Fish as an indicator of aquatic environment: Multielemental neutron activation analysis of nutrient and pollutant elements in fish from Indian coastal areas

Fish is the main food in coastal areas and its analysis for toxic metals has been used as an indicator of the pollution status of the aquatic environment. Several different fish species from the three Indian coasts, Visakhapatnam in the east, Mumbai in the west and Mangalore in the south west and also inland freshwater fish from Nagpur in the central region for comparison were analyzed for up to 20 elements (As, Au, Ba, Br, Cl, Co, Cr, Cu, Fe, Hg, K, Mn, Na, P, Rb, Sb, Sc, Se, Sr, Zn) by instrumental neutron activation analysis (INAA). Dried fish samples in powdered form were irradiated with thermal neutrons in a nuclear reactor followed by high resolution gamma ray spectrometry at different intervals. Several Reference Materials (RMs) of biological origin were analyzed for quality assurance and data validation. Elemental contents in different fish species vary in a wide range depending on the species, its size, location, and aquatic environment. Fish from Mangalore showed highest mean contents of Cr (14.8?±?29.9?µg?g^?1), Cu (1005?±?643?µg?g^?1) and Sb (849?±?888?ng?g^?1) whereas those from Mumbai exhibited highest Hg (2066?±?2146?ng?g^?1) and P (20.3?±?4.63?µg?g^?1) but lowest Cu (6.30?±?3.10?µg?g^?1) contents. Fish from all the regions showed significant amounts of nutrient elements such as Na, K, P, Mn, Fe, Se and Zn as well as some pollutant elements (Br, Cr, Sb, Hg). No regularity in variation of elemental contents with the size was observed. Prawn (Panaeus latisulcatus), a popular fish species from four different regions showed wide variation in elemental contents of Cr, Mn, Fe, Zn, Se, P including toxic pollutants, Sb and Hg. An attempt has been made to calculate daily dietary intake (DDI) for some nutrient elements from Indian fish. Elemental data for Cr, Cu, Fe, Hg, Se, and Zn have been compared with those from other fish exporting countries.     

Sediment-associated trace and major metals in the headwaters of a tropical reservoir

Bed sediment samples of the two headwaters of a tropical reservoir in Southwestern Nigeria were analysed for some metal concentrations using ICP-OES for a period of one year. Sediment samples were collected bi-monthly from both the lower and upper reaches of the streams from May 2013 to March 2014. Sediment samples were microwave-digested and analysed using ICP-OES. Concentrations of metals were higher in the lower reach than in the upper reach, and wet season concentrations were higher than in the dry season with the exception of Fe and Mn. The annual mean metal concentrations were as follows: Fe (121.72?±?6.82?µg/g); Mn (9.34?±?2.57?µg/g); Na (6.20?±?2.29?µg/g); K (0.65?±?0.57?µg/g); Mg (8.07?±?1.36?µg/g); Ca (13.92?±?2.85?µg/g); Ba (0.17?±?0.17?µg/g); Al (106.54?±?5.55?µg/g); and Se (0.6?±?0.19?µg/g). These values were lower in comparison with the baseline concentrations of elements on the earth’s crust. Contamination assessment of all the metals investigated in this study showed that metals in the bed sediments of the two headstreams had not reached pollution status with the exception of Se.     

Effects of propylparaben on fecundity and lifespan in Drosophila melanogaster

Parabensare are widely used as preservatives in cosmetics, foods and pharmaceutical products. Although parabens have generally been considered safe, several studies have cautioned that parabens have estrogenic or endocrine-disrupting properties. With the present study, the effects of four concentrations of propylparabens (200, 500, 1000, and 2000 mg L^?1) on fecundity, development and the lifespan of Drosophila melanogaster have been investigated. Decreased daily mean egg production was found in all exposure groups. In addition, the 100 mg L^?1 treatment significantly shortened egg-to-prepupa time and extended flies lifespan, consistent with a significant reduction in malonyldialdehyde (MDA) level and an increase in superoxide dismutase (SOD) activities. The 200 mg L^?1 treatment prolonged egg-to-prepupa time and decreased flies lifespan significantly, being consistent with a significant increase in MDA level and reduction in SOD activities.     

