Wang Zi-jian

Prediction of the environmental fate and aquatic ecological impact of nitrobenzene in the Songhua River using the modified AQUATOX model

An accidental discharge of nitrobenzene happened in November 2005 in the Songhua River, China. The AQUATOX model was modified and adapted to simulate the time-dependent nitrobenzene distribution in this multimedia aquatic system and its potential ecological impacts. Nitrobenzene concentrations in flowing water, sediment, and biota were predicted. Based on the initial concentrations of nitrobenzene observed in the field during the accidental discharge, that is, 0.167-1.47 mg/L at different river segments, the predicted water concentrations of nitrobenzene would be lower than 0.02 and 0.002 mg/L after twenty days and one month, respectively. Both model prediction and field observation were in good agreement. The predicted nitrobenzene concentrations in sediments and aquatic organisms would be lower than 0.025 and 0.002 mg/kg, respectively, after two months. Among the environmental factors affecting nitrobenzene concentrations in water, inflow water dilution, water temperature, and initial concentration were the most important, by sensitivity analysis. Comparing the perturbed simulation and control simulation, the biomass changes for diatoms and mussel were significantly affected, whereas, no influence on other organisms could be predicted. Therefore the results indicated that nitrobenzene pollution in the Songhua River should have a limited impact on the benthos community.

The ecological degradation and restoration of Baiyangdian Lake, China

Abstract Systematic investigations into the distribution of aquatic species and variation of community structure in Baiyangdian Lake, the largest natural freshwater body in the Northern China Plain, were conducted during 1993–1994. Water quality of this shallow and eutrophic lake was assessed by qualitative and quantitative analyses of aquatic communities. Chemical and biological data in 1990s were compared with data from 1950s, 1970s and 1980s. Results from this research showed that Baiyangdian Lake was highly enriched by ammonia (NH3), nitrate (NO3) and phosphate (PO4) at the present time. The negative responses to increase degradation included: (1) a clear decrease in biodiversity; (2) a dramatic increase in individual abundance of tolerant species; and (3) a great decline in aquatic products in the recent years. A demonstration project for water pollution control and ecological restoration in Baiyangdian Lake is proposed.

Biodiversity and water quality variations in constructed wetland of Yongding River system

Abstract This research was carried on in constructed wetlands of Guan-Ting Reservoir, Beijing, China, from 2004 to 2005. The phytoplankon community was composed of 8 divisions (94 species, including genus and varieties) and the average cell density was 980.93× 104 cells per liter. The dominant divisions were Chlorophyta (36.8%), Bacillariophyta (31.0%) and Cyanophyta (23.4%). The removal rate of phytoplankton density was 72.7%. There was a positive linear correlation between phytoplankon density and total phosphorus. Here, 7 families (13 species) of aquatic vasular plants were found, which constituted emerging and submerging macrophyte communities. In the wetland system, the zooplankton community consisted of Protozoa, Rotifera, Cladocera and Copepoda (70 species). The average density was 4883 individuals per liter. Protozoan and Rotifera were the dominant groups and the removal rate of their density was 81.9%. The correlation between zooplankton and phytoplankton presented a quadratic curve. Also, the zoobenthos community contained Olisochaeta, Uniramia, Crustacea and Mollusca (15 species). The average density was 5670 individuals per m2 (62.3% was Uniramia) and the removal rate of their density was 92.4 %. The wetland system reduced CODMn, BOD5, TN, NH3-N, NO3-N, TP (total phosphor), PO4-P and SS in the water of Yong Ding River at 52.9%–99.1%.

