Influence of some abiotic factors on the acute toxicity of cadmium to Cyprinus carpio

Hardness of water had significant effect on the acute toxicity of cadmium to common carp, Cyprinus carpio. The 96h LC sub(50) and safe application rate increased from 43.17 and 22.77 mg 1 super(-1) in soft water (0.9 mM Ca super(2+) l super(-1)) to 310.48 and 177.66 mg l super(-1), respectively, in very hard water (6.0 mM Ca super(2+) l super(-1)). In medium hard and hard water, 96h LC sub(50) values were 48.39 and 116.45 mg l super(-1). When sediments were included in the medium hard, hard and very hard water treatments, the 96h LC sub(50) were 111.20, 133.71 and 334.47 mg l super(-1), respectively. Among these values, the one for medium hard water with sediment treatment was significantly higher than medium hard water treatment; values for the other two treatments were non-significant when compared with respective water treatments. Sediment was able to reduce the acute toxicity of cadmium mainly due to the complexation of cadmium with dissolved organic carbon (DOC). At the lower hardness level, cadmium complexed with DOC and the acute toxicity was reduced significantly. At higher hardness, most of the DOC sites were occupied by calcium and the acute toxicity of cadmium was not significantly reduced in hard water with sediment and very hard water with sediment experiments in comparison to respective water treatments.

Acute toxicity of copper, zinc and mercury on intertidal gastropods of Mumbai coast

The acute toxicity test conducted by static bioassay techniques have revealed that among selected heavy metals, copper is more toxic than zinc and mercury to Planaxis sulcatus and Trochus radiatus. The natural availability of heavy metals in the surrounding environment of these organisms is found to be deciding factor for their toxicity. Natural habitat of the animal also contributes to the sensitivity of a particular animal to the heavy metals tested. In addition the tendency of the animal to overcome the adverse conditions in their surrounding also plays a significant role in toxicity of pollutants.

Acute toxicity of four heavy metals to Sphaeroma walkeri and Ciroiana bovina (Crustacea:Isopoda)

The median lethal concentrations (LC50) of two Isopoda species exposed to each tested metal (Cu. Co, Cd and Zn) in static tests for different exposure periods are quite variable depending on the tested metal The LC50 values for Sphaeroma walkeri after 24 hours exposure to Cu and Co were estimated graphically to be 11.20 and 7.00 mg/1 respectively. The correspoding values for Cirolana bovina exposed to Cu, Co, Cd and Zn were 3.60, 11.0, 3.80 and 4.80 mg/1 respectively. For 2 days the LC50 of S. walkeri exposed to Cd was 5.60 mg/l, but it was 10.10 mg/l for 3 days exposure to Zn. After prolonged exposure the LC50 values decreased proportionally with the exposure duration of the test the percentages of surviving animals demonstrated a progressive decrease with increasing concentratins as a main factor from the analysis of variance (ANOV A). The sensitivity of adult S. walkeri exposed to the four heavy metals for different exposure times ranked: Cd>Co>Zn>Cu. Cirolana bovina appeared to be more sensitive to Cu. Cd and Zn than to Co. Species in order of increasing sensitivity is C. bovina more than S. walker.

Acute toxicity of beta gamma-CAT, a naturally existing non-lens beta gamma-crystallin and trefoil factor complex from frog Bombina maxima skin secretions

In vertebrates, non-lens beta gamma-crystallins are widely expressed in various tissues, but their functions are unknown. The molecular mechanisms of trefoil factors, initiators of mucosal healing and being greatly involved in tumorigenesis, have remained

Effect of contact time on the acute toxicity of mercury to scale carp

The behaviour of metals in aquatic ecosystems is dependent on various environmental factors. Experiments were conducted in five different contact times (0.5, 2, 12, 24 and 48h) between soil sediment and mercury on Cyprinus carpio var communis. It was observed that contact time with soil sediment had significant effect in reducing the toxicity of mercury. Higher the time of contact, greater the effect. Medium hard water (150 mg/L CaC0 sub(3) of total hardness) had the highest effect as compared to other water in reducing the toxicity of mercury when combined with underlying soil sediment. With the increase in contact time, complexation and adsorption of inorganic mercury ions with the dissolved and particulate phases of water and soil sediment were increased; thereby bioaccumulation of mercury ions by scale carp was more. Applicability of the result of this experiment in natural ecosystems was also suggested.

