Baihua Lake Research Articles

Assessment of combined algal toxicity of TiO2 nanoparticles and organochlorines in karst surface waters

The widespread use of nanoparticles (NPs) and organic pollutants increases the risk of their coexistence in the aquatic environments. It is uncertain how the combined toxicities of NPs and OCs affect aquatic organisms in surface waters. In this study, the binary combined toxicities of TiO2 NPs with three different organochlorines (OCs)-pentachlorobenzene (PeCB), 3,3,4,4-tetrachlorobiphenyl (PCB-77), and atrazine on Chlorella pyrenoidosa in three karst surface water bodies were investigated. The correlation analysis results indicated that the toxicities of TiO2 NPs and OCs to algae were mainly related to the total organic carbon (TOC) and ionic strength of surface water. Surface water relieved the growth inhibition of the pollutants on algae as compared with ultrapure water (UW). The combined toxic effect caused by the co-exposure of TiO2 NPs-atrazine was synergistic and had an antagonistic effect for TiO2 NPs-PCB-77 in four types of water bodies. However, the co-exposure of TiO2 NPs-PeCB had an additive effect in the Huaxi Reservoir (HX) and synergistic effects in Baihua Lake (BH), Hongfeng Lake (HF), and UW. TiO2 NPs increased the bioaccumulation of OCs by algae. Both PeCB and atrazine significantly increased the bioaccumulation of TiO2 NPs by algae, except for PeCB in HX; however, PCB-77 reduced the bioaccumulation of TiO2 NPs by algae. The toxic effects of TiO2 NPs and OCs on algae in different water bodies were the result of the nature of the pollutants, bioaccumulation, hydrochemical properties, and other factors.

Dissolved Organic Matter Component and Source Characteristics of the Metropolitan Lakes and Reservoirs in a Typical Karst Region

In order to explore dissolved organic matter (DOM) components and their origins in metropolitan lakes and reservoirs in the karst region, the typical Hongfeng Lake, Baihua Lake, Songbaishan Reservoir, and Aha Reservoir were investigated in Guiyang City. Surface water parameters, including dissolved organic carbon (DOC), chlorophyll a (Chla), and optical parameters (a254, a280, a350, E2:E3, S275-295, FI, β:α, BIX, and HIX) were analyzed. Fluorescence peaks (B, T, A, M, C, D, and N) and three-dimensional matrix fluorescence with parallel factor analysis (EEM-PARAFAC) were employed to explain distinct DOM abundances and proportions. Meanwhile, Spearman's correlation coefficients and principal component analysis (PCA) were used to decipher parameter types and primary environmental processes. The results showed that aquatic ρ(DOC) and ρ(Chla) ranged between 4.24-11.9 mg·L-1 and 0.32-19.7 μg·L-1, respectively. High humic-like (a254) and protein DOM (a280) were observed in the Songbaishan Reservoir, resulting in higher DOM molecular weight when compared to that in other lakes and reservoirs. Surface water DOM mainly contained visible-light humic-like (23.8%-46.9%) and terrestrial fulvic-like components (17.6%-28.4%). High FI, β:α, and BIX but low HIX values in this study suggested that endogenous inputs largely contributed to aquatic DOM. Aquatic DOM component and source characteristics were significantly correlated with each other. Furthermore, inputs of humic-like DOM and microbial metabolism, as well as coupled carbonate dissolution and photosynthesis, drove dynamic DOM behaviors in the karst lakes and reservoirs.

Risk assessment of non-point source pollution in karst reservoirs based on ‘source–sink’ landscape theory

Abstract The quantitative identification of areas at risk for such pollution is conducive to allocating limited government funds to critical areas and the efficient and economical management of water environments. Here, the Baihua Lake watershed, an important drinking water source for Guiyang City, was taken as the study area. The location-weighted landscape contrast index (LCI) and non-point source pollution risk index (NSPRI) were developed based on the ‘source–sink’ landscape theory. The method takes into account the risk of pollution source formation and pollutant transport. A total of 348 natural sub-watersheds were used as assessment units by estimating the nitrogen and phosphorus pollution emission (absorption) potentials of different landscape types in the sub-watersheds and considering the influence of vegetation cover, distance from the reservoir, and slope in the transmission process, a quantitative assessment of Baihua Lake's pollution was carried out; the reliability of the method was verified by comparing the assessment results with measured water quality data and field surveys. The results indicate (1) 132 sub-watersheds (37.93%) dominated by source effects, mainly distributed in Yanshanhong Township, Yeya Township, and the Qinglong Subdistrict, with construction land and farmland as the main landscape types, and 216 sub-watersheds (62.07%) dominated by sink effects, mainly distributed in Zhanjie and Baihuahu Townships, with forests as the primary landscape type. (2) Additionally, 17 sub-watersheds (4.89%) show extremely high risk for non-point source pollution; these watersheds are mainly distributed in the Qinglong Subdistrict and mainly consist of urban residential areas and schools. These sub-watersheds discharge a large volume of sewage, which threatens the water quality of the upper reaches of Baihua Lake and must be managed. (3) The rivers corresponding to relatively high-risk, high-risk, and extremely high-risk sub-watersheds include the Dongmenqiao, Limu, Changchong, and Maixi Rivers.

