Toxicity of fluoroquinolone antibiotics to aquatic organisms

Toxicity tests were performed with seven fluoroquinolone antibiotics, ciprofloxacin, lomefloxacin, ofloxacin, levofloxacin, clinafloxacin, enrofloxacin, and flumequine, on five aquatic organisms. Overall toxicity values ranged from 7.9 to 23,000 microg/L. The cyanobacterium Microcystis aeruginosa was the most sensitive organism (5-d growth and reproduction, effective concentrations [EC50s] ranging from 7.9 to 1,960 microg/L and a median of 49 microg/L), followed by duckweed (Lemna minor, 7-d reproduction, EC50 values ranged from 53 to 2,470 microg/L with a median of 106 microg/L) and the green alga Pseudokirchneriella subcapitata (3-d growth and reproduction, EC50 values ranged from 1,100 to 22,700 microg/L with a median 7,400 microg/L). Results from tests with the crustacean Daphnia magna (48-h survival) and fathead minnow (Pimephales promelas, 7-d early life stage survival and growth) showed limited toxicity with no-observed-effect concentrations at or near 10 mg/L. Fish dry weights obtained in the ciprofloxacin, levofloxacin, and ofloxacin treatments (10 mg/L) were significantly higher than in control fish. The hazard of adverse effects occurring to the tested organisms in the environment was quantified by using hazard quotients. An estimated environmental concentration of 1 microg/L was chosen based on measured environmental concentrations previously reported in surface water; at this level, only M. aeruginosa may be at risk in surface water. However, the selective toxicity of these compounds may have implications for aquatic community structure.     

Toxicity of alkyldinitrophenols to some aquatic organisms

Conclusions The toxicity of alkyldinitrophenols to juvenile Atlantic salmon increases with increasing octanol-water partition coefficient of these compounds. Some alkyldinitrophenols are extremely toxic to juvenile Atlantic salmon, larvae and adult lobsters, but comparatively nontoxic to crayfish. The unexpected low toxicity of dinoseb to crayfish is interesting also from the point of structure-activity relations and emphasizes the need of testing these in different species of aquatic fauna. No data are available on the levels of alkyldinitrophenols in fresh water, estuaries, and coastal areas. There is an indication that at least in certain streams the concentration may temporarily exceed many times the lethal threshold and have a severe impact on aquatic life. Alkyldinitrophenols are not likely to be bio-accumulated and biomagnified and their presence would not be detected by analyses of aquatic fauna. A detailed survey of their levels in surface waters, linked to their usage patterns, should be carried out.     

Toxicity of selected priority pollutants to various aquatic organisms

Toxicity tests were conducted with selected compounds listed by the United States Environmental Protection Agency (EPA) as priority pollutants. Acute toxicity information was determined for acenaphthene, arsenic trioxide, cadmium chloride, mercury(II) chloride, silver nitrate, chlordane, endosulfan, and heptachlor. Acute tests were conducted using one or more of the following species: fathead minnows (Pimephales promelas), channel catfish (Ictalurus punctatus), rainbow trout (Salmo gairdneri), brown trout (Salmo trutta), brook trout (Salvelinus fontinalis), bluegills (Lepomis macrochirus), snails (Aplexa hypnorum), or chironomids (Tanytarsus dissimilis). Acute values from these tests ranged from a silver nitrate 96-hr LC50 of 6.7 micrograms/liter for fathead minnows to an arsenic trioxide 48-hr LC50 of 97,000 micrograms/liter for chironomids. In addition to acute tests, a fathead minnow embryo-larval exposure was conducted with silver nitrate to estimate chronic toxicity. The estimated maximum acceptable toxicant concentration for silver nitrate, based on fathead minnow survival, lies between 0.37 and 0.65 micrograms/liter.     

Toxicity of malathion to mammals,aquatic organisms and tissue culture cells

The effect of malathion on rats (75 and 38 mg/kg bwt), aquatic organisms (100 to 0.001 mg/L), and cells in tissue culture (1000 to 1 ppm) was studied. The conventional toxicological tests conducted for 90 days on rats yielded negative results. ChE activity was determined in plasma, liver, brain and erythrocyte samples. It was significantly reduced in the erythrocytes of animals treated with the larger dose for 21 days and in the cerebral cortex of rats fed either of the doses. ChE activity of rats consuming malathion for 90 days did not differ significantly from that of the controls. In contrast, the psychophysiological examinations utilized in the experiments indicated abnormalities within 21 days. Alterations were observed in the EEG and EMG records after 90 days of feeding.Malathion had a definitely harmful effect on phylogenetically and ontogenetically young aquatic organisms, as well as on the cells of monkey kidney culture. The latter finding suggests that the preparation has a direct destructive effect on cells.Although it is not suggested that malathion should be regarded a toxic agent thus requiring limitation of application, attention is directed to the fact that inconsiderate use of the preparation may involve potential dangers for man and his environment.     

