Y. Gao

Hong Kong Baptist University, Chiu-lung, Kowloon City, Hong Kong

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Publications (4)13.32 Total impact

  • Y Gao · S C Wu · X Z Yu · M H Wong
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    ABSTRACT: An experiment was conducted to reveal the effects of rice cultivation as well as polycyclic aromatic carbohydrates (PAHs) degrading bacterium (Acinetobacter sp.) on the dissipation gradients of two PAHs (PHE and PYR) in the rhizosphere. The results showed that the presence of rice root and bacteria significantly accelerated the dissipation rate of PHE and PYR. The root exudates contributed to the formation of dissipation gradients of PHE and PYR along the vertical direction of roots, with a higher dissipation rate in the rhizosphere and near rhizosphere zone than the soil far away the rhizosphere.
    No preview · Article · Aug 2010 · Environmental Pollution
  • J H Li · Y Gao · S C Wu · K C Cheung · X R Wang · M H Wong
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    ABSTRACT: Phenanthrene (Phe) and pyrene (Pyr) are two typical polycyclic aromatic hydrocarbons (PAHs) found in contaminated soil. This study investigated physiological and biochemical responses of rice (Oryza sativa L.) to PAH stress after they were planted in soils contaminated with Phe and Pyr, in the presence or absence of a PAH-degrading bacteria (Acinetobacteria sp.). A number of parameters including biomass and water, chlorophyll and chlorophyll a/b ratio, electrolyte leakage, activities of superoxide dismutase (SOD) and peroxidase, and soluble carbohydrate and soluble protein contents were monitored. Results show that rice plants have good resistance and tolerance to lower levels of PAHs stress, while adding high levels of PAHs to soils resulted in adverse effects on rice plants such as a reduction in biomass and damage to photosynthetic function. Water content and SOD activities were the most sensitive indicators of PAH stress among the observed parameters. Inoculation with PAH-degrading bacteria promoted growth and photosynthesis of rice.
    No preview · Article · Apr 2008 · International Journal of Phytoremediation
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    ABSTRACT: The effects of cultivation of rice (Oryza sativa L.) and PAH-degrading bacteria (Acinetobacter sp.) separately, and in combination, on the dissipation of spiked phenanthrene and pyrene (0, 50 + 50, 100 + 100, 200 + 200 mg kg− 1) in waterlogged soil were studied using pot trials. The population of introduced PAH-degrading bacteria remained at 105 CFU g− 1 dry soil after 20 days of treatment with Acinetobacter sp. only, but increased to 106 when planted with rice simultaneously. Shoot and root biomass of rice when grown alone was adversely affected by spiked PAHs, but significantly increased by 2–55% and 8–409%, respectively, when inoculated with Acinetobacter sp.. Phenanthrene and pyrene concentrations in roots ranged from 1–27 and 20–98 mg kg− 1, respectively, while their concentrations in shoots were generally lower than 0.2 mg kg− 1. The dissipation of phenanthrene was mainly due to abiotic loss as 70–78% phenanthrene was lost from the control soil at the end of 80 days, while removal of 86–87% phenanthrene had been achieved after 40 days in the treatment co-cultivated with Acinetobacter sp. and rice. Compared with the control where only 6–15% of pyrene was removed from soil, a much higher dissipation of pyrene (43–62%) was attained for the treatments co-cultivated with Acinetobacter sp. and rice at the end of 80 days. The results demonstrated that co-cultivation of rice and PAH-degrading bacteria may have a great potential to accelerate the bioremediation process of PAH-contaminated soil under waterlogged conditions.
    Full-text · Article · Jan 2007 · Science of The Total Environment
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    ABSTRACT: The concentration, distribution, profile and possible source of polycyclic aromatic hydrocarbons (PAHs) in soil were studied in Guiyu, an electronic waste (E-waste) recycling center, using primitive technologies in Southeast China. Sixteen USEPA priority PAHs were analyzed in 49 soil samples (0–10 cm layer) in terms of individual and total concentrations, together with soil organic matter (SOM) concentrations. The concentrations of a sum of 16 PAHs ranged from 44.8 to 3206 μg kg−1 (dry weight basis), in the descending order of E-waste open burning sites (2065 μg kg−1) > areas near burning sites (851 μg kg−1) > rice fields (354 μg kg−1) > reservoir areas (125 μg kg−1). The dominant PAHs were naphthalene, phenanthrene and fluoranthene, which were mainly derived from incomplete combustion of E-waste (e.g. wire insulations and PVC materials), and partly from coal combustion and motorcycle exhausts. All individual and total PAH concentrations were significantly correlated with SOM except for naphthalene and acenaphthylene. Principal component analysis was performed, which indicated that PAHs were mainly distributed into three groups in accordance with their ring numbers and biological and anthropogenic source. In conclusion, PAH concentrations in the Guiyu soil were affected by the primitive E-waste recycling activities.
    No preview · Article · Nov 2006 · Chemosphere