Vulnerability assessment of water resources in a karst mountainous area based on GIS/RS technology: a case study of Guiyang, Southwest China

Abstract Water resource vulnerability in ecologically vulnerable karst areas is a key issue for regional sustainable development and the sustainable use of water resources. In this study, geographical information system (GIS) and remote sensing (RS) technology were employed to explore the vulnerability characteristics and spatial distribution of water resources in Guiyang City. The water resource vulnerability indicator in Guiyang ranged from 0.10 to 0.59, with an average value of 0.26. Yanglongsi Town, in Xifeng County, in the northern and main central urban area exhibited the highest water resource vulnerability, whereas Huaxi District in the south, and regions around Hongfeng Lake and Baihua Lake, in Qingzhen City, exhibited the lowest water resource vulnerability. Water resource vulnerability was predominantly mild, accounting for 35.85% of the total land area, followed by moderate (28.99%), with some non-vulnerable areas (13.60%) and very few extremely vulnerable areas (3.20%). Compared with traditional methods, the proposed index selection and assessment methods, based on GIS/RS, are both scientific and intuitive. In addition, the results are presented in detail, accurately reflecting the actual situation of water resource system vulnerability.

<p><strong><em>Sporidesmium guizhouense</em></strong><strong> sp. nov. (Sordariomycetes<em> incertae sedis</em>), a new species from a freshwater habitat in Guizhou Province, China</strong></p>

During a survey of freshwater fungi in Guizhou Province, China, a collection from a submerged decaying twig in Baihua Lake was identified as a new species of Sporidesmium sensu lato based on morphological characters and phylogenetic analyses of combined LSU, SSU, ITS, TEF1α and RPB2 sequence data. Phylogenetic analyses supported its placement in Sordariomycetes but the fungus grouped distant from Sporidesmium sensu stricto, and its ordinal or familial position within the class remained inconclusive. Sporidesmium guizhouense sp. nov. is introduced with an illustrated account and notes on its taxonomy, phylogeny and systematic position are provided.

Accumulation of metals in zooplankton from karst plateau reservoirs with different eutrophic status in Guizhou Province, P. R. China

Metal concentrations in large zooplankton from three karst reservoirs with different eutrophic status (Hongfeng Lake reservoir, Baihua Lake reservoir, and Aha reservoir) in Guizhou Province, China, were investigated. Samples of zooplankton were collected in 2014 and 2015. It was found that accumulation of metals in zooplankton was significantly correlated with Chl-a (chlorophyll a), which can be attributed to the characteristic distribution of species of phytoplankton. A low concentration of metals in water means a higher bioaccumulation factor (BAF) and a stronger transfer to zooplankton via the trophic chain, and hence a higher ecological risk. Zooplankton in the eutrophic Aha reservoir had lower concentrations of Fe (mean 1264.25 mg/kg) than in Hongfeng (mean 2566.07 mg/kg) and Baihua (2246.87 mg/kg) in 2014-2015, because of high TP (Total Phosphorus) concentration, which has an affinity with suspended particles matter. A high level of Cd (mean 0.62 mg/kg) was found in Hongfeng. This study shows that zooplankton in the eutrophic Aha reservoir had higher concentrations of metals (Mn, mean 590.47 mg/kg; Pb, mean 7.6 mg/kg; Cr, mean 26.31 mg/kg; Ni, mean 8.54 mg/kg; Zn, mean 225.73 mg/kg; and Cu, mean 238.33 mg/kg) than in the mesotrophic Hongfeng and Baihua reservoirs. Thus, the eutrophic status was significantly, positively correlated with high concentrations of metals in the zooplankton, as also observed in other reservoir studies.

