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leaking of heavy metal ions in Xiangjiang River
heavy metal pollution in Ganxi River
While searching ideas of our project, some serious incidents caught our eyes . One of the most severe disasters was the one that happened in Hunan Province, China. It was mainly about the leaking of heavy metal ions in Xiangjiang River and the Huaihe River. The arsenic content of the main contaminated areas exceeded 715 times at maximum and the Cd^(2+) content exceeded 206 times at maximum.
In thirty-six Bay mining area of Chenzhou, Hunan Province, arsenic content of Guanxi River sediment exceeded 715.73 times. In Ganxi village’s paddy field, Cd^ (2+) content exceeded 206.67 times. The highest content of Pb^(2+) in paddy field reached to 1527.8mg / kg (that is per kilogram containing 1.5 grams), exceeding 5.093 times.
Looking for help from Government
After noticing the repeated pollution incidents, we began to do some surveys to find out whether the heavy metal pollution incident was particularly prominent not only in China but also all over the world. So we began to evaluate the meaning of our project. First, we started from China.
We visited the Chinese Ministry of Environmental Protection which was the highest environmental protection departments in China. We asked them how serious the heavy metal pollution was in China at present. The Vice Minister of Environmental Protection of China told us that the part of Yangtze River near the coast, whose water of the best quality in our seven major river systems had been affected by heavy metal pollution including Cd, Cu and Pb. And in the 21 cities along the river, six cities' percentage of heavy metal pollution accumulation had reached 65%.
Set up an alliance
Since serious pollution problems had brought up, we decided to do something. To gather all the forces together for more information and power, we established the China Heavy Metal Pollution Research and Investigation Alliance, which consisted of SJTU / SCUT / XMU / UCAS / JLU /FAFU.
Online conference of the China Heavy Metal Pollution Research and Investigation Alliance
Those were teams that were involved in researchers about water pollution or heavy metal pollution treatment in China. We discussed ideas and achievements of our own teams together, and we hoped to build a database by cooperating with each other, which contained data of heavy metal pollution
The pollution of copper worldwide
The pollution of cadmium worldwide
From the pollution map we can see the following:
1 The pollution in Asia, Africa, and Latin America is more serious than that in the United States and Europe: Although we don’t have comprehensive data for Africa and Latin America, but we still can find this phenomenon.
2, the distribution of pollution is not uniform or normal, but most of the region at a good level of the environment at the same time, there are some serious polluted areas.
3, many countries and regions are still lacking of investigation of copper and cadmium pollution and supervision, so there may be more areas having serious copper and cadmium pollution.
4, for our project, our work is of high social value. On the one hand, for the existence of the world's serious copper and cadmium pollution situation, our project can provide viable solutions and ideas. On the other hand, while some areas are seriously polluted, other regions even ignore the investigation of copper and cadmium pollution. Our projects can, to a certain extent, contribute to the attention of these countries for copper and cadmium pollution
Through the mapping of copper and cadmium pollution in the world, we understand the pollution of copper and cadmium around the world, but because of constraints of our team’s human resourse and time, the world copper and cadmium pollution map has a lot room for improvement, we sincerely hope and welcome other teams to participate in this work.
At the same time we would like to be able to play our own efforts to hold some science popularization activities, which aimed to attach importance to the issue of heavy metal pollution. In order to be able to make a real and effective database containing heavy metal pollution data around the world, we also launched an invitation on the official website of collaboration called for more iGEM teams to join our alliance or to provide some data and information. As a result, we received mails from iGEM EXETER, iGEM CSMU X NCHU TAIWAN and Nazarbayev University, and Exeter provided us with European data and shared their own protocol with us.
E-mails sent by iGEM EXETER and Nazarbayev University
Besides, CSMU X NCHU TAIWAN provided us with statistical information on heavy metal pollution in Taiwan and listed the major pollution incidents in Taiwan in recent years for us.
According to the results provided by the database, by using the alliance’s forces, we speared the questionnaire designed by us about the situation of heavy metal pollution throughout the country, and in the end, we received nearly 1,000 replies.
Consultation in many ways
In this situation, we consulted Professor Qu Hongyan who worked at the School of Environmental Sciences at Tianjin University. He told us that the study of heavy metal removal from groundwater was a very important subject that still needed to be studied. It was of great value to use micro-organisms in heavy metal removal. So we decided to focus our project on heavy metal treatments and on treatments of cadmium and copper due severity of pollution. Then, we learned that recently the heavy metal deposition research center in Hunan had made a great breakthrough. So we held a telephone conference to communicate with their technical teacher. During the conference, we asked the current situation about heavy metal pollution, and consulted their approach to chromium ions sedimentation. That was turning high-valent chromium into low-valent chromium to reduce toxicity. This inspired us to think about if there was any better way to completely settle the chrome ions from the water.
