Introduction



As a result of more than a century of domestic and industrial pollution, "Onondaga Lake is one of the most polluted lakes in the United States," however it can be repaired. Onondaga Lake is located along the northern end of the city of Syracuse in Onondaga County, New York. The tributaries to Onondaga Lake flush it four times a year. In the l9th century the lake was clean and was a popular beach and resort area. As the city became increasingly industrialized in the mid 1900s, water quality declined to the point where the lake was used primarily as a disposal for sewage and industrial wastes. Then in 1970 all fishing was banned due to the high mercury content of the water. There are many events that have led to the deterioration of the lake. High amounts of phosphorous from fertilizers and sewage have reduced water clarity and increased amounts of algae. The increase of algae decreases oxygen content needed for fish to survive. The murky brown color of Onondaga Lake is due to the high concentration of clay and silt mostly from Tully Valley mudboils, which are holes in the ground that release mud and silt into Onondaga Creek, which flows into Onondaga Lake. Our project will deal with the excess amounts of mercury in Onondaga Lake. The Allied Signal Corporation has deposited mercury into the lake that makes it the contaminant of the most concern. It has been measured in the flesh of fish at levels that exceed federal food standards.

If conditions were to improve, there would be a boost in the economy in the Syracuse area, because jobs would be provided on the lake front. The city of Syracuse would greatly benefit from new jobs which have recently been lost at Allied, Nynex, Miller, General Motors and Niagara Mohawk. Onondaga Lake is also connected to the New York State Canal System and gives access to all the Great Lakes and to the Atlantic Ocean through the St. Lawrence Seaway. This gives the lake the potential for boating, tours of the lake and fishing. With these new industries, the city of Syracuse will gain money for this and other community projects.

There are no measures currently being taken to deal with the problem. There is a current debate, Onondaga County vs. the New York State and U.S. government to determine who will fund clean up of Onondaga Lake. However, if this problem is not dealt with, a precious landmark 10,000 years oldwill be ruined. This natural resource which could be used for positive effects on the economy will be wasted.



Mercury Pollution and Onondaga Lake



Onondaga Lake is 4.6 miles long. It is one mile wide and has an average depth of 35 feet. It is a depression in the floor of the ancient Lake Iroquois, which was formed by glaciers and morraine damming. This lake has been in existence for 10,000 years. During colonial times, it was the accessibility of water that led to the settling of Syracuse, the building of the Erie Canal, and industrial development. Unfortunately, today Onondaga Lake is one of the most polluted lakes in the United States.

Mercury has contributed to the pollution in many ways. From 1946 to 1970, 165,000 lbs. were added to Onondaga Lake. Seven million cubic yards remained contaminated from 1970 to 1988. It entered the lake by the tributaries. It is also entered by Allied Signal, a chemical company, and the Metropolitan Sewage Treatment Plant, or METRO.

METRO and Allied-Signal have been the main contributors to the contamination of Onondaga Lake. METRO is responsible for 46.9% of the total mercury loading to Onondaga Lake. Allied has added mercury by opening its chlor-alkali plants. In 1970, these two plants reached nearly 21 lbs/day. The U.S. Attorney General sued Allied Signal to stop the release of mercury and banned all fishing. This order in 1970 reduced it to 11 lbs/day and three years later to 1.3 lbs/day.

The various tributaries contribute to mercury loading. As can be seen, mercury concentration increases as water travels over the land surface toward Onondaga Lake.

The process of removing mercury is costly. In 6,500,000 cubic yards (2, 610 acres) would cost $61,700,000. This would include assembling a hydraulic dredge on site, planning, engineering, designing, construction management, mobilization and demobilization, and a contingency. This does not include the cost of confined disposal facilities.



Biological Alternative for the Removal of Mercury



We plan to combine several principles studied in biology to create an innovative process to remove mercury from Onondaga Lake. This is a Biological Alternative for Reduction of Mercury (BARM). These fundamental principles include: agriculture, recycling.