Vertical Profile of Acid Volatile Sulfide (AVS) and Risk Assessment of Sediments from Baihua Lake, China

Acid volatile sulfide (AVS), simultaneously extracted metals (SEMs), and total concentrations of trace elements (Cu, Cd, Pb, Zn, Ni, Hg, As, and Cr) were studied in sediment cores from Baihua Lake in southwest China. The molar ratios of SEMs to AVS for all samples were lower than 1.0 except for the 25- to 30-cm layer of the sample collected at location YPZ, indicating that the heavy metals were currently not significantly bioavailable as a whole to benthic organisms. Based on the sediment quality guidelines and the potential ecological risk assessment, Hg presented a high ecological risk for the water body.

Phosphorus Speciation and Vertical Variation in Sediments from Lake Baihua

This paper reports a study on vertical distribution characteristics of phosphorus speciation in samples collected at four sites from Baihua Lake, based on the Standards, Measurements and Testing (SMT) programme. In this study, the total phosphorus (TP) concentrations of these sediments samples varied from 944.86 to 2591.56 mg/kg and inorganic phosphorus (IP) was the main phosphorus fraction. For this heavily contaminated sediment, the IP mainly consisted of the Fe/Al-P. The vertical variation of the phosphorus had a tendency to decrease with the depth at sites JYS and YPZ. Since the concentrations of the TP in sediments were high and the phosphorus release potential and bioavailability were significant, the lake is still facing an ecological risk.

Study on Release Potential of Heavy Metals in Sediments from Baihua Lake by Dredging Simulation

Baihua Lake is a key drinking water source for Guiyang City located on Guizhou Plateau in southwest China, however it has been seriously contaminated with various contaminants, such as nitrogen, phosphorus, and heavy metals. To solve this problem, some researchers have recommended dredging the lake sediment to remove these contaminants. The present research was aimed to assess the potential risk of five selected heavy metals (Cd, Cu, Cr, Hg and As) if the sediment dredging measure was taken for remediation of this water body. Core sediments collected from the site Guanyinshanzhuang were used to simulate the release of heavy metals in sediment from Baihua Lake if sediment dredging was carried out. The core sediments were dredged at 10 cm, 20 cm and 30 cm levels. The core sediments were then put into the lake again after simulation dredging to investigate their release potential in one day, five days, nine days and fifteen days. The mobility of selected heavy metals in the sediments were determined using the toxicity characteristic leaching procedure (TCLP) developed by the United States Environmental Protection Agency (USEPA). The results indicated that the release potential of the heavy metals varies with dredging depth and the lasting time after dredging. Cr and As showed the lowest release ability among the heavy metals under study followed by Cu. The release amount of Cd increased with the lasting time after dredging. Hg showed no clear trends of release at 10 cm dredging depth. At 20 cm and 30 cm dredging depth, Hg presented a small release in the five days after simulation dredging, and then no release in the following ten days. In fifteen days after simulation dredging, the percentages of the heavy metals extracted with TCLP were in the order of Cd (8.85%) > As (3.41%) > Cu (1.37%) > Hg (0.79%) > Cr (0.61%) at dredging depth of 10 cm, Cd (10.22%) > Hg (2.73%) > Cu (1.74%) >As (1.47%)> Cr (1.41%) at dredging depth of 20 cm, and Cd (10.38%) > As (2.07%) > Hg (2.51%) > Cu (1.74%) > Cr (0.87%) at dredging depth of 30 cm.

Occurrence and Implications of SEM-AVS for Surface Sediments from Baihua Lake, China

The concentrations of acid volatile sulfide (AVS) and simultaneous extracted metals (SEMs, including SEMCu, SEMCd, SEMPb, SEMZn, SEMNi, SEMHg, SEMAs and SEMCr) in 17 superficial sediment samples were determined to better understand their spatial distribution in Baihua Lake, Guizhou Province, in southwest China. The SEMs/AVS ratio was employed to assess the bioavailability of the eight cationic metals. The SEMs/AVS ratio was significantly lower than 1.0, indicating that AVS in the sediments was sufficient to shield the eight selected heavy metals; thus the eight heavy metals showed no significant bioavailability to the benthic organisms. In addition, a preliminary study on the crystal composition in the sediments from Baihua Lake before and after SEMs’ extraction by X-ray diffraction analysis partly confirmed the efficiency of the cold-acid purge-and-trap technique.