Chronic mixture toxicity study of Clophen A60 and diethyl phthalate in male rats

Chemical mixtures are an important area of research as individuals are exposed to low doses of persistent chemical agents known as environmental pollutants throughout their life time. Polychlorinated biphenyls (PCBs) and diethyl phthalate (DEP) are ubiquitous environmental pollutants that could be present in the same environmental compartment; hence organisms may get simultaneously exposed to both. Therefore, a study was undertaken to see whether PCB and DEP together show interactive chronic mixture toxicity in male Wistar rats. Healthy male Wistar rats weighing 70–100?g were randomly assigned to four groups of six each. Control rats were fed on normal diet and water ad libitum. Oil control rats were maintained on a normal diet mixed with corn oil. Rats were given Clophen A60 (PCB) and DEP dissolved individually in corn oil mixed with the diet at 50?mg?kg^?1 of the diet/day, as well as a mixture in corn oil mixed with the diet both at 50?mg?kg^?1 of the diet/day. After 150 days of treatment animals were sacrificed and enzymes and other biochemical parameters in the serum and liver were assessed. Liver weight to body weight ratio showed a significant increase in Clophen A60 and in Clophen A60?+?DEP treated rats. In the DEP, Clophen A60 and Clophen A60?+?DEP treated groups there was significant increase in liver and serum alanine aminotransferase (ALT) and acid phosphatase (ACP) activity. Aspartate aminotransferase (AST) was significantly increased in the liver and serum of DEP treated rats only. Cholesterol levels were significantly increased only in the serum and the liver of DEP treated rats. Triglyceride levels were significantly increased in the serum of treated rats and only in the liver of Clophen A60 and Clophen A60?+?DEP treated rats. Liver glycogen levels were significantly increased in DEP and Clophen A60?+?DEP treated rats. In all treated animals, there was a significant decrease in liver glutathione reductase (GR). Histology of liver showed severe vacuolations, fatty degeneration and loss of hepatic architecture in Clophen A60 and Clophen A60?+?DEP treated rats, whereas in DEP treated rats only loss of hepatic architecture and granular deposits in the hepatocytes was predominant with mild vacuolations of centrilobular and periportal area. It is evident from this study of mixture toxicity of Clophen A60 and DEP that there is no significantly enhanced toxicity due to the interaction of these two compounds. On the other hand, to some extent there is alleviation in toxicity as evidenced by enzyme ACP and AST levels in the liver. The hepatocellular damage and biliary congestion caused by these two compounds, which can be confirmed by significantly increased liver weights and elevated serum and liver enzyme levels as well as histology, was almost the same between individual and mixture treated group.     

Protective action of zinc against lead poisoning in tilapia Oreochromis niloticus

The accumulation of lead (Pb) in tilapias Oreochromis niloticus, acclimatized in cement tanks, and fed once a day with pellets of commercial food with lead nitrate, was investigated by square wave anodic stripping voltammetry (SWV). The head (including head bones, proteins, and brain) was the main target of lead uptake by tilapias, with a small amount in muscle tissue. A high concentration of Pb was found in feces which indicated low absorption by the organism when fed with high Pb concentration. The protective effects of zinc (Zn) against the Pb poisoning, the accumulation of Pb in the heads of the fishes of 107.8?±?3.1?mg?kg^?1 and in the viscera of 57.1?±?2.9?mg?kg^?1 with consequent decrease of calcium (Ca) concentration, were observed. In spite of the experimental time of 16 months and higher Pb concentration in the dietary food of 320?mg?kg^?1, no death of tilapias was observed due to the protective action of Zn.     

Morpho-histological and enzymatic alterations in earthworms Drawida willsi and Lampito mauritii exposed to urea,phosphogypsum and paper mill sludge

The effects of varying concentrations of urea, phosphogypsum and paper mill sludge (PMS) on the morphology, histology, tissue protein content, lipid peroxidation (LPX), activities of lactate dehydrogenase (LDH), acetylcholinesterase (AChE) and catalase in earthworms Drawida willsi and Lampito mauritii have been studied over an exposure period of 24?hr. Integumentary lesions, clitellar swelling and loss of pigmentations were found to be major morpho-pathological changes in the worms. Histology indicated cuticular damage, ruptured epithelium and muscle fibres with accumulation of cellular debris. Lowest tissue protein content (57.02?±?4.02?mg/g tissue) and highest LPX (0.113?±?0.04, 0.137?±?0.08?nmol/mg protein) were noticed in D. willsi at a high concentration of PMS, whereas highest tissue protein content was observed in L. mauritii (115.32?±?7.18?mg/g tissue) with the same treatment. In both the species, LDH activity was minimum at a high concentration of urea (0.172?±?0.02; 0.247?±?0.08?U/mg protein). AChE activity was highest (0.099?±?0.002?U/mg protein) at a high concentration of PMS in D. willsi, whereas catalase activity was the maximum (0.338?±?0.02?U/mg protein) at high concentrations of PMS in L. mauritii. The study indicated that morpho-histological and enzymatic alterations in these earthworms exposed to agrochemicals could be useful biomarkers to evaluate soil toxicity.     

