Indigenous oil-degrading bacteria (ODB) were screened from two islands, Iriomote, Japan and Con Dao, Vietnam. These islands are considered predicted contamination sites from oil spillage on a nearby busy transportation route. The aim of this study was to compare the degradation abilities of bacterial isolates from the two different study areas for crude oil, n-alkanes, and polycyclic aromatic hydrocarbons. Comparing the two study areas, the numbers of the total bacteria and ODB showed the same distribution tendencies. There were no differences between Iriomote and Con Dao in the counts of the total bacteria and ODB in sediment samples, while those in seawater samples were statistically lower for Iriomote than for Con Dao. A total of 45 isolates, 25 from Iriomote and 20 from Con Dao, belonging to 18 genera, were isolated. Among 11 genera detected on Iriomote, the dominant genera were Achromobacter, Pseudomonas, and Ochrobactrum. Among 11 genera from Con Dao, the dominant genera were Pseudomonas and Microbacterium. The degradation ability of the isolates was studied for crude oil, two kinds of n-alkanes, and two kinds of polycyclic aromatic hydrocarbons (PAHs). The numbers of the isolates that degraded more than 50 percent of the crude oil and n-alkanes and 25 percent of the PAHs present in the media were higher for Iriomote (3, 11, and 2, respectively) than for Con Dao (2, 4, and 1, respectively). It is noteworthy that the isolates of Pseudomonas putida and Ochrobactrum anthropi could degrade more than 40 percent of the oil and n-alkanes and more than 25 percent of the PAHs present in the media.

This study aims to assess acute and chronic toxicity of some typical industrial wastewater such as textile, latex processing, paper mill, alcohol processing and leachate from municipal landfills. This result of EC50 and LC50 tests using different testing organisms showed that the toxicity of effluent is not directly proportional to COD concentration, but it depends upon BOD, ammonia, nitrite and TDS. Based on results of this study, the limited COD value of the industrial effluent quality standards for the typical industry is suggested.

Oil-degrading filamentous fungi (ODF) were enumerated and isolated from two islands, Iriomote, Japan, and Con Dao, Vietnam. Iriomote has a subtropical and Con Dao a tropical climate. The counts of total fungi and ODF in sediment samples from supratidal and intertidal zones on Iriomote were statistically higher than on Con Dao. Water samples from seawater, however, gave a reverse result. In total, 23 ODF including 11 isolates in 5 genera from Iriomote and 12 isolates in 4 genera from Con Dao were isolated. On Iriomote, the isolates which showed the highest potential of oil degradation were 2 Penicillium isolates and one Trichoderma, however they did not grow at 37℃ nor survived at 37℃. One Candida isolate has higher potential of oil-degradation, and grew and survived at temperature 42℃. On the contrary, on Con Dao, 2 Aspergillus, one Penicillium and one Trichoderma isolates had potential of oil-degradation, and grew and survived at temperature 42℃. This result suggests that comparing with subtropical Iriomote, the tropical Con Dao maintains more oil-degrading fungi which have higher-temperature resistance.