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EC number: 236-337-7
CAS number: 13308-51-5
Boron orthophosphate (CAS 13308-51-5) will be hydrolytically
transformed in the ionic forms in water (B3+ and PO43-) which will
further associate with the ionic forms of H2O. Therefore a separate
assessment of the toxicity of boron and the PO43- ions is considered
Boron is ubiquitous in the environment and essential for many
organisms, e.g. for plant growth. Plants may require boron to stimulate
ascorbate metabolism, which was demonstrated in recent studies
(Mastromatteo E., Sullivan F. 1994). Boron retention in soil depends on
boron concentration in the soil solution, soil pH, texture, organic
matter, cation exchange capacity, type of clay and mineral coating on
the clay (Butterwick et al., 1989). The degree of boron fixation is
influenced by moisture content, wetting and drying cycles and
Boron may be found in four forms in soil: organically bound,
water-soluble, adsorbed and fixed in clay and mineral lattics (Adriano
1986). The highest concentration of Boron can be found in arid, saline
soils. In sandy soils, boron could be leached more readily than in clay
soils and is therefore less likely to accumulate (Adriano 1986). Boron
can bind with clays, suspended matter, and sediments of aquatic systems
(Maier and Knight 1991). As less than 5 percent of the soil boron is
available for plant uptake (Butterwick et al. 1989), a high uptake is
not expected for plants.
Phosphate is applied to soil as a fertilizer for a variety of
crops. Phosphate has low potential for adsorption to solid particles (as
it will be rapidly transformed in water into its dissociated forms).
Phosphate is an essential nutrient for terrestrial organisms. Therefore
bioaccumulation and toxicity are considered not relevant for phosphate.
One experimental study is ongoing investigating the effects of
Boron orthophosphate (CAS 13308-51-5) on mortality, behavior, body
weight and reproduction of Eisenia andrei. Until now the range finder
test with Eisenia andrei is available. Testing this representative
species of the soil fauna evaluates the exposure to the test substance
via soil pore water, surface contact as well as by ingestion of soil
particles. The available range finder study was performed according to
OECD 222 and did not result in any adverse effects on mortality,
behavior, body weight and reproduction. Thus, a NOEC (56 d) ≥ 1000 mg/kg
dw was derived for reproduction.
In addition, indirect exposure of soil via irrigation or
atmospheric transport is considered to be negligible, as the air
compartment is considered not relevant for Boron orthophosphate.
The available studies on the acute toxicity of Boron
orthophosphate on aquatic organisms determined no effects of the
substance on fish, aquatic invertebrates or algae. Toxic effects on
terrestrial organisms are therefore not expected.
The available data for toxicity to activated sludge microorganisms
support the proposal of Boron orthophosphate having a low toxicity to
soil microorganisms. No inhibition of respiration rate of a microbial
sewage treatment plant community was observed in the available study
according to OECD 209. The Guidance Document (ECHA, 2012, page 122)
states that a test on soil microbial activity will only be additionally
necessary for a valid PNEC derivation if inhibition of sewage sludge
microbial activity has occurred and this is clearly not the case. Based
on the available information, effects on soil microorganisms are not
expected to be of concern, and consequently, no further testing is
Based on the available data terrestrial toxicity testing is also
not deemed necessary.
Adriano, D.C. (1986). Trace elements in the terrestrial
environment. Springer-Verlag, New York. 533 p.
Butterwick, L.N. De Oude, and K. Raymond (1989). Safety assessment
of boron I aquatic and terrestrial environments. Ecotoxicol. Environ.
Safety 17: 339-371.
Maier, K.J., and A.W. Knight (1991). The toxicity of waterborne
boron to Daphnia magna and Chironomus decorus and the effects of water
hardness and sulfate on boron toxicity. Arch. Environ. Contam. Toxicol.
Mastromatteo, E. and Sullivan, F. (1994) Summary: International
Symposium on the Health Effects of Boron and Its Compounds. Environ
Health Perspect 102 (Suppl 7): 139 – 141
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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