Dimethyl octadecylphosphonate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.1 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

1 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.01 mg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

0.1 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

4 270 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

427 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

854 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

20 mg/kg food

Assessment factor:

300

Additional information

Micro-organisms

An activated sludge respiration inhibition study was not performed since it was considered technically infeasible to perform testing given that DMOP is highly insoluble in water (7.656E-07 g/l 25°C derived from the (Q)SAR WSKOW (v1.42)).

Exposure to STP microorganisms is expected to be limited, according to the ATIEL Group Specific Environmental Release Categories (SpERCs) factsheet for formulation of lubricant additives, lubricants and greases (SPERC Factsheet Ai-add-pack-(2012-10-05)) “User sites are assumed to be provided with oil/water separators or equivalent and for waste water to be discharged via public sewer system”.

In addition, the exposure and risk assessment for formulation (note:- formulation is considered to represent a worst case scenario relative to professional and consumer use) of DMOP, based on EU tonnage, and calculated using OECD ESD No.10 for Lubricants and Lubricant Additives combined with EUSES v2.1.2, indicates that there is no cause for concern for the aquatic environment.  The PNEC Micro-organisms was therefore based on the aquatic toxicity data.

Water compartment

The current strategy for deriving a protective PNEC water, outlined in the REACH Guidance (R.10: Characterisation of dose [concentration] – response for environment), indicates that the appropriate assessment factor should be applied to the lowest acute L(E)C 50 value obtained from toxicity testing in fish, aquatic invertebrate and algal species. In the event that chronic toxicity data are available from three separate trophic levels, the appropriate assessment factor is applied to the lowest NOEC value derived. Given that DMOP is highly insoluble, short-term toxicity testing has been performed only in invertebrates (Daphnia magna), as detailed below.

48-hour static acute toxicity study with Daphnia magna was performed in a test designed to meet the requirements of OECD Test Guideline 202. As DMOP is highly insoluble in water the Water Accommodated Fraction (WAF) procedure was applied to prepare the test solutions. In the limit test where 20 daphnids were exposed to a nominal loading rate of 100 mg/l for 48 hours and a second group of 20 daphnids was exposed to dilution test water (control solution), no immobilisation was observed in any of the test solutions at 0, 24 or 48 hours. The (Median Effective Loading rate) was >100 mg/l and the No Observed Effect Loading rate was ≥100mg/l.

The data derived from the daphnia study demonstrate that DMOP is not toxic at a loading rate of 100 mg/L. In consideration of these data and the difficulties in testing due to the very low water solubility of DMOP, further aquatic testing was not performed and the PNEC has been derived from the EL50 of >100 mg/l.

 

The proposed PNEC fresh water of 0.1 mg a.i./L is based on the EL50 derived from the daphnia study with an assessment factor of 1000. The proposed PNEC marine of 0.01 mg a.i./L is based on the application of an additional assessment factor of 10 to the assessment factor of 1000 applied to the EL50 value obtained from the invertebrate toxicity study.

Sediment

A PNEC sediment freshwater has been determined using the equilibrium partitioning method based on the PNEC freshwater derived above, in accordance with Equation R.10-2.

Where:-

RHOsusp = 1150 kg/m3

PNEC freshwater = 0.1 mg/l

PNEC sediment freshwater = 928 mg/kg wwt

PNEC sedimentfreshwater = 4270 mg/kgdwt

A PNEC sediment marine has been determined using the equilibrium partitioning method based on the PNEC marine water derived above, in accordance with the Equation R.10-2.

Where:-

RHOsusp = 1150 kg/m3

PNEC marine water = 0.01 mg/l

PNEC sediment marine = 92.8 mg/kg wwt

PNEC sediment marine = 427 mg/kgdwt

Terrestrial Compartment

A PNEC soil has been determined using the equilibrium partitioning method based on the PNEC freshwater derived above in accordance with Equation R.10-5.

Where:-

RHO soil = 1700 kg/m3

PNEC freshwater = 0.1 mg/l

PNEC soil = 753 mg/kg wwt

PNEC soil = 854 mg/kg dwt

 

Exposure to Man via the Environment

The PNEC oral for man via the environment of 2.5 mg/kg bw/d is based on the NOAEL of 300 mg/kg bw/d from the 28 day combined rat repeat dose toxicity and reproduction/developmental toxicity screening test. The PNEC was derived using a correction factor of 120 (assessment factors of 4 × 5 × 6 were applied for interspecies, intraspecies and conversion from sub-acute to chronic exposure, respectively).

Secondary Poisoning of Birds and Mammals

The PNEC oral of 20 mg/kg food is based on the NOAEL of 300 mg/kg bw/d from the 28 day combined rat repeat dose toxicity and reproduction/developmental toxicity screening test. A conversion factor of 20 was used to convert from mg/kg bw/day to mg/kg food/day together with an assessment factor of 300 to extrapolate from subchronic to chronic.

Environmental No effect Concentrations (PNECs)

Compartments	PNEC
Micro-organisms in STP	0.1*	mg/L
Fresh water aquatic	0.1	mg/L
Fresh water sediment	928 4270	mg/kg wwt mg/kg dwt
Sea water	0.01	mg/L
Marine sediment	92.8 427	mg/kg wwt mg/kg dwt
Terrestrial compartment	753 854	mg/kg wwt mg/kg dwt
Man via the environment (total daily intake)	2.5	mg/kg bw/d
Secondary Poisoning of Birds and Mammals	20	mg/kg food

* Based on PNEC freshwater as there are no data on STP micro-organisms.

 

Conclusion on classification

The EL50 (Median Effective Loading rate) for DMOP is >100 mg/l, therefore, DMOP does not merit classification based on toxicity as "Hazardous to Aquatic Environment - Chronic Category 1, 2 or 3".

DMOP however fulfils the criterion defined in Regulation (EC) No 1272/2008 DMOP for classification as Chronic Category 4 since DMOP is a poorly soluble substance for which no acute toxicity is recorded at levels up to the water solubility and has a log Kow of ≥ 4 (the estimated BCF derived from BCFBAF v3.01 is 684.6 L/kg).

In conclusion, the proposed classification for DMOP is:

Hazardous to the Aquatic Environment-Chronic Category 4

H413: May cause long lasting harmful effects to aquatic life.