Acid volatile sulfide and simultaneously extracted metals in superficial sediments from Baihua Lake, China

The bioavailability of five divalent cationic heavy metals (Pb, Cd, Cu, Zn and Ni) in 10 superficial sediment samples from Baihua Lake was assessed based on the molar ratio of simultaneously extracted metals (SEMs) to acid volatile sulfide (AVS). Atomic absorption spectrometry (AAS) and X-ray powder diffraction (XRD) were used to determine the heavy metal concentrations and examine the mineralogy of the crystalline phases, respectively. The AVS loadings in sediments from Baihua Lake ranged from 64.30 to 350.08 μmol/g (dry weight). The corresponding SEM levels for the sampling sites varied from 1.770 to 14.660 μmol/g. The molar ratio of SEMs to AVS ranged from 0.014 to 0.084 with a mean value of 0.034. The XRD analysis also confirmed the presence of some metal sulfides in sediments from Baihua Lake. The SEMs/AVS ratios for all sampling sites were significantly lower than 1.0, indicating that AVS in the sediments was sufficient to bind the five heavy metals; thus, these heavy metals are currently not significantly bioavailable to benthic organisms. Comparing the SEMs results to published guideline values for metal toxicity to benthic organisms in sediments, however, suggests that Zn and Ni pose a risk at some sampling locations in Baihua Lake.

Sulfate-reducing bacteria Desulfobulbus sp. strain BH from a freshwater lake in Guizhou Province, China

Sulfate-reducing bacteria (SRB) from the anaerobic sediments of the freshwater Baihua Lake (Guizhou Province, China) at eutrophicated sites polluted with heavy metals, particularly with mercury, have been studied. SRB belonging to the genus Desulfobulbus prevailed. A detailed study of the dominating Desulfobulbus isolate designated as strain BH revealed its difference in regards to genetic, morphological, physiological, and biochemical characteristics from the other species of this genus. Strain BH utilized a wide range of organic substrates, demonstrated a high level of hydrogen sulfide production, and could be considered an important component of the microbial community in the polluted lake.

Effects of Environmental Factors on Phosphorus Release in Sediment from Baihua Lake, China

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.

Release Kinetics of Phosphorus in Sediments from Baihua Lake

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.

Study on Correlations between Sulfate-Reducing Bacteria and Geochemical Factors in Sediments from Baihua Lake

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.

Heavy Metals (Cu and Zn) Release Kinetics in a Sediment Sample from the Inlet of Baihua Lake, China

Release kinetics of two selected heavy metals (Cu and Zn) in a sediment sample collected from the inlet of Baihua Lake was determined. The results show that the double-constant equation was considered as the best-fit equations describing the relationship of Cu and Zn release and time in the sediment from the inlet of the lake (R2 = 0.9759, 0.9226, P<0.01). The effects of temperature, acidity, salinity, and the water/soil ratio on the releasing of heavy metals in sediment sample were also investigated. The heavy metals release would increase as the temperature increased. A low pH value could promote the heavy metals release. The heavy metals in the sediment tended to be released under a relatively high salinity condition. The amount of the heavy metals released from the sediment decreased with the increase of the water/soil ratio.

Distribution of Heavy Metals in Core Sediments from Baihua Lake

In the present research, five core sediments from Baihua Lake, a man-made reservoir located in the karst area on the Yunnan-Guizhou Plateau in China, were analyzed to study the distribution, origin and contamination of three selected heavy metals (Cu, Zn and Mn). The results showed that the concentrations of these heavy metals in sediments varied from different sampling locations and layers. The average concentrations of these heavy metals at the same sampling location followed the order of Mn>Zn>Cu. The mean concentrations of Zn and Mn in the samples at the depth of 0-5 cm and the depth of 5-10 cm of the core sediments were higher than those in the other layers. All of Cu, Zn and Mn presented similar distribution characteristics at sampling site CFZ, and different distribution characteristics from the other four sampling locations. A statistical analysis indicated that there were some correlations between the concentrations of these three heavy metals and other studied six elements occurring in the core sediment samples. Three components were obtained with principal component analysis (PCA) analysis of heavy metals concentrations in core sediment samples.

Distribution of Several Microorganisms in Sediments from Baihua Lake

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.

Occurrence of Organochlorine Pesticides and Polychlorinated Biphenyls in Six Fish Species from Baihua Lake, China

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.

Estimation of Organochlorine Pesticides and Dioxin-Like PCBs in Surface Sediments from Baihua Lake

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.