Description
Project Inspiration and Design
Motivation and Inspiration
Story Behind the Project
Nowadays, environmental issues have easily grabbed many people’s attention, and among all the pollution issues, heavy metal pollution remains fatal yet prevailing.
Reading news are not enough for getting the clearer picture of where to start with. Feeling obliged to make positive changes to heavy metal pollution, our team researched several different types of pollution and finally fixed our attention on lead.
Why lead?
Among all the heavy metal pollution, lead pollution raised our attention because of its high toxicity to nervous systems as well as children’s vulnerability towards it [1]. Lead can directly damage the central nervous system and the peripheral nervous system by crossing the blood-brain barrier. As a type of highly persistent metal, lead can easily bioaccumulate in the environment through food chains and ma eventually end up with devastating concentration in human body. Yet, children are shown to be more vulnerable to pollutants because their digestive tracts are not fully developed and tend to absorb more lead [2]. Also, development of kidney and cardiovascular system is also affected [3].
Lead pollution is not simply an environmental issue that leads to compromised health but may potentially engender social problems. Research has shown that cognitive disability through childhood and puberty has related with high level of lead exposure, while some research indicates that aggressiveness and criminality may be well associated with lead poisoning (plumbism or saturnism). In recent years, several cases of large-scale lead poisoning have been reported in China, leading to severe health and social harms. This further reminds us of the emergence to take actions into detection and treatment of lead pollution. [4,5]
Current involvement by governments and inspiration
According to van der Kuijip at al, China has been taken up more than 30% of the world’s total production of lead -acid battery (LAB) output by 2015, becoming the largest LAB producer in the world [6].
Yet, due to the difficulty and high cost of the treatment of lead-containing acid as well as lack of rigorous regulation and law enforcement at local government, a small number of enterprises continues to illegally dismantle waste lead batteries and dump acid despite of the regulation imposed, resulting in environmental pollution [7]. Such phenomenon is more common at less developed areas where economics benefits outweigh environmental concerns [8].
Worse, waste lead-acid batteries will produce waste water, waste gas, and waste residue in the process of utilization and disposal. If improperly treated, it will pollute the atmosphere, water, and soil. Henceforth, we will focus on combating illegal collection and dismantling of waste lead batteries and soil-based lead refining through easier and cheaper mean that meets the demand of less developed areas, curbing environmental pollution caused by illegal collection and treatment due to high expenses.
Treatments Available
There are many technologies for remediation in soil and water already. The most effective methods right now are solidification/stabilization, ion exchange, and absorption. However, none of the methods nowadays could attain balance in both costs and efficiency well. We will introduce some of the most common methods governments or factories use to deal with lead pollution. [9-16]. There are 5 big categories of factories of general approaches to remediation listed below.[17]
i Isolation
Isolation prevents the contaminants from further contamination outside the designated area and going into groundwater when other treatment options are not physically or economically feasible.
ii Immobilization
Immobilization reduces the mobility of contaminants by changing the physical or leaching characteristics of the contaminated matrix.
iii Extraction
Extraction is a technique designed to extract the contaminated fraction from the rest of the soil, either in situ or ex situ.
Toxicity and/or Mobility Reduction
Toxicity Reduction is using chemical and/or biological processes to alter the form of metal contaminants to decrease their toxicity and/or mobility.
Our Goal
The goal is to improve detection and treatment of lead by using the biosensor we developed through synthetic biology in this project. By developing bacterial biosensors that are cheaper and easier to operate, the highly sensitive biosensor can be tested on sites to detect excessive lead in various levels of sewage and make lead pollution treatment more efficient and cost-effective.
Based on previous works, we constructed biosensors that include PbrR encoding regulatory protein, its different promoter regions and reporter genes without promoter of which expression is controlled by PbrR protein when lead is present. In this way, presence and concentration of lead pollution can be indicated through gene expression of the biosensor.
In addition, the product should be able to removal lead from the environment through integrating metal binding proteins—Metallothioneins (mtA) and Synthetic phytochelatin (EC20).
Our hope is to create a cheap, effective, and environmental friendly final product for solving the lead pollution in our society. The research results should be able for applications in lead polluted areas, such as lead mining areas, lead-related enterprises, and even combat difficulties due to price and complexity in treating lead pollution-related diseases. Eventually, we hope these biosensors can benefit adults and children by providing them with a safer growing and working environment!
