Keep on Truckin'
An increasing awareness of the environmental impact of vehicle oil and grease leakage from U.S. trucks and cars is leading to new approaches to prevent this major source of stormwater pollution
- By Arthur Cuse
- Sep 01, 2002
First, we discovered that our vehicles were polluting the air we breathe. Now, we're beginning to realize the extensive amount of stormwater pollution that is being caused by our trucks and cars.
There are approximately 3 million trucks in the United States with fifth wheels, which are the coupling bearing between a tractor or truck and its trailer. The bearing is open and greased when the vehicle is in use, typically with the chassis grease used on the truck. Why chassis grease? Because it's what's available. Depending mostly on weather, frequency of fifth wheel greasing is between once a day (usually in winter) and once a week (usually the rest of the year). The reason the bearing is re-greased is that most of the grease from previous applications is either washed down, squeezed out or dropped off when the vehicle is in use. Last week's lubing is this week's storm water pollution. A large amount of the stormwater pollution caused by leaked chassis grease is in truck terminals and loading and unloading areas. The remaining portion of the leaked chassis grease is found on streets and highways that are heavily traveled by trucks.
Up On the Radar Screen
Governmental agencies are beginning to pay more attention to the impact that vehicle lubrication practices can have on the environment. For example, in November 1999, Dennis A. Dickerson, the executive officer of the California Regional Water Control Board in the Los Angeles Region sent an advisory letter to officials in municipal and state government and environmental program managers in certain industrial sectors concerning lubrication practices for vehicle-trailer coupling. He pointed out the common practice of generously lubricating these couplings can result in oil and grease contamination of stormwater runoff from drippings on to roadways and highways. According to Dickerson, stormwater pollution from highways and roadways is a leading cause of surface water impairment in Southern California. He encouraged the evaluation of current vehicle maintenance practices and the options available for source control measures to reduce the potential contamination of stormwater from vehicle-trailer coupling lubrication practices.
The Impact on Stormwater Quality
Measuring highway stormwater runoff means measuring non-point source storm water contaminants. Testing is starting to be performed by various governmental agencies. Concerns about the negative effects of vehicle oil and grease leakage on stormwater runoff are supported by the data compiled by the California Department of Transportation (Caltrans). The state agency collected stormwater monitoring dated during both the 1999 to 2000 and the 2000 to 2001 monitoring seasons. Water quality samples were analyzed for a variety of constituents classified as hydrocarbons, organics such as volatile organic compounds, pesticides, polychlorinated biphenyls (PCBs) and miscellaneous others. Data was organized by categories and summarized by observed range, number of samples and percent detected as reported. The data for the 1999 to 2000 highway first flush water quality shows that tests were conducted to determine the presence of the following types of hydrocarbons: oil and grease, diesel, gasoline, heavy oil and motor oil. The test results indicate that hydrocarbons were present in significant quantities in the stormwater runoff.
The data for the 2000-2001 highway runoff water quality monitoring shows that tests were conducted to determine the presence of the same types of hydrocarbons as the prior year's monitoring. The testing data results demonstrate that heavy oil and diesel were present in significant quantities in the stormwater runoff from high ways. In addition, during the 2000-2001 period the agency tested the quality of the stormwater runoff at selected vehicle maintenance yards. The results show that oil and grease and heavy oil were present in significant quantities.
Estimating the Extent of the Problem
The monitoring conducted by Caltrans provides some insight into the impact that vehicles are having on stormwater runoff and our nation's overall water quality. No tests, however, have been conducted on the amount of vehicle oil and grease that is being released into the environment in the United States. Due to the lack of current scientific documentation, we can only attempt to estimate the quantities of vehicle oil and grease being leaked or dripped onto our nation's roadways. We are in the beginning stages of measuring many things about stormwater pollution. A survey comprised of an adequate number of vehicles will also be needed to give statistical validation. An expensive project, but one which presumably will have to be performed in the future in order to determine the magnitude of this source of stormwater pollution. Until precise data is generated, our rough estimates concerning the quantity of oil and grease leakage serves to give us a starting point to begin addressing this serious source of stormwater pollution. A survey comprised of an adequate number of vehicles will also be needed
Car and truck stormwater pollution is being caused by oil and grease drip of on-board lube systems, leaks through seals, boots, gaskets, exposed fittings and wash-off from truck fifth wheels. Our estimates do not include other sources of stormwater pollution, such as spills, used oil dumping, disposal of used oil by car dealers and service stations or and other forms of disposal of used oil.
