Recycling of animal protein wastes in the formulation of feed for Labeo rohita and Mystus vittatus-a comparative evaluation.

Lactic acid bacteria (LAB) are key players in the fermentation of organic wastes and their recycling as feedstuff for fish. Whey, a common dairy byproduct in India, is a cheap source of LAB and can be used to ferment animal byproducts. An experimental study was designed to explore whether the whey fermented animal protein blend (WFAPB) could be used as a fishmeal replacer in the formulation of feed for both stomach-less carp fish Labeo rohita and stomach-bearing catfish Mystus vittatus. Experiments were performed with five isoproteinous, isolipidous, and isoenergetic feeds with WFAPB replacing fishmeal (FM) by 0% (T1), 25% (T2), 50% (T3), 75% (T4), and 100% (T5). Fifteen days of laboratory experiments with these experimental feeds revealed that more than 50% FM replacement level could result in excess postprandial absorption (6 h) of some essential and non-essential amino acids in the plasma of both fish. The postprandial absorption was more in M. vittatus than L. rohita. Ninety-day experiments were conducted in outdoor cement vats to measure growths and deposition of amino acids (AA) in muscle. Regression analysis was performed to find the optimal FM replacement based on four growth parameters and fifteen AA deposition in muscle. A two-phase fuzzy methodology was used to obtain Pareto-optimal replacement levels for each fish. The results demonstrated that FM replacement levels were 7.63% and 36.79% respectively for L. rohita and M. vittatus when only four growth parameters were considered. However, based on the FM replacement level that maximized deposition of 15 amino acids and growth parameters, it was found that 12.23% and 40.02% replacement of FM by the WFAPB was ideal respectively for L. rohita and M. vittatus. The results revealed that only a fraction of both essential and non-essential amino acids absorbed in plasma could be converted into protein and deposited as bound amino acids in the muscle. It is concluded that fermentation by whey is an inexpensive, easily available, and environmentally sustainable technique to recycle animal protein in the formulation of feed for fish, and the stomach-bearing carnivorous fish are more efficient in utilizing fermented animal protein blend than the stomach-less carps.

Multi-criteria decision making to validate performance of RBC-based formulae to screen [Formula: see text]-thalassemia trait in heterogeneous haemoglobinopathies.

BACKGROUND: India has the most significant number of children with thalassemia major worldwide, and about 10,000-15,000 children with the disease are born yearly. Scaling up e-health initiatives in rural areas using a cost-effective digital tool to provide healthcare access for all sections of people remains a challenge for government or semi-governmental institutions and agencies. METHODS: We compared the performance of a recently developed formula SCS[Formula: see text] and its web application SUSOKA with 42 discrimination formulae presently available in the literature. 6,388 samples were collected from the Postgraduate Institute of Medical Education and Research, Chandigarh, in North-Western India. Performances of the formulae were evaluated by eight different measures: sensitivity, specificity, Youden's Index, AUC-ROC, accuracy, positive predictive value, negative predictive value, and false omission rate. Three multi-criteria decision-making (MCDM) methods, TOPSIS, COPRAS, and SECA, were implemented to rank formulae by ensuring a trade-off among the eight measures. RESULTS: MCDM methods revealed that the Shine & Lal and SCS[Formula: see text] were the best-performing formulae. Further, a modification of the SCS[Formula: see text] formula was proposed, and validation was conducted with a data set containing 939 samples collected from Nil Ratan Sircar (NRS) Medical College and Hospital, Kolkata, in Eastern India. Our two-step approach emphasized the necessity of a molecular diagnosis for a lower number of the population. SCS[Formula: see text] along with the condition MCV[Formula: see text] 80 fl was recommended for a higher heterogeneous population set. It was found that SCS[Formula: see text] can classify all BTT samples with 100% sensitivity when MCV[Formula: see text] 80 fl. CONCLUSIONS: We addressed the issue of how to integrate the higher-ranked formulae in mass screening to ensure higher performance through the MCDM approach. In real-life practice, it is sufficient for a screening algorithm to flag a particular sample as requiring or not requiring further specific confirmatory testing. Implementing discriminate functions in routine screening programs allows early identification; consequently, the cost will decrease, and the turnaround time in everyday workflows will also increase. Our proposed two-step procedure expedites such a process. It is concluded that for mass screening of BTT in a heterogeneous set of data, SCS[Formula: see text] and its web application SUSOKA can provide 100% sensitivity when MCV[Formula: see text] 80 fl.

