Papers by Author: Li Ya Fu

Abstract: This paper reports an investigation regarding the effects of temperature, pH, dissolved oxygen (DO) concentration and agitation on total phosphorus (TP) release in sediment form Baihua Lake. The results showed that an increase in the temperature led to a sharp increase in the TP release in the examined sediment. The TP release from the sediment decreased as the pH value increased until approximately pH = 7, and increased when pH > 7. There was phosphorus release in both aerobic and anoxic conditions, although the release quantities of TP were significantly higher in the anoxic condition than those in the aerobic condition. In addition, the TP release increased with agitation.

Abstract: Release kinetics of phosphorus in 17 sediments samples collected from Baihua Lake were determined, and the relationship between the phosphorus release kinetic parameters and the sediment composition was also investigated. The results showed that both the Elovich equation and power function equation were valid models for describing the phosphorus release data in the 17 sediments. Within the beginning 12 h, the rate of phosphorus release was high, and then decreased. Our correlation analysis demonstrates that there were no significant correlations between the maximum capacity of phosphorus release (Qmax) and the content of total nitrogen (TN), organic matter (OM), calcium-bound phosphorus (Ca-P), and organic phosphorus (OP). But the correlation between Qmax and iron/aluminum-bound phosphorus (Fe/Al-P) content was positive (R2 = 0.6064, P < 0.01), suggesting that Fe/Al-P might be the main contributor to the released phosphorus in the sediments.

Abstract: This paper reports a study on the distribution characteristics of sulfate-reducing bacteria (SRB) in seventeen sediment samples collected from Baihua Lake (a man-made deep plateau reservoir in Guizhou Province, China), and analyzes the correlations between the SRB content and pH value, organic matter (OM), AVS, Fe, Hg, As, Cu, Ca, Mg in the sediments. The results showed that the sediment collected from the sampling site of Yapengzhai had the highest population of SRB, and the sediment from the sampling site of Longtan SRB presented the lowest population of SRB. Moreover, there were positive correlations between SRB and OM, AVS, Fe, Hg, As, Cu, Ca, Mg whereas the negative correlations existed between the SRB content and pH value.

Abstract: Assessment of the pollution for the selected six heavy metals (Pb, Cu, Zn, Fe, Mn and Ni) in ten surface sediments sampled from Aha Lake in a dry season was made in the present investigation. Principal component analysis (PCA) was used to assess the sources of the heavy metals contamination and two components were extracted. Analysis of the lake characteristics and point source pollution revealed that the discharge of industrial effluent and coal mining wastewater were the possible sources of these heavy metals contamination. Based on the speciation characteristics of heavy metals in sediments, the method ratio of secondary phase to primary phase (RSP) was applied to evaluate the loadings and the bioavailability of these heavy metals. The RSP evaluation exhibited that Pb, Zn, Fe, Mn and Ni were mainly associated with Fe-Mn oxides besides residual phase, while Cu mainly existed in organic phase and residual phase. In summary, the potential risk posed to the lake caused by the heavy metals was high and descended in the order of Mn > Ni > Zn > Pb > Cu > Fe.

Abstract: Quantitative structure-property relationship (QSPR) models were developed in the present work for photodegradation rate constants (kp) of fifteen individual polybrominated diphenyl ethers (PBDEs) in methanol/water (8:2) by UV light in the sunlight region. The molecular descriptors used in the QSPR models were calculated by the two semi-empirical quantum mechanical methods, RM1 and PM6, respectively. Both multiple linear regression (MLR) and artificialneural network (ANN) were applied in this study. The statistic qualities of the MLR models based on the molecular parameters obtained by RM1 and PM6 calculations were both good with the R values of 0.987 and 0.990, respectively. The QSPR model built by the ANN method with the molecular parameters calculated with PM6 is slightly better than that with RM1.

Abstract: This paper reports a study on the distribution characteristics of bacteria, ammonifiers, ammonium-oxidizing bacteria, nitrite-oxidizing bacteria, denitrifiers, sulfatereducting bacteria, actinomycetes, and fungi in ten sediment samples from Baihua Lake (a man-made deep plateau canyon reservoir in Guizhou Province, China). In the present research, sampling site of Yueliangwan had the highest population of bacteria and sulfatereducting bacteria. Ammonifiers had the highest population at sampling site Yapengzhai while the other sampling sites showed a slight difference in the population number. Ammonium-oxidizing bacteria had the highest populaton number at sampling site Pingpu. The population number of nitrite-oxidizing bacteria in sediment at Longtan was higher than that at the other sampling sites. The highest population number of denitrifiers was at sampling site Jiangjiapu. Actionmycetes and fungi had the highest numbers at sampling sites Dachong and Laojiutu, respectively.

Abstract: A natural ditch wetland grown with nature annual bluegrass (Poa annua L.), alligator weed (Alternanthera philoxeroides (Mart.) Griseb.), common duckweed (Lemna minor L.) and curly pondweed (Potamogeton crispus L.) etc. were selected to study the removal capacity of agricultural non-point source pollutants in the Maixi River in Guiyang City, the capital of Guizhou Province, China. The removal characteristics and seasonal variation of chemical oxygen demand (COD), total phosphorus (TP), ammonia-nitrogen (NH+4-N), and suspended solids (SS) in the ditch water was studied. The results showed that there existed a certain seasonal diversity in the removal characteristics of nitrogen, phosphorus and organic pollutants by the ditch. The removal efficiency of TP, COD and SS demonstrated an increasing tendency with their increasing concentration at the ditch inlet, whereas that of the NH4+-N displayed contrary tendency as the concentration of NH4+-N increased.

Abstract: Baihua Lake, a man-made reservoir located in a typical plateau karstic area, is one of the five drinking water sources for Guiyang city. In the present research, the organochlorine pesticides and polychlorinated biphenyls in the muscle tissues of six fish species collected from Baihua Lake were estimated by gas chromatography/mass spectrometry (GC/MS) . The total concentration of OCPs ranged from 2.83 to 94.25 ng g-1 (dry weight), and that of PCBs ranged from ND to 4.78 ng g-1. p,p’-DDD, p,p’-DDE, γ-HCH and PCB28 were detected in the majority of the samples. However the biomagnifications of OCPs and PCBs were not significant in the selected fish from the lake.

Abstract: The concentration of eight organochlorine pesticides (OCPs) and twelve dioxin-like polychlorinated biphenyls (dl-PCBs) were estimated in nine surface sediment samples from Baihua Lake. Gas chromatography with mass spectrometry (GC-MS) was applied using selected ion monitoring (SIM) mode for the quantification of the OCPs and for the qualification of the dl-PCBs. The results showed that the concentrations of DDTs varied from 1.04 to 36.74 ng g^-1 (dry weight) in these sampling locations, and that of HCHs was in the range from 0.57 to 8.90 ng g^-1. In addition, PCB167 and PCB169 were detected in several sediment samples.