Enhanced remediation of BDE-209 in contaminated mangrove sediment by planting and aquaculture effluent.

Toxic and persistent flame retardant (BDE-209) and aquaculture effluent (AE) are ubiquitous in coastal environments, but how their co-existence influences their fate is not yet investigated. This study investigated AE effects on remediation and uptake of BDE-209 by Kandelia obovata (Ko) and Avicennia marina (Am), true and dominant mangrove species. After 12-months, a significant removal of BDE-209 was achieved in planted mangrove sediment and the removal was significantly enhanced by AE addition, possibly due to the enhancement of nitrogen (N) and phosphorous (P) content in sediment.

Physiological response and oxidative transformation of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) by a Chlorella isolate.

Polybrominated diphenyl ethers (PBDEs) are ubiquitous, toxic and persistent pollutants in environments. Microalgae frequent exposed to these pollutants may possess defense mechanisms against their toxicity and have the ability to metabolize them, thus are important in bioremediation. This study investigated the mechanism of a Chlorella isolate to degrade BDE-47, a common PBDE congener, and its subcellular responses to BDE-47 stress.

Changes of substrate microbial biomass and community composition in a constructed mangrove wetland for municipal wastewater treatment during 10-years operation.

Constructed wetlands (CWs) have been used for wastewater treatment for decades, but research on microorganisms involved, especially long-term changes, is still limited. In this study, we evaluated changes in the substrate microbial community in a pilot-scale horizontal subsurface-flow constructed mangrove wetland during 10-years operation. In the 3rd year of operation, microbial biomass carbon and phospholipid fatty acids (PLFAs) reached peak values in two vegetated belts planted with Aegiceras corniculatum (Ac) and Kandelia obovata (Ko), respectively, then stabilized or declined in the 9th and 10th years of operation.

Does energetic cost for leaf construction in Sonneratia change after introduce to another mangrove wetland and differ from native mangrove plants in South China?

Exotic species invasions are serious ecological problems. Leaf construction cost (CC) and growth traits of two Sonneratia (Sonneratia caseolaris and S. apetala) and four native species (Bruguiera gymnorrhiza, Kandelia obovata, Aegiceras corniculatum and Avicennia marina) in Hainan and Shenzhen mangrove wetlands were compared to evaluate invasive potentials of Sonneratia after introduced to Shenzhen, their new habitat.

Anaerobic biodegradation of PAHs in mangrove sediment with amendment of NaHCO3.

Mangrove sediment is unique in chemical and biological properties. Many of them suffer polycyclic aromatic hydrocarbon (PAH) contamination. However, the study on PAH biological remediation for mangrove sediment is deficient.

Cr(III) removal by a microalgal isolate, Chlorella miniata: effects of nitrate, chloride and sulfate.

In the present study, nitrate, chloride and sulfate anion systems were used to investigate the presence of anions on the removal of Cr(III) by Chlorella miniata. Kinetic studies suggested that the equilibrium time of Cr(III) biosorption was not affected by the presence of different sodium salts, even at the concentration of 1.0 M, and all reached equilibrium after 24 h.

Effect of Mn(IV) on the biodegradation of polycyclic aromatic hydrocarbons under low-oxygen condition in mangrove sediment slurry.

This study investigated the effect of manganese [Mn(IV)] amendment on the anaerobic biodegradation of four mixed PAHs, namely fluorene (Fl), phenanthrene (Phe), fluoranthene (Flua) and pyrene (Pyr) under low-oxygen condition, with and without the inoculation of enriched PAH-degrading bacterial consortia, in mangrove sediment slurries. The results revealed that the addition of Mn(IV) significantly inhibited PAH biodegradation, the rate of which was about 31-70% lower than the one of the groups without Mn(IV) addition. The amendment of Mn(IV) also showed adverse effect on the population size of enriched PAH-degrading bacteria and bacterial activity.

Modeling sorption and biodegradation of phenanthrene in mangrove sediment slurry.

A mathematical model, combining both sorption and biodegradation process, was developed to predict the biodegradation of phenanthrene by Sphingomonas sp. in different sediment slurries. The model includes two sorption parameters, α (the partition coefficient) and 1/K (the diffusion resistance); a kinetic parameter k (the first order rate constant); and a sediment parameter, A(V) (the specific sediment surface area in unit volume of slurry).

Dose and accumulative effects of spent lubricating oil on four common mangrove plants in South China.

The growth of four mangrove species seedlings, namely Bruguiera gymnorrhiza, Kandelia obovata, Aegiceras corniculatum and Acanthus ilicifolius in sediments contaminated by spent lubricating oil, even at the lowest oil dose (2.5 L m(-2)), showed different degrees of sub-lethal damages. All the seedlings of K.

Anaerobic biodegradation of polycyclic aromatic hydrocarbons with amendment of iron(III) in mangrove sediment slurry.

