|Substance Group: Citric Acids / Salts|
The member countries of the Organisation for Economic Co-operation and Development (OECD) systematically investigate High Production Volume (HPV) chemicals in order to determine the need for further work on these chemicals. The set of minimum data elements that must be available to draw recommendations is known as the 'Screening Information Data Set' or SIDS. A SIDS Initial Assessment Report (SIAR) for citric acid was presented at SIDS Initial Assessment Meeting (SIAM) 11 in January 2001, and its status was determined to be currently of low priority for further work.
This Initial Assessment Report (SIAR) is available and accessible at the following address: http://www.chem.unep.ch/irptc/sids/oecdsids/indexcasnumb.htm.
HERA is determined to avoid any duplication of effort and to discourage effort for the sake of only marginal improvements. However, HERA believes that HERA Risk Assessments should be carried out where significant additional risk information can be obtained, and where a refinement of the existing assessments would yield new or significantly different conclusions in particular for the detergent use scenario. A decision which option should be selected has to be taken on a case by case basis.
The available data confirm the low acute and (sub)chronic toxicity profile of Citric Acid. The NOAEL for repeated dose toxicity (for rats) is 1200mg/kg/d. It is not suspected of being a carcinogen nor a reprotoxic or teratogenic agent. Citric Acid is not mutagenic in vitro and in vivo, and its sensitising potential is seen as low.
Citric Acid has wide dispersive use, it is naturally present in common fruit and vegetables and is added to processed food and beverages. Potential consumer exposure to citric acid as a consequence of its presence in household laundry & cleaning products is expected to be several orders of magnitude below the rats` NOAEL and of little significance when compared with the normal dietary intake. The available information is judged to be adequate for concluding that the use of citric acid in household laundry and cleaning products raises no safety concerns for consumers.
Citric acid is a chemical substance with a very favourable ecological profile. Due to the very low aquatic toxicity and the ready biodegradability, wide dispersive use of citric acid does not present a hazard to the environment.
Several laboratory biodegradation tests (both ready and inherent) show that citric acid and citrate, respectively, is rapidly degraded in both sewage works and surface waters (OECD, 2001; Hoyt and Gewanter, 1992). Available environmental monitoring data show that while raw sewage contains up to 10 mg citrate/l, background concentrations in river water range between <0.04 and maximally 0.2 mg/l (OECD, 2001). It should be kept in mind that these citrate concentrations do not only derive from manmade citric acid, of which the HERA usage accounts for less than 20%, but that citric acid is extremely widespread in nature.
A worst case estimate of the environmental concentrations can be deduced from the available information (see 2.) about the total production figure of citric acid of max.500 000 tons/a in Europe, including Eastern Europe and Israel and a 20% share of wide dispersive use in technical applications. Based on a population figure of ca. 470 million of people (EU-25) and a per capita water consumption of 200 l/day, a raw waste water concentration of 2.9 mg/l can be calculated which shows a good agreement with the mentioned monitoring data. Conservatively assuming a degree of elimination in WWTP of 87% (based on the figure for readily biodegradable substances provided in Appendix 1 of Part II of the TGD), a WWTP effluent concentration of 0.38 mg/l can be calculated leading to a river concentration of approximately 0.04 mg/l. This figure corresponds again very well to the mentioned few river monitoring data.
In freshwater, citric acid appears to be of low acute toxicity to fish, daphnia and algae, with consistent LC50/EC50 values of several hundred milligrams per litre (OECD, 2001). Based on an overview of concrete acute toxicity data of sodium citrate on fish, daphnia and algae (Hoyt and Gewanter, 1992) with an EC50 range of 825 1750 mg/l, a PNEC of 0.8 mg/l can be derived (applying an assessment factor of 1000 acc. to TGD). Available (sub)chronic data with a long-term daphnia test giving a geometric mean EC50 of 98 mg/l and lowest reported EC0 in cyanobacteria of 80 mg/l (OECD, 2001) support the assumption that the derived PNEC is very conservative.
In spite of the conservativism of this rough exposure and effects assessment, the preliminary risk characterisation shows that the estimated river concentration of citrate is far below the PNEC. Therefore the available information is judged to be adequate for concluding that the use of citric acid in household laundry and cleaning products raises no safety concerns for the environment.