File No: NA/587 June 1998
NATIONAL INDUSTRIAL CHEMICALS NOTIFICATION AND ASSESSMENT SCHEME
FULL PUBLIC REPORT
Z-25
This Assessment has been compiled in accordance with the provisions of the Industrial Chemicals (Notification and Assessment) Act 1989 (the Act), and Regulations. This legislation is an Act of the Commonwealth of Australia. The National Industrial Chemicals Notification and Assessment Scheme (NICNAS) is administered by the National Occupational Health and Safety Commission which also conducts the occupational health safety assessment. The assessment of environmental hazard is conducted by the Department of the Environment and the assessment of public health is conducted by the Department of Health and Family Services.
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Director
Chemicals Notification and Assessment
NA/587
FULL PUBLIC REPORT
Z-25
1. APPLICANT
Lubrizol International Inc of 28 River Street SILVERWATER NSW 2128 has submitted a standard notification statement in support of their application for an assessment certificate for Z-25.
2. IDENTITY OF THE CHEMICAL Trade Name: Z-25
Generic Name: alkylamine salt of alkyl phosphoric acid
Molecular Weight: 1 000
Method of Detection and Determination:
the notifier supplied ultraviolet/visible, infrared, and nuclear magnetic resonance spectral data which serve to characterise the material
3. PHYSICAL AND CHEMICAL PROPERTIES
Appearance at 20°C
and 101.3 kPa: yellow viscous liquid
Melting Point: 20°C
Boiling Point: 123-192°C
Specific Gravity: 0.9458 at 20.5°C
Vapour Pressure: 5.0 x 10-6kPa at 25°C
Water Solubility: 1.72 g.L-1 at 25°C (see comments below)
Fat Solubility: totally soluble (see comments below)
Partition Co-efficient (n-octanol/water):
log Pow = 1.39 at 20.5 ± 0.5°C (see comments below)
Hydrolysis as a Function
of pH: not determined (see comments below)
Adsorption/Desorption: not determined (see comments below)
Dissociation Constant: pKa1 = 1.79 @ 25°C (see comments below)
pKa2 = 7.01 @ 25°C (see comments below)
Surface Activity: 32.4 mN.m-1 at 352 mg.L-1 and 20.5°C (see comments below)
Flash Point: 114°C
Flammability Limits: not determined Autoignition Temperature: not highly flammable Explosive Properties: not explosive
Reactivity/Stability: not an oxidising agent; not reactive toward water
Comments on Physico-Chemical Properties
Tests were performed according to EEC/OECD test guidelines at facilities complying with OECD Principles of Good Laboratory Practice.
The water solubility was determined as 1.72 g.L-1 using the flask method. A quantity of the test material considerably in excess of that readily soluble was shaken in distilled water at 30°C for a period of at least 24 hours. The supernatant was centrifuged, filtered (filter pore size not specified) and the phosphorous concentration determined using Inductively Coupled Plasma Emission Spectroscopy (ICPES) against a distilled water blank. The solubility of the test substance was calculated on the basis that this material contains phosphorus. This water solubility is high for a material containing a large proportion of saturated hydrocarbon, but the ionic head groups of both anionic and cationic portions of the material somewhat mitigate the hydrophobic character and are likely to bestow considerable affinity for water on the material. However, although an apparently homogeneous mixture was obtained in these tests it is likely that the material is not truly soluble to the level indicated at the molecular level, but that the solubility is enhanced through the formation of colloidal aggregates like micelles. This is supported by the low surface tension of the aqueous solutions, a very characteristic attribute of micelle forming systems, which is discussed below.
The compound is apparently completely miscible in fat, and this is a consequence of the high hydrocarbon content of the compound. However, the ionic charges carried by the two portions of the molecule will not favour incorporation into a fat matrix. To explain the very high miscibility with fat, it must be assumed that the new compound is assimilated into the fat phase as ion pairs (hence neutral), possibly in association with some bound water. In respect of this point, similar mechanisms must be operative to explain the apparently high solubility in n-octanol which is at least 2 g.L-1 as described in the report on the determination of partition coefficient - see below.
No data on hydrolytic degradation was provided, and the notifier indicated that no suitable test methods were available for appropriate tests on the new chemical. The anionic component(s) of the compound contain phosphate ester linkages (in some ways similar to those found in biological phospholipids) which are expected to be stable in the usual environmental pH region between 4 and 9. Similarly the primary amino bond in the cationic portion of the material is expected to be stable in the usual environmental pH region.
The partition coefficient was determined using the shake flask method. A stock solution of the notified material prepared at a concentration of 1.98 g.L-1 in water saturated n-octanol was shaken in a flask with various volumes of distilled water for 5 minutes, and the phases allowed to separate. Phosphorus content in each phase was analysed using ICPES and the solubility of test material is calculated as described above for water solubility. The mean partition coefficient (6 samples) was determined as 24.5±4.3, which indicate considerable affinity for water. This is probably due to formation of colloidal aggregates as mentioned above in connection with water solubility.
The screening test for adsorption/desorption was not performed for the new chemical. It is possible to make some predictions in respect of this property on the basis of the partition coefficient data and general chemical constitution of the material. Both the anionic and cationic portions of the molecule carry substantial aliphatic hydrocarbon groups which have a high affinity for natural organic matter. However, the potential for strong association with organic material will be mitigated by the ionic charges which favour association with water, and the "conflict" between these two opposing tendencies is reflected in the modest n- octanol/water partition coefficient. These considerations lead to the conclusion that the new chemical would have some affinity for organic matter, but if released into the environment is unlikely to be completely immobilised through association with the naturally occurring organic component of soils and sediments. In respect of this point, it should also be appreciated that most natural organic matter exists in the form of negatively charged colloidal particles, and consequently the binding of the cationic moieties to organic material is likely to be enhanced over that for the negatively charged phosphate ester ions.