Application of the SOS/umu test and high‐content in vitro micronucleus test to determine genotoxicity and cytotoxicity of nine benzothiazoles

Benzothiazole and benzothiazole derivatives (BTs) have been detected in various environmental matrices as well as in human beings, but little is currently available regarding their toxicities. In our study, genotoxicities of nine BTs (benzothiazole [BT], 2‐chlorobenzothiazole [CBT], 2‐bromobenzothiazole [BrBT], 2‐fluorobenzothiazole [FBT], 2‐methylbenzothiazole [MeBT], 2‐mercaptobenzothiazole [MBT], 2‐aminobenzothiazole [ABT], 2‐hydroxy‐benzothiazole [OHBT] and 2‐methythiobenzothiazole [MTBT]) are comprehensively evaluated by the SOS/umu test using the bacterial Salmonella typhimurium TA1535/pSK1002 for DNA‐damaging effect and the high content in vitro micronucleus test using two human carcinoma cells (MGC‐803 and A549) for chromosome‐damaging effect. The cytotoxicity of BTs on both bacteria and two human cells was also evaluated. Except for the cytotoxic effect of MBT on MGC‐803 and A549, the other tested BTs showed more than 50% cytotoxicity at their highest concentrations in a dose‐dependent manner, and their LC50s ranged from 19 (MBT in bacteria) to 270 mg l–1 (CBT in A549). Activation and inactivation were observed for specific BTs after metabolism. On the other hand, no evidence of genotoxicity was obtained for BT, FBT and MBT, and DNA damage was induced by ABT, OHBT, BrBT and MTBT in MGC‐803, by MeBT in A549 and by CBT in both cells. Through quantitative structure–activity relationship analysis, two structure alerts for chemical genotoxicity, including heterocyclic amine and hacceptor‐path3‐hacceptor are present in ABT and OHBT respectively; however, the underlying mechanisms still need further evaluation. Copyright

Selection of benthic macroinvertebrate-based multimetrics and preliminary establishment of biocriteria for the bioassessment of the water quality of Taihu Lake, China

Abstract To develop benthic macroinvertebrate-based multimetrics for the bioassessment of the water quality of Taihu Lake, benthic macroinvertebrate assemblages were sampled at 60 sites in 8 subareas of Taihu Lake. A total of 24 species of benthic macroinvertebrates were obtained: 14 species of Mollusca, 5 species of Arthropoda and 5 species of Annelida. A comprehensive evaluation of the metrics was carried out. The results showed that 7 metrics ( i.e. , total number of taxa, the number of Mollusca & Crustacea taxa, % Mollusca & Crustacea, % Gastropoda, Goodnight-Whitley index, Hilsenhoff biotic index and % Collector-gatherers) were sensitive. A score of 5, 3 or 1 was assigned to every metric for standardization of the metrics, and a multimetric on a scale ranging from 7 to 35 for bioassessment was developed. Four-level discriminatory biocriteria for water quality were eventually proposed by quartation: 7–14, very poor; 15–21, poor; 22–28, fair; 29–35, good. The re-scored results from the 60 sites showed that the water quality of southeastern Taihu Lake was relatively good, whereas that of northwestern Taihu Lake was relatively poor. Basically, the discriminatory biocriteria are suitable for the assessment of the water quality of Taihu Lake.

Assessing of genotoxicity of 16 centralized source-waters in China by means of the SOS/umu assay and the micronucleus test: initial identification of the potential genotoxicants by use of a GC/MS method and the QSAR Toolbox 3.0.

Only few studies were conducted to assess genotoxicity of centralized source waters in China and almost none of them dealt with the causal relationship between the genotoxic effect and genotoxicants. In this work, 16 centralized source waters in China were sampled from five river systems and genotoxicity of their organic extracts was assessed by use of the SOS/umu test for DNA-damaging effect and the miniaturized flow cytometry-based micronucleus (MN) test for chromosome-damaging effect. In addition, initial identification of potential genotoxicants for the six samples from the Yangtze River was done with a GC/MS method and the QSAR toolbox 3.0. The results demonstrate that eight samples showed both indirect and direct DNA-damaging effects, another four samples showed only indirect DNA-damaging effects, while chromosome-damaging effects were found for 14 out of the 16 samples, in which aneugenic and clastogenic modes of action were found for 4 and 10 samples, respectively. Both direct/indirect DNA-damaging effects and chromosome-damaging effects were induced by the six Yangtze River samples, and the existing different types of genotoxicant confirmed the results. Furthermore, o-phenylphenol was initially identified as the major cause for the DNA-damaging effects while PAHs, pesticides, phenol and anthraquinone were identified as ubiquitous chromosome-damaging agents among these samples. In conclusion, a combination of the SOS/umu test and the miniaturized flow cytometry-based MN test to detect both DNA-damaging and chromosome-damaging effects could be used as a comprehensive genotoxicity assessment tool for the evaluation and classification of genotoxicity of complex mixtures, and potential genotoxicants can be initially identified with additional information from chemical analysis and the QSAR toolbox.