Toxicokinetics,metabolism, and microsomal studies of chlorpropham in rats

A study on the toxicokinetic behavior, metabolism of chlorpropham, and its effect on cytochrome P₄₅₀ from liver microsomes was carried out in albino rats after a single and consecutive oral administration at 500?mg?kg^?1 body weight for 10 and 20 days. Chlorpropham was detected in the blood at 0.08?h (11.43?±?1.72?µg?mL^?1) reaching a maximum concentration at 2?h (30.90?±?2.55?µg?mL^?1) and a minimum at 48?h (1.95?±?0.20?µg?mL^?1) after a single oral administration of 500?mg?kg^?1. The absorption rate constant (K _a) was 0.66?±?0.48?h^?1. The Vd _area (18.01?±?2.78?L?kg^?1) and t _1/2 β (12.23?±?1.96?h) values suggested a wide distribution and long persistence of the compound in the body, respectively. The higher Cl_R (0.82?±?0.00?L?kg^?1?h^?1) compared to Cl_H (0.18?±?0.02?L?kg^?1?h^?1) value indicated that a major portion of chlorpropham was excreted through the urine (30%) compared to the faeces (2.81%). Chlorpropham residue was detected in all tissues of rat at 0.25?h while its metabolite, meta-chloroaniline was detected in liver, kidney, heart, lung, and spleen tissue at 0.25?h. Meta-chloroaniline was not detected in skeletal muscle, brain, fat, and stomach tissue at any time of the observation period. Maximum concentrations of chlorpropham and meta-chloroaniline were detected at 2?h (except in the spleen), and minimum concentrations of chlorpropham at 24 (heart, lung, spleen, skeletal muscle, and stomach) and 48?h (liver, kidney, brain, and fat tissue) respectively; and meta-chloroaniline at 24?h (except heart and spleen). The tissue half-life of chlorpropham in rat varied from 3.80 to 11.60?h. Repeated oral administration of chlorpropham at 500?mg?kg^?1 for 10 and 20 days caused an induction of the liver microsomal pellet of rat.     

Nutrients uptake and growth of Ulva lactuca (Linnaeus, 1753) in grey mullet (Mugil cephalus) wastewater versus natural estuarine water

This study investigates the capability of Ulva lactuca to grow in an integrated system, aiming to optimise the needing of resources and to decrease the ecological impact of wastewater. The nutrients uptake and the growth of U. lactuca in Mugil cephalus wastewater (WW) were evaluated and compared with U. lactuca cultivated in estuarine water (EW). Fresh thalli of U. lactuca were cultivated for 10 days in 5?L cylindrical tanks, 3 replicates per treatment. The uptake of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorous (DIP), as well as the biomass yield and specific growth rate of U. lactuca, were assessed every two days. At the end of the experiment, U. lactuca resulted in a higher assimilation of DIN in EW (95.7?±?0.3%, mean?±?SE) than in wastewater (68.7?±?1.0%) (p?80%), as well as in the biomass yield and specific growth rate. This study demonstrates the efficiency of U. lactuca in the assimilation of DIN and DIP from M. cephalus WW, contributing to reduce the release of dissolved inorganic nutrients in the natural environment.     

