Registration Dossier

Classification & Labelling & PBT assessment

PBT assessment

Administrative data

PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB
Justification:

Environmental fate considerations.

 

Phenethylammonium salt of fosfomycin is expected to be very stable in the environment.

 

In water no degradation is expected according to the results of the hydrolysis and of the ready biodegradation test. Indeed, at pH 9 (120 h at 50 °C) the hydrolysis was < 3.4%, while at 28 days biodegradation of Fosfomycin Pea Salt was 0% (not readily biodegradable).

 

Phenethylammonium salt of fosfomycin is an organic salt, freely soluble in water, which dissociates into fosfomycin ((3-methyloxiran-2-yl) phosphonic acid)) and phenethylammonium ions within the environmentally relevant pH range (5-8).

Experimental Log Koc for phenethylammonium is 4.54. Fosfomyc in anion has weak UV absorption and was not detectable at the selected wavelenght in the absorption study, then its Koc has been estimated by KOCWIN v2.00 (US EPA): calculated values of Log Koc for non-ionized fosfomycin are 0.09 (estimate from Log Kow) and 0.07 (estimate from MCI); Koc value for fosfomycin anion is not expected to be significantly different from its non-ionized form.

High mobility in soil is therefore expected for the fosfomycin anion, while pour mobility is expected for phenethylammonium.

 

Ecotoxicological data.

 

LC50 96h Danio rerio: > 100 mg/L

NOEC 96h Danio rerio: > 100 mg/L

 

EC50 48h Daphnia magna: 86 mg/L

NOEC 48h Daphnia magna: 59 mg/L

 

EC50 72h Pseudokirchnerella subcapitata: 4.6 mg/L (biomass)

EC50 72h Pseudokirchnerella subcapitata: 17.7 mg/L (biomass)

NOEC 72h Pseudokirchnerella subcapitata: < 1 mg/L (biomass)

NOEC 72h Pseudokirchnerella subcapitata: < 1mg/L (biomass)

 

NOEC 3h activated sludges = 100 mg/L

EC10 3h activated sludges = 90 mg/L (95% Confidence interval 63 – 120 mg/L)

EC50 3h activated sludges = 6200 mg/L extrapolated (95 % Confidence interval 4000 – 9900 mg/L)

 

Reasoning.

 

According to the above data and considering the lowest most relevant NOEL deriving from the toxicological section (50 mg/kg bw/day from the one-generation reproduction toxicity study), Phenethylammonium salt of fosfomycin meets the criteria for classification as persistent (P), but not the criteria for classification as bioaccumulative (B) (logKow = -3) and toxic (T). As the substance does not meet the criteria for classification as bioaccumulative, Phenethylammonium salt of fosfomycin is not regarded as vPvB (very persistent and very bioaccumulative).