Distribution and origin of biologically available phosphorus in the water of the Meiliang Bay in summer

The investigation and continuous monitoring with an innovative iron oxide embedded cellulose acetate membrane (FeO/CAM) on the concentrations of biologically available phosphorus (BAP) were conducted in the Meiliang Bay of the Taihu Lake during summer in 2004. The results showed that the concentrations of dissolved (FeO-DP), particulate (FeO-PP) and total bioavailable phosphorus (FeO-P) had similar horizontal distribution. The BAP concentrations were the highest in those estuaries in the northern bay. With the decrease of the distance to the estuary or long shore, there was little difference between BAP concentrations in an open lake area. During the observation period, algal blooms occurred in most waters of the northern bay, which was reflected from the high concentrations of chlorophyll a (Chl-a). While they were not highest in the estuarine waters of those major rivers, this is the case for the BAP concentrations. The concentrations of Chl-a had a significantly positive correlation with those of bioavailable phosphorus in the open area of the Meiliang Bay. With the sediment resuspension induced by wind and wave, BAP concentrations increased in a short-term, indicating that the riverine P inputs mainly contribute to the concentrations of BAP in the estuarine water while internal P release was the major source of BAP in the open lake area. In the eutrophic shallow lake, the blooms of alga may cause pH increase and further result in internal P release. The above results showed that the new membrane of FeO/CAM can be used to monitor the concentrations of BAP and provide the scientific justifications for the control strategy of the lake eutrophication.

Recognition of sea-level change duringthe Neolithic period in the Jiangsu Area, East China

Based on the detailed analyses, multi-proxies such as AMS14C dating, elevation measurements with GPS-CORS, and the identification of marine micropaleontology are used to research the archaeological stratums archived in the Qingdun site of Haian, the Taozhuang site and Kaizhuang site of Dongtai, and the Luotuodun site of Yixing, respectively. The results show that the depth of 389–489 cm (13.1–8.5 cal ka BP, 1985 Yellow Sea Datum - 0.65–1.65 m) of Qingdun site, the depth of 156–230 cm (12.6–9.2 cal ka BP, 1985 Yellow Sea Datum 0.97–0.23 m) of Taozhuang site, the depth of 228–390 cm (10.3–7.8 cal ka BP, 1985 Yellow Sea Datum 0.03–1.59 m) of Kaizhaung site, and the depth of 255–279 cm (12.0–9.2 cal ka BP, 1985 Yellow Sea Datum 1.08–1.84 m) of Qingdun site are significant marine sedimentary strata. These indicate that there was still a shallow sea sedimentary environment from the beginning of the Holocene to 7.8 cal ka BP in the region of Haian and Dongtai in north Jiangsu. Meanwhile, there was also a shallow sea environment from the beginning of the Holocene to 9.2 cal ka BP to the west of Taihu Lake in south Jiangsu. These research findings not only improve the resolution of Holocene sea level changes, but also provide scientific clues and evidence for searching the early Neolithic sites in Jiangsu. In addition, the elevations of 62 ancient wells and 102 ash pits under the Chenghu Lake of Suzhou were measured using the GPS-CORS. These measured data suggest that in the Songze cultural period, the Liangzhu cultural period, the Xia-Shang-Zhou dynasties and the Warring States period, the 1985 Yellow Sea Datum of the top of the wells and ash pits are mostly in between 0 - 2 m, and their bottom elevations are mostly around - 3 m. In the six dynasties and the Song Dynasty, some 1985 Yellow Sea Datum of the top of the wells and ash pits are lower than - 1 m, while some bottom elevations are lower than - 4 m. This evidence demonstrates that the forming age of Chenghu Lake in Suzhou is in the period after the Song Dynasty.