prolonged drought?

Groundwater Contaminants

Water quality can have a direct impact on our health and well-being. Contamination of an aquifer can spell disaster for the communities that depend upon it. This is especially true if the water becomes contaminated to the point that it cannot be used for even municipal purposes without negative consequences.

Sometimes natural aspects of the landscape and the geology of the aquifer can determine if a groundwater source is at risk of contamination. As water passes along rocks it can cause erosion and leach chemicals into the water. Some examples of chemicals that are often found in groundwater sources include sulfates, iron, chlorides, fluoride and arsenic.

Non-natural sources of groundwater pollution are of the most significant concern when it comes to our groundwater. These contaminants are often leached into the soil and carried toward the aquifer as water makes its way down. Some of the major sources of groundwater pollution include things such as:

●     Road salts and de-icer

●     Greases, oils, and other substances collected in parking lots and other paved surfaces

●     Leaking fuel (and other chemical) storage and spills

●     Mine tailing piles

●     Agricultural fertilizers, herbicides, and pesticides

●     Landfills

●     Septic systems

●     Pipelines

●     Uncontrolled hazardous waste

Many of the chemicals associated with these sources cause significant health problems if/when they make it into the aquifer and pollute drinking water.

Working to Improve Water Quality

Fortunately, there is quite a bit we can all do both personally and as a business to reduce the amount of groundwater contamination that is happening. Perhaps one of the biggest things that can be done is to check for leaking pipes. Leaks in septic systems, pipelines, or storage tanks around the house can be fixed and can make a big difference.

Additional things that we can do to reduce groundwater pollution include things like taking steps to reduce the number of chemicals that we use — whether that means allowing for some dandelions in the yard (which is great for pollinators!) or using more natural cleaning products. Likewise, all of the chemicals that are used should be disposed of properly. Many of the things we can do at home are also things we can advocate for in our communities, which will ultimately make the largest local difference.  

Contributed by Indiana Lee: Indiana Lee is a  journalist from the Pacific Northwest with a passion for covering workplace issues, environmental protection, social justice, and more. when she is not writing you can find her deep in the mountains with her two dogs. follow her work on contently, or reach her at [email protected]

The Importance of "Dirty" Rivers

Complex river systems are the foundation of much of what we have to enjoy here on this planet. They support wildlife populations, provide soil nutrients, and so much more. Humans have had a profound impact on river systems, however, changes in current practices and increased focus on restoring rivers to their natural status can make a major difference in our lives. 

Image Source: pixabay.com

 

Think of your local river. The place you take a walk when you’re looking for solitude or comfort in nature. The place you take your children fishing. Or perhaps where you go when you’re looking for relief from the brutal summer heat.

Chances are, that the river that you love for all the nature it brings into your life really isn’t all that natural. In fact, the majority of the river systems in our world today have been significantly altered by humans whether we recognize the changes we have made throughout history or not. A vast number of our river systems have been greatly simplified — they aren’t as messy or complex as they really should be.

Though in many ways these changes have produced some benefit for people at some point in time, they are catching up with us. Simplified rivers are not as resilient and the ecological damage we have inadvertently caused could come back to haunt us within our lifetimes. Small changes in our habits and priorities could lead to greater changes that will benefit our river ecology and could just save us all.

Complex Rivers

When we think of a complex, natural, healthy river, we are really talking about one of the greatest natural feats of engineering available in the world. These rivers have ebbs and flows that the foundations of the surrounding ecosystems are built around. They have variability in pitch and depth that creates homes for numerous species that our society depends upon. 

These complex rivers collect and move sediment across a landscape. For instance, seasonal flooding refreshes the floodplains with minerals and nutrients brought down by the river from mountain erosion and decomposing substances. This influx of sediment is critical for the long-term growth and survival of native vegetation and forms the basis of the food chain that all animals are part of.

Finally, a complex river is one that is resilient. It — and the surrounding habitats it supports — are able to recover from unexpected natural events and thrive after a short period. Many experts believe that healthy rivers and surrounding ecosystems are absolutely critical to our ability to deal with climate change. Basically, the more healthy, intact natural areas we have, the better our chances are in the long-run.

