Embryotoxic and genotoxic potential of sewage system biofilm and river sediment in the catchment area of a sewage treatment plant in Switzerland

In the present study an embryo toxicity test with zebrafish and the comet assay with primary cells isolated from the embryos were combined to assess the toxicity of native biofilms from the sewage system of the sewage treatment plant (STP) Mittleres Wynental and native sediments from the river Wyna (Switzerland). The aim of the study was to evaluate the applicability of the test system to investigate biofilms and to rank the results of the biofilm and sediment sampling sites with regard to embryotoxic and genotoxic effects.We demonstrated that the zebrafish embryo toxicity test in combination with the comet assay with embryo primary cells is a tool that can basically be applied for investigating the bioavailable toxic potential of native biofilms. By ranking the results for embryo toxicity and genotoxicity, we found clear differences in the toxic potential of the biofilm from different sewage system sections. Significant genotoxicity was determined in all biofilm samples and the sediments revealed a lower genotoxic potential upstream of the STP discharge compared to samples downstream and directly at the discharge. Temporal variability from samplings in autumn and spring were found for two of the five biofilm and for one of the three sediment samples.Based on the results of our study we suggest that ecotoxicological bioassays (such as the embryo toxicity test and comet assay with zebrafish) using biofilm can be a useful tool to assess (waste) water quality.     

Evaluating ammonia toxicity in sewage effluent to stream macroinvertebrates: I. A multi-level approach

A multi-level approach incorporating instream biological response, water quality, and toxicity testing was used to evaluate the toxicity of ammonia in sewage effluent to macroinvertebrates in two Ozark border streams. Macroinvertebrate community compositions at sites upstream from effluent discharge were most similar, while communities at upstream vs downstream sites were least similar. Upstream sites had abundant mayflies, blackflies, and caddisflies, which were absent immediately below effluent discharge. Water quality was also different at upstream vs downstream sites and was significantly correlated with differences in macroinvertebrate communities (r²=–0.66, P<0.05) when data for all months were combined. However, differences in water quality could not consistently be explained by ammonia, which contributed from <1% to 31% of total variation in water quality among sites.The failure of observed NH₃-N concentrations to consistently explain differences in water quality and macroinvertebrate community composition among sites in field studies was corroborated by results of 96-h, static-renewal, ammonia toxicity tests conducted on Chironomus riparius in undiluted sewage effluent and well water. Ammonia concentrations measured in-stream were not toxic to C. riparius in toxicity tests. By using a multi-level approach, a more realistic evaluation of ammonia toxicity in sewage effluent to macroinvertebrates was obtained than by using methods that focus on only one aspect of effluent toxicity.     

Effect of Titanium Dioxide Nanoparticles on Gamma-Ray Treatment of Phenol in Different Matrices: Implications in Toxicity Toward <Emphasis Type="Italic">Daphnia magna</Emphasis>

Gamma-ray treatment of phenol was studied in terms of both chemical degradation and toxicological change. About 90 % of phenol (5.0 × 10⁻⁴ M) in ultrapure water (UW) was eliminated by gamma-irradiation at a dose of 10 kGy, but acute toxicity was dramatically increased, particularly for dose of 1 kGy, due to the formation of more toxic by-products such as hydroquinone, benzoquinone, resorcinol and catechol. The addition of TiO₂ nanoparticles had little effect on the removal of phenol in UW, but substantially enhanced the mineralization of phenol compared with gamma-irradiation alone. Additionally, degradation of phenol by gamma-irradiation was inhibited in a wastewater effluent (WE) matrix, likely due to the presence of dissolved organic carbon (22.06 mg L⁻¹). Furthermore, lower concentrations of toxic by-products were generated both in WE and in the presence of TiO₂ nanoparticles, resulting in reduction of toxicity increase by gamma-irradiation. Meanwhile, the toxicity of gamma-ray treated phenol in WE was well estimated with simple summation of individual toxicity of phenol and by-products (R ² = 0.9678).     