Transfer of chromium from environment to fish in East Kolkata wetlands - evaluation by structural equation modeling.

Chromium (Cr) is a significant pollutant in the effluents from leather industries and domestic city sewage. Cr was determined in water, sediment, and different tissues (gill, muscle, intestine, liver, and kidney) of Nile tilapia, Oreochromis niloticus harvested from wastewater-fed aquaculture (WFA) situated at Bamonghata, Bantala, Chowbaga and Chingrighata of East Kolkata Wetlands (EKW), a Ramsar site in West Bengal, India. The results showed that Cr concentration in surface water ranged between 0.05 to 0.15 mg/L, while Cr was detected at high concentration (100-300 mg/kg) in the sediment soil of the first three WFAs and in moderate concentration (50-110 mg/kg) in Chingrighata WFA. Average Cr concentrations in the tissues were ranked in the following sequence: kidney>liver>intestine>gill>muscle. However, the extent of accumulation of Cr in different tissues varied between the WFAs. We used Structural Equation Modeling (SEM) to determine the route of Cr transfer. The fitness of the model was evaluated by the performance measures. Cr accumulation pathways varied between the sites depending upon the level of Cr in water or sediment. Except for Bamonghata WFA, sediment was found as the principal source of accumulation of Cr in different tissues of O. niloticus. Cr refluxed from sediment into overlying water and accumulated in fish either through the food chain or through direct accumulation from water. In Bamonghata WFA, the role of sediment in the transfer of Cr could not be established due to the high water depth or biological non-availability of Cr in the sediment. It is concluded from this study that fish reared in the WFAs of EKW are still not hazardous in respect to Cr but require proper management to avoid the influx of Cr-containing effluents into the WFAs.

Performance analysis of machine learning algorithms and screening formulae for ß-thalassemia trait screening of Indian antenatal women.

BACKGROUND: Currently, more than forty discrimination formulae based on red blood cell (RBC) parameters and some supervised machine learning algorithms (MLAs) have been recommended for ß-thalassemia trait (BTT) screening. The present study was aimed to evaluate and compare the performance of 26 such formulae and 13 MLAs on antenatal woman data with a recently developed formula SCSBTT, which is available for evaluation in over seventy countries as an Android app, called SUSOKA[16]. METHODS: A diagnostic database of 2942 antenatal females were collected from PGIMER, Chandigarh, India and was used for this analysis. The data set consists of hypochromic microcytic anemia, BTT, Hemoglobin E trait, double heterozygote for Hemoglobin S and BTT, heterozygote for Hemoglobin D Punjab and normal subjects. Performance of the formulae and the MLAs were assessed by Sensitivity, Specificity, Youden's Index, and AUC-ROC measures. A final recommendation was made from the ranking obtained through two Multiple Criteria Decision-Making (MCDM) techniques, namely, Simultaneous Evaluation of Criteria and Alternatives (SECA) and TOPSIS. RESULTS: It was observed that Extreme Learning Machine (ELM) and Gradient Boosting Classifier (GBC) showed maximum Youden's index and AUC-ROC measures compared to all discriminating formulae. Sensitivity remains maximum for SCSBTT. K-means clustering and the ranking from MCDM methods show that SCSBTT, Shine & Lal and Ravanbakhsh-F4 formula ensures higher performance among all formulae. The discriminant power of some MLAs and formulae was found considerably lower than that reported in original studies. CONCLUSION: Comparative information on MLAs can aid researchers in developing new discriminating formulae that simultaneously ensure higher sensitivity and specificity. More multi-centric verification of the formulae on heterogeneous data is indispensable. SCSBTT and Shine & Lal formula, and ELM and GBC are recommended for screening BTT based on MCDM. SCSBTT can be used with certainty as a tangible cost-saving screening tool for mass screening for antenatal women in India and other countries.

A decision support scheme for beta thalassemia and HbE carrier screening.

