Safety

Handling Mercury

Hey you! We are working with mercury here!
Safety is not a joke! It helps a lot if we choose a well documented and Class 1 organism (Escherichia coli) but the question about what to do with handling when comes to mercury still an issue! Mercury is a silver metal that is liquid at normal temperature and odorless. When the temperature increases, it becomes more dense, toxic and corrosive. It is a harmful product when inhaled, ingested or in contact, causing skin, eyes and respiratory system irritation. Mercury is present in various forms (metallic, organic and inorganic) and can be found in three oxidation states (0, +1 , +2), generally readily interconvertible in nature.

Both humans and animals are exposed to all mercury forms through the environment. The mercury vapor present in the atmosphere is eventually converted to the water soluble form and returns to the earth's surface in rainwater. At this point, two important chemical changes may occur. The metal can be reduced again to mercury vapor and returns to the atmosphere or can be methylated by microorganisms in sediment from water, including fresh or seawater.

We turn our attention to the Brazilian legislation, and read it all. From the material of the Ministry of Health to the National Environmental Council (CONAMA). In summary, Brazilian legislation only attempts to control the discharge of effluents, does not legislate on concentration of harmful substances as mercury. We followed the WHO (World Health Organization) guidelines. Also there’s no regulation for the use of mercury in research. In addition, Brazilian law does not establish how should be the handling of toxic metals. It mentions only regarding to their levels to be released into the environment. This brings us to a question: how to control the amount of mercury in the environment if there is no control in handling it? Due to lack of appropriate legislation in not only to dump mercury but also for use in research, the team UFAM-UEA_Brazil have been engaged in trying to propose a legislation improvement. To avoid harm, we’ve used mercury in aqueous solution. In its ionic form Hg2+ at Mercury(II) Chloride form (HgCl2), through stock solution to test our biobricks. To do it, we had to dilute mercury to the desired concentration using sterilized water. The disposal was done following strict sanitary rules and directed to a proper container to further incineration process . The handling of heavy metals cannot be made in ordinary laboratories, without any degree of certainty. In the absence of a suitable laboratory, to handle heavy metals at the university, the team had to redesign one of UFAM laboratories to use mercury. This lab is exclusive for this heavy metal handling.

We, most of the time worked in a level 1 lab, were all the genetic constructions take place. This lab always has some research happening there, so the biosafety protocol is standardized. This include attention to personal hygiene, i.e., hand washing and a prohibition on eating, drinking or smoking in the lab, mechanical pipetting only, avoidance of splashes or aerosols, and decontamination of all work surfaces before and when work is complete, e.g., daily. All potentially infectious materials are decontaminated prior to disposal, by autoclaving. We avoid handeling our chassis organism in the bench and we did it in a laminar flow hood.