Toxicity of laundry detergent components to a freshwater cladoceran and their contribution to detergent toxicity

The toxicity of 39 laundry detergent components including surfactants, enzymes, builders, fabric brighteners, fillers, and coloring agents to the cladoceran Ceriodaphnia cf. dubia was determined. The difference between the most and the least toxic components was approximately 17,000-fold and 1,000,000-fold for the mg/L and mmol/L EC50 data, respectively. Two of the components had high toxicity (EC50 values < 1 mg/L), 11 moderate toxicity (EC50 values between 1 and 10 mg/L), and the remaining 26 components had low toxicity (EC50 values > 10 mg/L). Analysis revealed that mixtures of the components interacted antagonistically, additively, and synergistically. On a molarity basis the most toxic group of compounds was the surfactants followed by the brighteners. The most toxic individual components included sodium carboxymethyl cellulose, sodium silicate solution, four brighteners, sodium perborate tetrahydrate, and the surfactants. Many of the most toxic components, however, contributed very little to the toxicity of the detergents due to being present in the detergents at low concentrations. The main contributors to the toxicity of detergents were the sodium silicate solution and the surfactants-with the remainder of the components contributing very little to detergent toxicity. The potential for acute aquatic toxic effects due to the release of secondary or tertiary sewage effluents containing the breakdown products of laundry detergents may frequently be low. However, untreated or primary treated effluents containing detergents may pose a problem. Chronic and/or other sublethal effects that were not examined in this study may also pose a problem.     

Application of toxicity tests into discharges of the pulp-paper industry in Turkey

The aim of this study was to investigate the acute toxicity of pulp-paper industry wastewater using traditional and enrichment toxicity tests and to emphasize the importance of toxicity tests in wastewater discharge regulations. Enrichment toxicity tests are novel applications and give an idea of whether there is potential toxicity or growth-limiting and -stimulating conditions. Different organisms were used such as bacteria (floc and coliform bacteria), algae (Chlorella sp.), protozoa (Vorticella sp.), and fish (Lepistes sp.) to represent four trophic levels. Furthermore, chemical oxygen demand (COD) fractionation results were compared with these tests to assess the effect of COD subcategories on the determination of possible toxicity. The pulp-paper industry results revealed acute toxicity to at least two organisms in 6 of 20 effluent samples. The toxicity test results were assessed with chemical analyses such as COD, biochemical oxygen demand (BOD), color, absorbable organic halogen (AOXs), and phenol. It was observed that the toxicity of the effluents could not be explained by using physicochemical analyses in four cases for the pulp-paper industry. The results clearly indicate that bioassay tests provide additional information on the toxicity potential of industrial discharges and effluents.     

A microbial assay for determining the influence of physicochemical environmental factors on the toxicity of organics: Phenol

The toxicity of phenol to filamentous fungi was unaffected by pH or water hardness, but it was potentiated by salinity at levels comparable to those occurring in estuarine and off-shore marine waters. The effect of temperature on the response of the fungi to phenol was highly variable: depending on the fungus, the toxicity of phenol was either not affected, increased, or decreased as the temperature was raised from 22 to 32°C. The toxicity of phenol was not affected by heavy metals. The mediating influences of these abiotic environmental factors on the toxicity of phenol to filamentous fungi were similar to those reported for aquatic macrobiota. This similarity, which has also been noted with the effects of environmental factors on the toxicity of heavy metals, strengthens the concept of using microbial assays to evaluate initially the potential mediating influence of physicochemical factors of natural environments on the toxicity of organic pollutants. An antagonistic interaction in toxicity occurred between phenol and endrin aldehyde orp-chloro-m-cresol, and an additive interaction occurred between phenol and toxaphene, but no interactions were apparent between phenol and other phenolic compounds and pesticides.     

