Phytoremediation in the Tropics—The Effect of Crude Oil on the Growth of Tropical Plants

ABSTRACT

Phytoremediation is a nondestructive, cost-effective in-situ technology to clean up contaminated soils. In the case of contamination with petroleum hydrocarbons, plants enhance microbial degradation of the contaminant in the rhizosphere. The potential of this technology for the tropics should be high due to prevailing climatic conditions favoring plant growth and stimulating microbial activity. Investigations of the potential of tropical plants for phytoremediation, however, are scarce. The present work studied two grasses and six legumes from the eastern savannah of Venezuela on their reaction to crude oil contamination in soil. Results shall help to identify plants with a potential for phytoremediation and subsequent studies. Seedling emergence and biomass production were determined for plants growing in soil contaminated with 0%, 3%, and 5% heavy crude oil. Contamination had, in general, a tendential but not significant negative influence on seedling emergence. Dry matter production was reduced by only a few percent to up to 85%. Furthermore, in some legumes inhibition of nodulation was observed. The grass Brachiaria brizantha and the legumes Centrosema brasilianum and Calopogonium mucunoides are promising for phytoremediation because in contaminated soil they combined high seedling emergence with least affected biomass production. Since they are cultivated forage/soil cover species also in other regions of the tropics, their potential for phytoremediation of petroleum contaminated soils extends beyond Venezuela.

Keywords:

• Brachiaria
• Centrosema
• Calopogonium
• savannah
• forage species
• grasses
• legumes
• oil contamination
• petroleum hydrocarbons

ACKNOWLEDGEMENTS

This work was supported by the Fellowship Program of the Gottlieb Daimler- und Carl Benz Stiftung, Germany, project number 02–07/01. We thank Adalberto Flores and Instituto Nacional de Investigaciones Agrícolas de Venezuela for the supply of seeds.

Notes

¹ León et al. (1998).

¹ n.d. not determined.