Toxicity of 2,4-D acid to phytoplankton

Okay, OS
Gaines, A
The toxic effects of 2,4-D on Phaedoactylum tricornutum (Bohlin) and Dunaliella tertiolecta (Butcher), two species of phytoplankton well suited to bioassay studies and responsive to pollutants, were studied by monitoring changes in growth in terms of cell populations, chlorophyll fluorescence and the rate of (CO2)-C-14 assimilation. Short term bioassays, batch and continuous cultures were studied. Pure 2,4-D acid appeared more toxic than the commercial amine form of the herbicide but this may have been due to small quantities of acetone present in the solvent. Concentrations of amine herbicide in excess of 100 mg l(-1) extended the duration of the lag phase and inhibited growth but smaller concentrations stimulated growth, the amine being consumed by phytoplankton in preference to nitrate. Continuous culture confirmed the ability of phytoplankton to adapt slowly to herbicide concentrations even as high as 500 mg l(-1). It is suggested that green algae adapt more rapidly to environmental change than do diatoms.


SURUCU, G; Sanin, Faika Dilek (Elsevier BV, 1989-11-01)
This study investigates the effect of aeration basin temperature, pH and dissolved oxygen (DO) concentration on filterability and compressibility characteristics of activated sludge. Laboratory-scale semi-continuous reactors, fed with synthetic wastewater were used. Effects of temperatures of 15, 20, 25, 30, 35°C; pH values of 5.7, 7.2, 8.2, 9.0 and DO concentrations of 0.5, 1.0, 1.5, 2.0, 5.0 ml/l were studied by keeping all the other parameters constant in each case. Results indicated that as the operatin...
Enzymatic extraction of activated sludge extracellular polymers and implications on bioflocculation
Sesay, Ml; Özcengiz, Gülay; Sanin, Faika Dilek (Elsevier BV, 2006-04-01)
This study examines enzyme hydrolysis, a mild, effective, but a rarely used method of extracellular polymer extraction, in removing polymers from mixed culture activated sludge flocs. Two carbohydrate specific enzymes (a-amylase and cellulase) and a protein specific enzyme (proteinase) are used during the study. First, the kinetic aspect is investigated, then enzyme dose optimization is carried out on laboratory grown activated sludge samples cultured at solids retention times (SRT) of 4 and 20 days. A more...
Effects of nickel, chromium and initial feed concentration on the batch growth of a microbial consortium developed from sewage
Gökçay, CELAL FERDİ; Dilek, Filiz Bengü (Informa UK Limited, 1991-01-01)
Effects of nickel, chromium and substrate concentration on the microbial growth of acclimatized and unacclimatized microbes of sewage origin were studied in batch cultures at a constant temperature of 25 °C, at pH 7.0. A synthetic medium supplemented with Ni(II) (5 and 10 mgl‐1) or Cr(VI) (1 and 50 mgl‐1) or with their combinations and at various feed concentrations (650, 975, 1300 mgl‐1) was employed to investigate the effects on the specific growth rate (μm) of the microbial culture. The experimental resu...
Carbon-to-nitrogen and substrate-to-inoculum ratio adjustments can improve co-digestion performance of microalgal biomass obtained from domestic wastewater treatment
Calicioglu, Ozgul; Demirer, Göksel Niyazi (Informa UK Limited, 2019-02-23)
This study comparatively evaluated the effect of co-substrates on anaerobic digestion (AD) and biochemical methane potential of wastewater-derived microalgal biomass, with an emphasis on carbon-to-nitrogen (C:N) and substrate-to-inoculum (S:I) ratios. A semi-continuous photobioreactor was inoculated with Chlorella vulgaris and the nutrient recovery potential was investigated. Derived microalgal slurry was subjected to AD in the absence and presence of co-substrates; model kitchen waste (MKW) and waste activ...
Effect of Anaerobic Azo Dye Reduction on Continuous Sludge Digestion
Ozkan-Yucel, Umay Gokce; Gökçay, Celal Ferdi (Wiley, 2014-10-01)
Effect of continuous feeding of a reactive azo dye, reactive orange 107, and its hydrolyzed form (HRO107), on a conventional anaerobic digester was investigated in this study together with observation of change in microbial community. Laboratory-scale digesters were fed with waste activated sludge and azo dye for 575 days continuously. The influent concentrations of reactive azo dye were between 200 and 3200 mg/L. The digester performance was not adversely affected by azo dye and its reduction metabolites t...
Citation Formats
O. Okay and A. Gaines, “Toxicity of 2,4-D acid to phytoplankton,” WATER RESEARCH, pp. 688–696, 1996, Accessed: 00, 2020. [Online]. Available: