Ecotoxicological assays to determine the median lethal concentration (LC50) of formalin for fish

The aim of this study was to determine the acute toxicity effect and the accumulation of microcystin-leucine-arginine (MC-LR) on the crayfish Procambarus clarkii (Girard, 1852). Juvenile P. clarkii (5.47 ± 1.3 g) were cultured under 5 different MC-LR concentrations (0.3, 0.6, 1.2, 2.4, 4.8 mg/l), then the acute toxicity effect was observed. The median lethal concentration (LC50) of MC-LR on juvenile P. clarkii was 3.741 mg/l at 24 h, 1.494 mg/l at 48 h, 0.817 mg/l at 72 h and 0.567 mg/l at 96 h. Accumulation of MC-LR was measured in different organs of mature P. clarkii (58.7 ± 3.8 g) exposed to 0.3 mg/l MC-LR for 120 h. The detected MC-LR concentration decreased in the sequence: hepatopancreas > ovary > abdominal muscle > intestine. Hepatopancreas and ovary were found to be the main targets of the toxin. The results suggested that the MC-LR produced by cyanobacteria blooms could not only reduce the survival rate of juvenile P. clarkii but also affect the fecundity of mature crayfish. This research also provides a reference basis for the detection and assessment of the pollution of water bodies in P. clarkii culture.

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Fumigant toxicity of some essential oils against Red Flour Beetles, Tribolium castaneum (Herbst) and its safety to mammals

Brazilian Journal of Biology ◽

10.1590/1519-6984.219529 ◽

2020 ◽

Vol 80 (4) ◽

pp. 769-776

Author(s):

T. M. Sileem ◽

A. L. Mehany ◽

R. S. Hassan

Keyword(s):

Essential Oil ◽

Essential Oils ◽

Tribolium Castaneum ◽

Larval Stage ◽

Adult Stage ◽

Lethal Concentration ◽

Median Lethal Concentration ◽

Histological Changes ◽

Garlic Oil ◽

Garlic Essential Oil

Abstract Fumigant activities for three essential oils; Garlic oil (Allium sativum L); Chili pepper (Capsicum annuum L.) and Nigella (Nigella sativa L.) were assessed at different concentrations against the adult and 20-days old larval stages of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) in the laboratory. The accumulative mortality was observed at different exposure periods (3, 5 and 7 days). The residual effect of garlic oil that was the effective oil, on the treated wheat grains was evaluated with respect to histological changes in the liver, kidney, and stomach of rat fed on this treated wheat. The results showed that the mortality rates of treated stages increased with increasing the time of fumigation treatment. Moreover the highest essential oils toxicity at the Median lethal concentration (LC50) values for exposure periods (3, 5 and 7 days) to fumigation were (126, 53, and 47 mg/L air) for adult stage and were (79, 62, and 41 mg/L air) for larval stage, respectively in the case of Garlic oil treatment. While, the lowest essential oils effective was Nigella oil at the Median lethal concentration (LC50) values for exposure periods (3, 5 and 7 days) to fumigation were (3594, 629, and 335 mg/L air) for adult stage and were (1040, 416, and 227 mg/L air) for larval stage, respectively. The toxicity effect of various essential oils against adults and larvae of T. castaneum at the LC50at 7 days fumigation could be arranged in descending order as follows: Garlic oil, Chili pepper oil, and Nigella oil. The histological changes showed that the organs slightly affected at the fumigation for 3 days. It may be concluded that the garlic essential oil is the good effective fumigant to control T. castaneum in the stored products and it recommended that the fumigation period does not exceed 3 days. The garlic essential oil has the potential for applications in IPM programs for stored-grain pests because of its high volatility and fumigant activity and its safety.

