Dimethyl Mercury

I'll use this substance as an example of a search for information on a hazardous substance. A main point I'd like to make is that you have to look lots of places --no single source was anything like adequate for this (relatively simple) problem.

The first thing to do is find the CAS Registry Number, which I did using ChemFinder (http://chemfinder.camsoft.com/):


This CAS number is an essential key, since it resolves terminological questions (in this case pretty simple: dimethyl mercury? dimethylmercury?)
ChemFinder pointed to several other links:
Reproductive Toxicity Review (from ftp://alternatives.com/library/envchem/mercurytxt.html)

New Jersey Hazardous Chemical Factsheet (from ftp://alternatives.com/library/envchemh/chemh309 )

NIST Chemistry Web Book

from an AltaVista search:

When I'm beginning a search I often search the Web for a quick start, but never with any illusion that it'll tell me everything or even that it will necessarily be completely dependable.

MSDS sheet

Low Level Mercury Measurement (from Tekran Inc.)

Mercury monitors from DOE

and 'dimethylmercury' nets these:

Evolution of Our Understanding of Methylmercury as a Health Threat (Watanabe and Satoh)
Genotoxicity of Mercury Compounds - A Review (Deflora et al.)
Methylmercury is derivatized with tetraethylborate and analyzed by GCMS (WCAS)

PubMed (a version of MEDLINE) is a good bet for medical sources, and a query produced 15 articles, one very recent:
Met Ions Biol Syst 1997;34:321-370
Physiology and toxicology of mercury.
Magos L
BIBRA Toxicology International, Carshalton, Surrey, UK.

(the journal is Metallic Ions in Biological Systems, which W&L does not have)

I used UnCover because it's pretty exhaustive (16,000+ journals) and up to date; it has the limitation that one can only search for worlds in the titles of artices, and by author's name. Here's what the search netted:

TitleDartmouth Cited.
Journal Info Chemical and engineering news.
AUG 25 1997 v 75 n 34: 9
SummaryOSHA fines college for inadequate personal protection procedures in death of researcher from dimethyl mercury poisoning.

This led me to a search of news coverage --which might have been a good place to start, except that I knew I wanted chemistry details (and so went for the CAS Number first). Here are some recent news stories from Lexis/Nexis
A search of Science in its online version turned up 2 articles which mention "dimethyl mercury" in their text, one being the report of Karen Wetterhahn's death (June 20, pg 1797) [which gives a good summary of the background to the incident] and the other mentioning DMM in an MIR context (same issue, pg 1861).
A search for Wetterhahn in UnCover turns up 25 articles of which Karen Wetterhahn is author or co-author, many of them having to do with chromium, but there's also this one:
     Methyl Transfer to Mercury Thiolates: Effects of Coordination 
     Number and Ligand Dissociation.
           Lippard, Stephen J.
           Wilker, Jonathan J.
           Wetterhahn, Karen E.
 Journal Info
           Inorganic chemistry.
           MAY 07 1997 v 36 n 10: 2079
As it happens the text of this article is available via ACS through December 1997.

Another article:

           Environmental metal carcinogens: genotoxicity and altered gene 
           expression by direct metal-mediated and indirect oxidative 
           Wetterhahn, K. E.
           Dudek, E. J.
 Journal Info
           New journal of chemistry.
           FEB 01 1996 v 20 n 2
          Chromium and nickel can produce genotoxicity and alterations in
gene expression through two pathways: Direct metal-mediated interactions 
that produce metal-DNA binding and metal-nuclear protein complexes; and 
indirect generation of reactive oxygen species that produce oxidative DNA

A search of AltaVista for "wetterhahn" turned up a variety of documents, among them this summary of some of Karen Wetterhahn's work:
TITLE: Induction of Oxidative Stress and Activation of Transcription 
Factors by Toxic Metals