Effect of calcium and magnesium on copper,cadmium, and some essential elements of Indian major carps Labeo rohita (Hamilton) and Catla catla (Hamilton) treated with copper and cadmium

The effect of calcium and magnesium either singly or in combination on accumulation of cadmium and copper in Labeo rohita (rohu) and Catla catla (catla) was investigated in this study under laboratory conditions. The investigation showed that copper accumulation in rohu exposed to 0.25 mg L^?1 of copper for 14 days reduced from 31.0 ± 0.4 mg kg^?1 at no calcium/magnesium treatment to 3.5 ± 0.2 and 2.2 ± 0.1 mg kg^?1, respectively, at 75 mg L^?1 calcium or magnesium treatment. The copper level in catla exposed to 0.20 mg L^?1 of copper for 14 days reduced from 5.7 ± 0.1 mg kg^?1 at no calcium/magnesium treatment to 3.4 ± 0.2 and 3.3 ± 0.1 mg kg^?1, respectively, at 300 mg L^?1 calcium or magnesium treatment. The cadmium accumulation in rohu exposed to 0.20 mg L^?1 of cadmium for 14 days reduced from 1.7 ± 0.1 mg kg^?1 at no magnesium treatment to 1.4 ± 0.1 mg kg^?1 at 120 mg L^?1 magnesium treatment. The cadmium accumulation in catla exposed to 0.20 mg L^?1 of cadmium for 14 days reduced from 0.8 ± 0.2 mg kg^?1 at no magnesium treatment to 0.6 ± 0.2 mg kg^?1 at 80 mg L^?1 magnesium treatment. Copper and cadmium treatments also reduced some essential microelements of rohu and catla. Both the fishes restored these elements at different levels of calcium and magnesium.     

Protective properties of filamentous blue–green alga Spirulina against the oxidative stress induced by cadmium in freshwater mussel Unio ravoisieri

ABSTRACT

Cadmium (Cd) is a toxic-heavy metal that induces a wide range of behavioural, biochemical and physiological effects in aquatic organisms. Oxidative damage has been proposed as a possible mechanism involved in cadmium toxicity. The current study was carried out to evaluate the antioxidant activity of Spirulina as feed additive (1?mg/L) against the toxicity of cadmium (Cd) 0.5?mg/L in freshwater mussel Unio ravoisieri. At the end of the exposed period of 4 days, digestive gland antioxidant status Superoxide dismutase, Catalase, Glutathione-S-transferase and damage markers such as Malondialdehyde and Protein carbonyl were determined. Associations between biomarkers were assessed by a multivariate analysis technique, principal component analysis (PCA). The results of this study revealed that digestive gland antioxidant status showed a significant decrease when mussels were exposed to Cd. Superoxide dismutase, Catalase and Glutathione-S-transferase activities in the Cd?+?SP group were significantly higher than the Cd group (p P?相似文献   

Acephate-induced shortening of developmental duration and early adult emergence in a nontarget insect Drosophila melanogaster

Similar to several environmental monitoring studies, the present study used Drosophila melanogaster as a model nontarget organism to explore the interfering effects of an organophosphate (OP) insecticide acephate on insect life cycle parameters. Acephate, a common OP, is readily available in nature from agricultural sources as an environmental contaminant. Along with target pests, nontarget fruit flies also suffer exposure to such environmental chemical. To evaluate the effects of such exposure, initially, acute LC₅₀ of acephate for third instar larvae was investigated and found to be between 14 and 16 μg/ml. This information yielded the following experimental concentrations (0.5, 1.5, 2.5, 3.5, 4.5, and 5.5 μg/ml) of test chemical for evaluation of effect, if any, on the insect model. Results showed that mean larval duration of insect significantly decreased on treatment with acephate, whereas the mean pupal duration remained unaffected. Interestingly the decreasing trend was seen to persist in case of mean adult emergence, where treated flies emerged significantly earlier in comparison to controls. Thus, the study demonstrated that acephate-induced shortening of developmental time and early emergence in Drosophila melanogaster.     

The potential of Berkheya coddii for phytoextraction of nickel,platinum, and palladium contaminated sites