Human Impacts

Once humans entered the equation things began to change. Typically that which benefited us in the short-term negatively impacted the entire ecosystem (including future generations of humans) in the long-term. For instance, dams and overfishing have powered many of our cities and made many people rich selling food, but they have altered the geomorphology of streams, ruined quality habitat, and caused populations we could be sustainably harvesting today to crash.

Many dams built back in the day are reaching a point where they are requiring more and more maintenance to keep up. Many of them are a collecting point for sediment, which hinders the sediment renewal cycle in floodplains downstream and leads to decreases in soil and vegetation health. Furthermore, the sediment causes wear and tear on the dams and must be monitored regularly.

It may come as a shock with all of the environmental regulations that have been put in place since the 1960s, but one study conducted in 2013 found that nearly half of America’s rivers were still too polluted to be healthy for people, let alone the ecosystems they originally supported. The current administration has worked diligently to roll back numerous environmental regulations, so it can only be assumed that these rivers and possibly more will remain too polluted.

Polluted and unhealthy rivers also pose a more direct impact on our health. For example, different forms of human-caused pollution in rivers can lead to the growth of different bacterias that can make people seriously ill. It is one of many ways that diseases of the future could evolve to pandemic level proportions.

Contributed by Indiana Lee: Indiana Lee is a  journalist from the Pacific Northwest with a passion for covering workplace issues, environmental protection, social justice, and more. When she is not writing you can find her deep in the mountains with her two dogs. Follow her work on Contently, or reach her at [email protected]

Guest Blog: How Speleothems Are Used To Determine Past Climates?

About author: Alex Graham is an undergraduate student at University of Newcastle, Australia. He is interested in Geology as a whole but his major interests include fluvial processes, karst systems and ocean science. During his visit to New Zealand, he has obeserved the glow worms in Waitomo Caves and spelunking in Nikau Caves.

Speleothems, more commonly known as stalactites or stalagmites, consist of calcium carbonate (calcite or aragonite) crystals of various dimensions, ranging from just a few micrometers to several centimetres in length, which generally have their growth axis perpendicular to the growth surface. Speleothems are formed through the deposition of calcium carbonate minerals in karst systems, providing archives of information on past climates, vegetation types and hydrology, particularly groundwater and precipitation. However, they can also provide information on anthropogenic impacts, landscape evolution, volcanism and tectonic evolution in mineral deposits formed in cave systems.

Stalagmite Formation

Rainfall containing carbonic acid weathers the rock unit (generally either limestone or dolomite) and seeps into the cracks, forming caverns and karst systems. The groundwater, percolating through such cracks and caverns, also contains dissolved calcium bicarbonate. The dripping action of these groundwater droplets is the driving force behind the deposition of speleothems in caves.

Core drilling of an active stalagmite in Hang Chuot cave.

Speleothems are mainly studied as paleoclimate indicators, providing clues to past precipitation, temperature and vegetation changes over the past »500,000 years. Radioisotopic dating of speleothems is the primary method used by researchers to find annual variations in temperature. Carbon isotopes (d^13C) reflect C3/C4 plant compositions and plant productivity, where increased plant productivity may indicate greater amounts of rainfall and carbon dioxide absorption. Thus, a larger carbon absorption can be reflective of a greater atmospheric concentration of greenhouse gases. On the other hand, oxygen isotopes (d^8O) provide researchers with past rainfall temperatures and quantified levels of precipitation, both of which are used to determine the nature of past climates.

Stalactite and stalagmite growth rates also indicate the climatic variations in rainfall over time, with this variation directly influencing the growth of ring formations on speleothems. Closed ring formations are indicative of little rainfall or even drought, where-as wider spaced ring formations indicate periods of heavy rainfall or flooding. These ring formations thus enable researchers to potentially predict and model the occurrence of future climatic patterns, based off the atmospheric signals extrapolated from speleothems. Researchers also use Uranium –Thorium radioisotopic dating, to determine the age of speleothems in karst formations. Once the layers have been accurately dated, researchers record the level of variance in groundwater levels over the lifetime of the karst formation. Hydrogeologists specialise in such areas of quantitative research. As a result, speleothems are widely regarded as a crucial geological feature that provide useful information for researchers studying past climates, vegetation types and hydrology.


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