4-hydroxybenzoic acid

Endpoint summary

Additional information

Environmental findings (natural occurrence) and behaviour

 

Findings in plants and food (natural occurrence)

Naturally occurring 4-HBA has been detected in plants. It was found in 83 out of 86 tested plant families. 4-HBA does naturally exist in food. It was detected in flour, honey, cheese and olive oil (based on many peer reviewed references in the substance evaluation report No. 164 (BUA, 1996) of the GDCh-Advisory Committee on Existing Chemicals of Environmental Relevance (BUA)). Details are summarised in the tables documented in the respective endpoint study record. 4-HBA is part of the metabolism in plants. It does not belong directly to the metabolism creating or storing energy but it is an intermediate in the synthesis of numerous compounds in plants and can thus be found in fruits or vegetable. This creates a considerable natural background level in the food and the environment.
4-HBA was found in soils, peat, sediments and compost (based on many peer reviewed references in BUA (1996), Turtura et al. (1998)). For details see attached tables (of BUA, 1996)

in the respective endpoint study record

.

Further, 4-HBA is formed during the degradation of wood (Haider et al., 1964 cited in BUA, 1996).

Environmental findings in the compartment air

4-HBA has been found in airborne particulate matter in concentration of 66 mg/kg dry mass dust (Cautreels and Van Cauwenberghe, 1976; 1977 cited in BUA, 1996). The authors mention vegetation as potential source.

4-HBA in the air compartment from synthetic sources (manufacture and use of 4-HBA) can be neglected (see exposure scenarios 1 and 2 and overall combined exposure in the Chemical Safety Report sections 9.1, 9.2 and 10.1, 10.2 and 10.3).

 

Environmental findings in the compartment water

4-HBA is found in the hydrosphere. As summarised in BUA (1996), 4-HBA has been detected in water samples (e.g. spring water, surface water both fresh and sea water) in the range of 0.05 µg/L to 6.5 µg/L. There was apparently no difference between surface water of highly industrialised areas, waste waters and waters left largely in a natural state. Plants, their composition products (detritus) and metabolism of bacteria, fungi and algae are given as possible main sources (BUA 1996).

4-HBA in the water compartment from synthetic sources (manufacture and use of 4-HBA) can be neglected (see exposure scenarios 1 and 2 and overall combined exposure in the Chemical Safety Report sections 9.1, 9.2 and 10.1, 10.2 and 10.3). This view is supported by OECD SIDS (1999). Direct and indirect emissions to the environment can be neglected based on the calculations for 4-HBA done by the authors of the OECD SIDS (1999) evaluation.

 

Environmental findings in the compartments soil and sediment

4-HBA is found in the soil compartment. See attached table in the respective endpoint study record in IUCLID for details. According to the authors Raina and Goswami (1988) reviewed in BUA (1996), the quantities analysed are mainly attributable to decomposition products of dead vegetable material. In sediments 4-HBA is mainly present in the form of esters (Matsumoto and Hanya, 1980, cited in BUA, 1996).