Vehicle Fuel's Water Pollution: Understanding The Harmful Impact

Water pollution caused by vehicle fuel is a pressing environmental issue. While the exact impact of vehicle fuel on water pollution remains uncertain, it is known that fuel leaks and spills from storage facilities, pipelines, and shipping accidents can contaminate water sources, posing risks to human life, wildlife, and vegetation. Improperly discharged motor oil and emissions from gasoline vehicles contribute to water pollution, with one litre of oil capable of contaminating one million litres of water. The costs of addressing these environmental impacts are significant, ranging from billions of dollars for cleaning leaking underground storage tanks to controlling highway runoff. As a result, regulations, economic incentives, and preventive measures are crucial to mitigating the water pollution caused by vehicle fuel.

How does vehicle fuel cause water pollution?

Leaking underground storage tanks

To address these issues, the US Environmental Protection Agency (EPA) has established the Leaking Underground Storage Tank Trust Fund. The fund was created by Congress in 1986 to specifically tackle petroleum releases from federally regulated underground storage tanks. Over time, the fund's scope has expanded to include leak prevention activities, with a focus on providing financial support for cleanups and prevention programs. The fund is financed by a tax on motor fuel sales, with the money being used to oversee cleanups, conduct inspections, and support leak prevention initiatives.

When a leak occurs, responsible parties, including tank owners and operators, are required to respond promptly and efficiently to minimise the potential threats. This includes investigating the entire underground storage tank system, not just the area where the leak occurred, as per EPA regulations. The EPA also encourages the use of risk-based decision-making to determine the appropriate cleanup method, taking into account factors such as risk factors, cost, local policies, available technologies, and community input.

Performance monitoring and evaluation are crucial to assess the progress and effectiveness of the cleanup efforts. This includes evaluating the performance of remedial technologies and assessing conditions at identified compliance points, such as groundwater monitoring wells, surface water, and soil gas. The EPA provides guidelines and requirements for managing corrective actions, and states and tribes use the LUST Trust Fund money to support their cleanup and prevention programs.

The EPA's Office of Underground Storage Tanks works in partnership with its regional offices to implement the UST program in Indian country, providing technical and financial assistance to tribal governments to prevent and address petroleum releases from USTs.

Highway runoff

Vehicle-related particulates in highway runoff come primarily from tire and pavement wear, contributing about a third each. Engine and brake wear account for approximately 20% of the pollutants, while exhaust emissions make up about 8%. In addition to these direct sources, roads also collect pollutants from other sources, such as agricultural runoff, wind-blown contaminants from manufacturing and energy production, and road salts used for maintenance in colder climates.

The impact of highway runoff on water quality is significant. Each year, millions of gallons of improperly discharged motor oil contaminate streams, lakes, and coastal areas. The US Environmental Protection Agency (EPA) estimates that one gallon of used oil has the potential to contaminate one million gallons of water. This pollution can lead to severe ecological consequences, including the contamination of freshwater sources for communities.

The costs of addressing highway runoff pollution are substantial. Estimates suggest that controlling highway runoff pollution in the US alone could range from $2.9 billion to $15.6 billion per year over 20 years, representing a significant proportion of annual highway transportation expenditures. These costs include implementing preventive environmental measures, such as engineering solutions, and adopting policies that combine economic incentives, information campaigns, and enforcement.

While the focus here is on highway runoff, it is important to recognize that motor vehicle transportation impacts water quality in various ways, including leaking underground storage tanks (LUSTs) and the improper disposal of waste coolant/antifreeze, used oil, and metal dust from brake pads. The complex nature of these pollution sources and the potential for new contaminants to be introduced into the environment make it a continuous area of study and a challenging issue to address.

Air pollution

Carbon dioxide is a well-known greenhouse gas that contributes to global warming and climate change. When gasoline burns, carbon and hydrogen separate. Carbon combines with oxygen to form CO2, while hydrogen combines with oxygen to form water vapour. The amount of CO2 produced depends on the vehicle's fuel type, fuel economy, and annual mileage. A typical passenger vehicle emits approximately 4.6 metric tons of CO2 annually, and each gallon of burned gasoline produces about 8,887 grams of CO2.

