Comparison of the sensitivities of fish, Microtox and Daphnia-magna bioassays to amoxycillin in anaerobic/aerobic sequential reactor systems

2012 ◽  
Vol 66 (5) ◽  
pp. 1117-1131 ◽  
Author(s):  
H. Çelebi ◽  
D. T. Sponza

In this study the anaerobic treatability of amoxycillin (AMX) was investigated in a laboratory-scale anaerobic multi-chamber bed reactor (AMCBR)/aerobic continuously stirred tank reactor (CSTR) system. The chemical oxygen demand (COD) and AMX removal efficiencies were around 94% in the AMCBR reactor at hydraulic retention times (HRTs) between 2.25 and 5.5 days. Decreasing the HRT appeared not to have a significant effect on the performance of the AMCBR up to a HRT of 1.13 days. The maximum methane production rate and methane percentage were around 1,100–1,200 mL/day and 55%, respectively, at HRTs between 2.25 and 5.5 days. The decrease in HRT to 1.5 days decreased slightly the gas productions (1,000 mL/day and 500 mL for total and methane gases) and methane percentage (45%). The AMCBR recovered back to its baseline performance within a couple of days. The acute toxicity of 150 mg/L AMX was monitored with Daphnia magna, Lepistes sp., and Vibrio fischeri acute toxicity tests. The acute toxicity removals were 98, 96 and 96% for V. fischeri, D. magna and Lepistes sp. in the effluent of the sequential system treating 150 mg/L AMX at HRTs of 2.25–5.5 days. Among the trophic organisms used in the acute toxicity tests the most sensitive organism was found to be bacteria (V. fischeri) while the most resistant organism was found to be fish (Lepistes sp.).

Author(s):  
Ana Zapata ◽  
Isabel Oller ◽  
Raphael Gallay ◽  
César Pulgarín ◽  
Manuel Ignacio Maldonado ◽  
...  

AbstractThis paper compares the feasibility of two different treatment approaches, chemical oxidative treatment by the solar photo-Fenton method and a combined approach applying the solar photo-Fenton method as a pre-treatment for aerobic biological wastewater treatment. The targets are two biorecalcitrant substances used as synthesis intermediates in the pharmaceutical industry, 2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-ylmethanol (CAS 84682-23-5) (DIDM) and 2-(2,4-dichlorophenyl)-2-(1H-1,2,4-triazol-1-ylmethyl)- 1,3-dioxolan-4-ylmethanol (CAS 67914-85-6) (DTDM). Solar photo-Fenton treatment was performed in Compound Parabolic Collector pilot-plants, and biological treatment in an immobilized biomass reactor pilot-plant. Analytical determinations included the measurement of dissolved organic carbon, chemical oxygen demand, inorganic compounds (chloride, ammonium, nitrate), formed during degradation, acute toxicity tests applying Vibrio Fischeri luminescence bacteria and the Zahn-Wellens biodegradability test. The synthetic wastewater contained 200 mg/L of each compound, an initial DOC of 200 mg/l and an initial COD of 700 mg/L. The target compounds proved to be susceptible to complete degradation and partial mineralization (95%) by photo-Fenton. Total elimination of both substances occurred after 74 minutes of illumination and required the consumption of 27.5 mM of hydrogen peroxide. Nevertheless, acute toxicity persisted practically to the end of the treatment, and biodegradability could only be slightly enhanced, never rendering the wastewater completely biodegradable at any stage of the chemical oxidative treatment. By Zahn-Wellens test DIDM and DTDM proved to be non-biodegradable and only samples pre-treated by photo-Fenton until achieving a DOC below 98 mg/L showed a significant degree of biodegradability (60% after 11 days of biotreatment). This particular behaviour contrasts with other substances that have been tested before and may be related to the refractory nature of the imidazole and triazole moieties in the molecular structure of DIDM and DTDM.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
J. Kalka

Combined treatment of landfill leachate and municipal wastewater was performed in order to investigate the changes of leachate toxicity during biological treatment. Three laboratory A2O lab-scale reactors were operating under the same parameters (Q-8.5–10 L/d; HRT-1.4–1.6 d; MLSS 1.6–2.5 g/L) except for the influent characteristic and load. The influent of reactor I consisted of municipal wastewater amended with leachate from postclosure landfill; influent of reactor II consisted of leachate collected from transient landfill and municipal wastewater; reactor III served as a control and its influent consisted of municipal wastewater only. Toxicity of raw and treated wastewater was determinted by four acute toxicity tests withDaphnia magna, Thamnocephalus platyurus, Vibrio fischeri,andRaphidocelis subcapitata. Landfill leachate increased initial toxicity of wastewater. During biological treatment, significant decline of acute toxicity was observed, but still mixture of leachate and wastewater was harmful to all tested organisms.