In this project we propose to use: agricultural techniques in which plants take up minerals (including Hg) and control sediments; Plant physiology to identify a plant with tissues that can process mercury; genetic engineering to transfer the genes from a plant to seaweed/marine plant to increase the uptake of mercury from the lake bottom sediments; aquaculture methods that employ sea farming techniques to "harvest" seaweed and plants on periodic basis to remove mercury-laden tissues; and recycling in which the seaweeds/plants that have the mercury extracted are offered for sale to industry to make useful products. The revenue gained from this will be contributed to the funding of the project.

In searching the library at the Environmental Science of Forestry at Syracuse University, a master's thesis has identified a plant that can process mercury. The plant, Phragmites communis, is found on the shoreline of Onondaga Lake. It is a perennial reed plant that has annual cane-like shoots of 2-3 meters. It is usually found in low-lying areas flooded with shallow, still water. It can live where the pH is anywhere from 3.6-8.6. This plant has been shown to have a volatile release of mercury from its leaves into the atmosphere.

In the investigation involving Phragmites communis, sites were set up at various locations on the lake shoreline. Mercury was released by the plants enclosed in a chamber, proving that the plants use an active, not passive process.

In the investigation involving Phragmites communis, the maximum mercury emission was from late morning to early afternoon.

Photosynthesis is obviously affected by the amount of sunlight, so therefore the rate of photosynthesis increases when there is more sunlight. That is why in the investigation involving Phragmites communis, more mercury was released in the late morning-early afternoon. It is reasonable to assume that the enzymatic process controlling photosynthesis is linked biochemically with the enzymatic process controlling mercury use.

Since photosynthesis is an enzymatic process, it is involved with the genetic makeup of a chloroplast in a plant cell. It has been established that DNA is located in the chloroplasts in the form of fibrils. It isn't derived from nuclear DNA and it is specific to the chloroplats, mRNA is also located in the chloroplasts and protein synthesis (the building up of proteins) does occur. But some enzymes and other proteins of the chloroplasts are encoded in the nuclear genes, and these help increase the rate of protein synthesis. Since enzymes are specific proteins that speed up specific chemical reactions in a cell (such as photosynthesis), it makes it possible to identify the exact enzyme responsible for the release of mercury in a plant.

Genetic engineering is the process of inserting altered or recombinant DNA, DNA which has been changed by the addition or deletion of other sections of DNA, into a recipient nucleus. In our project we propose to genetically engineer a recipient seaweed plant with a donor plant DNA that possesses the ability to trap mercury inside the plant. This DNA in turn will remove amounts of mercury from Onondaga Lake. These plants will take the mercury out of the lake bottom by the process of transpiration pull (the process of transport and absorption throughout a plant).

The extensive reedbelt lining of Onondaga Lake has the potential for removing large amounts of mercury from the waste beds and sludge disposal areas. The net flux of mercury out of the entire reedbed on the shoreline of the lake was 90 g/day). So, this could help prevent more mercury from entering the lake, but what about the mercury already at the bottom of the lake? Since it is possible for a vascular plant to take mercury from the sediments it is growing on and release that mercury into the air, it could be possible to find the enzyme in this plant that is capable of releasing the mercury and genetically engineer it into another vascular marine plant such as Zostera marina (Eelgrass). Vascular plants contain specialized transport tissue of xylem, which carries food down the leaves to the root. Zostera marina can grow in waters deep enough for dredging and its leaves can grow to a height of up to three feet. The mercury from the bottom could be trapped in the leaf tissue of this newly developed plant. Then the question arises of what to do with this plant species once it's on the lake bottom.

After researching Japan's seaweed industry, it was found that to harvest their seaweed, they stretch horizontal net beds between bamboo poles. Then, spores collect on the nets. After the spores have grown, the seaweed is picked or cut. We could cut off the top two feet of the Eelgrass periodically when it is full of mercury. Then we wouldn't need to keep replanting and the mercury wouldn't end up back in the water where it started.