郑州市某污水处理厂尾水毒性评价

目的探讨郑州市某污水处理厂进出水的急性毒性和遗传毒性。方法采集该厂进水、二级出水和三级出水,利用发光细菌毒性测试法检测进出水的急性毒性,利用蚕豆根尖微核试验检测进出水的遗传毒性。结果进水、二级出水和三级出水对发光菌的抑光率分别为(33.96±7.51)%、(14.32±7.36)%、(7.24±5.58)%,二级出水和三级出水对发光菌的抑光率低于进水(F=12.159,P=0.008)。蚕豆根尖微核细胞率分别为(12.67±2.08)‰、(6.33±1.53)‰和(2.67±0.58)‰,污染程度分别为重度污染、轻度污染和基本无污染,二级出水及三级出水蚕豆根尖微核细胞率低于进水(F=56.850,P<0.001)。结论进水经处理后急性毒性及遗传毒性显著下降,但对环境仍具有一定的生态风险性。     

二溴海因消毒剂废液的再利用

目的研究二溴海因消毒剂在生产中所产生的废液，用于医疗污水消毒处理的效果。方法使用二溴海因消毒剂废液对医疗污水消毒，按“GB 18466—2001（医疗机构污水排放要求）”进行检测。结果当污水中二溴海因消毒剂含量达到25、30、35mg／L时，粪大肠菌群均少于90个／L，污水中微生物指标达到排放要求。结论二溴海因消毒剂废液用于医疗污水消毒时，当污水中二溴海因消毒剂含量达到25mg／L时污水消毒合格。     

Pesticide toxicity on the ciliate protozoan Colpidium campulum: Possible consequences of the effect of pesticides in the aquatic environment

The effects of 39 pesticides on the growth of Colpidium campylum in monoxenic culture are reported. Most of these substances are not toxic up to 10 ppm (the maximum concentration tested out). When the toxicity is examined with regard to the chemical structure of the products or their use, it appears that (1) organophosphorous products are generally more toxic than organochlorine chemicals; (2) fungicides are generally harmful for the ciliates; (3) herbicides are not very toxic; (4) the toxicity of organochlorine compounds seems to be in some way related with the basic chemical structure of the compound (phenol or cyclohexane). The results are discussed on the basis of the structure of the products, their possible incorporation into the cell, and their effect at the subcellular level.     

Assessment of feminization of male fish in English rivers by the Environment Agency of England and Wales

In recent years there has been considerable concern over the ability of substances discharged into the environment to disrupt the normal endocrine function of wildlife. In particular, the apparent widespread feminization of male fish in rivers has received significant attention from regulators in the United Kingdom, the United States, Europe, and Japan. The U.K. and European epidemiological data sets have demonstrated that the occurrence of feminized fish is associated with effluent discharges and that the incidence and severity is positively correlated with the proportion of treated sewage effluent in receiving waters. Although weakly estrogenic substances may contribute to the overall effect, studies have concluded that steroid estrogens are the principal and most potent estrogenic components of domestic sewage. Extensive laboratory data sets confirm that steroid estrogens are capable of eliciting the effects observed in wild fish at concentrations that have been measured in effluents and in the environment. Based on evaluation of the available information, the Environment Agency (England and Wales) has concluded that the weight of evidence for endocrine disruption in fish is sufficient to develop a risk management strategy for estrogenically active effluents that discharge to the aquatic environment.     

污染物毒性效应分析在荆江航道工程水质监测中的应用

目的研究长江中游(荆江段)航道沿线取水口、排污口水中污染物的毒性效应,分析其在航道工程水源地水质监测中的作用。方法 2015年2月以荆江航道工程沿线取水口水源水和排污口排污水为分析对象,采用鼠伤寒沙门氏菌回复突变试验(Amestest)检测水中污染物潜在致癌性;采用重组基因酵母细胞检测水中环境类雌激素活性。结果荆江航道沿线取水口、排污口水中污染物TA98、TA100突变率均较低,且两者比较差异无统计学意义(P>0.05);取水口水中可检出环境雌激素活性,但明显低于排污口(P<0.05)。结论长江中游(荆江段)航道沿线取水口水源水已具有潜在的环境雌激素活性,需重点监测,密切关注施工期水源地水质变化,避免施工加重污染。     

