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Substance Flow Analysis of Resorcinol

Summary and conclusions

The present report presents a substance flow analysis (SFA) for resorcinol in Denmark. The SFA has been initiated by the Danish EPA as a follow-up to the report on endocrine disrupters prepared by the Parliament's Environment and Regional Planning Committee in September 2002. Resorcinol is listed as a category 1 substance (substance of high concern) in the EU priority list of substances for further evaluation of their role in endocrine disruption (BKH, 2000). The report states that resorcinol is not under the on-going risk assessment procedure in the EU and therefore an analysis of use patterns and exposure will be carried out in order to evaluate if there is a need for regulatory measures regarding its use.

The approach in the SFA is essentially similar to that recommended in the Danish paradigm for substance flow analysis. Only a limited amount of statistical information is available for import, production and export of resorcinol-containing products, and a survey of relevant Danish industries was performed in order to enhance and detail the statistical information regarding consumption of resorcinol.

In order to give an estimate of environmental exposure to resorcinol, the calculation rules and default values in the EU Technical Guidance Document were used to calculate emissions to air, water and soil from the processes taking place in Denmark. Amounts of waste generated were estimated based on interviews with technicians in relevant industries.

The information regarding resorcinol is summarised in Table 0.1. The minimum amounts given in the table are best case (lowest values) information from the industrial survey and the maximum amounts are combined statistical and survey information using the best possible level of detail.

Table 0.1. Minimum and maximum amounts (in kilo) of resorcinol imported for processing and use in Denmark.

It is noted that the maximum estimate is lower – about 5% - than the estimate based on statistical information. The difference can be ascribed to the different levels of detail of the information sources. The difference in minimum and maximum values for import of wood glue is primarily related to the content being reported in intervals, while the difference for rubber production reflects the differences between information from the industrial survey and the available statistical information. However, the range given in the table are judged to be fair estimates of minimum and maximum amounts for the flow of resorcinol in Denmark.

In Table 0.2, the low consumption estimate from the survey is combined with the high (worst case) estimate from the combined statistical and survey information. Together, they are assumed to give a realistic figure for the range of emissions of resorcinol to different compartments of the environment when the EU TGD calculation rules are applied.

Table 0.2. Minimum and maximum estimates (in kilo) of emission of resorcinol in Denmark.

There is very little information available on generation of waste containing resorcinol. The information is summarized in Table 0.3 below.

Table 0.3. Generation of waste (in kg) containing resorcinol in Denmark.

1 Chemical waste disposed at Kommunekemi
2 Household waste, disposed by incineration

The following figures are the most important conclusions from the substance flow analysis:

• The annual turnover of resorcinol in the Danish society lies in the range between 6,650 and 22,350 kg
• The emissions to air lies in the range between 274 kg and 1343 kg
• The emissions with waste water lies in the range between 855 and 1416 kg
• The emissions to soil lies in the range between 1 and 2 kg
• The amount of resorcinol in chemical and household waste lies between 97 and 310 kg

The largest potential for human exposure is assumed to be from hair dyeing with resorcinol containing products. Using the EU calculation rules when testing cosmetic ingredients for their safety evaluation, the potential intake through skin contact can be estimated to 60 mg per hair dyeing process, or 1 mg/kg body weight. It is remarked that the EU Cosmetics Directive permits a concentration of resorcinol up to 5% and in this case, the exposure will be a factor five higher. It is also the hair dyeing process that holds the largest potential for emissions via waste water.

Additionally to the above figures for turnover of resorcinol in Denmark it is mentioned that there is an import and export of resorcinol that is strongly bound in a matrix in tires and wood products. This resorcinol is assumed not to be available for environmental exposure and is therefore not included in the overall material balance for Denmark.

It is difficult to point to a trend in the Danish consumption of resorcinol. The statistical information shows a fairly constant consumption, while the survey of Danish industries indicates a small decrease in consumption. In practice, changes in the turnover of resorcinol in Denmark will primarily be related to the development in the wood industry, using resorcinol for production of laminated wood construction and high-quality plywood. Other important areas are manufacturing of rubber products (conveyor belts and V-belts), chemical synthesis and hair-dye products. It is, however, not possible to establish a general trend for either of the applications.

Click here to see Figure 0-1.

Figure 0-1. Mass balance of resorcinol in Denmark. The stated amounts refer to the minimum and maximum estimates in kilos.

The mass balance for resorcinol in Denmark thus shows that the use primarily relates to products in which resorcinol is bound in a matrix where further emissions cannot be expected. A significant amount is transformed by chemical synthesis (to an unknown product or products), while the use in hair dye products and pharmaceuticals causes an exposure of humans and environment before the substance is degraded.

It is difficult to point to alternatives to resorcinol that have the same properties and are readily available. In the wood industry, the United Soybean Board (an interest organization for US soybean farmers) claims that soy-based glues can be used as extenders for resorcinol-containing glues in some applications. The soy-based glue can only replace some of the resorcinol, and the main difference is therefore that smaller amounts are used.

With respect to rubber products, it is very possible that substitutes for resorcinol are available. However, the rubber industry is traditionally very secretive about its materials and processes, and it is therefore not possible to point to specific solutions.

In hair dyeing products, resorcinol is used as a coupler in the colouring system but it has not been possible to determine the exact function more precisely in the current project. Accordingly, it is also not possible to point to possibilities for substitution of resorcinol.

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Version 1.0 November 2004, © Danish Environmental Protection Agency