1986 ◽  
Vol 15 (6) ◽  
pp. 741-749 ◽  
Author(s):  
F. M. Gersich ◽  
F. A. Blanchard ◽  
S. L. Applegath ◽  
C. N. Park

2014 ◽  
Vol 26 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Raquel Aparecida Moreira ◽  
Adrislaine da Silva Mansano ◽  
Lidiane Cristina da Silva ◽  
Odete Rocha

AIM: In this study we compared the sensitivity of three species of Cladocera, Daphnia magna, Ceriodaphnia silvestrii and Macrothrix flabelligera, to the commercial product of the herbicide Atrazine, the Atrazine Atanor 50 SC® (500 g/L), widely used on crops in Brazil. METHODS: Acute toxicity tests were performed at the nominal atrazine concentrations 2.25, 4.5, 9.0, 18.0, 36 and 72 mg L-1, on C. silvestrii and M. flabelligera and at 2.25, 4.5, 9.0, 18.0, 36, 72 and 144 mg L-1 on D. magna. The range of concentrations tested was established in a series of preliminary tests. RESULTS: The toxicity tests showed that the two species naturally occurring in water bodies in Brazil were more susceptible than Daphnia magna. The effective concentrations of Atrazine Atanor 50 SC® (EC50- 48 h) to the species M. flabelligera, C. silvestrii and D. magna were 12.37 ± 2.67 mg L-1, 14.30 ± 1.55 mg L-1 and 50.41 ± 2.64 mg L-1, respectively. Furthermore, when EC50 observed here for M. flabelligera and C. silvestrii were compared with published values of EC50 or LC50 (mg L-1) for various aquatic organisms exposed to atrazine, it was seen that these two cladocerans were the most sensitive to the herbicide. CONCLUSIONS: Considering these results and the broad distribution of C. silvestrii and M. flabelligera in tropical and subtropical regions, it is concluded that these native species would be valuable test organisms in ecotoxicological tests, for the monitoring of toxic substances in tropical freshwaters.


1998 ◽  
Vol 33 (1) ◽  
pp. 95-110 ◽  
Author(s):  
W.R. Bennett ◽  
A.P. Farrell

Abstract The primary goal of this study was to investigate the possibility of using early life stages of white sturgeon (Acipenser transmontanus) (eggs, larvae and fry) as a species relevant to the Fraser River, B.C., for the acute and sublethal toxico-logical testing of forest industry effluents. Here we report the first successful acute toxicity tests for 8-day-old larvae and 42-day-old fry exposed to several chemicals known to be released into the Fraser River (i.e., 6 monochlorovanillin [6 MVAN], 4,5 dichloroguaiacol [4,5 DCG], 4,5 dichlorocatechol [4,5 DCAT], pentachlorophenol [PCP], and didecyldimethylammonium chloride [DDAC]). In most cases, white sturgeon fry were at the lower end of the range for acute toxicity values for chlorinated phenolic compounds, when compared with other juvenile fish species, and they were extremely sensitive to DDAC. The larval stage was usually more sensitive than the fry stage. Acute toxicity tests with fertilized eggs were unsuccessful. A postexposure growth study was inconclusive because neither control nor toxicant-exposed larvae and fry withstood the additional handling used for measuring body mass. At 62-days-old, fry were more tolerant of handling. This allowed measurement of their swimming performance. Although we have concerns about the reliability of using larvae for acute toxicity testing at this time, 60-day-old white sturgeon fry would appear to be both a sensitive and relevant species for assessing environmental impacts relevant to the Fraser River.


Sign in / Sign up

Export Citation Format

Share Document