The transformation from above the ground storage facilities to Underground Storage Tanks (USTs) was commenced at a time when there were no stringent regulatory frameworks or any scientific literature relating to the role of USTs on the quality of underground water reservoirs.
Through the decades, the effects of pollution of ground water supplies were comparatively muffled or plainly ignored because there were no prevalent adverse ecological or human health manifestations. Florida is endowed with an abundance of the underground water resource. Through foresight, stringent regulations and compliance mechanisms, the state has largely succeeded in ensuring that this fundamental resource is free from pollution from any other subterranean input save from the pervasive pollution from underground spillages and leakages. This paper offers a succinct analysis of the policies, regulatory frameworks and compliance mechanism that have been instituted to ensure that the integrity of the underground water system is maintained. Additionally, the paper also offers some novel approaches for future interventions as well as calling on all humanity to honor and protect the environmental health for the justification of our own physical health.
Originally, liquid chemical storage tanks were kept above the ground. Underground storage started after the realization that these chemicals were more prone to vehicular accidents, tampering, and theft. Such facilities also took up real estate space. It, therefore, meant that if these facilities were buried then such problems as theft or tampering would be eliminated. At that period in time , there were no mechanisms in existence that could be used to assess the longevity of these containers under the ground nor other problems that could originate from this shift to underground storage.
In the years that spanned from the 1920s to the 1980s, millions and millions of tanks were installed at residential, industrial, commercial and governmental sites. In most cases after the initial installation, these tanks were completely forgotten until the leaks and spills presented themselves as a notable environmental and health threat . As early as the 1960s and 1970s these tanks had been incriminated to be the principal sources of underground water contamination. Earlier tanks were made of unprotected steel that could leak even before ten years elapsed. Moreover, the state and longevity of the tank were also determined by other factors such as the type of soil and the prevalent climatic condition.
Underground Water Storage Tanks
Usually abbreviated as USTs, these tanks contain a variety of chemicals, notably gasoline, other petroleum derived products and a myriad of hazardous substances. In the United States, there are millions and millions of these potentially dangerous and hazardous chemicals before they are either used or disposed of. The variety of chemical substances that are contained in USTs increases the likelihood of groundwater contamination hence the inscription “ticking time bombs” . The threat is further magnified due to the paucity of accurate data showing the exact number of USTs but they are estimated to be as many as 15 million units .Only 1.5-3 million units are encompassed under the federal regulations because they are relatively large and possess some special features. The remainders are generally unregulated. This projection in the number of USTs is not inclusive of the long forgotten and abandoned units despite the fact that they present an equally terrifying possibility of leakage.
Generally, old and dilapidated tanks will leak. Of the federally regulated tanks, 25% are already leaking while 30-35% is not compliant with federal regulations such as the tank tightness tests . The main threat of USTs is that they are distributed everywhere unlike other hazardous wastes. This means that since both urban and rural regions store gasoline and other petroleum products; UST derived contamination is not an industrial concern but rather a concern for every private citizen.
Causes of Spills and Leaks
- Operational errors
- Improper installation
- Piping failures and,
- Tank failure
Operational errors are principally caused by filling and dispensing errors; key human errors. This form of contamination occurs both above and under the ground. Overfills are a problem especially in underground tank systems that do not have cut off or overfill protection devices. Such systems are usually comparatively small but the frequent losses are a cause of concern for underground water integrity especially if these losses occur for a relatively long period of time.
Improper installations that are not compliant with laid down local, state and federal regulations account for a comparatively high percentage of the amount of spillage or leakages. Tanks and piping failures surmise as the other causes of underground contamination. Piping leaks are principally due to corrosion, loose fittings or improper sealing of the pipe joints, stresses resulting from freeze-thaw cycles, hydraulic shock, pump induced vibrations or even the wetting-drying cycles that are usually common in high shrink-swell soils. Tank failures represent the most damaging leaks to the environment. Tank failures are predominantly caused by corrosion; a natural electrochemical process that should always be factored in the design and installation of underground tank systems.