Guide to the safe handling of solvents in a bituminous ... - Aapaq.org

• The use of High Performance Liquid Chromatography (HPLC), GasChromatography (GC) or Thin Layer Chromatography (TLC) tocharacterise the chemical composition of bitumen;• The Dean and Starke test for the determination of binder content ofbitumen emulsions or water content of bituminous mixtures;• The determination of the softening point of bitumen where thesoftening point is expected to exceed 85 o C.Best practice for any bituminous laboratory would be to eliminate the use ofsolvents altogether for all test methods, as well as for cleaning purposes.Advances in laboratory equipment over the last decade have made this aviable option for some test methods, such as the determination of bindercontent, as well as for certain cleaning requirements.However, it is not always possible to eliminate the use of solventsaltogether. Under these circumstances, the following approach isrecommended:• The substitution of more hazardous solvents with lesshazardous solvents - A number of test method developments overthe last decade have allowed for the validation of existing testmethods by replacing unsafe solvents such as tricholorethylene (TCE)with "safer" solvent combinations such as toluene/ethanol (85/15) orblends of n-propylbromide (1-bormopropane). The word "safer" isplaced in quotation marks as it is important for any operator in alaboratory to understand that no solvent is completely safe. Even for"safe" solvents, there will always be some laboratory operators whowould be sensitised to such solvents, whether through a medical orgenetic predisposition;• The substitution of more hazardous solvents with one of thenew generation "non-toxic", environmentally friendly solvents -These new generation solvents, based on blends of naturallyoccurring compounds (eg limonene blends of oils derived from lemonpeels) are easier to dispose of and are generally biodegradable;• Minimising risk exposure - Where it is not practical to replace ahazardous solvent, it is important, depending on the toxicity of thesolvent as well as legislative requirements, that the requiredmeasures to minimise risk exposure for a laboratory operator beundertaken. Such risk management (even for less toxic solvents)would entail:8