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The Susceptibility of various Species of Mosquitos to DDT, Dieldrin and BHC

Bulletin of Entomological Research ◽

10.1017/s0007485300030935 ◽

1955 ◽

Vol 46 (2) ◽

pp. 301-309 ◽

Cited By ~ 10

Author(s):

R. H. Wharton

Keyword(s):

Aedes Aegypti ◽

Culex Pipiens ◽

Lethal Concentration ◽

Median Lethal Concentration ◽

Adult Females ◽

Anopheles Maculipennis ◽

Culex Pipiens Molestus ◽

Filter Papers

The susceptibility of various mosquitos to DDT, dieldrin and BHC has been studied. Adult females were exposed in small tubes lined with filter papers impregnated with insecticide-oil solutions. Larvae were exposed to insecticideacetone suspensions in water.Adult mosquitos tested in London showed no striking differences in susceptibility to DDT, though the median lethal concentration (MLC) of Culex pipiens molestus Forsk. (1·6 per cent.) was greater than the MLC of Aëdes aegypti (L.) (0·9), Anopheles maculipennis var. atroparvusvan Thiel (1·0), or A. quadrimaculatus Say (·7). C. p. molestus and Aë. aegypti showed the same order of susceptibility to dieldrin and BHC, with Anopheles m. atroparvus more susceptible to both insecticides.

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Arsenic resistance in a strain of cattle tick Boophilus microplus (Canestrini) from Northern NSW.

Australian Journal of Agricultural Research ◽

10.1071/ar9550666 ◽

1955 ◽

Vol 6 (4) ◽

pp. 666 ◽

Cited By ~ 10

Author(s):

LF Hitchcock ◽

WJ Roulston

Keyword(s):

Reference Strain ◽

New South ◽

New South Wales ◽

Boophilus Microplus ◽

Lethal Concentration ◽

Cattle Tick ◽

Median Lethal Concentration ◽

Arsenic Resistance ◽

South Wales

Laboratory trials were carried out with ticks of a northern New South Wales strain which had proved impossible to control by dipping in 0.2 per cent. As2O3. The concentration of arsenic required to prevent 50 per cent. of engorged female ticks of this strain from laying viable eggs was found to be approximately double that for females of a reference strain. The median lethal concentration of arsenic for larvae of the northern New South Wales strain was also found to be approximately double that for larvae of the reference strain.

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Toxaphene-resistant cattle ticks (Boophilus microplus (Canestrini)) occurring in Queensland

Australian Journal of Agricultural Research ◽

10.1071/ar9560211 ◽

1956 ◽

Vol 7 (3) ◽

pp. 211 ◽

Cited By ~ 10

Author(s):

KR Norris ◽

BF Stone

Keyword(s):

Body Weight ◽

Reference Strain ◽

Boophilus Microplus ◽

Peanut Oil ◽

Lethal Concentration ◽

Median Lethal Concentration ◽

Subcutaneous Injections ◽

Cattle Ticks ◽

History Of ◽

Very High

Cattle ticks on four herds in southern Queensland survived dipping in a vat charged with 0.5 per cent. w/v toxaphene, which nevertheless disinfested a fifth herd. Protective periods afforded by toxaphene against attachment of resistant larvae were much shorter than against susceptible strains. Laboratory concentration-response tests on a culture of the toxaphene-resistant ticks indicated that the median lethal concentration of toxaphene for engorged females was 19 times higher than that of a reference strain, and t h at f o r the larvae was also significantly higher. The toxaphene-resistant ticks were not affected when cows were sprayed with 0.05 per cent. w/v gamma-BHC. This was consistent with an earlier history of BHC resistance in the ticks on these herds. Spraying trials indicated no marked arsenic resistance in the toxaphene-resistant ticks. The mortality of the toxaphene-resistant ticks on cattle sprayed with 0.5 per cent. W/V pp'-DDT, and the protective period against larval reinfestation, were as high as usually observed in other tick populations. A very high kill resulted from spraying the toxaphene-resistant ticks with 0.05 per cent. w/v diazinon. Subcutaneous injections of peanut oil solutions of lindane, dieldrin, and aldrin at the rate of 25 mg toxicant/kg host body weight were without effect on toxaphene-resistant ticks.

