Organics in wheat and rye straw pulp bleaching and combined mill effluents (II) ecotoxicological screening

Potential environmental effects of the discharge of industrial wastewater from manufacturing of bleached straw pulp have been studied. Bleached neutral sulphite straw pulping results in discharges of both black cooking and spent bleaching liquors. Time proportional samples were taken from the combined bleaching effluent and the combined mill effluent, (i) Mutagenic activity of the two samples in an Ames’ test, and (ii) acute toxicity of the combined mill effluent sample towards the photosynthetic activity of natural marine phytoplankton from the receiving waters were determined. Also, acute toxicity was determined of the slowly biodegradable or persistent organics remaining after aerobic stabilization of the sample towards (ii) photosynthetic activity of natural phytoplankton, (iii) mussels (Mytilus edulis), (iv) eels (Anguilla anguilla) and, (v) crustacean (Nitocra spinipes); and furthermore, (vi) reproduction test of the crustacean and (vii) growth inhibition test of the marine diatom (Phaeodactylum tricornutum) were performed. Mutagenicity emission factors (MEF's) and toxicity emission factors (TEF's) were calculated to classify the effluents. Combined mill effluent sample showed a mutagenic activity per t₉₀ of one fourth the activity of a kraft pulp bleaching effluent, and the inhibition of the photosynthesis of natural phytoplankton was significant up to 2600 times dilution. After aerobic stabilization, inhibition was observed up to 400 times dilution. Other effects of the combined mill effluent sample were only significant below 40 times dilution. The bleaching effluent showed a mutagenic activity per t₉₀ comparable to kraft bleaching effluents. Other effects were only significant below 20 times dilution.     

Attraction to prey and stimulus to attack in the predatory gastropod Urosalpinx cinerea

Urosalpinx cinerea (Say), accustomed to feeding on Balanus balanoides, were strongly attracted in a choice chamber by the effluents of B. balanoides and B. eburneus, were indifferent to the effluents of Crassostrea virginica, Crepidula fornicata and Mytilus edulis, and responded negatively to the effluent of their own species. Oyster drills from a population feeding on Crassostrea virginica were attracted to oyster effluent; when these snails were offered a choice between Crassostrea virginica and B. balanoides effluents, they responded in equal numbers to the two effluents. Concentrations of NH₄Cl-ammonia in the range 18.2 to 73.3 mol did not attract the snails, and their responses to animal effluents were not correlated with the ammonia and amino-acid concentrations of the effluents, which ranged from 11.8 to 21.0 mol. It is argued that these results deny ammonia the role of a nonspecific distance attractant. Confined separately with various potential prey species, Urosalpinx drilled Balanus balanoides, B. eburneus, Crassostrea virginica, Crepidula fornicata, C. plana, Mercenaria mercenaria, Modiolus demissus, Mya arenaria, Mytilus edulis, Spisula solidissima, and Yoldia limatula, but not Anomia simplex. The prey species that were the least attractive in running water were generally rendered attractive and subject to attack in standing water. Freshly shucked Crepidula fornicata shells were scarcely drilled unless continuously perfused by C. fornicata effluent, and then only in small numbers. Altering the texture of living C. fornicata shells by wrapping them in nylon netting, by polishing, or by roughening, did not make them immune to drilling. Oyster drills in contact with C. fornicata attacked only if they received the effluent of the living prey, proving that tactile stimuli alone are not adequate to induce drilling.     

成组生物毒性测试法综合评价典型工业废水毒性

为了更加准确地评估典型工业废水的综合生物毒性以及处理工艺对废水毒性的削减情况,采用发光细菌急性毒性实验、大型溞急性毒性实验和单细胞凝胶电泳实验,结合潜在生态毒性效应探测(potential ecotoxic effects probe,PEEP)指数对常州市7种典型工业废水的综合生物毒性进行了评价。结果表明,7种工业原水都表现出了急性毒性或遗传毒性,综合生物毒性强度的排序为电子厂>电镀厂>综合污水处理厂>印染厂>化工厂>食品厂>制药厂。而7种工业废水的处理后出水综合生物毒性强度的排序为印染厂>化工厂>电子厂>综合污水处理厂>食品厂>制药厂>电镀厂。其中,印染和化工厂出水综合生物毒性高于原水,分别增加了43.3%和38.7%,PEEP评价结果显示分别属于剧毒和高毒,而电镀、电子、综合污水处理和食品厂出水的综合生物毒性削减明显,分别比原水削减了76.9%、53.1%、48.3%和26.6%,PEEP结果表明基本无毒。建立在成组生物毒性实验基础上的PEEP评价方法可全面反映工业废水的综合生物毒性,进而更客观地评价废水对水生态系统乃至人类健康的潜在影响。     

