It is against the law to cause pollution and for the last five years, fuels have consistently been among the UK’s top three pollutants. This means that any fuel spill or leak needs serious and imminent attention. Just one litre of oil is enough to contaminate one million litres of water, putting human life, wildlife and vegetation at severe risk. Depending on the density of the oil, it will either float, semi-submerge or sink in river, lake or stream water. The same oil, however, may have a different reaction when in seawater as the salt changes the density of the water.

Oil leaks and spills are tightly monitored in the UK and polluters run the risk of running foul of the wealth of legislation covering any such incidents:

• Control of Pollution (Oil Storage) Regulations (Northern Ireland) 2010
• Control of Pollution (Silage, Slurry and Agricultural Fuel Oil) Regulations (Northern Ireland) 2003, as amended
• Environmental Civil Sanctions (England) Order 2010Environmental Civil Sanctions (Wales) Order 2010
• Environmental Permitting (England and Wales) Regulations 2016, as amended
• Environmental Protection Act 1990
• The Control of Pollution (Oil Storage) (England) Regulations 2001 (as amended) in England.
• The Control of Pollution (Oil Storage) Regulations (Northern Ireland) 2010 (as amended) in Northern Ireland.
• The Water Resources (Control of Pollution) (Oil Storage) (Wales) Regulations 2016 (as amended) in Wales.
• Water Environment (Controlled Activities) (Scotland) Regulations 2011 (as amended) in Scotland.
• Water Environment and Water Services (Scotland) Act 2003
• Water Resources (Control of Pollution) (Silage, Slurry and Agricultural Fuel Oil) (England) Regulations 2010, as amended

Contaminated water can have any number of serious health effects. Diseases such as hepatitis and dysentery may be caused by contamination from septic tank waste. Poisoning may be caused by toxins that have leached into well water supplies. Wildlife can also be harmed by contaminated groundwater. Other long-term effects such as certain types of cancer may also result from exposure to polluted water, and the BTEX set of compounds carry risks of their own.

Types of fuel

Conventional diesel fuel is a mixture of hydrocarbons obtained by the distillation of crude oil. Unlike a spark-ignited petrol engine, diesel engines are ignited by the heat generated through air compression.

Biodiesel is an alternative to conventional diesel. As biodiesel is primarily derived from plants it’s considered a renewable resource. Usually, biodiesel is blended with ordinary diesel and works in most diesel engines without the need for engine modification. Because the UK government aims to reduce vehicle emissions – and burning biodiesel releases lower emissions than conventional diesel – it is most commonly used in transport. In shipping, the use of biodiesel is more popular in leisure engines than the marine ones. In fact, the Finland-based Meriaura Group of companies make the maximum use of biodiesel, proudly pronouncing their vision “to be the leading forerunner in environmentally friendly, innovative and solution-oriented maritime transport and ship management services”. However, the use of biodiesel in marine engines does present challenges. It has to meet the EU’s strict fuel standard before being used on the ships, and biodiesel is also not stable and can become oxidized in the fuel oil system.

“It is against the law to cause pollution and for the last five years, oil has consistently been among the UK’s top three pollutants. This means that any oil spill or leak needs serious and imminent attention. Just one litre of oil is enough to contaminate one million litres of water, putting human life, wildlife and vegetation at severe risk”

Storing red diesel onsite is often a necessity for farmers as legally the fuel is only meant for usage off public roads. Storing white diesel is also a popular practice in the agricultural industry to speed up workload during busy times. In the late summer and early autumn diesel storage is particularly essential as farmers work long hours to harvest but also to plough, cultivate and sow ready for the following year. This requires big machines working long hours against the seasonal clock and on-site diesel storage can make a difference between profit and loss.

Heavy fuel oil is the most common fuel oil used for shipping. Due to its high viscosity, heavy fuel oil is mixed with diesel to make it float. Today, over 60,000 vessels globally use heavy fuel oil for propulsion, and this can be seen in many of the nation’s harbours. Most shipping owners and companies still use it despite its negative impact on the environment because of its lower prices and wide-scale availability. Limited availability and infrastructural constraints also impede the large-scale adoption of greener fuels. Heavy oils, which have a density of 1.01 g/cc, would float in the ocean, but sink in a river, and are therefore especially problematic to clean up in rivers.

Currents in a river are generally directed downstream which is the direction oil will run, but unlike the sea (which has a sandy barrier, a beach), plants and trees grow right up to the river’s edge. It’s much harder to remove oil from vegetation than from a hard-packed sand beach. Spill responders try to protect the plants by using booms, but if the vegetation gets oiled, responders often either cut, burn, or flush it with water to try to get the oil out. Oil that sinks also gets caught in particles, making extraction expensive and challenging.

LNG is often promoted as an alternative to oil fuels and the most commonly used non-oil fuel used in sea vessels today. Shipowners can either fit a gas-burning engine or incorporate a dual-fuel engine to run their vessels using LNG. Despite some commendable projects, the collective take-up has been low due to the infrastructural restriction in terms of supply and storage.

Aviation fuel is a specialized type of petroleum-based fuel used to power aircraft. It is generally of a higher quality than fuels used in less critical applications, such as heating or road transport, and often contains additives to reduce the risk of icing or explosion due to high temperature, among other properties. Airports, and the pipelines supplying airports, are also a cause of oil pollution into the water table.

Storing fuel

Groundwater provides approximately a third of public water supply in England, and makes an important contribution in Wales and Scotland, which is why oil entering waters from storage facilities is a clear concern. In the UK, everyone storing oil (including diesel, biodiesel, kerosene and petrol) in a container with a capacity of over 200 litres must follow oil storage regulations, ie requiring bunds. The exact regulations that apply depend on the quantity of diesel being stored, whether it’s used for commercial or domestic applications, and the UK country in which the diesel tank resides. A bund is an outer container surrounding the inner tank which stores the fuel and is required to have a capacity of at least 110% of the inner tank. The bund works to catch any spillages from the inner tank and reduces the risk of oil contaminating waterways and the environment.

In the US, gasoline, heating oil, and other liquid petroleum products that form the bulk of the nation’s fuels and energy supply are often stored in underground storage tanks, commonly referred to by the acronym UST.

There are more than 553,000 USTs throughout the US storing petroleum and other hazardous substances (see UST finder). Leaking can lead to serious environmental and health risks, including the contamination of groundwater, which is also the source of drinking water for nearly half of all Americans.

Recommended fuel sensors

UviLux FUEL – Highly sensitive UviLux sensor for detection of aromatic hydrocarbons.
UviLux BTEX – Highly sensitive UviLux sensor for detection of the highly refined BTEX group of contaminants (benzene, ethylbenzene, toluene and xylene).