Both the cationic and anionic portions of the new compound are structurally very similar to conventional ionic surfactants, and consequently the new chemical could be expected to exhibit surfactant properties. This is confirmed by the significant lowering of surface tension in aqueous solution from around 72.5 mN.m-1 for the blank (distilled water saturated with n- octanol) to less than half this value for a 352 mg.L--1 solution of the test material. As pointed out above in connection with the water solubility, lowering of surface tension to the degree
observed is characteristic of surfactant solutions which can form colloidal aggregates such as micelles.
The dissociation constant data provided by the notifier correspond to the first and second acid dissociation constants of mono and di esters of phosphoric acid, and indicate that the material would normally display acidic behaviour in an aqueous environment. However, pH measurements of the solutions taken during the water solubility and partition coefficient tests were between pH 4.4 and pH 5.8 indicating only modest acidic reactivity.
4. PURITY OF THE CHEMICAL Degree of Purity: high Toxic or Hazardous
Impurities: none
5. USE, VOLUME AND FORMULATION
The notified chemical will not be manufactured in Australia, but will be imported for use as an antiwear agent for gear oil lubricants. Z-25 will be imported as a component of an additive package, which will contain up to 12% of the notified chemical. The notified chemical will be used as a component of gear oil at concentrations of up to 1%.
Less than one tonne of Z-25 will be imported in the first year following notification. Import volumes will increase to greater than one tonne per year for the following four years.
6. OCCUPATIONAL EXPOSURE
Drums of product containing up to 12% of the notified chemical will be imported, and transported to customers Australia-wide by road or rail. Waterside, warehouse and transport workers would not be exposed to the notified chemical under normal circumstances.
At the customer’s site, workers may be dermally exposed while decanting the product containing Z-25 into a trough, from where it would be pumped into the blend tank. Alternatively, the imported product may be pumped directly from drums into the blend tank. Accidental ocular exposure may also occur if there is splashing during this transfer process. Inhalation exposure is not expected, because of the notified chemical’s low vapour pressure.
The imported products will be mixed with oil and possibly other additives during blending operations. The notifier states that customer blending and packaging facilities are expected to be well ventilated and fully automated. Some dermal exposure to the imported product within the finished gear oil product (containing up to 1% of the notified chemical) is likely to occur when workers are cleaning and maintaining machinery and equipment.
The gear oil containing the notified chemical is packaged in containers of 1 to 205 litres. Gear oil will be sold to commercial operators (such as fleet operators) for use in trucks. It is anticipated by the notifier that gear oil will be changed in these trucks approximately every 800 000 km, and mechanics will be routinely dermally exposed to the gear oil during oil changes. Ocular exposure is also likely while draining gearbox oil, as mechanics will be working under vehicles when carrying out this operation. Indirect eye exposure is also possible by transfer of grease from hands to eyes.
7. PUBLIC EXPOSURE
Public exposure from transport or reformulation is expected to be negligible except in the event of an accident, where spills will be contained, collected and disposed of to approved industrial facilities or recycled. Used gear oils are expected to be disposed of according to government regulations or recycled, and public exposure from disposal is expected to be low.
Public exposure may occur through the dermal or ocular route when changing gear oils for do- it-yourself services, but exposure will be infrequent.
8. ENVIRONMENTAL EXPOSURE Release
During blending of the additive concentrate containing Z-25 into lubricant products, there is little likelihood of release, since these processes are conducted in purpose constructed facilities which are expected to be fully automated. The notifier indicates that during the blending operation (typical blend sizes are 1 000 to 2 000 kg), the contents of the 200 L drum of Z-25 are decanted into a storage vessel and then pumped to a blend tank. Alternatively, Z- 25 is pumped directly to the blend tank from the drums. Following the blending operations, the product is repacked into containers for distribution to customers. The container sizes used for product distribution are between 1 and 205 L, with little release of the blended product expected during the re-packing operations since fully automated equipment is used. Any spills resulting from either the blending or repackaging operations would be contained within bundling, and would very likely be soaked up in earth or sand and sent to an approved industrial facility for appropriate disposal. This is expected to be either incineration or placement into landfill. Residuals left in the drums are anticipated to be small. In typical operations involving transfer of drum contents to other vessels, approximately 1.0% of the drum contents may remain as residual. In the present case this would account for an annual release of around 50 kg of the notified material. The notifier indicated that these residuals would be removed during drum reconditioning and would probably be incinerated.
Release during transfer of the product during the filling of transmissions would be low. While no information was provided by the notifier, it is estimated (on the basis of experience in assessing lubricant products with similar use patterns) to be a maximum of 50 mL per transfer operation. If it is assumed that each transfer uses 10 L of lubricant these losses amount to
0.5% of lubricant. In the majority of cases the filling of transmissions with the product would take place at sites of vehicle production or maintenance workshops. These releases could be expected to be contained and disposed of with other lubricant and petroleum product waste. In most cases this would be through incineration or oil recycling. When used as a component of automotive transmission oil the material will be contained in an enclosed system, and release is expected to be insignificant. The notifier indicated that gear oils are changed infrequently, and typically would not be changed till the vehicle had "clocked up" around 800 000 km. Few of these major transmission overhauls are likely to be undertaken by independent owners, and in the majority of cases such operations be performed in specialist heavy transport maintenance workshops.