Team:Gaston Day School/Description

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Cadmium Detector

     Cadmium leakage poses a serious threat to environmental health around the world as well as at our teams home. The surrounding areas of Duke Energy’s Buck Steam Station in North Carolina have unintentionally been affected with millions of tons of coal ash containing multiple toxic chemicals including cadmium. In a world moving towards the use of alternative fuels, this problem only stands to grow.

A History With Heavy Metals

     Since 2012, Gaston Day iGEM has focused on heavy metal detectors, further focusing on cadmium detection starting in 2013. The release of the ash at the Buck Stream Station has caused the water to become a health hazard with the potential to cause a wide range of complications: flu-like symptoms, kidney damage, fragile bones, and possibly death through prolonged exposure. This hard reality motivates us to work towards solutions, both locally and globally.

Prompted by reports of the adverse health effects of heavy metal contamination in water, our 2012 iGEM team began working on the first of several heavy metal detectors. We wanted to help both local farmers and farmers in other countries, especially third-world ones, who have found their crops tainted by heavy metals such as cadmium, arsenic, and lead. In 2013, we read reports showing that areas surrounding Duke Energy's Buck Steam Station are affected by coal ash containing cadmium, in a region fairly close to home for our team. We decided to focus primarily on our cadmium detector, especially after learning that water affected by the cadmium containing coal ash becomes hazardous and can potentially cause health issues ranging from kidney damage to death. Our detector creates green fluorescence while in the presence of cadmium. After building the first version of our detector, we worked to increase its sensitivity, allowing it to respond to much lower levels of cadmium, at an amount where the knowledge could be useful and not redundant due to the deaths already caused by the cadmium. Last year, we added the 2007 Cambridge team's sensitivity tuners to the detector. After seeing indications of a peak at lower levels of cadmium than we had previously, we began to use test points that were closer together and discovered a peak of fluorescence. This year we built and tested an alternate version of our previous detector. The new detector uses a phi-delta activator instead of an Ogr activator, and we discovered promising differences between the detector and the control. According to the 2007 Cambridge team's website, they saw differing results for the efficacy of the phi-delta activator versus the Ogr activator, especially when tested with or without an induction system. We decided to test the phi-delta activator as well as the Ogr activator to see if in our different environment we had improved results with one of them.

To test the cadmium detector, use this procedure. Place 100 microliters of E.coli control cells into 11 test tubes that each already contain four milliliters of LB broth. Also, place 100 microliters of cadmium detector cells into 11 more test tubes that each already contain four milliliters of LB broth. Into the tubes with the cadmium detector cells, add four microliters of chloramphenicol. Add cadmium chloride to tubes according to this chart: