Chunxia Wang

Toxicity evaluation of reactive dyestuffs, auxiliaries and selected effluents in textile finishing industry to luminescent bacteria Vibrio fischeri

The toxicity of 17 selected process effluents, 11 reactive dyestuffs and 8 auxiliaries from a textile dyeing and finishing mill in Ayazaga, Istanbul, Turkey was evaluated by bioluminescence test using bacteria Vibrio fischeri in LUMIStox 300. The EC20 and EC50 for auxiliaries, the EC20 for dyestuffs were determined. For selected process effluents GL-values, the dilution level at which a wastewater sample causes less than 20% inhibition, were examined. Our results demonstrate that the toxicity assessment with luminescent bacteria is effective and of practical use for chemicals applied in textile finishing industry with the limitation of the deep dark-colored dye bath samples and for the related effluents. Inhibition effects of numerous dyestuffs as well as auxiliaries to luminescent bacteria differed considerably with a range 5-600 mg l(-1) for EC20 and 9-6930 mg l(-1) for EC50, respectively. Among 17 effluents, I sample exhibited high toxicity (GL = 100), 7 showed moderate toxicity (GL = 12-32), and 9 had a GL-value <10 indicating a low or no toxicity.

Ozonation of an azo dye C.I. Remazol Black 5 and toxicological assessment of its oxidation products

The effect of ozonation (20.5 mgl(-1)) on the degradation processes of an azo dye, Remazol Black 5 (RB5; CI) was studied. Conventional parameters such as chemical oxygen demand (COD), total organic carbon (TOC), pH, conductivity, colour removal, biodegradability (BOD(5/28)), and toxic potential of the dye and its degradation products were monitored during the process. The results obtained indicated that ozonation is a highly effective way to remove the colour of a corresponding dye solution. However, a considerable organic load still remained as indicated by high COD and TOC residues. The COD, TOC reductions were about 40% and 25% for 6 h ozonation of 2 gl(-1) RB5 aqueous solution. During the ozonation process the rapid decrease of pH and the sharp increase of conductivity indicated the formation of acidic by-products and small fragments and ions which were identified by high performance ion chromatography. The BOD28 data revealed that first by-products after partial ozonation (10-150 min) of RB5 were more biodegradable than the parent compound and ozonation can enhance the biodegradability of azo dyes. During the first 150 min of total 360 min of oxidation, the formation of first by-products with high toxic potential took place as it could be confirmed by two acute toxicity-screening tests, the bioluminescence test (Vibrio fischerii) and the neutral red cytotoxicity assay (rat hepatoma cells). The significant enhancement of microbial biodegradability after long-term ozonation could also be seen as a decrease of toxic intermediates in correlation with the ozonation time as indicated in BOD28 biological degradation test results.

Persistent organic pollutants in water and surface sediments of Taihu Lake, China and risk assessment

Organic pollutants, especially persistent organic pollutants were examined in the water and surface sediments of Taihu Lake, China. Both 12 water and 12 sediment samples were collected over the lake. C-18 solid-phase extraction technique was applied to extract organic pollutants in collected water samples. Soxhlet extraction procedure was used to extract organic pollutants in sediment samples. The analysis was performed by GC-MS controlled by a Hewlett Packard chemstation. Two hundred and seventy-three kinds of organic chemicals in water were examined, 200 more than that detected in 1985; 188 kinds of chemicals in sediments were detected as well. Among them 21 kinds of chemicals belong to priority pollutants as well as 17 kinds to be the endocrine disruptors. The concentrations of the pollutants were more than 2 times higher than that in 1985. The possible source and relation to anthropogenic activity were discussed.

Ecotoxicological and chemical characterization of selected treatment process effluents of municipal sewage treatment plant

The triolein-containing semipermeable membrane devices (SPMDs) were deployed for 4 weeks in a sewage treatment plant in Beijing, China, to sample and concentrate priority hydrophobic organic pollutants in a sewage treatment process. The chemical analyses and ecotoxicities of the residuals of SPMDs dialysate were examined. The data from the chemical analyses by gas chromatography-mass spectrometry selected ion monitoring mode indicated the lower removal for polychlorinated biphenyls (PCB) congeners and polycyclic aromatic hydrocarbons (PAHs) coincided with the persistence of them in the environment. The acute toxicity examined by bioluminescence test with Vibrio fischeri revealed approximately only 20% decrease in the overall toxicity of the influent after the activate sludge treatment process. The ethoxy resorufin-O-deethylase (EROD) induction with a micro-EROD assay in vitro using H4-IIE rat hepatoma cell cultures demonstrated the presence of persistent organics in influent and sequency effluents. Results obtained suggested that integration of the SPMD technique and chemical analyses and bioassay might be a valuable approach for the risk assessment of hydrophobic organic pollutants in water ecosystem. It revealed the necessity for organic pollutants monitoring and ecotoxicities examining of sewage treatment plants.

