Abstract

ADAMS, RH; ALVAREZ-OVANDO, AL  and  CASTANON N, G. Effect of hydrocarbon concentration of pasture production (Brachiaria humidicola) in Texistepec, Veracruz. Phyton (B. Aires) [online]. 2015, vol.84, n.1, pp.222-232. ISSN 1851-5657.

In this study, the relationship between the concentration of extra-heavy crude petroleum in a clayey material and the toxicity, field capacity, temperature, and growth of a tropical forage grass (Brachiara humidicola) was determined empirically. For this type of petroleum the acute toxicity (Microtox^®) was slight (CE₅₀ = 63200 - 76400 mg/kg) even at high hydrocarbon concentrations (29279 mg/kg). Nonetheless, serious impacts were encountered in terms of an increase in soil temperature (+ 1.3 °C), reduction in field capacity (-10.7%) and reduction in aerial biomass (-97%). The relationship between hydrocarbon concentration and biomass resulted in a typical dose-response curve (r = 0.99), where a concentration of 2626 mg/kg of hydrocarbons corresponds to a maintenance of 90% biomass. Furthermore, during the duration of this study (one year) the biodegradation was proportional to the pasture biomass production (r = 0.997) indicating a synergistic relationship between the petroleum biodegrading microorganisms in the rhizosphere and the pasture.

Keywords : Contamination; Soil; Dose-response; Field capacity; Phytoremediation.

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