Detaljerad miljöinformation

Environmental Risk Classification

Predicted Environmental Concentration (PEC)

In order to normalize the different chlorhexidine varieties on the active ingredient chlorhexidine, all sales volumes are adjusted to the molecular weight of chlorhexidine.

Chlorhexidine variety	Molecular weight (g/mol)	Tonnage conversion factor
Chlorhexidine	505,4	1
Chlorhexidine digluconate	897,8	1,78
Chlorhexidine diacetate	625,5	1,24

PEC is calculated according to the following formula:

PEC (μg/L) = (A*10⁹*(100-R))/(365*P*V*D*100) = 1.37*10^-6*A(100-R)

PEC = 0,317 μg/L

Where:

A = 2314,82kg Chlorhexidine as the total of 3983,21kg Chlorhexidine digluconate and 95,55 Chlorhexidine diacetate all normalized to Chlorhexidine molecular weight (ref. 1)

R = 0 % removal rate (due to loss by adsorption to sludge particles, by volatilization, hydrolysis or biodegradation) = 0 if no data is available.

P = number of inhabitants in Sweden = 10 *10⁶

V (L/day) = volume of wastewater per capita and day = 200 (ECHA default) (Ref. 2)

D = factor for dilution of waste water by surface water flow = 10 (ECHA default) (Ref. 2)

PEC = 0,317 μg/L

Predicted No Effect Concentration (PNEC)

Ecotoxicological studies

Blue-green algae (Cyanobacteria) (Ref. 5):

M. aeruginosa, (OECD 201 Guidelines (2006)

EC₅₀ 96h (growth inhibition) = 0,2064 mg/L

M. panniformis, (OECD 201 Guidelines (2006)

EC₅₀ 96h (growth inhibition) = 0,1714 mg/L

Green algae (Scenedesmus subspicatus) (ECHA c2007-2015b) (ref. 3):

EC₅₀ 72 h (growth inhibition) = 0,0062 mg/L

Green algae (p. subcapitata) (ECHA c2007-2015b) (ref. 3):

EC₅₀ 24 h (growth inhibition) = 0,0233 mg/L

Crustacean (Daphnia magna) (ECHA c2007-2015b) (ref. 3):

EC₅₀ 48 h (immobilization) = 0,049 mg/L

Bluegill sunfish

(Lepomis macrochirus) (US EPA 2011b) (ref. 3):

LC₅₀ 96 h = 0,29 mg/L

(L. macrochirus)

LC₅₀ 96 h = 0,5 mg/L

Zebrafish (Danio rerio) (ECHA c2007-2015b) (ref. 3):

LC₅₀ 96-h = 1,17 mg/L

Rainbow trout (Oncorhynchus mykiss) (US EPA 2011b) (ref. 3):

LC₅₀ 96-h = 1,3 mg/L

Chronic toxicity

Green algae (S. subspicatus) (guideline ECHA c2007-2015b) (ref. 3):

EC₁₀ 72 h (growth inhibition) = 0,002 mg/L

NOEC 72 h (growth inhibition) = 0,0042 mg/L

Green algae (p. subcapitata)

EC₅₀ 24 h (growth inhibition) = 0,0116 mg/ml

Crustacean (Daphnia magna) (guideline ECHA c2007-2015b) (ref.3):

NOEC 21 days (mortality) = 0,0116 mg/L

Based on the most sensitive acute species; Green algae (p. subcapitata) EC50 24 h = 0,0116 mg/ml (equivalent to 11,6 μg/L) and an assessment factor of 50 is applied, in accordance with ECHA guidance (Ref 2).

PNEC = 11,6/50 μg/L = 0,232 μg/L

Environmental risk classification (PEC/PNEC ratio)

PEC/PNEC = 0,317 / 0,232 = 1,366 , 1 < PEC/PNEC ≤ 10 which justifies the phrase Use of Chlorhexidine has been considered to result in moderate environmental risk.

Degradation

Biotic degradation

Chlorhexidin is not biodegradable in accordance to OECD 301D (ref.3)

Test results 0 % degradation in 28 days

Justification of chosen degradation phrase:

Based on the data presented above, the phrase, Chlorhexidine is potentially persistent is chosen.

Bioaccumulation

Bioconcentration factor (BCF):

Golden eye (Leuciscus idus melanotus) (OECD 305), exposing fish to chlorhexidine at 0.05 mg/L for 3 days. (ref. 3)

BCFs = 42

Since BCF < 500, the substance has low potential for bioaccumulation.

Physical Chemistry Data

Partition Coefficient Octanol Water Log P= 4,51(ref. 4)

Water Solubility  0.0261 mg/mL (ref. 4)

Refrences

1. Data from IQVIA ”Consumption assessment in kg for input to environmental classification - updated 2022 (data 2021)”.

2. [ECHA] European Chemicals Agency. Guidance on Information Requirements and Chemical Safety Assessment. Chapter R.10: Characterisation of dose [concentration]-response for environment. May 2008.

3. Screening Assessment, Chlorhexidin and its Salts, Environment and Climate Change Canada, Health Canada, June 2019.

4. https://go.drugbank.com/drugs/DB00878

5. Fernanda Cristina Rezende Azevedo, Izabela Cristina Dias Vaz, Francisco Antônio Rodrigues Barbosa, Sérgia Maria Starling Magalhães. Toxicological effects of ciprofloxacin and chlorhexidine on growth and chlorophyll a synthesis of freshwater cyanobacteria. Braz. J. Pharm. Sci. 2019;55:e17661