Mangrove sediment, influenced by tidal cycles, switches between low-oxygen and non-oxygen conditions, and iron is abundant in it. Polycyclic aromatic hydrocarbon (PAH) contamination often occurs in mangrove wetlands. In the present paper, the effects of iron [Fe(III)] amendment on the biodegradation of four mixed PAHs, namely fluorene (Fl), phenanthrene (Phe), fluoranthene (Flua) and pyrene (Pyr), in mangrove sediment slurries, with and without the inoculation of the enriched PAH-degrading bacterial consortia, under low-oxygen (2 + or - 0.

Using orthogonal design to determine optimal conditions for biodegradation of phenanthrene in mangrove sediment slurry.

In the present paper, the effects of four factors, each at three levels, on biodegradation of phenanthrene, a 3-ring PAH, in contaminated mangrove sediment slurry were investigated using the orthogonal experimental design. The factors and levels were (i) sediment types (clay loam, clayey and sandy); (ii) different inoculums (Sphingomonas sp., a mixture of Sphingomonas sp.

Effects of humic acid on solubility and biodegradation of polycyclic aromatic hydrocarbons in liquid media and mangrove sediment slurries.

The effects of humic acid (HA) on the solubility and biodegradability of mixed polycyclic aromatic hydrocarbons (PAHs) (phenanthrene (PHE), pyrene (PYR), and benzo[a]pyrene (BAP)) in liquid media and mangrove sediment slurries were investigated. The addition of HA to the liquid media (0-1.6%, w/v) significantly enhanced the solubility of all mixed three PAHs and the biodegradation of PHE and PYR (but not BAP) by MP-PYR1, a PYR-degrading bacterium isolated from mangrove sediment.

Static and dynamic sorption of phenanthrene in mangrove sediment slurry.

The static and dynamic sorption of phenanthrene (Phe) in three types of mangrove sediment slurries (sandy, silty and muddy) were described by three models, namely linear model, Freundlich adsorption isotherm model and Langmuir adsorption isotherm model. The Freundlich adsorption isotherm was the best model to describe the static sorption behavior of Phe in mangrove sediment slurry with the regression coefficients ranging from 0.96 to 0.

Feasibility of using microalgal biomass cultured in domestic wastewater for the removal of chromium pollutants.

The feasibility of obtaining and using the biomass of a microalga, Chlorella miniata, from domestic wastewater (DW) cultures for the removal of chromium(III) [Cr(III)] and chromium(VI) [Cr(VI)] was compared with that from commercial Bristol medium (BM). Results showed that Chlorella miniata cultured in DW under 16-8 hours light-dark cycle [DW(16-8)] had similar growth to that in BM [BM(16-8)], but these two biomass had different biochemical compositions, and the former one had lower carbohydrate and higher protein content. When cultured in domestic wastewater, a higher biomass was obtained under continuous illumination [DW(24-0)], and the cells had higher carbohydrate and lower protein concentrations than that of DW(16-8).

Effects of anion species and concentration on the removal of Cr(VI) by a microalgal isolate, Chlorella miniata.

The presence of nitrate, chloride and sulfate anions on the removal of Cr(VI) by Chlorella miniata was investigated. Results of kinetic studies indicated that the equilibrium time in each anion system increased with increases of the initial salt concentration, and the inhibitory order was NO(3)(-)>Cl(-)>SO(4)(2-) for Cr(VI) removal and was SO(4)(2-)>Cl(-) approximately NO(3)(-) for the biosorption of the bioreduced Cr(III). The inhibitory effect caused by different anions was attributed to biosorption mechanism and metal speciation.

Biosorption and bioreduction of Cr(VI) by a microalgal isolate, Chlorella miniata.

The ability and mechanism of a microalgal isolate, Chlorella miniata to remove Cr(VI) were investigated. Kinetic studies indicated that both biosorption and bioreduction were involved in the Cr(VI) removal. The adsorbed Cr(VI) was reduced to Cr(III), and desorption studies indicated that Cr(III) occupied most of the adsorption sites on the biomass.

Surface complexation mechanism and modeling in Cr(III) biosorption by a microalgal isolate, Chlorella miniata.

The mechanism involved in the removal of Cr(III) by a green microalgal isolate, Chlorella miniata, was examined based on a series of batch experiments and microscopic analyses, and a mathematical model was proposed. Results showed that Cr(III) biosorption increased with the increase of pH from 2.0 to 4.

Removal of fluoranthene and pyrene by different microalgal species.

In this work, the efficiency of four microalgal species, namely, Chlorella vulgaris, Scenedesmus platydiscus, Scenedesmus quadricauda, and Selenastrum capricornutum to remove fluoranthene (1.0 mg l(-1)), pyrene (1.0 mg l(-1)), and a mixture of fluoranthene and pyrene (each at a concentration of 0.

Pyrene-induced changes of glutathione-S-transferase activities in different microalgal species.

The glutathione-S-transferase (GST, EC 2.5.1.