Searching the source of pollution: Zhongtiao Mountain Heavy Mental Factory, electric drill factory
Because our experiment needed to base on the actual problem in our life, in the beginning, we left school for Zhongtiao Mountain Heavy Mental Factory factory in Shanxi Province and electric drill factory in Henan Province.
Before we went to the drill factory, we turned to the EPA of Shanxi province for help. We had a teleconference at first, they showed their interests in us and gave us a chance to talk face to face. With excitement, we went to the EPA of Shanxi province and after they talked to us, they offered to send a director to accompany us. It's actually a really amazing reponse of EPA.
The Zhongtiao Mountain Heavy Mental Factory mainly produced waste water that contained copper and cadmium ions while the electric drill factory mainly produced cadmium and nickel ions. The staff there told us, the reason why factories and EPA usually didn't use yeasts for water treatment was mainly about treatment efficiency. Pollution sources usually contained more than one kind of heavy metal ions, a single species couldn't absorb a variety of metal ions, mixed yeasts needed stricter conditions. It also cost too much.If they were going to use yeasts, then it must create high economic benefit, and it would be better to recycle heavy metal ions. They also pointed out that nowadays nearly 90% of the treatment was through chemical methods. And most of the time, in order to deal with that two kinds of heavy metals, some factories tended to use simple and quick ways which could be harmful to the environment.
Waste liquid from chemical treatment
And some factories directly choosed to only deal with one kind of the
heavy metals that had a larger amount, then abandoned another kind of heavy metal
without treatment. Based on the current situation that the treatment for a variety
of heavy metals are not well developed, the issue of how to deal with a variety
of heavy metals contained in polluted water has been considered as the primary
problem, we hope to use yeats to collect two metals separately in different
In order to deal with this problem, we put forward a method named mating switcher, using the natural function of Saccharomyces cerevisiae. We hope to use the gender transition of Saccharomyces cerevisiae to realize the transition of function so we can settle different kinds of heavy metal step by step.
Seek advice by communication with other teams
After those surveys, we had a meeting with Professor Zhang Haoqian and the leader Zhang Yihao from Peking team of Peking University. They expressed a keen interest on our team's mating switcher, and pointed out the defects of our experiment: 1. How could we improve the specificity of yeast to absorb heavy metals? 2. How to separate these two metals?
Photo taken by Professor Zhang Haoqian、 the leader Zhang Yihao from Peking team of Peking University and TianJin iGEM.
Detection problems: domestic sewage treatment plant
With some problems to solve, we went to the domestic sewage treatment plant of Wugang City, Henan Province. The processing plant was representative, but we found that as a demonstration unit of the sewage treatment plant, they did not detect heavy metal ions usually. Only when the heavy metal content exceeded standard emissions, the information could be transferred to the Environmental Protection Agency. Thus, there existed two problems. 1.Domestic sewage treatment plant did not have its own set of a detection system. 2. Once the heavy metal content exceeded, there was no corresponding solution.
At the same time we were told that mixed yeasts were mainly used in the process of the treatment of domestic sewage. Our goal is to realize a heavy metal treatment system as well as an automatic detection system in our yeast. We hope that we can have the chance to put our yeast into treating sewage one day, so the second thing we need to do is to put a detector in our yeast.
To solve this problem, we should come up with a method that allows people test the content of heavy metal and when the concentrations are higher than the standard, the settling process can be started. So we put promoter induced by copper into our gene route, so that when the concentrations of copper are higher than the standard, the gene route can start.This method is called RFP detection.
Things did not let us down, we went back to the sewage plant after we constructed our detector, the general manager met with us and listened to our feedback, and they were very glad that we had very interesting ideas. At the end of the day, they offered to have a long-term relationship with us, if we had any problems or need to put it on trial, they would be glad that we turn to them in the first minute. We were so amazed by the outcome that we decided to do more to perfect our project.
Tolerance issues: steel companies
Next, with our own ideas, we communicated with technical staffs from the pollution department of Hebei Iron and Steel Group Wugang company, Henan Province. (China's first base of thick steel plate production and scientific research. The main bearing frame of The Nest, Chongqing Chaotianmen Bridge and The Shanghai Central Building's are produced in this company). They led us to visit their cycle industrial waste water treatment equipments and they told us that generally the industrial wastewater was discharged to a sewage pool at first, then they would carry out the treatment of heavy metal ions. General strain could not tolerant such heavy metal concentration in industrial sewage, and the treatment using microbial required oxygen and nutritional conditions. Therefore, we planned to improve the tolerance of yeast and they agreed that if our strains could meet the requirements, they were willing to make their sewage pool be our first batch of test.
