Investigation on bioremediation of oil-polluted wetland at Liaodong Bay in northeast China

The impact of water temperature on water quality indexes in north of Liaodong Bay

The north of Liaodong Bay is one of the most severely polluted areas in Bohai Sea. Because the self-purification capacity from the sea water exchange process is limited, the pollutants from the land and river sources cannot be completed degraded and an obviously contaminated zone was formed in the north of Liaodong Bay. Therefore the self-purification capacity from biological process is essential for maintaining ecosystem balance. Marine heterotrophic bacteria play an important role in degradation of the dissolved organic matters and constitution of the primary production in the coastal areas. The shift of water temperature between winter and summer is about 28 °C in the north of Liaodong Bay, which causes changes in the self-purification capacity of the sea area. Certain indexes of water quality in Liaodong Bay were investigated in order to detect how these indexes response to the changing of water temperature. The experimental results show that COD, DO and the concentration of fecal coliform vary a little with the changing of water temperature; TBC increases dramatically when the water temperature is over 16 °C; and TBC in summer is 30 times more than that in winter. By this study, the paper provides a reference to assess the environmental purification capacity of the sea area during different seasons.

Pyrosequencing investigation into the bacterial community in permafrost soils along the China-Russia Crude Oil Pipeline (CRCOP)

The China-Russia Crude Oil Pipeline (CRCOP) goes through 441 km permafrost soils in northeastern China. The bioremediation in case of oil spills is a major concern. So far, little is known about the indigenous bacteria inhabiting in the permafrost soils along the pipeline. A pilot 454 pyrosequencing analysis on the communities from four selected sites which possess high environment risk along the CRCOP is herein presented. The results reveal an immense bacterial diversity than previously anticipated. A total of 14448 OTUs with 84834 reads are identified, which could be assigned into 39 different phyla, and 223 families or 386 genera. Only five phyla sustain a mean OTU abundance more than 5% in all the samples, but they altogether account for 85.08% of total reads. Proteobacteria accounts for 41.65% of the total OTUs or 45% of the reads across all samples, and its proportion generally increases with soil depth, but OTUs numerically decline. Among Proteobacteria, the abundance of Beta-, Alpha-, Delta- and Gamma- subdivisions average to 38.7% (2331 OTUs), 37.5% (2257 OTUs), 10.35% (616 OTUs), and 6.21% (374 OTUs), respectively. Acidobacteria (esp. Acidobacteriaceae), Actinobacteria (esp. Intrasporangiaceae), Bacteroidetes (esp. Sphingobacteria and Flavobacteria) and Chloroflexi (esp. Anaerolineaceae) are also very common, accounting for 8.56% (1237 OTUs), 7.86% (1136 OTUs); 7.35% (1063 OTUs) and 8.27% (1195 OTUs) of total libraries, respectively. The ordination analysis indicates that bacteria communities in the upper active layer cluster together (similar), while bacterial consortia from the lower active layer and permafrost table scatter (less similar). The abundance of Rhodococcus (12 OTUs), Pseudomonas (71 OTUs) and Sphingomonas (87 OTUs) is even less (<0.01%). This effort to profile the background diversity may set the first stage for better evaluating the bacterial dynamics in response to accidental oil spills.

Degradation of n-alkanes and polycyclic aromatic hydrocarbons in petroleum by a newly isolated Pseudomonas aeruginosa DQ8

A bacterial isolate, designated as DQ8, was found capable of degrading diesel, crude oil, n-alkanes and polycyclic aromatic hydrocarbons (PAHs) in petroleum. Strain DQ8 was assigned to the genus Pseudomonas aeruginosa based on biochemical and genetic data. The metabolites identified from n-docosane as substrate suggested that P. aeruginosa DQ8 could oxidize n-alkanes via a terminal oxidation pathway. P. aeruginosa DQ8 could also degrade PAHs of three or four aromatic rings. The metabolites identified from fluorene as substrate suggested that P. aeruginosa DQ8 may degrade fluorene via two pathways. One is monooxygenation at C-9 of fluorene, and the other is initiated by dioxygenation at C-3 and C-4 of fluorene. P. aeruginosa DQ8 should be of great practical significance both in bioremediation of oil-contaminated soils and biotreatment of oil wastewater.

Biorremediação de solos contaminados por petróleo e seus derivados

Em vista da eficiência comprovada da biorremediação na degradação de compostos tóxicos ao ser humano, como o benzeno, tolueno, etilbenzeno e xilenos (BTEX), diversas empresas, principalmente as relacionadas com consultorias e remediação ambiental, têm despertado grandes interesses pela implantação da biorremediação como opção para a reabilitação de áreas contaminadas. Em países desenvolvidos, como os Estados Unidos, Canadá e vários países da Europa, a técnica bioquímica de remediação vem sendo amplamente utilizada em trabalhos que se baseiam, por exemplo, no tratamento de solos contaminados por hidrocarbonetos de petróleo. Porém, ao contrário do que se tem notado nesses países, no Brasil, os projetos de biorremediação ainda estão no campo da teoria, com poucos casos práticos, embora exista uma probabilidade real de expansão. A esse despeito, uma das maiores pertinências dessa revisão é elucidar as vantagens que essa técnica pode oferecer quando é utilizada para a degradação de compostos, como os BTEX, em solos tipicamente brasileiros, cujas características físico-químicas contribuem, em muito, para a degradação desses contaminantes. Nessa conjuntura, pesquisas revelam que os fatores ambientais (como teores de umidade e oxigênio) e a disponibilidade de nutrientes nos solos, além das condições climáticas do Brasil, são bastante adequadas para o emprego dessa técnica. Isso pode trazer como vantagens, ótima relação custo-benefício e maior eficiência na degradação de compostos tóxicos e recalcitrantes frente à maioria das técnicas convencionais de remediação. Em síntese, a presente revisão busca enfocar o estado da arte das técnicas de biorremediação de contaminantes em solos, apresentando as mais atuais e recentes aplicações e inovações, tanto no âmbito nacional quanto no internacional.

Wise use of wetlands: current state of protection and utilization of Chinese wetlands and recommendations for improvement

Wetland protection and utilization sometimes appear to be in conflict, but promoting the wise use of wetlands can solve this problem. All countries face the challenge of sustainable development of wetlands to a greater or lesser extent, but the problem is especially urgent in developing countries, such as China, that want to accelerate their economic development without excessive environmental cost. Chinese wetlands contribute greatly to economic development, but improper use of these natural resources has endangered their existence. It is thus necessary to provide scientific guidance to managers and users of wetlands. In this paper, we analyze the present status of Chinese wetland protection and utilization, and discuss problems in six categories: a lack of public awareness of the need for wetland protection; insufficient funding for wetland protection and management; an imperfect legal system to protect wetlands; insufficient wetland research; lack of coordination among agencies and unclear responsibilities; and undeveloped technologies related to wetland use and protection. The wise use of Chinese wetlands will require improvements in four main areas: increased wetland utilization research, scientific management of wetland utilization, improved laws and regulations to protect wetlands, and wider dissemination of wetland knowledge. Based on these categories, we propose a framework for the optimization of wetland use by industry to provide guidance for China and other countries that cannot sacrifice economic benefits to protect their wetlands.