References:
[1]. Hon, K.L., C.K. Fung and A.K. Leung, Childhood lead poisoning: an overview. Hong Kong Med J, 2017. 23(6): p. 616-21.
[2]. Hai, D. N., Tung, L. V., Van, D. K., Binh, T. T., Phuong, H. L., Trung, N. D., … Khue, P. M. (2018). Lead Environmental Pollution and Childhood Lead Poisoning at Ban Thi Commune, Bac Kan Province, Vietnam. BioMed research international, 2018, 5156812. doi:10.1155/2018/5156812Pocock, S. J., Shaper, A. G., Ashby, D., Delves, T., & Whitehead, T. P. (1984). Blood lead concentration, blood pressure, and renal function. Br Med J (Clin Res Ed), 289(6449), 872-874.
[3]. Huang, R., et al., "What do you know?"--knowledge among village doctors of lead poisoning in children in rural China. BMC Public Health, 2017. 17(1): p. 895.
[4]. Needleman, H. L., Schell, A., Bellinger, D., Leviton, A., & Allred, E. N. (1990). The long-term effects of exposure to low doses of lead in childhood: an 11-year follow-up report. New England journal of medicine, 322(2), 83-88.
[5]van der Kuijp, T.J., Huang, L., Cherry, C.R., 2013. Health hazards of China's lead-acid battery industry: a review of its market drivers, production processes, and health impacts. Environment. Health 12, 1-10.
[6]Liu, W., Sang, J., Chen, L., Tian, J., Zhang, H., & Palma, G. O. (2015). Life cycle assessment of lead-acid batteries used in electric bicycles in China. Journal of Cleaner Production, 108, 1149-1156.
[7]Wang, F., 2014. Lead-acid battery market application and future prospects in China. Storage Battery 171-175, 178 (in Chinese).
[8]. Leighton, J,, Klitzman, S., Sedlar, S., Matte T., and Cohen N.L. 2003. The effect of lead-based paint hazard remediation on blood lead levels of lead poisoned children in New York City. Environ Res. 92(3), 182-190.
[9]. Von Lindern, I., Spalinger, S., Petroysan, V., Von Braun, M. 2003. Assessing remedial effectiveness through the blood lead:soil/dust lead relationship at the Bunker Hill Superfund Site in the Silver Valley of Idaho. Science of the Total Environment 303(1-2), 139-170.
[10]. Hadioui, M., Sharrock, P., Mecherri, M.O., Brumas, V., and Fiallo, M. 2008. Reaction of lead ions with hydroxylapatite granules. Chemical Papers 62(5), 516-521.
[11]. Kaur, S. Walia, T.P.S., Mahajan, R.K. 2008. Comparative studies of zinc, cadmium, lead and copper on economically viable adsorbents. Journal of Environmental engineering and Science, 7(1), 83-90.
[12]. Kurniawan, T.A., Chan, G.Y.S., Lo, W.H., Babel S. 2006. Physico-chemical treatment techniques for wastewater laden with heavy metals. Chemical Engineering Journal 118(1-2), 83-98.
[13]. Zhang, Q.R., Pan, B.C., Zhang, Pan, B., Lva, L., and Wangb., X. 2009. Selective removal of Pb(II), Cd(II), and Zn(II) ions from waters by an inorganic exchanger Zr(HPO3S)(2). Journal of Hazardous Materials 170(2-3), 824-828.
[14]. Dole, L. R. 2004. Treatability Study Work Plan: Cedartown Industries Superfund Site, Environmental Remediation Consultant, PQ Corporation. http://www.atomicwidget.com/lesdole/Cedartwn.PDF
[15]. Babel, S., and Kurniawan, T. 2003. Low-cost adsorbents for heavy metals uptake from contaminated water: a review. J. Hazardous Materials 97(1-3), 219-243.
[16]. Yabe, M.J.S., De Oliveira, E. 2003. Heavy metals removal in industrial effluents by sequential adsorbent treatment. Advances in Environmental Research 7(2):263-272
[17]. LaGrega, M.D., Buckingham, P.L., and Evans, J.C. (1994), Hazardous Waste Management, McGraw Hill, New York.
[18]. Rosetti, P.K. (1993), Possible Methods of Washing Fine Soil Particles Contaminated with Heavy Metals and Radionuclides, M.S. Thesis, Carnegie Mellon University, Pittsburgh, PA.