The study involved assessing the potential of the native plant species (Berkheya coddii) for the phytoextraction of nickel, palladium, and platinum contaminated sites. Plant and soil samples were randomly collected from Barberton area, near Agnes mine, Mpumalanga Province, South Africa. Samples were analysed for total nickel, palladium, and platinum concentrations together with other elements found in the soil and in the plants' roots, and leaves. Soil versus leaves and soil versus roots uptake of these metals by the plant were compared. The mean concentration of nickel in the leaves/canopy was found to be 13,980?±?10,780?mg?kg^?1?dry mass, in the roots it was 2046?±?789?mg?kg^?1 dry mass, and in the soil it was 1040?±?686?mg?kg^?1?dry mass. This resulted in a mean concentration ratio in the leaves to soil of 13.44. The platinum mean concentration in the leaves was 0.22?±?0.15?mg?kg^?1?dry mass, in the roots it was 0.14?±?0.04?mg?kg^?1?dry mass, and in the soil it was 0.04?±?0.03?mg?kg^?1?dry mass. This resulted in a mean concentration ratio in the leaves to soil of 5.5. Palladium was found to have a mean soil concentration of 0.07?±?0.045?mg?kg^?1?dry mass. The mean concentrations in the roots and in the leaves were 0.18?±?0.07 dry mass and 0.71?±?0.52?mg?kg^?1?dry mass, respectively. This gave a mean concentration ratio in the leaves to soil of 10.1 for palladium. Other elements that were found to have a mean concentration ratio in the leaves to soil of around 2.5 or above are sodium, potassium, magnesium, calcium, and sulfur. Berkheya coddii was found to be most efficient in accumulating nickel, palladium, and platinum from the soil. The results for the first time revealed that the plant may have the potential to uptake platinum and palladium; both metals are in the same group of the periodic table as nickel.     

Morphological and behavioral alterations induced by endocrine disrupters in amphibian tadpoles

Developmental toxicity effects of endocrine disrupter chemicals, acephate and cypermethrin were studied in Bufo melanostictus tadpoles. Thirty developing eggs of B. melanostictus were exposed to each concentration (0.01, 0.05, 0.1, 0.5, and 1?µg?L^?1) of acephate or cypermethrin in the laboratory (temperature: 23?±?1°C; photoperiod: 11.5–12.5?h). Eggs maintained in conditioned water alone served as controls. After hatching, larvae were fed on boiled spinach until the completion of metamorphosis. In control group, larvae that hatched on 3rd day were heavily pigmented, voracious feeders, and active swimmers; in these tadpoles, hind limb and forelimb-buds emerged on 16th and 24th day and metamorphosis was complete on 32nd day. Eggs exposed to acephate also hatched on 3rd day but larvae exhibited deformities such as, (i) tail distortions, (ii) laterally crooked trunk, (iii) decreased pigmentation, (iv) inactivity, (v) peeling of the skin, and (vi) delay in emergence of limbs and completion of metamorphosis. Cypermethrin-exposed eggs exhibited a delay (4–8 days) in hatching, there was no mortality, deformities in tail, trunk and head region, delay in the emergence of limbs, and completion of metamorphosis were evident. The demonstrated data indicate that these pesticides interfere with amphibian development when present in the aquatic system.     

Development of a complex-based flow injection spectrophotometric method for determination of the herbicide pinoxaden in environmental samples

A flow injection (FI) spectrophotometric method for the determination of the herbicide pinoxaden (PXD) has been proposed. PXD was converted in alkaline media with hydroxylamine hydrochloride to the hydroxamate salt. The salt was reacted with iron(III) chloride, and the absorbance of the red colored tris iron hydroxamate complex was measured at 500?nm using a FI system. The method was found to be linear between 0.5 and 40?mg?L^?1 with a molar absorptivity of 1.53?×?10^4?L?mol^?1?cm^?1. The limit of detection and limit of quantification were found to be 0.1?±?0.01?mg?L^?1 and 0.6?±?0.05?mg?L^?1, respectively. Any interference of fenoxaprop-p-ethyl (FE) was avoided by the separation of PXD by liquid chromatography with a mixture of dichloromethane and n-hexane (1?:?1) as eluent. The method was applied to the determination of PXD in soil, water, and wheat grains with percent recoveries of 98?±?2, 100?±?2, and 98?±?5, respectively. Sample throughput of 60 samples per hour was achieved under optimized conditions.     

Genotoxic assessment of anthracene and benzo [a] pyrene to milkfish Chanos chanos

Mutagenic and genotoxic effects of polycyclic aromatic hydrocarbons, anthracene and benzo [a] pyrene (BaP), in milkfish Chanos chanos were determined using micronucleus (MN) test and comet assay (CA). Distinct mean frequencies of nuclear abnormalities such as MNs; binucleated micronuclei, nuclear bud, and fragmented apoptotic cells were measured. Significant increase in DNA damage with five classes of damage level was observed and expressed in terms of arbitrary unit (AU). Mean frequencies of total nuclear abnormalities were 0.5?±?0.25 cells in control; 0.67?±?0.33 cells in solvent control; 70?±?9.60 cells in 0.176?mg?L^?1 anthracene, and 91.83?±?6.25 cells in 0.031?mg?L^?1 BaP. The greatest DNA damage of 170AU was observed in 0.176?mg?L^?1 anthracene-exposed group and 182AU was observed in 0.031?mg?L^?1 BaP-treated fish. This study confirmed that the CA and MN assays are useful tools in determining potential genotoxicity of water pollutants and might be appropriate as a part of monitoring program.     

