ABC of Safety in the Biological Sciences




A toxic substance causes systemic damage to the body in contrast to corrosive substances or irritants which cause localised damage.9 20 29 126 130 131 Not all chemicals used in laboratories, and this is particularly true of dyes, have been tested for their toxic effects. Yet all chemicals can cause harm if there is sufficient exposure (sodium chloride taken in excess doses can be carcinogenic). Consult material safety data sheets to determine the risk of exposure to all chemicals and dyes used in your workplace.

The term 'toxicity' includes:

  • acute toxicity - the ability to cause damage from a single exposure.
  • chronic toxicity - the ability to cause damage from repeat low doses over a period of time.
  • mutagenicity - the ability to cause heritable genetic damage.

Examples of mutagenic agents include the following (this list is not complete):
carbon tetrachloride
ethylene glycol
lithium carbonate
sodium chloride in excess
auramine O
Congo red
crystal violet
gentian violet
indigo carmine
methyl orange
methylene blue
orange g
Sudan III
Sudan IV
toluidine blue

  • teratogenicity - the ability to cause non-heritable birth defects (some chemicals also fall into the category of embryotoxin which cause foetal death - these chemical should not be handled during pregnancy.

Teratogenic agents include the following (this list is not complete):
trypan blue

  • carcinogenicity - the potential to cause tumour development (See carcinogenic chemicals)
Some of the effects of various toxic chemicals which may be used in the laboratory are given in TABLE 13.

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