Biodegradable, Environmentally Acceptable and Non-Toxic Lubricants
It is relatively common for terms referring to ’biodegradability’, ’environmental acceptance’, or ’toxicity’ to be confused or used in the wrong context within the lubricants industry. End users of such lubricants, especially those operating in environmentally sensitive areas, should make themselves aware of the actual requirements that apply to their particular operation and make appropriate lubricant choices to ensure their equipment assets and the surrounding environment are protected in the event of any accidental or inadvertent discharge of lubricant.
Lubricants Biodegrability Test Method
OECD 301B is the currently accepted international standard biodegradability test method in use for lubricants and is utilized by the majority of the environmental agencies globally. This test evaluates primary and final degradation of the tested substance within a controlled time frame.
Lubricant Types Based on Biodegradability Level
Depending on their level of biodegradability, lubricating oils and greases could fall into the following main categories:
- Readily biodegradable
- Inherently biodegradable
- Environmentally acceptable
What are the differences between these lubricant types?
Readily Biodegradable Oils and Lubricants
Products are considered ‘readily biodegradable’ when they have the natural ability to biodegrade to their natural state, when subjected to sunlight, water and microbial activity, at least 60% within 28 days in accordance with OECD 301B protocol.
To achieve such biodegradability, readily biodegradable lubricants are typically formulated with renewable or alternative base oils. These oils include plant based oils such as soy, canola, or sunflower. Other products utilize synthesized esters or combinations of plant and ester base oils. In all cases, the same basic biodegradation criteria apply. Readily biodegradable lubricants must also be free of heavy metals such as zinc. Additives containing zinc are common in the lubricants industry because of zinc’s exceptional anti-wear properties. Zinc, however, is an element and has high environmental persistence. Once in the environment, it stays for a very long time and at high concentrations can have detrimental effect on living organisms. Therefore, readily biodegradable products use alternative anti-wear additive chemistry which does not contain components with high environmental persistence or hazard.
Readily biodegradable lubricating oils and greases are also often called Environmentally Acceptable Lubricants (EAL’s). EAL’s are defined and classified by the United States Environmental Protection Agency (EPA) and are legally specified on marine vessels or applications affecting marine environments on or near the coastline of the USA.
Inherently Biodegradable Oils and Lubricants
A product may be classified as ‘inherently biodegradable’, if it will biodegrade to its natural state, when subjected to sunlight, water and microbial activity at least 20% but not greater than 60% within 28 days in accordance with OECD 301B protocol.
Products classified as inherently biodegradable may be made with plant or synthetic base material but are often made with highly refined virgin base oil. These fluids also utilize additive chemistry that is free of zinc and other heavy metals with high environmental persistence. This category of lubricants is often where the grey area is in interpretation as the same fluids could be legitimately described as environmentally sensitive or environmentally friendly. Ultimately, if a spill was to occur with fluids classified here, the fluid would degrade over time, there would be very little, if any, environmental persistence and the overall impact to the directly affected environment would be dramatically reduced as compared with a ‘standard’ lubricant designed for similar performance.
Non-Toxic Oils and Lubricants
A lubricant fluid may be classified as ‘non-toxic’ or ‘not environmentally toxic’ if it or its base components have passed tests confirming it is not acutely toxic to fish, daphnia, or algae according to the United Nations Globally Harmonized System (GHS) criteria.
Some fluids that are classified as readily or inherently biodegradable may also meet GHS non-toxic criteria. Typically, non-toxic oils and lubricants are specified for use in marine environments, applications in operation near fresh water, or where such fluids may be at risk of exposure to people.
The terms ‘readily biodegradable’, ‘inherently biodegradable’, ‘environmentally acceptable’ and ‘non-toxic’ do mean different things and in some cases, choosing the wrong lubricant type may mean serious environmental consequences should there be an accidental spill or a piece of equipment has a blown hose. By being aware of the differences between the above terms and the advantages, disadvantages and price points of this variety of lubricants, users of lubricating oils can make an informed decision considering both the environmental impact and their business objectives and priorities. To support its partners that need readily biodegradable hydraulic fluids, KLONDIKE offers BIO AW 32 Hydraulic Fluid and BIO AW 46 Hydraulic Fluid. Within the inherently biodegradable, also known as environmentally acceptable lubricants, KLONDIKE offers Zinc Free AW 46 Hydraulic Fluid.