Bioremediation of Petroleum Hydrocarbons in the Upper Parts of Sandy Beaches

Abstract

The biodegradation of dispersed crude oil in the ocean is relatively rapid (a half-life of a few weeks). However, it is often much slower on shorelines, usually attributed to low moisture content, nutrient limitation, and higher oil concentrations in beaches than in dispersed plumes. Another factor may be the increased salinity of the upper intertidal and supratidal zones because these parts of the beach are potentially subject to prolonged evaporation and only intermittent inundation. We have investigated whether such an increase in salinity has inhibitory effects on oil biodegradation in seashores. Lightly weathered Hibernia crude oil was added to beach sand at 1 or 10 mL/kg, and fresh seawater, at salinities of 30, 90, and 160 g/L, was added to 20% saturation. The biodegradation of oil was slower at higher salinities, where the half-life increased from 40 days at 30 g/L salts to 58 and 76 days at 90 and 160 g/L salts, respectively, and adding fertilizers somewhat enhanced oil biodegradation. Increased oil concentration in the sand, from 1 to 10 mL/kg, slowed the half-life by about 10-fold. Consequently, occasional irrigation with fertilization could be a suitable bioremediation strategy for the upper parts of contaminated beaches. However, dispersing oil at sea is probably the most suitable option for the optimal removal of spilled crude oil from the marine environment.

Exploring the Role of Nanobubbles in the Fate and Transport of Spilled Oil on Shorelines

“…Bubbles produced by breaking waves are also found in offshore areas . More importantly, the shoreline is not only a sink for pollutants but also plays host to further transport and transformation of pollutants. − As a traditional pollutant in the ocean, oil spills seriously harm local ecosystems once stranded in the shoreline environment. , There have been many studies investigating the fate and transport of oil stranded on shorelines, but almost all have paid attention to only light irradiation, temperature, salinity, shoreline substrate, microbial degradation, and other conventional factors. − NBs affect not only the physical transport of pollutants but also their chemical weathering, biodegradation, and adsorption with other environmental pollutants. Meanwhile, no studies have thus far focused on the potential effects of NBs on spilled oil in the shoreline environment.…”

Post-Formation of Oil Particle Aggregates: Breakup and Biodegradation

“…The exploitation and transportation of crude oil in marine environments have resulted in numerous catastrophic oil spills that ended up contaminating coastal ecosystems. − When oil spills contaminate shorelines, the biodegradation of stranded petroleum hydrocarbons becomes much slower, − especially in the upper intertidal and supratidal zones. ,,− In addition, if the concentration of suspended particles in subtidal zones , is high (e.g., 400–800 mg/L), the oil droplets get trapped by the particles, , thereby slowing down their biodegradation due to entrainment and settlement. − …”