A study on genotoxicity of textile dyeing industry effluents from Rajshahi,Bangladesh, by the Allium cepa test

Textile dye effluents are believed to be toxic as they might exert various harmful effects on living organisms including genotoxicity. These effluents are the main source of direct and continuous input of pollutants into the aquatic ecosystems. In this study, dye effluents from a local silk dyeing industry were analysed for their genotoxic potential by the Allium cepa genotoxicity test. The A. cepa test is characterised as a genotoxicity test where the roots of A. cepa are grown in different concentrations of the test material. The macroscopic results clearly showed that the toxicity of the dye effluents prompted A. cepa root growth inhibition, and this effect increased with higher concentrations of the effluents. At the cellular level, no dividing cells were found at higher concentrations such as 60%, 80% and 100% of the effluents. However, at a lower concentration of 20%, dividing cells were identified, although the mitotic index was much lower than that of the control. Microscopic analysis showed that the dye effluents induced chromosomal aberrations at significant levels. Taken together, these results revealed that the textile dyeing industry effluents are toxic to eukaryotic cells and these dyes have genotoxic properties that can potentially lead to cancer development and adverse health conditions.     

Bioremediation of shrimp biofloc wastewater using clam,seaweed and fish

The aim of this study was to evaluate the bioremediation of effluents in the biofloc culture of shrimp juveniles using clams, seaweed and fish. Four treatments were considered: CLT – without bioremediating organisms; AB – using Anomalocardia brasiliana; GB – using Gracilaria birdiae and ON – using Oreochomis niloticus with 2.5?kg wet weight per m³ of shrimp effluent. In the AB treatment, significant differences were observed in the effluent at the end of the experiment (96?h) for values of nitrite-nitrogen, nitrate, alkalinity, TSS and orthophosphate. The ISS and VSS levels recorded for the AB treatment varied respectively from 336 to 127?mg?L^?1, and from 505 to 130?mg?L^?1, with a corresponding gradual reduction of approximately 62% and 74% at the end of the experiment. The use of a clam species to treat effluents in a biofloc system with salinity near 25?g?L^?1 reduced waste solids and increased the nitrification process from 72 to 96?h, indicating that this clam can be used as a bioremediator and contributes to effluent treatment in shrimp.     

Hydrographic and plankton variability in the Saronikos Gulf

Five stations in the Saronikos Gulf were studied during 1983–1984. One located in Elefsis Bay an industrial area, and the others, located at a distance where the effects of effluents were minimized. A differential discharge of untreated urban wastes and industrial effluents adds to the distinctiveness of the two parts. Various physical, chemical and biological (Chlorophyll‐a, phytoplankton, Zooplankton) factors were measured seasonally. Temporal and spatial distribution of surface temperature, salinity, nutrients (N, P, Si), chlorophyll‐a, and plankton were reported and the areas exposed to local eutrophication identified. Significant correlations between phytoplankton standing crop, chlorophyll‐a Zooplankton and various environmental parameters were demonstrated.     

Seasonal differences in treatment efficiency of a set of stabilization ponds in a semi-arid region

This article aims to determine the significant differences of the seasonal changes of pH, chemical oxygen demand (COD), biological oxygen demand (BOD), and total suspended solids (TSS) parameters in a wastewater stabilization pond. The variation of these parameters followed the seasonal pattern of temperature. The mean seasonal pH of the influent wastewater ranged between 7.8 (in spring) and 7.9 (in summer), while in the final effluents it was between 7.9 (in winter) and 8.3 (in summer). The mean seasonal COD of the influent wastewater ranged between 650?mg?L^?1 in spring and 600?mg?L^?1 in autumn, whereas in the effluents it was between 150?mg?L^?1 in autumn and 270?mg?L^?1 in spring. The mean seasonal BOD₅ of the influent wastewater ranged between 360?mg?L^?1 in autumn and 390?mg?L^?1 in winter, whereas in the effluents it was between 66?mg?L^?1 in summer and 130?mg?L^?1 in winter. The results showed that the percent removals of COD, BOD₅ and TSS from final effluents were maximum in summer for COD and BOD₅ (76%), summer (83%) and for TSS in winter (78%), respectively. Data analysis showed that there were significant differences between parameters of pH, COD, BOD₅ and TSS at four different seasons (p?相似文献   

