Solvents Survey Results

Authors: Mariana Escamilla, Lucile Pourret, Aline Assumpção, Bianca Gonçalves

After last year’s survey “Materials in Conservation” showed that solvents are some of the most frequently-used materials in our field, SiC’s research team conducted its “Solvents and Alternatives” survey in July 2018. We now present the results of the project.

In general, there appears to be a high level of interest in alternative solvents, but many respondents expressed disbelief in their functionality.

The survey has received responses from 202 professionals in different countries around the world, and it remains open for further updating. It consists of 8 questions intended to help SiC identify the most common solvents used in conservators’ workplaces, the extent to which green solvents are part of the daily life of professional conservators, and how often toxic solvents are used.

The three solvents used most frequently by the respondents were Acetone (162 answers), Ethanol (160), and water (152), which are materials of relatively low-toxicity. Solvents such as Isopropanol and other hydrocarbon solvents like ShellSol (A/T/D40/D38), white spirit, Xylene, Toluene, and Ligroine were also frequently mentioned.

Respondents considered Toluene and Xylene to be the most toxic solvents used in the workplace; they appeared in, respectively, 39.3% and 38.8% of the answers. Even though they seem to be a resource in the day-to-day work of conservators, most of the respondents (70%) wrote that they rarely use them.

Of the 202 respondents, 44% felt that they had enough knowledge related to the toxicity and environmental impact of each solvent they use. Interestingly, 45% said that they had enough information regarding toxicity, but not on environmental impact. One participant wrote:

“I’d like to say that I try to find out as much as possible about safety, toxicity and the environmental impact, but I'm not sure if I always manage to find all the information available.”

As we found previously in our Materials in Conservation survey, many participants were interested not only in knowing more about alternative materials, but also in finding information related to the real impact of the various solvents - i.e. a life cycle assessment.

When asked which alternatives they currently use, the participants often referred to solvent mixtures (based on the TEAS Diagram) that improve the solubility or the handling of certain materials to be removed or applied (49%). Many conservators (68%) also use gels and emulsions, but as compresses or pads (Evolon was mentioned frequently). Materials such as Brij, Tween and Papina were also named.

When asked about the definition of green solvents, most of the respondents answered that the term refers to non-toxic materials (79%). However, the second most common answer shows that many participants (62%) did not know the precise meaning of the term but were very interested in learning more.

In the comments, many participants brought up other ideas about green solvents. Some expressed doubts concerning their efficacy and real environmental impact:

“A solvent with a theoretically lower level of environmental impact and/or toxicity, often plant-based. Often completely useless. Often not as green as it says it is.”

“I somewhat suspect this is a marketing term...similar to "natural"

“A ridiculas [sic] name given to some alternatives that are only slightly less toxic”.

“I think it means less toxic both to humans and to the environment, but not necessarily with regard to energy use in production”.

Most of the participants said that they do not use any type of green solvent in their work, usually because they are not familiar with the concept or do not believe in their efficacy.

However, those who did use alternative materials often mentioned Ethyl Lactate (5), D-Limonene (2), Delta Green Solvents, Rhodiasolv IRIS (2), 1-methoxy-2-propanol (1) and essential oils (1).

When asked about gels, 41% of the participants said that they use them regularly to reduce the amount of solvent required, among other reasons. However, 39% said that they are not used in their workplaces. Interestingly, many of those who indicated that they never use gels wrote that they did not have recipes to make them or experience in using them (20%). Some comments bring up new questions regarding the use of gels:

“I use gels but I am not convinced that they reduce the amount of solvents used because of the need to rinse them using solvents, and also of the other ingredients that add up.”

“Yes, but only when it is important to avoid too much solvent exposure for the object, not necessarily for environmental/safety/sustainability reasons.”

“I only know the theory, but I never practised it, it's too difficult”

It is apparent that conservators have many questions regarding the sustainability of gels and how to use them.

Both conclusions and questions arise from the results of the survey. Conservators are aware that solvent alternatives exist, but they are generally not informed about the real meaning of the term “green solvents”. Once again, it is clear that the main factor hindering the use and dissemination of alternative solvents is the lack of information available on the topic in our field.