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Median Lethal Concentration

IUPAC Standards Online ◽

10.1515/iupac.76.0291 ◽

2016 ◽

Author(s):

Monica Nordberg ◽

John H. Duffus ◽

Douglas M. Templeton

Keyword(s):

Lethal Concentration ◽

Median Lethal Concentration

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Toxicity bioassays of cadmium on selected freshwater invertebrates and the interaction of cadmium and zinc on the freshwater shrimp, Paratya tasmaniensis Riek

Marine and Freshwater Research ◽

10.1071/mf9740097 ◽

1974 ◽

Vol 25 (1) ◽

pp. 97 ◽

Cited By ~ 74

Author(s):

VJ Thorp ◽

PS Lake

Keyword(s):

Calcium Carbonate ◽

Acute Toxicity ◽

Lethal Concentration ◽

Total Hardness ◽

Median Lethal Concentration ◽

Toxic Unit ◽

Seasonal Differences ◽

Freshwater Invertebrates ◽

Invertebrate Species ◽

Freshwater Invertebrate

In acute toxicity bioassays with cadmium sulphate at 15� C in soft water (total hardness 10 mg/l as calcium carbonate), the concentrations fatal to 50 % of the test animals were determined for five freshwater invertebrate species. The 96 hr median lethal concentration (LC50) of cadmium was 0.04 mg/l for the amphipod Austrochiltonia subtenuis Sayce, 0.06 mg/l for the shrimp Paratya tasmaniensis Riek, 0.84 mg/l for the ephemeropteran nymph Atalophlebia australis Walker, 250 mg/l for the zygopteran nymph Ischnura heterosticta (Burmeister) and well over 2000 mg/l for a trichopteran larva of the Leptoceridae. The bioassays on Paratya indicared that there may be seasonal differences in sensitivity to cadmium. The 96 hr LC50 for zinc for Paratya was 1.21 mg/l. Zinc and cadmium appeared to interact less than additively at concentrations below 1 toxic unit. Above this concentration, their interaction was strictly additive.

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Toxicity study on clinacanthus nutans leaf extract using danio rerio embryos

International Journal of Research in Pharmaceutical Sciences ◽

10.26452/ijrps.v10ispl1.1681 ◽

2019 ◽

Vol 10 (SPL1) ◽

Author(s):

Maryam Anis ◽

Suganya Murugesu ◽

Vikneswari Perumal ◽

Qamar Uddin Ahmed ◽

Bisha Fathimah Uzir ◽

...

Keyword(s):

Probit Analysis ◽

Antioxidant Effect ◽

Lethal Concentration ◽

Hexane Fraction ◽

Median Lethal Concentration ◽

Toxic Level ◽

Morphological Defects ◽

Clinacanthus Nutans ◽

Gas Chromatography Mass Spectroscopy ◽

Danio Rerio Embryos

Plants are believed to have various medicinal benefits from their constituents, but they might also give toxic effects to the human's body. Clinacanthus nutans that belongs to Acanthaceae family, which has been reported to have an antidiabetic and antioxidant effect. The study has been done to determine the toxic level and the lethal concentration of non-polar extract of C. nutans leaves using zebrafish embryos. Crude extract of 80% methanolic solution was further partitioned to obtain the n-hexane fraction. Upon spawning and fertilization, the eggs were collected, transferred into a 96-well plate, and incubated with the n-hexane fraction at different concentrations ranging from 15.63-500 µg/ml prepared in 2% DMSO. The median lethal concentration (LC50) was calculated to be 75.49 µg/mL using probit analysis. The reading is considered toxic to the embryos. The heartbeat rate was measured using DanioScope software, and the mortality and survival rate were assessed by microscopic observation at 24, 48, 72, and 96 hours post-fertilization. Some of the morphological defects observed include less pigmentation, crooked backbone, dented tail, and oedema. The n-hexane fraction's profiling using gas chromatography-mass spectroscopy (GC-MS) analysis showed the presence of some fatty acids, organic acid, and sterols, which is known to be toxic in synergism.

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