Dense non-aqueous phase liquids, also known as DNAPLs are chemicals denser than water, which do not typically dissolve into water. These toxic chemicals seep through the soil and find ways into groundwater depending on the physical chemistry of the substance(s). When the dense non-aqueous phase liquids (DNAPLs) have entered the groundwater they will continue to flow with it as a result of the hydrological cycle. There is no absolute way of knowing where the source of the DNAPLs is located, or if any bodies of water are contaminated even after they are discovered. As a result of the constant flow of the ground water, it creates further difficulty in locating the exact source of the DNAPLs contamination, even after the source is found. Since the substance is denser than water it will sink and accumulate at the bottom of an aquifer. If the DNAPLs are in a fractured rock environment (cracks and spaces in which the DNAPLs can hide), they can reach very deep, stopping only when they touch impermeable bedrock (as seen in the Figure 1. below) (Power, Gerhard, Karaoulis, Tsourlos, & Giannopoulos, 2014). The DNAPLs are extremely difficult to remove as a result of, the limitations of research/technology that exists, the geographic location of the spills/leaks, as well as the health and environmental concerns related to their consumption. However, advancements on this issue are being looked into offering possible solutions. Figure 1. The movement of DNAPLs in groundwater. The DNAPLs as residuals and pools in fractures within bedrock, making the remediation of the DNAPLs released nearly impossible. (Power et al., 2014) The most common DNAPLs is chlorinated solvents, coal tar, creosote, heavy petroleum, polychlorinated biphenyls, and pesticides. Chlorinated solvents, are typically in dry cleaning fluids, degreasers, spot removers, and break cleaners (Ontario Ministry of Environment and climate change, 2015). These compounds move with the flow of groundwater. In large cities, drinking water is rarely tested for these contaminants. Taking this into account, groundwater makes up for approximately 30 percent of the fresh water on earth. On top of this, nearly 30 percent of the Canadian population uses groundwater as their main source of drinking water (Howard Perlman, 2016). There is not a lot of attention brought to this issue because it is not widely considered that groundwater is vulnerable to pollution. DNAPLs being dumped or leaking into the environment poses a threat to those who use it as a source for drinking water, livestock, irrigation, and aquaculture, among other uses (Society, 2016). The problems with the groundwater contamination is that it may take close to a decade for the DNAPLs to be detected considering groundwater flows very slowly. Removing the contamination from an aquifer if possible, is very expensive. Therefore, taking precautionary measures is the only method of preventing or eliminating groundwater contaminations as well as other bodies of water. When water pollution becomes a major issue, Canadian inhabitants and the ecosystems will be strongly effected by a water supply problem. This will impact the animals in the ecosystems which are settled around the body of water possibly forcing them to relocate, be killed, or adapt to the conditions. There are many places where contaminations have occurred, however have not yet been reported.
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Compounds such as polychlorinated biphenyls ([PCBs], mercury) are residual in the environment for decades. Other chemicals can become more toxic as they break down (South Georgian Bay lake Simcoe protection region, 2014). These chemicals can lead to serious health issues in humans. Since they are carcinogenic, even at low levels, they will have severe impacts on health. (Ontario Ministry of the Environment and Climate Change, 2015). There is also the fact groundwater replenishes lakes, which happens to also be from where a large portion of Canada draws its water from. Around 8 million people rely solely on the groundwater for their main source of water (Society, 2016). DNAPLS can exist in smaller lakes and wells where people draw water from, these sources are not often tested. Towns/cities which draw their main source of drinking water from groundwater are more prone to water shortages, this can be even worse if the water is polluted with toxic chemicals. Therefore, cautionary action must be taken to insure that DNAPLs do not get into any
Compounds such as polychlorinated biphenyls ([PCBs], mercury) are residual in the environment for decades. Other chemicals can become more toxic as they break down (South Georgian Bay lake Simcoe protection region, 2014). These chemicals can lead to serious health issues in humans. Since they are carcinogenic, even at low levels, they will have severe impacts on health. (Ontario Ministry of the Environment and Climate Change, 2015). There is also the fact groundwater replenishes lakes, which happens to also be from where a large portion of Canada draws its water from. Around 8 million people rely solely on the groundwater for their main source of water (Society, 2016). DNAPLS can exist in smaller lakes and wells where people draw water from, these sources are not often tested. Towns/cities which draw their main source of drinking water from groundwater are more prone to water shortages, this can be even worse if the water is polluted with toxic chemicals. Therefore, cautionary action must be taken to insure that DNAPLs do not get into any