Effects of Matricaria chamomilla L. on lipid peroxidation,antioxidant enzyme systems,and key liver enzymes in CCl4-treated rats

In this study, we investigated the effects of Matricaria chamomilla L. extract (MCE) on lipid peroxidation, antioxidant enzyme systems, and several liver enzymes in carbon tetrachloride (CCl₄)-treated rats. Rats were divided into five groups. The first group (control group) was fed on standard feed. The rats in the other groups (CCl₄, MCE50, MCE100, and MCE200) were injected intraperitoneally with 0.8?mL?kg^?1 CCl₄. Moreover, rats in the MCE50, MCE100, and MCE200 groups were gavaged with 50?mg?kg^?1, 100?mg?kg^?1, and 200?mg?kg^?1 MCE, respectively. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, whole blood malondialdehyde (MDA) and glutathione (GSH) levels, and erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activity levels were measured after 14 days of exposure. ALT and AST in the CCl₄ group increased significantly in comparison to the control group (p?4, MCE50, MCE100, and MCE200 groups at different significance levels. In conclusion, the findings suggest that, depending on the dose administered, MCE decreases CCl₄-induced damage and consequent oxidative stress in rats; it affects the antioxidant system positively.     

Biological effects of water soluble fraction of crude oil on the Arctic sea ice amphipod Gammarus wilkitzkii

With increasing petroleum related activity in the Barents Sea and the subsequent risk of accidents, there is a demand for knowledge about the effect of oil pollution in Arctic ecosystems. In the present study, the sea ice amphipod Gammarus wilkitzkii was exposed to a water soluble fraction (WSF) of oil in two experiments, using a rock column system. First, three groups of adult females were exposed for 36 days for control (n=9), low dose (n=10) (initial and final oil concentration: 14, 115 and 120 μ g/l) and high dose (n=10) (initial and final oil concentration: 78, 764 and 395 μ g/l). Total oxyradical scavenging capacity (TOSC), malondialdehyde (MDA), catalase activity (CAT), respiration rate and mortality were measured. In the second experiment, moulting rate was measured in immature individuals of two groups, control (n=10) and exposed (n = 20), over 113 days. No mortality was observed in either of the experiments. There was a dose-related significant increase in respiration rate (40.69 (±22.82), 55.63 (±20.98), 94.57 (±22.80)) mg O₂ h^?1g ww^?1 in control, low dose and high dose, respectively. A higher MDA level was detected in the low dose group (25.04 (±6.00) nmol g^?1 of tissue) compared to both control (20.44 (±2.62) nmol g^?1 of tissue) and high dose groups (20.93 (±4.79) nmol g^?1 of tissue). Likewise, the low dose group had the highest value of TOSC towards hydroxyl (727.74 (±475.58), 1157.58 (±278.62), 1067.30 (±369.22) TOSC unit value mg^?1 of protein for control, low and high dose, respectively). Although no difference in the catalase activity between control and exposed groups was detected, higher activity was measured at 0 °C (average: 248 μ mol^?1 min^?1 mg^?1 of protein) than at the standard temperature for catalase measurement of 25 °C (average: 140 μ mol^?1 min^?1 mg^?1 of protein), indicating a need to optimise the standard operational procedure when working with Arctic organisms. No effect of WSF exposure on moulting rate was detected. In conclusion, little mortality was observed during the experiments, indicating some degree of tolerance levels. However, the biomarker results indicated sub-lethal effects in G. wilkitzkii after exposure to WSF.     