Toxicity of ambient atmospheric particulate matter from the Lake Michigan (USA) airshed to aquatic organisms

Short-term chronic and acute aquatic bioassays are valuable tools in screening a variety of environmental samples. However, only a limited number of studies have used these methods for testing the toxicity of atmospheric particulate matter samples. Previous studies have shown that compounds known to have adverse biological effects, such as polycyclic aromatic hydrocarbons, are deposited in significant quantities into Lake Michigan (USA); however, these compounds comprise a small portion of the total particulate matter deposition. In the present study, a method is described for using Ceriodaphnia dubia, Selenastrum capricornutum (green algae), and MitoScan bioassays to compare the toxicities of reconstituted hard freshwater and methylene chloride extracts of atmospheric particulate matter collected at three locations around the southern shore of Lake Michigan in August 2000. The locations include an urban/industrial site in Milwaukee (WI, USA), an urban-impacted/industrial site in Porter (IN, USA), and a rural site in Bridgman (MI, USA). The bulk chemistry, including organic and elemental carbon, sulfate, nitrate, ammonium, and chloride, shows regional similarities over the sampling event, but the toxicities vary spatially by site, by extraction solvent, and by bioassay. Thus, the bioassays are sufficiently sensitive to show differences in toxicity among the atmospheric particulate matter extracts and have significantly different responses to the samples to enable an initial comparison of toxicity from the different sites.     

Toxicity of ozonated seawater to marine organisms

Ballast water transport of nonindigenous species (NIS) is recognized as a significant contributor to biological invasions and a threat to coastal ecosystems. Recently, the use of ozone as an oxidant to eliminate NIS from ballast while ships are in transit has been considered. We determined the toxicity of ozone in artificial seawater (ASW) for five species of marine organisms in short-term (< or = 5 h) batch exposures. Larval topsmelt (Atherinops affinis) and juvenile sheepshead minnows (Cyprinodon variegatus) were the most sensitive to oxidant exposure, and the mysid shrimp (Americamysis bahia) was the most sensitive invertebrate. Conversely, benthic amphipods (Leptocheirus plumulosus and Rhepoxinius abronius) were the least sensitive of all species tested. Mortality from ozone exposure occurred quickly, with median lethal times ranging from 1 to 3 h for the most sensitive species, although additional mortality was observed 1 to 2 d following ozone exposure. Because ozone does not persist in seawater, toxicity likely resulted from bromide ion oxidation to bromine species (HOBr and OBr-), which persist as residual toxicants after at least 2 d of storage. Total residual oxidant (TRO; as Br2) formation resulting from ozone treatment was measured in ASW and four site-specific natural seawaters. The rate of TRO formation correlated with salinity, but dissolved organic carbon and total dissolved nitrogen did not affect TRO concentrations. Acute toxicity tests with each water over 48 h using mysid shrimp, topsmelt, and sheepshead minnows yielded results similar to those of batch exposure. Addition of sodium thiosulfate (Na2S2O3) to ozonated waters resulted in TRO elimination and survival of all organisms. Our results provide necessary information for the optimization of an efficacious ozone ballast water treatment system.     

Toxicity of vanadium to different freshwater organisms

Bulletin of Environmental Contamination and Toxicology -     

Reaction mechanisms responsible for transformation of pertechnetate in photoautotrophic organisms

