Evaluation of toxicity effect of Datura innoxia root extract to Clarias gariepinus fingerlings

Clarias gariepinus fingerlings were exposed 96 hours under laboratory conditions using static bioassays with continuous aeration to determine acute toxicity of Datura innoxia root extract. The LC sub(50) of the exposed fingerlings was 128.83 mg/L. The fish exhibited loss of balance, respiratory distress and swam erratically just prior to death

Toxicity of Gramoxone super(R) and detergent to nile tilapia (Oreochromis niloticus) L. fingerlings

Acute toxicity tests on the effects of Gramoxone and detergent (both applied as a single dose) to nile tilapia, Oreochromis niloticus, fingerlings (mean weight 2.7~c1 g) were conducted using static bioassay. The 96-h LC sub(50) of Gramoxone and detergent applied were 0.08ml/l and 0.004 g/l, respectively. The fingerlings showed increased hyperactivities exemplified by erratic movement, loss of reflex, and hyperventilation during the period of exposure. These effects increased with increasing concentrations of Gramoxone or detergent throughout the duration of exposure. Tilapia fingerlings of the same size showed different levels of tolerance to the same concentration of both pollutants

Acute toxicity of atrazine to Oreochromis niloticus fingerlings

Acute toxicity of atrazine to Oreochromis niloticus was undertaken to find the lethal concentration (LC) 50 of atrazine using fingerlings. Different concentrations were prepared in mg/L. There were six different concentrations with a control and each treatment was replicated three times. A total number of twenty-one aquaria were used. The highest concentration was 30mg/L. Ten test organisms were used in each aquarium. At 24, 48, 72 and 96 hours there were LC 50 of 15.6mg/L, 14mg/L, 11mg/L and 9.4, respectively. At 24, 48, 72 and 96 hours there were mean survivals of 49.0%, 34.3%, 28.6% and 28.1%, respectively

Toxicity of linear alkylbenene sulphonate (LAS) detergent, to Clarias gariepinus fingerlings

The acute toxicity of Linear Alkylbenzene Sulphonate (LAS) detergent to Clarias gariepinus fingerlings was investigated using static bioassays and continous aeration over a period of 96h. The 96h LC sub(50) was determined as 24.00mgL super(-1). During the exposure period, the test fish exhibited several behavioural changes before death such as restlessness, rapid swimming, loss of balance, respiratory distress and haemorrhaging of gill filaments amongst others. Opercula ventilation rate as well as visual examination of dead fish indicates lethal effects of the detergent on the fish. Water quality examination showed increase in pH from 6.55 to the alkaline, death point of 10.55. There was also a remarkabel rise of alkalinity from 20.00mgL super(-1) to 52.50mgL super(-1)

On the toxicity of some pesticides for fish [Translation from: Izv.gos.nauchno-issled.Inst.ozern.rybn.Khoz. 121, 95-96, 1977]

In the piscicide laboratory of GosNIORKh over a series of years was carried out the ichthyological evaluation of different agricultural pesticides, used both in our country and abroad. In all more than 300 different chemical substances were tested. Here, it was established that around 10% of them possessed high ichthyotoxic properties. Experiments were conducted under laboratory conditions on aquarium fish in groups, and also on representatives of different species of lake ichthyofauna. The basic criterion of evaluation of toxicity was the death of experimental fish during 120 hours. This short paper summarises the findings of this reasearch and offers a table presenting acute toxicity of pesticides for fish.

The ecological impact of different mechanisms of chronic sub-lethal toxicity on feeding and respiratory physiology

Sub-lethal toxicity tests, such as the scope-for-growth test, reveal simple relationships between measures of contaminant concentration and effect on respiratory and feeding physiology. Simple models are presented to investigate the potential impact of different mechanisms of chronic sub-lethal toxicity on these physiological processes. Since environmental quality is variable, even in unimpacted environments, toxicants may have differentially greater impacts in poor compared to higher quality environments. The models illustrate the implications of different degrees and mechanisms of toxicity in response to variability in the quality of the feeding environment, and variability in standard metabolic rate. The models suggest that the relationships between measured degrees of toxic stress, and the maintenance ration required to maintain zero scope-for-growth, may be highly nonlinear. In addition it may be possible to define critical levels of sub-lethal toxic effect above which no environment is of sufficient quality to permit prolonged survival.