To achieve the mercury removal effect on our genetically engineered plants, we must make recombinant DNA. In our case, the gene which controls the mercury removal in the donor plant and a gene in the recipient seaweed plant are combined together to form a new gene. Special enzymes called ligases are found in nature and have the ability to cut and paste DNA together. These ligases hold the newly formed gene firmly in place. This newly formed gene changes the original structure of the DNA and forms recombinant DNA.

Before the formation of recombinant DNA is possible, the specific genes being altered must be located, which is known as gene mapping.

Once located and recombined, the new genes must be transferred to the recipient plant. A naturally-occurring bacterium known as Agrobacterium tumefaciens (common soil bacterium) is used as a genetic manipulator in plants. It will transport new genes into a plant cell of the recipient seaweed plant, thereby creating a new plant cell with the ability to trap mercury.

The entire genetically engineered cell produced will then have to develop into an entire seaweed plant, with the ability to remove and trap mercury. Plant cells are totipotent ("undifferentiated cells can generate a whole organism"). This means that an adult seaweed plant can be regenerated from a single cell growing in a tissue culture. The problem with this is that once each regenerated plant cell has become a leaf, root or other part, many genes may shut off. To eliminate this, we must place the specific cells of the leaf, roots, etc. on media containing specific hormones which aid in the formation of callus (undifferentiated tissue). The callus in turn promotes the growth of more leaf, roots, etc., cells which will then grow into an adult. This genetically engineered plant will be introduced into Onondaga Lake and pass on its acquired traits to its offspring.

The process we developed takes several involved steps. First, a plant that can process mercury and the appropriate enzyme must be located. The plant process is active and is related to photosynthesis. Photosynthesis is controlled by its enzyme system which is controlled by genes, which must also be identified. This plant must be able to grow underwater and on the shoreline. It will be genetically engineered with the recombinant DNA so it will be tall, vascular and have the ability to process mercury. Next, we allow the plants to grow for an ample amount of time. Then, the plants must be harvested, leaving the roots, so they can continue their growth. The harvested plants can have the mercury extracted from their leaves; this will provide money to fund this project and at the same time, a useful product can be manufactured. After five to ten years, when the mercury levels are at federal standards, the plants would be totally removed and natural plant and algae populations would be reintroduced.





Positive & Negative Effects



The people of central New York would benefit a great deal if the mercury were to be removed from Onondaga Lake. People are hopeful that by redeveloping the lakefront area, people will return to the lake. Even though at the present time the lake is polluted, the Inner Harbor is being turned into a waterfront attraction. This harbor is to serve as a tourism destination. Carousel Center, a $250 million shopping center, is the centerpiece. Franklin Square, an industrial graveyard, has been turned into an office complex and houses 300 residents. All these have been accomplished even with one of the most polluted lakes in the world. If the lake were cleaned up, even more economic development could follow.

The project to develop the "Oil City" area in Syracuse will cost one billion dollars. It will convert the land to high and better uses and produce 10,000 new jobs. In the future, a marina could accommodate up to 200 boat slips for powerboats. Also bike paths will join with a trail being constructed by Tonodaga County to ring the lake. The future of the lake looks bright, if it gets cleaned up.

Even though this process is meant to abate the pollution problem, it is possible that negative effects could result. While there is virtually no possibility that genetic engineering will result in any harmful side effects, the public's apprehension may prevent the entire proposal from being implemented. Another problem with genetic engineering is that it is very time consuming. Attempting to locate a single gene can take several years. This in turn would also cause a delay in the cleanup.

Several issues of concern could result from the extensive amounts of mercury concentration in the genetically engineered plants. One concern is the possible contamination of the food chain. Fish, birds, and other herbaceous organisms may ingest the mercury-containing plants and in turn this toxic substance would be passed onto high level organisms in the food chain, including humans. Further-more, there is a possibility that plants would be unharvested due to weather conditions or other factors and be transported to other bodies of water. This would happen during the frigid winters, when the lake is frozen over, or if the lake were to flood.

Although this approach is only theoretical, it could have an extremely bright future. There are possible negative effects, as there are in any endeavor, but the positive effects outweigh the negative. In conclusion, BARM creates a relatively inexpensive way for the city of Syracuse to restore its natural resources. u