Identification of chlorfenvinphos toxicity in a municipal effluent in Sydney, New South Wales, Australia

Acute toxicity in a municipal sewage treatment plant in Sydney, New South Wales, Australia, was traced to chlorfenvinphos, an organophosphorous pesticide. Toxicity identification evaluation procedures led to the tentative identification of chlorfenvinphos as the toxic contaminant in the sample. Subsequent analytical verification revealed 0.95 microg/L of chlorfenvinphos in the effluent sample, and spiking studies confirmed that it accounted for the observed toxicity. The 48-h median lethal concentration of chlorfenvinphos to Ceriodaphnia dubia averaged 0.28 microg/L (n = 4). Source-control measures were effective at eliminating chlorfenvinphos and associated toxicity from the discharge.     

Biochemical and Physiological Responses of Rice (Oryza sativa L.) Grown on Different Sewage Sludge Amendments Rates

Using sewage sludge, a biological residue from sewage treatment processes, in agriculture is an alternative disposal technique of waste. To study the biochemical and physiological responses of Rice (Oryza sativa L.) grown on different sewage sludge amendments (SSA) rates a field experiment was conducted by mixing sewage sludge at 0, 3, 4.5, 6, 9, 12 kg m⁻² rate to the agricultural soil. Rate of photosynthesis and stomatal conductance increased in plants grown at different SSA rate. Chlorophyll and protein contents also increased due to different SSA rates. Lipid peroxidation, ascorbic acid, peroxidase activity and proline content increased, however, thiol and phenol content decreased in plants grown at different SSA rates. The study concludes that for rice plant sewage sludge amendment in soil may be a good option as plant has adequate heavy metal tolerance mechanism showed by increased rate of photosynthesis and chlorophyll content and various antioxidant levels.     

Effect of the South Bay Ocean Outfall (SBOO) on ocean beach water quality near the USA-Mexico border

In early 1999, primary treatment and discharge of sewage from Tijuana, Mexico (approximately 95 million liters per day) began through South Bay Ocean Outfall (SBOO) into the ocean 4.3 km offshore. In this study, statistical comparisons were made of the bacterial water quality (total and fecal coliforms and enterococci densities) of the ocean, both before and after discharge of sewage to the SBOO began, so that the effect of this ocean discharge on nearshore ocean water quality could be quantitatively assessed. The frequency of exceedence of bacterial indicator thresholds was statistically analyzed for 11 shore (surfzone) stations throughout US and Mexico using the Fisher's exact test, for the years before (1995-1998) as compared to after the SBOO discharge began (1999-2003). Only four of the 11 shoreline stations (S2, S3, S11, and S12) showed significant improvement (decreased frequency of exceedence of bacterial indicator thresholds) after SBOO discharge began.     

Genotoxic and ecotoxic effects of urban waste water disinfected with sodium hypochlorite or peracetic acid

Genotoxic and ecotoxicologic effects of urban wastewater disinfected with sodium hypochlorite or peracetic acid were analyzed. The formation of genotoxic species was studied by determining clastogenic and mutagenic activity of aqueous samples and their extracts with in vivo and in vitro tests, respectively. In particular, we have applied citogenetic tests to Allium cepa roots and Tradescantia inflorescence (Allium cepa test and Tradescantia/micronuclei test) and reversion test to Salmonella typhimurium according to the microsuspension procedure (Kado test). The latter is the method of choice for the analysis of complex matrices due to its high sensitivity and specificity. The mutagenic activity of disinfected effluents was similar to the corresponding untreated wastewater both sampled in four different periods. Therefore, the disinfection process did not seem to contribute to aquatic mutagenicity in the examined range of biocide concentration. The potential toxicity of disinfected wastewater for aquatic organisms was evaluated using Daphnia magna. The acute toxicity of peracetic acid in sewage was 0.4 mg/L (24 h E(L)C50). By comparing this value with peracetic acid concentrations detected in effluents from a pilot plant it is expected that treated wastewater would show acute toxic effects on aquatic organisms. Dissociation compounds (hydrogen peroxide and acetic acid) and possible by-products of peracetic acid did not seem to contribute significantly to the toxicity of sewage treated with peracetic acid.     

