The Process: Chemist
Your job as the chemist is to investigate some of the chemical properties of mercuric chloride and some of the safety risks that are a concern. Some of your work will require you to investigate special data sheets about mercuric chloride and report the information to other groups. Calculations will be necessary for some of the problems that you will face here. Be sure to answer your questions from the perspective of a chemist.
Before starting your task, here are some helpful hints you may want to consider:
You will need to first determine what some of the common heath risks and chemical properties for mercury containing substances. The label on the barrels indicates that the material includes mercuric chloride. Although chemical nomenclature is relatively uniform, there are a variety of ways mercuric chloride can be written. The nomenclature, as well as some basic properties of mercuric compounds can be investigated using this online periodic table.
As a professional chemist, a Material Safety Data Sheets (MSDS) for every chemical is located at a particular site where that chemical is used. This includes factories, labs, hospitals, and schools. The MSDS contains a variety of information, much of which will be valuable to you as you assess the damage the mercuric chloride has made. J.T. Baker is one reputable corporation that makes their MSDS available online.
Many of the terms and phrases used on the MSDS may be unfamiliar. There are a variety of sources that help "translate" this information. Here's a site designed just for people who are trying to make sense out of the MSDS.
Some of the calculations you will be asked to perform inherently throw in an extra step for unit conversions. Scientists measure quantities in units that are not typically used by the American public, despite the fact that they are commonly used overseas. You will need to incorporate the usage of these formulas to satisfactorily complete these conversions.
It is important for you to understand the chemist's usage of the phrase heavy metal. You may want to read this good synopsis of mercury and other heavy metals. In addition, this Dartmouth page offers some insight into toxic metal research.
What is mercury? Include the dictionary definition with examples. Give the scientific explanation of why the chemical is harmful and how the common understanding differs from the scientific understanding of the contaminant.
What were the effects of the mercury poisoning tragedy in Minamata Bay, Japan (1959) due to the lack of a clean-up effort?
Identification of the material:
What is the formula for mercuric chloride?
Are there alternative names for mercuric chloride using other acceptable nomenclature methods?
You notice that there is a diamond symbol painted on the sides of one of the barrels, resembling the one below:
What organization is in charge of designing the information contained in this diamond?
What is the significance if the numbers/symbols in each quadrant? Are the colors of the quadrants important?
Construct a diamond based on mercuric chloride that could be posted in other appropriate areas.
Upon reading some more about the chemical, you are concerned about the possibility of heavy metal poisoning. List the elements that are considered heavy metals and describe what properties (of the metal in particular) qualify them as heavy metals.
Since the spill occurred at a lake, the compound's solubility in water becomes a particular concern.
Where can information on a compound's solubility be found on a MSDS?
Town water records and weather reports indicate that the average summer water temperature of the lake at the location of the spill is 68°F. If the volume of the water in the lake is 850,000 gallons, calculate the maximum amount of material that could dissolve in the lake.
If the total weight of the material spilled at the site is estimated to be 2,500 pounds, could all of the material have been dissolved over the fifteen years (assume your location is sea level).
Describe how the mercuric chloride that contaminated the lake was transformed into (mono- and/or di-) methyl mercury. Which organisms are most responsible for this transformation and which organisms are most affected?
What do the phrases ppb, LD-50, and LC-50 mean? How can the calculation in part 6b important as a means of comparison to the LD-50 or LC-50?
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What is the maximum level of mercury (in ppb) that a fish can ingest?
What are the LD-50/LC-50 values for a 50 lb child?
What are the LD-50/LC-50 values for a 120 lb teenager?
What are the LD-50/LC-50 values for a 180 lb adult?
What population will be most likely affected by the mercury contamination levels found in question 6? Discuss you answer in terms of the calculations performed above.
Why is it necessary to undergo a speedy clean-up in the case of the Millersville spill? Create a list of points that should be made to convince the task force to get moving.
Author: Travis Everett