Acute toxicity of cadmium to six intertidal invertebrates

Following a static bioassay techniques the acute toxicity of cadmium to six species of intertidal invertebrates was determined. The sensitivity of the animals to cadmium was of the following order: Emerita sp. (burrowing crustacean) Donax spiculum (burrowing bivalve) Perna viridis (sedentary bivalve) Sabellaria clandestinus (tube-dwelling polychaete) Modiolus carvalhoi and Modiolus sp. (sedentary bivalves). The above observation was based on the median lethal concentrations recorded for the different species, Emerita sp. 1.35 p.p.m., Donax spiculum 1.8 p.p.m., Perna viridis 2.5 p.p.m., Sabellaria clandestinus 2.8 p.p.m., Modiolus carvalhoi 5.6 p.p.m. and Modiolus sp. 9.6 p.p.m. The findings throw insight into the toxicity of cadmium to the common intertidal animals which are either suspension or detritus feeders.

Acute toxicity of metasystox to wedge clam, Donax cuneatus from west coast

96h acute toxicity tests were performed using commercial grade metasystox on the marine wedge clam, Donax cuneatus during summer 1985. The behaviour and mortality rates were recorded periodically. Most of the dams responded in opening the shell valves and extending the siphons quicker in low test concentrations (0.004-0.0052 p.p.m) but this was slow and late in high concentrations (0.0056-0.008 p.p.m). Mortality began to occur in 0.008 p.p.m. from 12 h, whereas, in 0.0052 p.p.m. from 60 h onwards. The observed LC sub(0) value was 0.004 p.p.m. and LC sub(50) 0.0064 p.p.m. The regression equation established was Y = 79.0891 + 33.4523 X. The rate of oxygen concentration increased at LC sub(0) and LC sub(50) values compared to control indicating the disturbed physiological adjustment. The results are correlated with physico-chemical parameters of seawater and discussed in the light of pesticide toxicity to the dam.

Acute toxicity of un-ionized ammonia to milkfish (Chanos chanos) fingerlings

The acute toxicity of un-ionized ammonia to milkfish (Chanos chanos) fingerlings was determined using a static bioassay system. Median lethal concentrations found show that milkfish fingerlings have a high tolerance to ammonia and it is unlikely that levels as high as those employed for the acute exposure would be found to occur under natural conditions. Although the threat of acute toxicological effects induced by ammonia are remote, such conditions might be encountered in stressed natural environments or in heavily loaded aquaculture systems.

Acute toxicity of unionized ammonia to milkfish (Chanos chanos Forsskal) fry

The study was conducted to determine the effects of varying concentrations of ammonia to milkfish fry. Two runs of static 96h bioassays were conducted to determine the median lethal concentration (LC 50) of unionized ammonia (NH₃) to milkfish fry. Test concentrations were based on exploratory 24h and 48h bioassays and were made in three replicates. Reagent grade ammonium chloride (NH₄Cl) was used to adjust the level of unionized ammonia. The 96h median lethal concentration, determined by the Reed Muench method was calculated at 28.029 ppm NH₃ 29.69 ppm. Even at high concentrations of unionized ammonia, most of the fry mortality occurred after 48 to 96 hours exposure. Severe gill damage occurs only at concentrations above 20 ppm, especially above the LC 50. The high LC 50 value obtain shows that milkfish fry has great tolerance to ammonia, that even fry with severely-damaged gills can still recover days after it is returned to favorable culture condition. The result suggest that observed mortalities of milkfish fry under culture conditions are not due to ammonia toxicity.