Methane and nitrous oxide are also potent greenhouse gases. Methane has a higher global warming potential than CO2, and while its emissions from gasoline vehicles are smaller, they can still have a significant impact on the environment. In addition to tailpipe emissions, all vehicles can release hydrofluorocarbon (HFC) from leaking air conditioners, which further contributes to air pollution.

To address air pollution from vehicle fuel, several alternatives are being explored. Electric vehicles (EVs) have gained popularity as they do not produce tailpipe emissions. Instead, they run on battery power and electric motors, significantly reducing air pollution from tailpipe emissions. Fuel cell electric vehicles (FCEVs), which operate on hydrogen, only emit water vapour, making them even more environmentally friendly.

Plug-in hybrid electric vehicles (PHEVs) are another option, but their emissions are more complex as they use both gasoline and electricity. When operating solely on electricity, PHEVs produce zero tailpipe emissions, but when using gasoline, they emit similar pollutants to traditional gasoline-powered vehicles. The overall emissions of PHEVs depend on various factors, including battery capacity, driving patterns, and charging frequency.

While the use of biodiesel, a renewable resource derived from plants, has been explored as an alternative to conventional diesel, it faces challenges. Biodiesel must meet strict fuel standards and has stability issues, as it can become oxidized in the fuel oil system. Nevertheless, companies like the Finland-based Meriaura Group have embraced biodiesel as part of their commitment to environmentally friendly practices in maritime transport.

Oil spills and leaks

On land, oil spills and leaks often occur due to accidents or malfunctions involving storage facilities and pipelines, which then contaminate nearby water sources. Underground storage tanks (USTs) have been a particular cause for concern, with over 450,000 confirmed fuel leaks in the US alone, as reported by the US EPA in 2005. The cleanup costs for these leaking tanks are estimated to range from $0.8 billion to $2.1 billion per year over a decade.

Highway runoff is another significant contributor to oil pollution in water bodies. This occurs when oil and other vehicle-related particulates from tire, pavement, engine, and brake wear, as well as exhaust emissions, accumulate on highways and are subsequently washed into nearby streams, lakes, or coastal areas during rainfall or snowmelt. The US EPA estimates that up to half of the suspended solids and a sixth of the hydrocarbons in streams originate from freeways.

In harbours and rivers, oil spills from shipping accidents or direct spills are a primary cause of water pollution. The impact of oil spills can be devastating, with just one litre of oil capable of contaminating one million litres of water. This poses a severe risk to human life, wildlife, and vegetation. The density of the oil determines whether it floats, semi-submerges, or sinks in freshwater bodies, while the presence of salt in seawater can alter the oil's behaviour due to changes in water density.

The environmental impact of oil spills and leaks is not limited to immediate contamination. Oil can persist in the environment for extended periods, leading to long-term effects such as wildlife poisoning, vegetation damage, and increased cancer risks for humans and animals exposed to polluted water.

Groundwater contamination

Petroleum products contain various potentially toxic compounds, including solvents and additives. Some of these compounds, such as ethylene dibromide (EDB) and benzene, are known or suspected carcinogens. Methyl tertiary-butyl ether (MTBE), a fuel additive, has been frequently detected in shallow groundwater samples from urban areas in the United States. When gasoline is released into the subsurface, its organic components can be transported through bulk movement, leading to groundwater contamination.

Mechanic shops and vehicle repair facilities are also known to release petroleum products into the environment, which can eventually reach and contaminate groundwater. This contamination can occur through soil and vapour, with some constituents undergoing biotic or abiotic degradation or transformation, leading to the spatial and temporal distribution of contaminants within the subsurface environment.

Additionally, condensation in fuel tanks can introduce water into the fuel system, causing various issues such as engine misfires, corrosion, and decreased fuel efficiency. While not directly related to groundwater contamination, it is worth noting that rainwater infiltration into fuel tanks due to faulty or improperly sealed fuel caps can compromise fuel quality and lead to engine damage.

To prevent groundwater contamination from vehicle fuel, regular inspections and proactive protective measures are necessary. This includes addressing leaks in underground fuel tanks and proper waste management at mechanic shops and vehicle repair facilities.

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