Metallothionein as an indicator of water quality: assessment of the bioavailability of cadmium, copper, mercury and zinc in aquatic animals at the cellular level

The study of metallothioneins (MTs) has greatly improved our understanding of body burdens, metal storage and detoxification in aquatic organisms subjected to contamination by the toxic heavy metals, Cd, Cu, Hg and Zn. These studies have shown that in certain organisms MT status can be used to assess impact of these metals at the cellular level and, whilst validation is currently limited to a few examples, this stress response may be linked to higher levels of organisation, thus indicating its potential for environmental quality assessment. Molluscs, such as Mytilus spp., and several commonly occurring teleost species, are the most promising of the indicator species tested. Natural variability of MT levels caused by the organism's size, condition, age, position in the sexual cycle, temperature and various stressors, can lead to difficulties in interpretation of field data as a definitive response-indicator of metal contamination unless a critical appraisal of these variables is available. From laboratory and field studies these data are almost complete for teleost fish. Whilst for molluscs much of this information is lacking, when suitable controls are utilised and MT measurements are combined with observations of metal partitioning, current studies indicate that they are nevertheless a powerful tool in the interpretation of impact, and may prove useful in water quality assessment.

Protocols for conducting dolphin capture-release health assessment studies

Marine mammals, such as dolphins, can serve as key indicator species in coastal areas by reflecting the effects of natural and anthropogenic stressors. As such they are often considered sentinels of environmental and ecosystem health (Bossart 2006; Wells et al. 2004; Fair and Becker 2000). The bottlenose dolphin is an apex predator and a key component of many estuarine environments in the southeastern United States (Woodward-Clyde Consultants 1994; SCDNR 2005). Health assessments of dolphins are especially critical in areas where populations are depleted, show signs of epidemic disease and/or high mortality and/or where habitat is being altered or impacted by human activities. Recent assessments of environmental conditions in the Indian River Lagoon, Florida (IRL) and the estuarine waters surrounding Charleston, South Carolina (CHS) highlight the need for studies of the health of local bottlenose dolphins. While the condition of southeastern estuaries was rated as fair in the National Coastal Condition Report (U.S. EPA 2001), it was noted that the IRL was characterized by poorer than expected benthic communities, significant sediment toxicity and increased nutrient concentrations. Similarly, portions of the CHS estuary have sediment concentrations of aliphatic aromatic hydrocarbons, select inorganic metals, and some persistent pesticides far in excess of reported bioeffect levels (Hyland et al. 1998). Long-term trends in water quality monitoring and recent scientific research suggest that waste load assimilation, non-point source runoff impacts, contaminated sediments, and toxic pollutants are key issues in the CHS estuary system. Several ‘hot spots’ with high levels of heavy metals and organic compounds have been identified (Van Dolah et al. 2004). High concentrations of anthropogenic trace metals, polychlorinated biphenyls (PCB’s) and pesticides have been found in the sediments of Charleston Harbor, as well as the Ashley and Cooper Rivers (Long et al. 1998). Two superfund sites are located within the CHS estuary and the key contaminants of concern associated with these sites are: polycyclic aromatic hydrocarbons (PAH), lead, chromium, copper, arsenic, zinc and dioxin. Concerns related to the overall health of IRL dolphins and dermatologic disease observed in many dolphins in the area (Bossart et al. 2003) initiated an investigation of potential factors which may have impacted dolphin health. From May-August 2001, 35 bottlenose dolphins died in the IRL during an unusual mortality event (MMC 2003). Many of these dolphins were diagnosed with a variety of skin lesions including proliferative ulcerative dermatitis due to protozoa and fungi, dolphin pox and a vesicular dermatopathy of unknown etiology (Bossart et al. 2003). Multiple species from fish to dolphins in the IRL system have exhibited skin lesions of various known and unknown etiologies (Kane et al. 2000; Bossart et al. 2003; Reif et al. 2006). On-going photo-identification (photo-ID) studies have documented skin diseases in IRL dolphins (Mazzoil et al. 2005). In addition, up to 70% of green sea turtles in the IRL exhibit fibropapillomas, with the highest rates of occurrence being seen in turtles from the southern IRL (Hirama 2001).

Increased toxicity of Karenia brevis during phosphate limited growth: ecological and evolutionary implications

Karenia brevis is the dominant toxic red tide algal species in the Gulf of Mexico. It produces potent neurotoxins (brevetoxins [PbTxs]), which negatively impact human and animal health, local economies, and ecosystem function. Field measurements have shown that cellular brevetoxin contents vary from 1–68 pg/cell but the source of this variability is uncertain. Increases in cellular toxicity caused by nutrient-limitation and inter-strain differences have been observed in many algal species. This study examined the effect of P-limitation of growth rate on cellular toxin concentrations in five Karenia brevis strains from different geographic locations. Phosphorous was selected because of evidence for regional P-limitation of algal growth in the Gulf of Mexico. Depending on the isolate, P-limited cells had 2.3- to 7.3-fold higher PbTx per cell than P-replete cells. The percent of cellular carbon associated with brevetoxins (%C-PbTx) was ~ 0.7 to 2.1% in P-replete cells, but increased to 1.6–5% under P-limitation. Because PbTxs are potent anti-grazing compounds, this increased investment in PbTxs should enhance cellular survival during periods of nutrient-limited growth. The %C-PbTx was inversely related to the specific growth rate in both the nutrient-replete and P-limited cultures of all strains. This inverse relationship is consistent with an evolutionary tradeoff between carbon investment in PbTxs and other grazing defenses, and C investment in growth and reproduction. In aquatic environments where nutrient supply and grazing pressure often vary on different temporal and spatial scales, this tradeoff would be selectively advantageous as it would result in increased net population growth rates. The variation in PbTx/cell values observed in this study can account for the range of values observed in the field, including the highest values, which are not observed under N-limitation. These results suggest P-limitation is an important factor regulating cellular toxicity and adverse impacts during at least some K. brevis blooms.