Effect of Pb,Cd and Cu on survival and development of Culex quinquefasciatus (Diptera: Culicidae)

ABSTRACT

The present research aimed to determine the lowest levels of three heavy metals (Pb, Cd and Cu) to which the larvae of Southern House Mosquito, Culex quinquefasciatus are susceptible in water. The study also aimed to investigate the effects of these heavy metals on the development of Cx. quinquefasciatus at concentrations set by Pakistan Environmental Protection Agency (Pak-EPA) as permissible levels for liquid industrial effluents. The 2nd instar larvae of Cx. quinquefasciatus were exposed to different concentrations of Pb, Cd and Cu and their effects on oviposition preference, egg hatching rate and larval development were studied. The LC₅₀ values of Pb, Cd and Cu were 12.6, 6.3 and 2.6?ppm, respectively. Gravid female mosquito adults deposited a significantly lower number of egg rafts in containers containing 0.50?ppm Pb or 1.0?ppm Cu in water. Each of the heavy metals in water resulted in significantly (p?<?0.05) lower egg hatching rate, prolonged time to pupation, lower pupation rate, prolonged time to adult emergence, lower adult emergence rate and higher female to male ratio. It is concluded that the 2nd instar larvae of Cx. quinquefasciatus are susceptible to Pak-EPA permissible levels of Pb, Cd and Cu in municipal and liquid industrial effluents.     

Comparison of membrane fouling in ultrafiltration of down-flow and up-flow biological activated carbon effluents

Fouling during ultrafiltration of down- and up-flow biological activated carbon effluents was investigated to determine the roles of polysaccharides, proteins, and inorganic particles in ultrafiltration membrane fouling. During ultrafiltration of down- flow biological activated carbon effluent, the trans-membrane pressure was £26 kPa and the permeate flux was steady at 46.7 L?m^–2?h^–1. However, during ultrafiltration of up-flow biological activated carbon effluent, the highest trans-membrane pressure was almost 40 kPa and the permeate flux continuously decreased to 30 L?m^–2?h^–1. At the end of the filtration period, the normalized membrane fluxes were 0.88 and 0.62 for down- and up-flow biological activated carbon effluents, respectively. The membrane removed the turbidity and polysaccharides content by 47.4% and 30.2% in down- flow biological activated effluent and 82.5% and 22.4% in up-flow biological activated carbon effluent, respectively, but retained few proteins. The retention of polysaccharides was higher on the membrane that filtered the down- flow biological activated effluent compared with that on the membrane that filtered the up-flow biological activated carbon effluent. The polysaccharides on the membranes fouled by up-flow biological activated carbon and down- flow biological activated effluents were spread continuously and clustered, respectively. These demonstrated that the up-flow biological activated carbon effluent fouled the membrane faster. Membrane fouling was associated with a portion of the polysaccharides (not the proteins) and inorganic particles in the feed water. When there was little difference in the polysaccharide concentrations between the feed waters, the fouling extent was exacerbated more by inorganic particles than by polysaccharides.

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Photoinduced degradation of sulfonamides,kinetic, and structural characterization of transformation products and assessment of environmental toxicity

This study focuses on the degradation of the sulfonamide antibiotics, sulfadiazine, sulfamethazine, sulfamethoxazole, and sulfathiazole, using ultraviolet irradiation in various conditions. Different pHs were investigated in combination with the addition of hydrogen peroxide and further oxygen removal. High-performance liquid chromatography electrospray ionization ion-trap mass spectrometry was used to identify and elucidate degradation products and to establish concentration–time curves. Previously unknown degradation products could be characterized. Reaction rate constants of all compounds and transformation products were determined. The parent sulfonamides decayed according to first-order kinetics, while the concentrations of the transformation products varied with time according to a subsequent reaction of an intermediate product. Quantum efficiencies were analyzed for mechanistic purposes. As example, sulfamethoxazole was added to effluents from a wastewater treatment plant and irradiated. Phototoxicity and environmental hazard were assessed through quantitative structure-activity relationship computations. In addition, the minimal inhibition concentrations were determined for Pseudomonas fluorescens and Bacillus subtilis. Conclusions for UV-C irradiation as a fourth purification wastewater treatment stage were derived.