To estimate the amount of vehicle oil and grease being released on highways, streets and vehicle maintenance yards requires first determining the approximate number of automobiles currently in use in the United States. In 1999, 7,951,737 trucks of all sizes were sold. (Source: Commercial Carrier Journal.) Sales were lower in 2000 and 2001. If we multiply 7,951,737 by an average 10 year life per vehicle, this indicates an estimated 79.5 million trucks are presently in use on U.S. roads. Wards Communications of Southfield, Mich. estimates, as of July 1999, there were 126.9 million cars on U.S. roads.
Combining 79.5 million trucks with 126.9 million cars equals a total of 206.4 million vehicles. This does not include farm, construction and other off-road vehicles. Wards calculated a combined total of 209.5 million vehicles, so our estimate of 206.4 million seems reasonable.
Based on looking for many years at drip quantities, we estimate approximately one ounce of discarded oil and grease per car and truck each month. Again, there is no scientific evidence to document this so we are forced to make an educated guess about this quantity based upon real world observations under a variety of conditions.
Our estimates indicate the following totals:
206.4 million vehicles x 1 ounce leak or drip of oil and grease per month?
206.4 million ounce. per month
= 12.9 million pounds per month
= 154.8 million pounds per year
Add 100 million pounds of grease pollution from truck fifth wheels each year. (Source: BSI 1999 data sheet)
Stormwater pollution from above vehicles...155 million pounds per year
+ 100 million pounds per year
= 255 million pounds per year
Until scientific studies are conducted to better determine the total amount of vehicle oil and gas leakage in the United States, we must rely upon our rough estimates as a starting point in helping us better understand the magnitude of this non-point source of stormwater pollution.
Perhaps the best way to measure vehicle oil and grease leakage is at each and every potential discharge point located on the vehicle. This means at each gasket, seal, boot, bolt and other potential leak points - perhaps as many as 100 to 200 per vehicle. The following is a listing of some of the major potential discharge points.
Onboard Lubricatoin Systems: These are used on some of the big trucks and trailers. They typically consist of an oil or grease reservoir, a pump, timer and plastic tubes that carry the lube to bearings. Due to high-priced real estate, these systems really started in Asia. High cost kept service stations there small and spread out. But low level truck service caused so much trouble for truck owners, on board lube systems were adopted. In terms of stormwater pollution, these are a complete disaster. It's like the truck fifth wheel bearing - you put more oil or grease in the reservoir because the previous amount has been pumped to bearings and now has dripped to the ground and is becoming stormwater pollution. Unless you add seals, boots or accumulation points on the vehicle and service these on some schedule, this is a big stormwater polluter.
Seals: Engines, transmissions, wheels and other moving parts use seals of some form to keep oil and grease from dripping. The problem is many of the seals have one side fixed and the other rapidly rotating. The seals wear and start to drip. Many times they are not replaced. Drip spots under your car tell you should replace seals, but when was the last time you did this? To keep seals from dripping, it may be practical to tie into the service cycle of cars and trucks. The big seal replacement problem is labor cost. It takes a lot of time (read cost) to change an engine front seal and also seals between the engine and transmission and transmission rear seals. The real world solution to this leaking may be change in mechanical and seal design, better quality seal material and/or a reservoir to catch drip.