In utero domoic acid toxicity: a fetal basis to adult disease in the California sea lion (Zalophus californianus)

California sea lions have been a repeated subject of investigation for early life toxicity, which has been documented to occur with increasing frequency from late February through mid-May in association with organochlorine (PCB and DDT) poisoning and infectious disease in the 1970's and domoic acid poisoning in the last decade. The mass early life mortality events result from the concentrated breeding grounds and synchronization of reproduction over a 28 day post partum estrus cycle and 11 month in utero phase. This physiological synchronization is triggered by a decreasing photoperiod of 11.48 h/day that occurs approximately 90 days after conception at the major California breeding grounds. The photoperiod trigger activates implantation of embryos to proceed with development for the next 242 days until birth. Embryonic diapause is a selectable trait thought to optimize timing for food utilization and male migratory patterns; yet from the toxicological perspective presented here also serves to synchronize developmental toxicity of pulsed environmental events such as domoic acid poisoning. Research studies in laboratory animals have defined age-dependent neurotoxic effects during development and windows of susceptibility to domoic acid exposure. This review will evaluate experimental domoic acid neurotoxicity in developing rodents and, aided by comparative allometric projections, will analyze potential prenatal toxicity and exposure susceptibility in the California sea lion. This analysis should provide a useful tool to forecast fetal toxicity and understand the impact of fetal toxicity on adult disease of the California sea lion.

Toxicity of phenyl-mercuric lactate for fish

Phenyl-mercuric lactate is included in the pulp processing reagents by some paper mills to eliminate slime formation in the pulp. Small quantities of this chemical are added to the wet pulp in the beaters, particularly for the bactericidal action against Aerobacter aerogenes. Subsequently the mecurial is carried away in the wash waters. However, as the highly poisonous nature of many compounds of mercury is well known, questions have been raised concerning the pollution hazards created by phenyl-mercuric lactate in streams receiving effluents from mills using this substance.

Toxicity of some organic biocides to exotic carp fingerlings Hypophthalmichthys molitrix (C and V)

A bioassay study was conducted using three organic pesticides to determine their comparative toxicity to fingerlings of Hypophthalmichthys molitrix. There was wide variation in the toxicity of different pesticides with 24 hr LC sub(50) values ranging from 0.000403 to 0.294 mg/l. Endosulfan appeared to be the most toxic, whereas BHC was the least.

Biochemical variation during ovarian vitellogenic growth in a hill stream teleost Garra mullya (Sykes) due to cadmium toxicity

Some biochemical variations during ovarian vitellogenic growth in hill-stream teleost Garra mullya due to sublethal concentration of cadmium has been discussed. Total protein, cholesterol and glycogen in ovary and liver along with gonadosomatic index (GSI) and hepatosomatic index (HSI) in Cd-treated fish exhibited significant decrease while liver glycogen remained unaltered.

Comparative toxicity of some detergents on an estuarine fish, Ambassis commersonii

The comparative toxicity was evaluated using four detergents, viz, linear alkylbenzene sulfonate (LAS), branched alkylbenzene sulfonate (BAS), sodium sulfonate (SS) and alfa-olefin sulfonate (AOS) on an estuarine fish, Ambassis commersonii, abundant in Kali estuarine system. Standard toxicity bioassay method was followed as per APHA (1980). AOS concentration in "Mega" soap was determined by the standard MBAS method described in APHA (1980). The results indicate that LAS was the most toxic detergent to fish relative to the other types and the other of toxicity was LAS > AOS > SS > BAS. A significant correlation was seen between observed and calculated mortalities for all the detergents. Some behavioural responses of fishes to all detergents were also observed.

Toxicity of methyl amine on Catla catla (Ham) fingerlings

The toxicity of methyl amine was studied by finding out its LC 50 values for Catla catla fingerlings. On the basis of LC 50 values, the harmless concentration of methyl amine was found to be 12.8 ppm. This indicates that methyl amine is fairly toxic to C. catla fingerlings and needs care for its disposal in aquatic environment.