The Hackensack River winds for forty-five miles through southeastern New York, the suburbs of New York City, and northeastern New Jersey before emptying into the Newark Bay. Its meandering, brown-tinged waters once contained a toxic brew of industrial pollutants and pesticides, and some areas are still littered with plastic bottles, bags, and other waste from the densely populated surrounding areas . At one point, it was believed to be the most polluted waterway in the United States.
However, the Hackensack River is bouncing back. Once a dead zone in which few species could survive, today it sustains marshes and estuaries vital for freshwater and marine species of plants, fish, birds, and other wildlife. Biodiversity is increasing as the levels of pollutants have decreased . Rather than a dead zone, the marshes that the river flows through, and the river itself, seem to be returning to life.
How did this once-dead river, seemingly lost cause, recover? While human mismanagement and industry were to blame for its decline, human efforts are also the cause of its ongoing recovery. The creation of Clean Water Act regulations and the efforts of conservation groups, as well as the creation of the New Jersey Meadowlands Commission (NJMC) to manage the critical wetland environments, have played a crucial role in the river’s comeback. One way the NJMC has improved the condition of the river and surrounding areas is through environmental remediation, which involves a set of strategies to remedy the damage already done by pollutants . It would be idealistic to expect to return a damaged environment to its original state anytime soon, but the current science of remediation may enable these environments to return to a functional ecosystem with indigenous species.
Environmental remediation involves the removal of pollutants or contaminants from water and soil . Pollutants and industrial waste have a number of features which make them difficult for the environment to absorb or degrade on its own. They are toxic not only to humans, but also to most wildlife, which are unable to metabolize them and return them to the ecosystem. They often have poor solubility, making them slow to dilute to less hazardous concentrations or to be removed by water . These compounds can persist in an unchanged state for extremely long periods, often taking years, centuries, or even millennia before they return to the chemical cycle. These characteristics make remediation necessary to improve the condition of a damaged area, since it means that we cannot simply “wait it out and let nature do its business.”
However, the advancement of technology and increased attention to environmental issues has produced new technologies that could have enormous implications for the future of remediation. One area that is rapidly growing in importance is bioremediation, which utilizes and enhances the natural role of plants, microbes, and other organisms in the chemical cycle to break down toxic chemicals and return them to the environment in less hazardous forms. Pesticides, herbicides, fertilizers, PCBs, oil and fuels, some plastics, and even inorganic contaminants like mercury can be broken down by soil microbes, species of which can be seeded in contaminated areas and stimulated with nutrients to accelerate decomposition and reduce remediation times . Plants naturally take up dissolved minerals and compounds from the soil and air as part of their metabolism. Some plants have developed resistance against specific toxins . These plants can be used in phytoremediation to absorb toxins from the environment and store these toxic materials in plant tissue, which is easier to remove and treat offsite than soil or groundwater. An example is the use of ferns, which can store extremely high concentrations of arsenic in their tissue when grown in soil contaminated with arsenic . Used to preserve lumber, arsenic is one of the top ground contaminants in the United States, and the use of ferns to remove arsenic is only one of many successful applications of remediation technologies currently in practice.
Another promising development in bioremediation is the use of fungi in a process called mycoremediation. Mycoremediation has exciting future implications; in one experiment, oyster mushroom mycelia were found to be over 95% efficient in breaking down PAH compounds, a major pollutant, in just four weeks, and in 2007, mycoremediation was successfully used to help clean up the San Francisco Bay oil spill . Since bioremediation does not use of chemicals or the removal of soil and water to treatment facilities, it is safer and less invasive than other strategies, minimizing disruptions to the land and wildlife. Bioremediation techniques are also often cheap and easy to implement, since they do not require costly equipment or extensive maintenance .
Other technologies are still in the experimental stage, but may one day provide cheaper, more commercially viable and efficient alternatives to current methods. The implications of nanotechnology, in particular, have garnered recent interest. Nanoscale iron particles have been shown to treat ground contamination by PCBs and chlorinated pesticides. Easily transported through water, nanoscale iron particles can remain in one area for a long period of time, removing PCBs and pesticides from soil and water with high efficiency . These features give nanoscale iron particles advantages over the methods currently in use, and are only one example of the advances in remediation that the future holds.
In today’s world, pristine environments no longer exist. Human-induced atmospheric, land, and water pollution has touched every habitat, environment, and ecosystem in the world. Globally, only 17% of land remains relatively untouched, mostly in regions inhospitable to humans / Preventing the loss of natural areas is already a lost cause in many regions. However, with the technologies of remediation, it is not impossible to make up for past mistakes and move towards a more sustainable future.
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Image Credit: http://commons.wikimedia.org/wiki/File:Environment_%286350569238%29.jpg
Irene is a first year student at the University of Chicago majoring in Biological Sciences and potentially Visual Arts. She likes animals of all kinds, long walks in the woods, and exploration, and is currently looking into a specialization in ecology.