Boots: Most people, especially teenagers, really like these. Typically made of shiny black plastic, with accordion pleats, they look neat. But what happens to boots is quite like gaskets and seals. There can be both chemical and mechanical wear. Ozone, high and low temperature cycling, vibration, deposited oil, grease, road chemicals - all can cause cracking or drastic loss of strength and failure. Road rocks, driveways, parking lots, squirrels and other vectors can punch holes in the boots. The result is oil and grease accumulation safely in a boot are discarded from the vehicle and become a source of stormwater pollution.
Boots can be replaced on a schedule, but with current designs this again may be very expensive labor-wise. For example, to change boots on tie rods, you have to take the rod ends off. The most practical solutions may be to increase lube quality, boot material quality or provide a reservoir that can be pumped or replaced.
Gaskets: All too often leaks occur in today's vehicles. Head, valve, pan and other gaskets should seal better than they do in many vehicles currently on our roads. The answer is design improvements.
Sealed for life: This is the popular concept of the last few years. The only thing we don't know is whose life. Is it the life of the car, the length of the warranty plus five thousand miles, the car manufacturer, the life of the initial car owner or the life of the little old lady at the end of the street - the one who takes an oxygen bottle when she goes to the supermarket?
Without fanfare, since 1996 and perhaps earlier, auto manufacturers have sold some cars with no chassis lube fittings. The question is how long will the front end last? The way zerk grease fitting elimination was done by the manufacturer of our car is interesting. To save money, not even screw plugs were put in. Drilling and tapping to create customer paid lube points to extend front-end life is made difficult because it has been made expensive. Let's say design life is 100,000 odometer miles. Anyone want to guess what the total pollution will be? Add to the stormwater pollution all pollution amounts from the whole parts manufacturing cycle: Ore mining, making steel, rolling steel, machining and forming parts, parts packaging and distribution - on and on. Add the costs of old parts disposal; now this is pollution, big time!
Since fifth wheels typically cause a large amount of total vehicle stormwater pollution, regulations prohibiting the use of chassis grease on fifth wheels will and should start here. Why are regulations required? Well, it's the human factor again - resistance to change. Remember what the truckers say: "pollution is not a problem for me at this time and until it is, I am not going to change what I do." Mark Twain commented he loved new things, but he didn't like change. Maybe it's similar to how seat belts, air bags, high mounted rear stoplights and other safety items were adopted. It's just the way it gets done with people being what they are.
Solving Leaks from Fifth Wheels
There are three effective ways to stop the stormwater pollution from truck fifth wheels.
Plastic Plates: These are typically an extruded polyethylene sheet, about a fifth wheel wide (36 inches, more or less). This sheet fits between the truck and trailer portions of the fifth wheel bearing. It's usually about ¼ inch thick. Useful plate life is one month to three years. It mostly depends on how badly cut the plastic plate becomes from inaccurate backing of the truck under the trailer when they hook up.
Fifth Wheels with Plastic Inserts: More expensive than regular fifth wheels, these have plastic bearing inserts on which the trailer rides. Wear rates have been high (low mileage plus high cost) but are improving.
Alternative Lubrication: A highly adhesive synthetic chemical paste, Adhesive Lube™, of almost food grade quality with no solvents or volatile organic compounds, takes the place of grease on the fifth wheel. Typically only 2 ounces to 3 ounces. are used to cover a fifth wheel. Storm water pollution is cut 95 percent to 99 percent. This product is nonhazardous and can be disposed of in a municipal landfill.
Further Down the Road
The large quantity of oil and grease stormwater pollution from vehicles is just now beginning to be realized and understood. And most people are just beginning to appreciate the value of good clean water, especially if they live in major cities where water purification plants are working overtime to keep water safe.
After some time period for education, perhaps 10 to 20 years from now, we predict there will be nationwide vehicle regulations, for both cars and trucks?that will embody the basic concept that "If it drips from anywhere you can't drive it.".
This article originally appeared in the 09/01/2002 issue of Environmental Protection.