DESCRIPTION: The overall objective of this project is to understand the
mechanism by which toxic metals effect cellular oxidative stress.
Oxidative stress has been implicated in a number of human diseases,
including cancer, aging, atherosclerosis, and fibrosis. The ability of the
toxic and/or carcinogenic metals-chromium, nickel, cadmium, lead, iron and
arsenic- individually and in combinations found at contaminated Superfund
sites, to induce oxidative stress will be determined in chick embryo in
vivo and cultured endothelial cells. The focus will be on genotoxic and
non-genotoxic effects of low levels of chromium and arsenic. The project
will examine possible induction of oxidative DNA damage by toxic metals,
and the propensity of these metals to cause aberrant gene induction
through alteration of cell signaling. The proposed studies should provide
evidence of oxidative pathways for toxic metal action on expression of
specific genes, and provide insight into the mechanism by which metals
cause their toxic effects. This, in turn, could provide fundamental
insights into strategies designed to prevent metal induction of oxidative
stress and related proliferative diseases such as cancer, atherosclerosis
and angiogenesis. 
(from http://jeeves.niehs.nih.gov/sbrp/newweb/rescateg/exp-ass.htm)
And the text of a tribute from the Congressional Record.

Another sort of information which can be very useful to chemists is buried in patents. A search in the Lexis/Nexis patents database turned up 37 with 'dimethyl mercury' mentioned. (brief records shown, for context)
Still looking for chemistry sources.

A search of the CAS database (using the CAS Registry number: 593-74-8) via STNEasy produced more than 580 references. Two really apposite ones are:

Blayney, Michael B.; Winn, John S.; Nierenberg, David W.
Handling dimethylmercury
Chem. Eng. News (1997), 75(19), 7

Toribara, Taft Y.; Clarkson, Thomas W.; Nierenberg, David W.
More on working with dimethylmercury
Chem. Eng. News (1997), 75(24), 6

When this turned up I realised that I needed to redo the above searches for 'dimethylmercury'? Indeed, these two do show up with that search in the FirstSearch Applied Science and Technology database. It's interesting that neither of the general indexes (Periodical Abstracts Online and Expanded Academic Index) contains Chem. Eng. News. EAI does list a New York Times article:

    Source:  The New York Times, June 11, 1997 v146 pA20(N) pA23(L) col 4 

    Title:  Rare form of mercury kills Dartmouth chemistry teacher. 
            (Karen E. Wetterhahn of Dartmouth College dies from exposure 
            to dimethylmercury 10 months after conducting laboratory 
            (National Pages)

A search in PubMed for 'dimethylmercury' turns up 8 hits, including

Mutat Res 1994 Feb;317(1):57-79

Genotoxicity of mercury compounds. A review.

De Flora S, Bennicelli C, Bagnasco M

Institute of Hygiene and Preventive Medicine, University of Genoa, Italy.

This article reviews literature data concerning the genotoxicity of 29 mercury-containing agents, including laboratory compounds as well as ingredients of preparations used as fungicides, dyes, disinfectants and drugs. A variety of genetic end-points were investigated in bacteria, yeasts, moulds, plants, insects, cultured cells from fishes, rodents or humans, aquatic organisms, amphibians, mammalia and exposed humans. The overall evaluation is quite complex. Mercury compounds failed to induce point mutations in bacteria but often exerted clastogenic effects in eukaryotes, especially by binding SH groups and acting as spindle inhibitors, thereby causing c-mitosis and consequently aneuploidy and/or polyploidy. Inorganic mercury compounds were also found to induce the generation of reactive oxygen species and glutathione depletion in cultured mammalian cells. Although different mercury compounds tended to produce qualitatively comparable genetic effects, which suggests the involvement of a common toxic entity, methylmercury derivatives and other ionizable organomercury compounds were more active in short-term tests than either non-ionizable mercury compounds (e.g., dimethylmercury) or inorganic mercury salts (e.g., mercuric chloride). The results of cytogenetic monitoring in peripheral blood lymphocytes of individuals exposed to elemental mercury or mercury compounds from accidental, occupational or alimentary sources were either negative or borderline or uncertain as to the actual role played by mercury in some positive findings. Both genotoxic and non-genotoxic mechanisms may contribute to the renal carcinogenicity of mercury, which so far has been convincingly demonstrated only in male rodents treated with methylmercury chloride.

MeSH Terms:


Upon reading that dimethyl mercury had formerly been used as a crop fumigant, it occurred to me to do a search in the FirstSearch database AGRICOLA, which got 9 hits; 'dimethylmercury' got 2 more. In fact these don't advance our knowledge much, but serve to indicate the necessity to look in multiple places.