Experimental data on the physiological effects of Tc on photoautotrophic and N2-fixing organisms all suggest a relation between their ability to generate strong reducing power and the incorporation of Tc. A series of biochemical experiments were undertaken to elucidate this problem. Isolated spinach chloroplasts, thylakoids and purified compounds of the photosynthetic electron transport chain were incubated with TcO4-. After illumination, the quantity of TcO4- transformed was measured with gel filtration chromatography. For part of the samples, the amount of extractable Tc(V) was determined. Isolated thylakoids showed reduction of TcO4- in the light, suggesting direct interference of TcO4- with the electron transport chain. Use of specific inhibitors and artificial electron carriers indicated that TcO4- withdraws electrons from ferredoxin. Competitive inhibition of TcO4- reduction by O2 and NADP+, as well as its capacity to function as a terminal acceptor in the diaphorase reaction with NADPH, indicates its interaction with the transport chain to be comparable to that of O2. In suspensions of thylakoids, TcO4- is mainly reduced into an extractable Tc(V) compound. Only part of the Tc fraction reduced by intact chloroplasts could, however, be extracted, whereas negligible quantities of unstable Tc(V) complexes were detected in intact plants. The stable complexes in vivo are supposed to originate through ligand exchange with strong complexing agents, such as thiol compounds. Disproportionation reactions of unstable Tc(V) compounds might result in complexes with Tc in lower oxidation states.     

Toxicity of aqueous and sediment-associated fluoride to freshwater organisms

Inorganic fluorides were declared toxic under the Canadian Environmental Protection Act in 1993 based on their potential to cause long-term harmful effects in aquatic and terrestrial ecosystems, but information on the toxicity of sediment-associated fluoride to freshwater benthic organisms was considered incomplete. The purpose of this study was to determine the toxicity of aqueous and sediment-associated fluoride to several species of freshwater organisms and to determine if toxic effects could be expected under environmentally realistic exposures. Toxicity of fluoride (as NaF) in short-term (48-96-h) lethality tests was greatest for the amphipod Hyalella azteca (median lethal concentration [LC50] = 14.6 mg F-/L), followed by the mayfly Hexagenia limbata (32.3), the midge Chironomus tentans (124.1), the fathead minnow Pimephales promelas (262.4), and the cladoceran Daphnia magna (282.8). Relative toxicity in long-term (10-28-d) growth and survival tests in spiked sediment was similar. Hyalella azteca was the most sensitive species for growth (25% inhibitory concentration [IC25] = 290.2 microg F-/g), followed by C. tentans (661.4), H. limbata (1,221.3), and P. promelas (>5,600); H. azteca was also the most sensitive species for survival (LC50 = 1,114.6 microg F-/g), followed by H. limbata (1,652.2) and P. promelas and C. tentans (>5,600 for both). Concentrations of fluoride measured in sediments near some industrial point sources exceed some of these toxicity thresholds. Fluoride is highly mobile in aquatic systems and could potentially reach toxic levels in the water column during dredging to remove fluoride-contaminated sediment.     

Acute lethal toxicity of environmental pollutants to aquatic organisms

The acute lethal toxicity of environment pollutants including chlorophenol, haloalkane, quinone, and substituted nitrobenzene (i.e., nitrophenol, nitrobenzene, nitrotoluene, and aniline) compounds to aquatic organisms was determined. Determination of toxicity of chemicals was performed with chlorella, daphnia, carp, and tilapia. The toxicity of chlorophenols had no relation to the number of chlorine atoms on the benzene ring, but monochlorophenol had lower activity than more chlorine-substituted compounds. The tolerance levels of daphnia and carp to haloalkanes was found to be higher than that of chlorella; toxicity to chlorella was several hundred times higher than to daphnia. The toxicity of naphthoquinone compounds to chlorella and carp was higher than that of anthraquinone. A compound with a monochloride substitution on anthraquinone ring was less toxic to carp than those substituted with amine, hydroxyl, and dichlorine groups. Nitrobenzene compounds with an additional substitution group on the p position were extremely toxic to daphnia and carp.     

焦性没食子酸对3种不同水生生物的毒性作用

目的研究焦性没食子酸对水生生物的毒性作用。方法以蛋白核小球藻(Chlorella pyrenoidosaChick)、斜生栅藻(Scenedesmus obliquus)和多刺裸腹溞(Moina macrocopa)作为受试对象,探讨不同浓度的焦性没食子酸(pyrogallol)的急性毒性效应。结果随焦性没食子酸浓度的增加藻细胞密度和溞数量明显下降,呈现剂量-效应关系;焦性没食子酸对蛋白核小球藻和斜生栅藻半抑制效应浓度(EC50)分别为19.7mg/L和19.8mg/L,对多刺裸腹溞24h和48h半抑制效应浓度分别为18.25mg/L和13.96mg/L。结论焦性没食子酸对蛋白核小球藻、斜生栅藻和多刺裸腹溞均属于中毒。