Evaluation of alternative oil spill cleanup techniques in a Spartina alterniflora salt marsh.

Three oil spill situations which cause long-term impact were simulated in 1 m(2) salt marsh plots to evaluate the effectiveness of alternative cleanup techniques at removing oil and reducing damage to Spartina alterniflora. Cleanup techniques, implemented 18-24 h after oiling, were not effective at removing oil after sediment penetration. When oil remained on the sediment surface, flushing techniques were most effective at removal, reducing levels of added oil by 73% to 83%. The addition of dispersant to the flushing stream only slightly enhanced oil removal. Clipping of vegetation followed by sorbent pad application to sediment was moderately effective, reducing added oil by 36% to 44%. In contrast to flushing and clipping, burning increased the amount of oil in sediment by 27% to 72%. Although flushing and clipping were effective at oil removal, neither technique reduced initial damage to plants or enhanced long-term recovery. While flushed plots sustained no additional plant damage due to cleanup, clipped and burned plots sustained additional initial plant damage. Based on these results, first considerations should be given to natural tidal flushing as the means to remove oil, especially in salt marshes subject to ample tidal inundation. Although our results do not support cleanup in salt marshes with ample tidal inundation, low pressure flushing may be warranted when fuel oils or large quantities of crude oil impact salt marshes subject to reduced tidal flushing. Flushing, when warranted, should be initiated prior to oil penetration into the substrate. Clipping may be considered as a cleanup response only when heavy oil cannot be effectively removed from vegetation by flushing. Burning is not recommended because it enhances oil penetration into sediment and causes substantial initial plant damage.