Origins and Mobility of Phosphorus Forms in the Sediments of Lakes Taihu and Chaohu, China

Abstract Phosphorus release from the sediment is generally an important factor for lake eutrophication. We have investigated phosphorus forms in surface sediments from Lake Taihu and Lake Chaohu by a chemical extraction method. The results showed that the concentrations of Fe/Al-bound phosphorus (Fe/Al-P) and organic phosphorus (Org-P) had significant correlations with those of amorphous Fe/Al oxides and organic matter in the sediments. Furthermore, Ca-bound phosphorus (Ca-P) concentrations were well related to total organic carbon (TOC) concentrations. The results also indicated that higher pH weakened the association of phosphates with the Fe/Al hydroxides and then resulted in Fe/Al-P release. The increase of pH was companied with autogenetic progresses of calcium carbonate and then elevated Ca-P concentrations in the sediments. In conclusion, external P loadings determine spatial distribution of P fractions, especially Fe/Al-P and Org-P, and partially contribute to additional Ca-P fractions in these highly human-disturbed lakes. The pH-induced phosphorus mobility in the sediments is very important for these lakes.

Uptake of weakly hydrophobic nitroaromatics from water by semipermeable membrane devices (SPMDs) and by goldfish (Carassius auratus)

Semipermeable membrane devices (SPMDs) filled with triolein, and goldfish (Carassius auratus) were simultaneously exposed to nine weakly hydrophobic nitroaromatics in a laboratory continuous-flow experiment. The results showed that the device concentrated the compounds in most cases to a larger extent than fish and that the overall uptake rate constants (Kmu) and average pollutant sampling rates (R(S)) were similar. We conclude that the SPMDs may be used to determine the levels of weakly hydrophobic nitroaromatics in water. It is obvious, however, that more researches at laboratory in order to establish kinetic database for a wide spectrum of compounds varying in lipophilicity and other properties are needed to elucidate various theoretical and practical aspects of the use of membranes in the environmental research and for related practical applications.

Uptake of moderately hydrophobic chlorophenols from water by semipermeable membrane devices (SPMDs) and by goldfish (Crassius auratus)

Semipermeable membrane devices (SPMDs) filled with triolein and goldfish (Crasslus auratus) were simultaneously exposed to nine moderately hydrophobic chlorophenols in a laboratory continuous-flow experiment. The results showed that the tested compounds were concentrated in the device to an extent very closed to that in fish. The overall uptake rate constants (K-u) and average pollutant sampling rates (R-s) were similar for both SPMDs and goldfish. We conclude that the SPMDs can be used to estimate the levels of moderately hydrophobic chlorophenols in field water as an environmental monitor

Assessing toxicities of hydrophobic organic pollutants in Huaihe River by using two types of sampling.

Abstract Hydrophobic organic pollutants in water from the Huaihe River were extracted by solid phase extraction and sequestered by semipermeable membrane device (SPMD), and those in sediments were extracted by organic solvent. Combined with chemical analysis, Lumistox test and ethoxyresorfin O-deethylase (EROD) assay were carried out for assessing the acute toxicities and the Ah-receptor-related toxic effects of the trace hydrophobic organic pollutants in this aquatic environment. The acute toxicants in water and sediment of the Huaihe River included substituted benzenes and pesticides, mainly 2,4,6-trichlorophenol, atrazine, hexachlorobenzene, and nitrobenzenes as well as persistent EROD inducers or Ah-agonists, including PAHs and PCBs, were determined. The highest acute toxicant concentration occurred at the center of the river (H3), while highest chronic toxicants occurred at upstream (H1). At downstream (H4), the EROD inducers in sediment depicted more persistency. The results also showed that the sampling procedures for waters have significant influences on the results of bioassays. Bioassay for acute toxicants in water using SPE was unable to obtain important information. However, bioassays for sediment extracts and SPMD concentrates showed similar pattern of toxic variation among different locations.

Persistent organic pollutants (POPs) in surface sediments of Donghu Lake, Wuhan, Hubei, China

ABSTRACT Surface sediment samples from five different sites were collected in Donghu Lake, Wuhan City, Hubei Province, China during November 2000. Over 180 organic chemicals were detected using GC-MS controlled by a Hewlett Packard Chemstation after soxhlet extraction. Derivatives of benzene, phthalate esters, PAHs, phenols, isophorone as priority pollutants or endocrine disruptors, respectively, were detected. The concentration of organic pollutants were found to be highest at the sampling site located at Southwest Donghu Lake (Shuiguo), caused most probably by the untreated wastewater discharge, average at the southern and lowest at the northern part of the lake.

Toxicological evaluation of drinking water in Beijing waterworks

Abstract The mutagenicity and acute toxicity of source water, water from five different treatment units as well as tap water from waterworks in Beijing were studied. The aim of this research was to examine the seasonal variation of water toxicity during water treatment processes, and to evaluate the effects of each treatment process. The results indicated the existence of frame shift mutagens in the source water in Beijing, but not base pair substitute mutagens. Prechlorination, coagulation and chlorination may cause mutagenic effects to increase, while coal‐sand filtration and granular activated carbon adsorption may remove most of the mutagens formed. Similar conclusions were drawn from the acute toxicity assay.