Persistence of chlorpyriphos in okra (Abelmoschus Esculentus) fruits and soil

Persistence of cypermethrin and chlorpyriphos in okra and soil were studied following the application of pre-mix formulation of insecticides Action 505EC (chlorpyriphos 50%?+?cypermethrin 5%) at single (275?g a.i.?ha^?1) and double dose (550?g a.i.?ha^?1). The average initial deposits of chlorpyriphos in okra were observed to be 0.07 and 0.15?mg?kg^?1 in single and double dose, respectively, which dissipated to 92% after 10 days for both the dosages. Residues of soil under okra crop were found to be 0.15?mg?kg^?1 at the single and 0.36?mg?kg^?1 at the double doses. These residues persisted up to 3 days at single and 5 days at double dose. The half-life (t _1/2) periods of chlorpyriphos on okra and soil were observed to be 0.6 days and 1.9 days for single and double dose, respectively. Residues of chlorpyriphos reached below detectable level (BDL) of 0.01?mg?kg^?1 in okra fruits after 7 days at single dose and in 15 days in double dose. In soil, residues of chlopyriphos persisted up to 5 and 7 days in single and double dose, respectively. Following foliar applications of a insecticide formulation (Action 505EC, (chlorpyriphos 50%?+?cypermethrin 5%) on okra at @ 275 and 550?g active ingredient (a.i.)?ha^?1 resulting in active applications of chlorpyriphos at the rate of 250 and 500?g a.i.?ha^?1 the average initial deposits of chlorpyriphos in okra were observed to be 0.07 and 0.15?mg?kg^?1, respectively. These residue levels dissipated to 92% after 10 days at both the dosages. Residues of soil under the okra crop were found to be 15?mg?kg^?1 at the single and 36?mg?kg^?1 at the double dose. The residues persisted up to 3 days at the single and 5 days at the double dose. The half-life (t _1/2) periods of chlorpyriphos on okra were observed to be 0.6 days for application rates, and 1.9 days for soil. Okra fruits and soil samples collected on the 7th and 15th day after application did not show any chlorpyriphos residues above their determination limits of 0.01 and 0.005?mg?kg^?1, respectively.     

Screening of endogenous antioxidants in some medicinal plants

The evaluation of antioxidant enzymes and antioxidant metabolites was done in leaf tissues of Azadirachta indica, Butea monosperma, Cassia fistula, Mangifera indica, and Syzygium cumini growing in the Thar Desert, Rajasthan, India. The plants are naturally exposed to drought stress and high temperatures during summer. Enzymatic reactive oxygen species (ROS) scavenging mechanisms in plants include superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase, catalase, and guaiacol peroxidase, and non-enzymatic antioxidants including the carotenoids, proline, and vitamin C were studied. The strategies to cope up with ROS under these extreme conditions are plant-specific. The highest activity of APX was found in M. indica (13.6?±?2.4?units?g^?1 fresh wt.). A. indica exhibited maximum guaiacol peroxidase activity (0.024?±?0.006?units?min?g^?1 fresh wt.), while S. cumini showed maximum SOD (12.5?±?2.3?units?g^?1 fresh wt.) and catalase activities (6.9?±?2.2?units?g^?1 fresh wt.). M. indica and S. cumini have been found to be more potent antioxidant systems among the studied plants.     

Depth distribution and temperature preferences of wahoo (Acanthocybium solandri) off Baja California Sur, Mexico

The depth distribution and temperature preferences of wahoo (Acanthocybium solandri) were quantified in the eastern North Pacific using archival tags. One hundred and eight data-loggers were deployed on wahoo (105?C165-cm fork length) from 2005 to 2008 at three locations off of the coast of Baja California Sur, Mexico (Alijos Rocks, 25°00??N/115°45??W; Magdalena Bay Ridge, 25°55??N/113°21??W; Hurricane Bank, 16°51??N/117°29??W). Twenty-five tagged individuals (23%) were recaptured within close proximity (<20?km) of their release sites. Collectively, depth and temperature data from 499?days revealed a predominant distribution within the upper mixed layer, with an average (±SD) depth of 18?±?4?m during the day and 17?±?6?m at night. Wahoo spent 99.2% of the daytime and 97.9% of night above the thermocline, and the greatest depth achieved by any fish was 253?m. Mean dive duration (3.8?±?2.9 vs. 2.3?±?0.8?min) and the vertical rate of movement (3.8?±?1.3 vs. 3.0?±?0.5?m?min^?1) were greater at night when compared to day. Ambient temperatures obtained from tag records ranged from 11.1 to 27.9°C, with an average of 25.0?±?1.1°C. These data identify the importance of the warm, upper mixed layer for the wahoo. High recapture rates proximal to the deployment sites suggest seasonal site fidelity and reveal the economic importance of this resource to both commercial and recreational fisheries of the region.