Effect of natural dissolved humic material on bioavailability and acute toxicity of fenpropathrin to the grass carp, Ctenopharyngodon idellus

The effects of aquatic humic acids on the bioconcentration and acute toxicity of fenpropathrin were evaluated using grass carp, Ctenopharyngodan idellus, in laboratory freshwater systems. The results demonstrated that both bioavailability and acute toxicity decreased in the presence of aquatic humic acid 5 and 10 mg/liter. In addition, the extent of influence increased with increasing concentration of aquatic humic acid, (C) 1999 Academic Press.

Arsenate causes differential acute toxicity to two P-deprived genotypes of rice seedlings (Oryza sativa L.)

Significant genotypic difference in response to arsenate toxicity in rice (Oryza sativa) was investigated in root elongation, arsenate uptake kinetics, physiological and biochemical response and arsenic (As) speciation. Uptake kinetics data showed that P-deprived genotype 94D-54 had a little higher As uptake than P-deprived 94D-64, but the difference was not large enough to cause acute toxicity in P-deprived 94D-54. There was no difference in tissue P concentrations between the two genotypes under P deficient conditions. In addition, arsenic speciation in plant tissues (using high performance liquid chromatography-inductively coupled plasma mass spectrometry) was not different between P pretreatments and between genotypes. P-deprived genotype 94D-54 suffered much higher stress induced by arsenate toxicity than P-deprived genotype 94D-64, in terms of lipid peroxidation, tissue H2O2 concentrations and exosmosis of K, P and As. However, P-deprived 94D-54 also had higher overproduction of enzymatic antioxidants (with higher GPX, SOD, CAT) and NPT (non-protein thiols) than P-deprived 94D-64. It appeared that, the higher sensitivity of P-deprived 94D-54 to arsenate toxicity might cause the overproduction of NPT, thus leading to the depletion of GSH and to the accumulation of H2O2. The differential sensitivity of the two genotypes has major implications for breeding rice for As affected paddy soil.

Lung stereotactic body radiation therapy (SBRT) delivered over 4 or 11days: A comparison of acute toxicity and quality of life.

Abstract
PURPOSE:
The optimal duration over which lung SBRT should be delivered is unknown. We conducted a randomized pilot study in patients treated with four fractions of lung SBRT delivered over 4 or over 11days.
METHODS:
Patients with a peripheral solitary lung tumor (NSCLC or pulmonary metastasis) ?5cm were eligible. For NSCLC lung tumors ?3cm, a dose of 48Gy in 4 fractions was used, otherwise 52Gy in 4 fractions was delivered. Patients were randomized to receive treatment over 4 consecutive days or over 11days. The primary end-point was acute grade ?2 toxicity. Secondary end-points included quality of life (QOL) assessed using the EORTC QLQ-C30 and QLQ-LC13 questionnaires.
RESULTS:
Fifty four patients were enrolled. More patients in the 11day group had respiratory symptoms at baseline. 55.6% patients treated over 4days and 33.3% of patients treated over 11days experienced acute grade ?2 toxicity (p=0.085). Dyspnea, fatigue and coughing domains were worse in the 11day group at baseline. At 1 and 4months, more patients in the 4day group experienced a clinically meaningful worsening in the dyspnea QOL domain compared to the 11day group (44.5% vs 15.4%, p=0.02; 38.5% vs 12.0%, p=0.03, respectively). However, raw QOL scores were not different at these time-points between treatment groups.
CONCLUSIONS:
Grade 2 or higher acute toxicity was more common in the 4day group, approaching statistical significance. More patients treated on 4 consecutive days reported a clinically meaningful increase in dyspnea, although interpretation of these results is challenging due to baseline imbalance between treatment groups. Larger studies are required to validate these results.