城镇污水综合处理卫生学指标评价

目的观察城镇污水处理厂污水处理前后微生物数值变化,分析对环境的影响,探讨排放标准.方法定点定时采集污水源水和经处理后的出厂水,按国家规定的方法检测细菌和病毒,同时收集理化指标检测数据.结果出厂水菌落总数高达720000cfu/L总大肠菌群和粪大肠菌群＞16000个/L;源水肠道病毒阳性率为58.33%出厂水肠道病毒阳性率为16.67%.结论理化指标处理效果较好,细菌、病毒处理效果较差,应加强对城镇污水综合处理厂出厂水有关标准的研究.     

Design considerations to avoid bias in the construction of toxicity indices

Species vary widely in their sensitivity to different toxicants. It is best to use a battery of toxicity tests, using organisms from very different trophic levels and taxonomic groups, to assess complex mixtures. The results of the various tests can then be collapsed into a toxicity index that will express the relative hazard of the different samples in a single number. As an example, a case study is presented to illustrate how decisions about the design of a toxicity index influence the ranking of effluents entering a large Canadian river. An index based on acute toxicity ranked municipal effluent as more toxic than pulp mill effluent, but when chronic tests were included the order reversed. Including the volume of discharge into the calculation caused another repositioning of the risk estimate for the two sources. This example illustrates the importance of clear objectives and precise construction of toxicity indices.     

Sediment-contact fish embryo toxicity assay with Danio rerio to assess particle-bound pollutants in the Tietê River Basin (São Paulo, Brazil)

The Tietê River and its tributary Pinheiros River receive a highly complex organic and inorganic pollutants load from sanitary sewage and industrial sources, as well as agricultural and agroindustrial activities. The aim of the present study was to evaluate the embryotoxic and teratogenic effects of sediments from selected locations in the Tietê River Basin by means of the sediment contact embryo toxicity assay with Danio rerio, in order to provide a comprehensive and realistic insight into the bioavailable hazard potential of these sediment samples. Lethal and sub-lethal effects were recorded, and high embryo toxicity could be found in the samples not only in the vicinity of the megacity São Paulo (Billings reservoir and Pinheiros River samples), but also downstream (in the reservoirs Barra Bonita, Promissão and Três Irmãos). Results confirm that most toxicity is due to the discharges of the metropolitan area of São Paulo. However, they also indicate additional sources of pollutants along the river course, probably from industrial, agricultural and agroindustrial residues, which contribute to the degradation of each area. The sediment contact fish embryo test showed to be powerful tool to detect embryo toxicity in sediments, not only by being a sensitive method, but also for taking into account bioavailability. This test provides an ecological highly realistic and relevant exposure scenario, and should therefore be added in ecotoxicological sediment quality assessments.     

Water soluble toxins of Stachybotrys alternans

To attempt to clarify the mechanism of the action of mycotoxins under physiological conditions, the effect of simulated gastrointestinal conditions on the toxicity of Stachybotrys alternans was studied. Components, extracted into a simulated gastrointestinal system and into organic solvents were compared, regarding toxicity and chromatographic properties, with particular reference to a chromatographically characterized Stachybotrys-toxin found by us. It was established that, in addition to those toxic components which were soluble in organic solvents, some toxic, highly water soluble substances were extracted from the fungal culture by the gastrointestinal system. The total toxicity extracted by organic solvents was about fifteen times as much as the toxicity extracted by the simulated system, as measured by cell toxicity tests. All of the toxicity can be transferred from the fungus culture to the aqueous simulated system. This means that the simulated system altered the nature of the toxic components extractible with organic solvents.