Lubricant Biodegradation & Toxicology Testing

Although great effort is put into prevention, its standard practice to presume that some lubricant will enter the environment. The ability to biodegrade and maintain low toxicity to organisms are key considerations in product development; especially for sensitive environments than could see a significant impact from the introduction of potentially hazardous liquids. For customers in the energy and maritime industries, biodegradability and toxicology testing are important steps to gaining market acceptance for both new and existing products. It also helps add value and distinguishes a product from the competition.

Lubricant Biodegradation

For biodegradation testing of solution-based (liquid) formulations OECD 301B and ISO 14593 are the most commonly requested methods in the U.S. and Europe.

Claims about a products’ biodegradability are challenging. It can be loosely applied as a description, yet depending on the market it can also be a strictly regulated performance parameter.

Graph showing Ready and Ultimate Biodegradation of a control material. Biodegradation is measured in this case by Theoretical Oxygen Demand (%ThOD).

Readily Biodegradable – is seen in the shaded area within day 4. Its precise definition is the required biodegradation within a 10 day window in the 28 day maximum period.

Ultimate Biodegradability – the maximum attained degradation within the test period. Example shown in the graph at around 80%.

Before making a claim about a products performance consider:

1. What type of Biodegradability is needed? Inherent, Readily or Ultimate Biodegradability?
2. Is toxicity a concern?
3. Does the customer have specific regulatory needs?

Ready and Ultimate Biodegradability are the most common measurements for biodegradability.  Readily Biodegradable is rate of biodegradation that occurs within a specified time frame. At a certain point, the rate of biodegradation will plateau and no more of the material will biodegrade. This is Ultimate Biodegradability. Both values are analyzed in ISO 14593 and in OECD 301B.

Solution Based Biodegradation is covered  either OECD 301B or ISO 14593 methods will provide a satisfactory assessment. The two methods have been harmonized and represent very similar test methods. Although there may be some preference depending on the needs of a customer in a given region, a customer’s familiarity with one of the methods, or if there are specific regulatory requirements.

Toxicology Testing

Toxicology testing is commonly required for different product applications claiming to be environmentally acceptable. The EU Ecolabel for Lubricants requires marine or freshwater toxicology testing and recommends the three following toxicology tests: OECD 201; Algae Growth Inhibition test, OECD 202; Daphnia Immobilization test, and OECD 203; Fish, Acute Toxicity Test.

Toxicity testing can also be used to determine if liquid components are introduced into the environment that will hinder or even prevent plant growth. Customers use the OECD Guideline 208 for Terrestrial Plant Growth in conjunction with the OECD 301B Test Series. Other aquatic plant toxicology methods include OECD 221; Lemna sp. Growth Inhibition test and OECD 238; Myriophyllum spicatum toxicity test.

Have questions? Just contact us at 847-483-9950 or info@situtest.com and we can help guide the process to select the appropriate test.

Sources/Links:

• OECD.org
  – OECD Organisation for Economic Co-operation and Development
• OECD 301B
  – Request a test quote for OECD 301B
  ISO.org
  – ISO International Organization for Standards
• ISO 14593 and OECD 301B
  – EPA Inherent Biodegradability Test Guidelines
• ISO 14593
  – ISO 14593 Test Quotes