Team:Cornell/project/background/lead

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Cornell iGEM

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Project Background

Health Risks

Lead has no known function, and therefore no place, in the human body. The lack of any robust, evolved system to deal with lead means that when it enters the organism, it will not be filtered naturally, and instead act as a disruptive, persistent, and often unnoticed antagonist to normal function. What makes lead so insidious? As it accumulates, lead will begin to take the place of other metals in biochemical reactions, replacing zinc or calcium when it is available for chemical reactions. In fact, “Lead binds to calcium-activated proteins with much higher (105 times) affinity than calcium.” As a result, 75-90% of lead body load is in mineralizing tissues such as teeth and bones.
Because of these issues, the United States’ Environmental Protection Agency, which was tasked to set safe levels of chemicals in drinking water by the 1974 Safe Drinking Water Act, has set 0 as the Maximum Contaminant Level Goal for lead. The U.S. Environmental Protection Agency sets the maximum allowable lead concentration at .015 mg/L (74.8 nM). Any concentration above the set maximum requires additional treatment for removal of lead. On January 4th, 2014 a new provision of the Safe Drinking Water Act requires that any pipe used for the transport of potable water must contain less than 0.25% lead--a reduction from 8% under the previous law. Lowering levels of lead in piping will help to reduce lead in drinking water, but environmental routes of pollution still exist.
This is especially dangerous for children, as their porous GI tracts, and the increased vulnerability and volatility of their developing body systems make them highly susceptible to the disruptive effects of even small amounts of lead. It also takes them much more time to clear it: the half-life of lead in the adult human body is 1 month, but 10 months in a child’s [5]. Low-level exposure can be quite harmful: an increase in blood lead level from 10μg/dL to 20μg/dL is associated with an almost 3-point drop in IQ all on its own [8]. Lead has also been shown to inhibit hippocampal long-term potentiation, a neural mechanism required for learning [8]. Common effects in children: gastrointestinal distress, anemia, kidney failure, irritability, lethargy, learning disabilities, erratic behavior Common effects in adults: gastrointestinal distress, weakness, pins and needle, kidney failure Extreme cases: neurological damage, death

Case Studies



Current Remediation Techniques



CBP4



References


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