The few drops of gasoline that fall from a fuel nozzle when you fill up your car probably seem insignificant. However, a recent study suggests that these drips could accumulate over time and cause serious contamination to nearby soil and groundwater. This problem poses the greatest threat to busy gas stations near residential areas, where people are more likely to be affected by the minor spills over time.
The study, published by Markus Hilpert and Patrick N. Breysse, faculty members at the John Hopkins Bloomberg School of Publich Health, is based on a mathematical model the researchers designed to simulate the effect dripping gasoline might have over time. In a report published by the Journal of Contaminant Hydrology, Hilpert and Breysse calculated that an estimated 1,5000 liters of gasoline are spilled at an average gas station over a period of 10 years. The impact could be even greater at larger gas stations and roadside stops, which often help refuel over 10,000 vehicles a month. Because of this, the study concludes that the problem may need further research to understand the full effects this may be having on local environments.
Despite this final point, however, earlier research supports the study’s claims: for example, a 2002 study in North Carolina found higher levels of toxic gasoline components in stormwater samples taken near service stations and in groundwater originating from a former leaking underground storage tank. However, state officials in the researchers’ state of Maryland say that state regulatory standards, as well as dispensary and tank equipment, can largely ensure that the area’s water supply is protected.
Naturally, most environmental protection groups and public health organizations are more concerned with large-scale leaks that have occurred at gas stations in the past. For example, one 25,000-gallon leak underneath an ExxonMobil station in Baltimore County resulted in the contamination of a number of household wells in Jacksonville, Maryland. Because of this, most gas stations and their equipment suppliers invest in leak testing services to prevent any problems that might result from faulty machinery or other flaws.
However, Hilpert and Breysse insist that even droplets can have a significant impact on the environment over time. Although they admit that they collected no field samples and there is no hard evidence suggesting that gasoline drops have contaminated groundwater, they pointed out that rainfall can easily wash gasoline traces into the surrounding area. Moreover, research has indicated that gasoline can soak into pavement and possibly even into the underlying ground, putting the soil at risk for contamination. And while spill-prevention technology helps, it isn’t infallible. But whether their data is correct has yet to be proven, an event that may come sooner rather than later: scientists at St. Johns Hopkins have contacted state regulators about conducting further studies at selected service stations.