Hydraulic oil spills: Reducing the damage

The first step in cleaning up a spill comes when you decide which oil to buy - mineral or vegetable

Rock Gaussion, Ph.D.

A mower returns from the greens with tires glistening. Somewhere on the course a hydraulic line split, and it won't take long to figure out where the leak started. The effect of 160- to 200-degree Fahrenheit oil on actively growing turf is rapid and disastrous. The question is: What should be done?

In addition to questions about remedies, other questions also arise after a spill. How long will it take for the damage to heal? Can the damaged area be overseeded or will the oil impair germination? Do oils differ in their potential damaging effects? These questions were addressed in research at the University of Nebraska in 1997.

Previous research
Little research information is available on hydraulic fluid spills and turfgrass. Research in 1978 (2) evaluated treatments such as activated charcoal, calcined clay, detergent and water, applied within 20 minutes after petroleum spills. (The researchers didn't heat the hydraulic fluid to normal operating temperatures reached during equipment use.) Detergent was the only treatment found to increase recovery.

It has been reported that activated charcoal will absorb oil from spills but will not increase breakdown, resulting in an unsightly, messy black residue within the damaged turf (1).

Another research project on petroleum spills (4) evaluated granular dishwashing detergent, liquid dishwashing detergent, activated charcoal, calcined clays, waterless skin cleaner and a non-ionic wetting agent. Liquid dish detergent was the best corrective treatment. Researchers recommended treatment within 60 minutes of the spill. Other products, such as oil emulsifiers and synthetic absorbents, are also available to alleviate damage caused by hydraulic fluid spills (3).

Research procedure
In 1997, a bentgrass putting green located at The John Seaton Anderson Turfgrass Research Facility near Mead, Neb., was subjected to a series of hydraulic oil spills. The green was Penncross creeping bentgrass maintained at 1/8 inch.

Two hydraulic oils, a standard mineral grade oil (SAE 10W-30) and a biodegradable plant seed oil, were heated to between 140 and 160 F in a microwave and sprayed on the green in three strips, each 4 inches by 5 feet. One strip of each oil type was left untreated, one strip each was flushed with water and the final strips were treated with liquid dishwashing detergent and flushed with water within 20 minutes after the spill. For statistical purposes, this process was repeated three times for a total of 18 treatments (two oils, three treatments, three replications).

Over the next eight weeks, researchers collected data and removed cores from each treatment weekly. The cores went into the greenhouse where they were overseeded with creeping bentgrass. Data collected from the cores revealed percent germination and regrowth of injured turf.

Results
Turf injury was greatest one week after the spill, regardless of oil type, for plots treated with dishwashing detergent and a water drench. It appeared that the soap dispersed the oil, causing injury over a greater area of the green, which confirms earlier researchers' work (2).

By two weeks after treatment, however, all plots were equally damaged. At three to four weeks, all plots began to show recovery. The greatest recovery was exhibited by the biodegradable seed oil flushed with water or both soap and water. The seed-oil spill with no treatment was equivalent to the soap-and-water flush of the mineral oil spill seven weeks after treatment.

The seed oil spills, treated or untreated, showed acceptable recovery four to five weeks after treatment. Among the mineral oil treatments, only the spill treated with soap and water exhibited acceptable recovery at four to five weeks. The untreated mineral oil and the mineral oil spills flushed with water were still exhibiting extensive injury up to seven weeks after treatment

The greenhouse cores that were overseeded did not show a difference, based on regrowth or germination, among treatments. Germination and regrowth were excellent among all treatments, indicating that spills can be successfully overseeded with no adverse effects on germination.

Summary
This investigation reveals:

Soap-and-water flushing of a hydraulic oil spill will increase injury initially, but this effect is short-lived.

Recovery of turf from a hydraulic spill is significantly better when the spill is a biodegradable seed oil, especially if the spill is flushed with water or soap and ater.

The hydraulic oils tested had no effect on germination of creeping bentgrass.

Hydraulic oil spills have a disastrous effect on bentgrass golf greens. Depending on the type of oil used and the corrective action taken, recovery can occur within four weeks after the spill or take longer than two months. Prompt action, as well as the right choice in hydraulic oil, can significantly improve recovery.

Acknowledgments

The author gratefully acknowledges Dave Ferguson of Ransomes for providing technical information and the oils used in this investigation.

Literature cited

1. Anonymous. 1986. Handling oil spills. Divots 36(3):8.
2. Johns, D., and J.B. Beard. 1978. Effects and treatments of petroleum spills on bermudagrass turf. Agronomy Journal 71(6):945-947.
3. Falkner, M.R. 1991. Emergency repair products. Golf Course Management 59(6):90-94.
4. Powell, A.J. 1981. Recovery of creeping bentgrass after a hydraulic oil spill. p.37-46. In: Kentucky Turfgrass Research. University of Kentucky, College of Agriculture, Lexington, Ky.

Roch Gaussoin is an Extension turfgrass specialist at the University of Nebraska.