However, the tolerance of natural yeast to copper ions and cadmium ions conditions cannot be able to put into production. Improving the tolerance and competitiveness of yeast to heavy metals is a necessary condition for our project.
Improving the growth of yeast in high concentrations of heavy metal ions is the a key part of the application in production. We choose the cre-loxp system to rapidly evolve Saccharomyces cerevisiae to improve its resistance to copper and cadmium ions. The cre-loxp system utilizes the cre enzyme and the loxp site on the chromosome to cause the gene to be replicated, inverted, displaced and deleted, which is semi-rational changing of the chromosome structure. The modification of the gene depends on the direction of the loxp site. When in the same direction, the gene between sites will be deleted. On the contrary when in the reverse direction, the gene in the locus will flip. The genes located on different chromosomes may also be translocated. Based on artificial synthetic chromosome No.5 and No. 10, we use the loxpsym site inserted between the genes of the chromosome to turn on the recombination system through the cre enzyme. The difference between the loxpsym locus and the traditional loxp site is that the special palindromic structure of loxpsym locus will cause the possible structural changes of chromosomes. The strains with the high concentration of metal ions will be selected under different concentrations of metal ions. So that the biological treatment of heavy metal pollution is more feasible.
Cooperate with the government and the Environmental Protection Agency
Visit the tailing in ShanXi Province
In the end, we brought our results to an iron ore factory belonging to Anshan Iron and Steel Group in Henan Province and Zhongtiaoshan Nonferrous Metal Company in Shanxi Province, hoping to find the source of pollution and deal with the pollution from there. Their staffs told us that the main way of emissions in China was at present through the discharging to the tailings.
We contacted the Shanxi Provincial Environmental Protection Bureau, the staffs were very supportive of our ideas, so they sent a full-time staff to lead us to Shanxi's largest copper mine, where we understood the existence of tailings. The Tailings was a place that collected the sewage especially. Because of the high cost and a long period of treatment, the EPA generally did not deal with it. However, it could be harmful to the environment. So we hope that in the future we can utilize our yeast here.
Tailings deal with heavy metals by means of physical filtration. The processing intensity is not enough and there also exists harm to the environment. Generally the Environmental Protection Agency will take over the pollution, then outsource it to the heavy metal processing company to treat the pollution. At the same time we were informed that if the tailings was handled properly, there would be chances to create a huge wealth by re-extract the heavy metal here. We gave them the suggestion that they were supposed to consider withdrawing the water from the tailings reservoir and using our Saccharomyces cerevisiae to handle the heavy metals remaining in the tailings reservoir. At the same time, we consulted the Beijing, Shanxi, Henan Environmental Protection Bureau and their counterparts in the outsourcing company, Zhongke Dingshi Non-ferrous Metal Company. This company had a nice response on our results and they were willing to be our first experimental units if our experiment reached the point of maturity.
Multi - party communication and self – examination
We also participated in the Fourth CCiC conference. At the meeting, we exchanged our ideas and shared our experiment with other teams, and received questions raised by them: 1. Whether the synthetic yeast would mate with natural yeast after delivered in nature, which resulted in gene integration. 2. It would be better if we could make the original copper detection switching device switch on and off automatically according to the concentration of copper ions.
take part in the Fourth CCiC conference.
take part in the Fourth CCiC conference.
How we affect the world
Human practice is about how the world affects us, but also about how our project affects the world, so it is quite important that we expand the scope of our influence and make a real difference. So we put major effort in responding the society. We aim to make some economic benefits through our project to prove that our project has potential to invest. We also aim to promote our project ideas in the places that need our ideas. Although our ideas haven’t been able to be applied to real processing system right away, we hope to promote our ideas and influence the world as much as we can.
Get an investment of nearly 100,000 RMB
we talked with the leaders of these companies about our project, we contacted some influential biological companies. At first, we aimed to solve the heavy metal pollution problems in our planet. And then they showed extremely high interests to our project and decided to help us by donating some money and biological reagents so that we could carry out our project more smoothly. In the end, we had raised 80 thousand RMB in all and biological reagents cost ten thousand RMB.
First trial station
Besides, we also kept a close contact with the EPA in a various province in order to know more about the policies and situation of heavy metal pollution. They all answered our questions enthusiastically，and told us that if we needed any help they could offer, they would not be hesitant to help us. And every time we finished a small section, we would contact with them to discuss whether it is feasible in policy.
What' s more, we also had a talk with heavy metal treatment company to know more about the recent technology of settling down the heavy metal so that we could know what we should do to make it more suitable for the environment. They said that our total project was extraordinary because we used genetically modified strains to settle down heavy metal, which solved the problem that these strains could not survive in water containing so many heavy metal ions and they said that they would be willing to use our method to remove heavy metal from water when our project became more mature.