Discussion

            Many human activities and structures affect biodiversity within countless ecosystems. Creation of man made dams fragment ecosystems by limiting amounts of water, nutrients and migration patterns. Acts carried out by men like dredging rivers reverses natural movements and dispersal. Sculpting our landscape to better suite conditions productive for farming and ideal stormwater runoff create unnatural flows of water, which can create unbalanced amounts of sediment and nutrients, good or bad.  

            So what happens when a location is so poorly contaminated that it must be abandoned? The EPA has named a government program, Superfund sites, dedicated to identifying, categorizing and requiring long-term clean up of abandoned hazardous waste sites all over America.  (Basic Information, n.d.) A popular Superfund Site that continues to make its way into article topics and documentary films is the Tar Creek Superfund Site. Tar Creek Superfund Site was greatly minded in the 1900s-1980s and its soil, water and air have become contaminated with zinc, lead, and cadmium. (Hays, 2007) The Tar Creek Superfund Site is hard to sample because the people that inhabited the area dispersed at a high rate, but even with that said, studies have shown that 62.5% of children > the age of 6 years old that were exposed to the contaminated site had elevated lead blood levels of 10 μg/dl. (Neuberger, 2009) Even with a majority of the population that once called this section of Oklahoma home dispersed, there are still large amounts of animals inhabiting this toxic land.  Red-Eared Slider Turtles were studied from Beaver Creek from within Tar Creek and from Lake Carl Blackwell and Sequoyah National Wildlife Refuge, which showed a difference in size amongst females but there was no significant difference in comparison to survival and recapture. (Hays, 2010) Every species is affected differently by different contaminants.

            Many aquatic organisms are subject to bioaccumulation in respect to contaminated sediment. A study has shown that low amounts of sediment volume or TOCs (total organic carbon) have adverse affects on high organism density in large invertebrate species like the mayfly nymph Hexagenia spp. and the need to standardization of TOC levels is necessary. (Van Geest, 2011) Bioaccumulation contaminants varies in many different species but the use of  fourier transform ion cyclotron resonance mass spectrometry can identify the levels on specific contaminants in tissue. (Myers, 2014)

            Changes in temperature and the existence of pollution, due to climate change, can greatly effect bioaccumulation levels in the Great Lakes. (NG, 2011) Many fish species acquire high levels of metals through exposure to polluted environments. Bioaccumulation is easily spread to humans through the ingestion of polluted fish species. Water and sediment health is essential to every living organism on planet Earth. Even species of birds that lay eggs resting on the ground are susceptible to sediment contamination. Studies have shown an increase in mortalities and birth defects in Daphnia longispina species hatchlings that came from eggs laying on contaminated sediment. (Möst, 2015) Studies in wetlands in Hong Kong have shown a linear relationship in OCP contamination levels from contaminated sediment between the prey fish and the eggs of water birds, which has proven to be highly noninvasive method of determining contamination when it comes to endangered bird species. (Kwok, 2013)

            So what can be done to mitigate or reverse contaminated sediment? Sediment contaminated with heavy metals, like Cu, can be put into a pressure washed bath at 10 atm with chelating liquids for 60 minutes to decrease amounts of the heavy metal by 70%. (Lin, 2014) Just like in humans, chelation methods can take many sessions to eliminate heavy metals and can be detrimental to the subjects because of the chelation toxicity. So the question is posed, is it better to stop contamination from point source and nonpoint source pollution or develop ways to reverse contaminated material? Implementing both styles are necessary to stop and reverse already existing contaminated sediment and water. Even though the research done by Lin can reduce heavy metals with chelating agents, this process is not available or realistic on a large scale in which our planet needs it. Government and private companies simply do not have the time, money or resources to put this method into affect on a large scale. But these organizations to have the choice to do the right thing.

            A more current and local issue on the topic is the annual dredging of the Cuyahoga River in Cleveland, Ohio.  Many events in history have brought bad press to Cleveland, Lake Erie and the Cuyahoga River but there has also been a lot of research and conservation issues put in place as a result. Even with that said, annual dredging has been an activity in the Great Lakes for decades. More that 10 million cubic feet of dredges sediment are relocated every year in the Great Lakes. (Seelye, 1982) Even though open lake dumping of sediment is the most cost efficient option, viability and sediment selectivity tests have been run in cities occupying the coasts of the Great Lakes and a high mortality rate of amphipods has occurred. (Gannon, 1971) In regards to the disposal of the dredged material removed from the Cuyahoga River, the EPA has once again stated that open lake dumping qualifies as a public hazard and in 2015 the dredged material will not be openly dumped back into Lake Erie. (Board, n.d.)
            So what can be done to help promote healthy nutrient rich sediment? Increasing nutrient levels can be difficult because it is extremely hard to correctly control water fluctuation. Studies have shown that the existence of wetlands in coastal areas around the Great Lakes have the ability to mitigate pollution, even though coastal wetlands and water levels of the Great Lakes are diminishing. (Krieger n.d.)

            The key is to continue to educate the public on such topics and find ways for them to relate to these issues. Contaminated sediment, water and air is a global problem and is undoubtedly in your local communities. The public must have pride for the places they experience and call home.  Promotion of wetland construction, restoration, and conservation is a sustainable way to promote mitigation of harmful contaminants. Fighting to have laws put in place to monitor industrial and manufacturing discharge and wastewater runoff are key. We must find a balance between limiting our discharge of pollution and taking the necessary steps to control and decrease the amount of already existing pollution on our planet.