The most effective way to combat ß-thalassemias is to prevent the birth of children with thalassemia major. Therefore, a cost-effective screening method is essential to identify ß-thalassemia traits (BTT) and differentiate normal individuals from carriers. We considered five hematological parameters to formulate two separate scoring mechanisms, one for BTT detection, and another for joint determination of hemoglobin E (HbE) trait and BTT by employing decision trees, Naïve Bayes classifier, and Artificial neural network frameworks on data collected from the Postgraduate Institute of Medical Education and Research, Chandigarh, India. We validated both the scores on two different data sets and found 100% sensitivity of both the scores with their respective threshold values. The results revealed the specificity of the screening scores to be 79.25% and 91.74% for BTT and 58.62% and 78.03% for the joint score of HbE and BTT, respectively. A lower Youden's index was measured for the two scores compared to some existing indices. Therefore, the proposed scores can obviate a large portion of the population from expensive high-performance liquid chromatography (HPLC) analysis during the screening of BTT, and joint determination of BTT and HbE, respectively, thereby saving significant resources and cost currently being utilized for screening purpose.

Fermented mulberry leaf meal as fishmeal replacer in the formulation of feed for carp Labeo rohita and catfish Heteropneustes fossilis-optimization by mathematical programming.

Search for cost-effective, eco-friendly and sustainable plant resources as potential feedstuff to replace fishmeal in the formulation of feed for fish has been in the forefront of aquaculture researches since the last few years. In this study, experiments were conducted to evaluate if replacement of fishmeal by the fermented leaf meal of mulberry (Morus indica) was viable in the formulation of feed for carp fish Labeo rohita and catfish Heteropneustes fossilis. Four iso-proteinous, iso-lipidic and iso-energetic experimental feed were formulated by replacing 0, 25, 50 and 75% of fishmeal by the fermented mulberry leaf meal (FMLM), and both species were grown on these feeds for 8 weeks. Since the results revealed differences in response to fishmeal replacement level between parameters, we determined optimum fishmeal replacement level (OFRL) for each parameter from the polynomial curve equation. While maximum weight gain and specific growth rate and minimum feed conversion ratio was found at 30-32% OFRL for L. rohita and at 52-53% OFRL for H. fossilis, other parameters responded differently in both fish. Therefore, we applied a two-phase fuzzy goal programming technique using all parameters, which showed overall OFRL for L. rohita and H. fossilis as 30.95% and 52%, respectively. We also applied the concept of 'decision tree' to identify the key factor behind utilization of FMLM. It was concluded that activity of amylase and subsequent utilization of carbohydrate was the key factor in utilizing FMLM. Interestingly, H. fossilis was found more efficient in utilizing carbohydrate of FMLM than L. rohita.

Acute and sublethal effects of organophosphate insecticide chlorpyrifos on freshwater fish Oreochromis niloticus.

Chlorpyrifos is a widely used organosphosphate insecticide in India. Residue of the insecticide is frequently detected in trace to moderate concentration in food grains and in surface water of different freshwater ecosystems of the country. In this study, 96 h LC50 of the technical grade (94% a.i.) and commercial formulation (20% EC) of chlorpyrifos to freshwater fish Oreochromis niloticus were determined as 90.0 and 42.0 µg/L based on 2 h actual concentration of chlorpyrifos in water. About 96 h exposure to sublethal concentrations (0, 12.0 and 25.0 µg/L) of the commercial formulation (20% EC) of chlorpyrifos reduced the level of hepatic glycogen, activities of alkaline phosphatase, acetylcholinesterase, and catalase in liver and elevated the level of plasma glucose and activities of hepatic acid phosphatase, aspartate aminotransferase, and alanine aminotransferase in O. niloticus. About 28-day exposure to these sub-lethal concentrations caused anemia in fish, while 90 days exposure reduced growth of the fish and carcass concentration of crude protein and crude lipid as compared to control. It was concluded from this study that commercial formulation of chlorpyrifos (20% EC) was highly toxic to O. niloticus. Exposure to sub-lethal concentrations of the insecticide could induce oxidative stress and anemia resulting in reduced growth of the fish.

Exploring potential applications of a novel extracellular polymeric substance synthesizing bacterium (Bacillus licheniformis) isolated from gut contents of earthworm (Metaphire posthuma) in environmental remediation.

The aim was to isolate, characterize, and explore potentials of gut bacteria from the earthworm (Metaphire posthuma) and imply these bacteria for remediation of Cu(II) and Zn(II). An extracellular polymeric substance (EPS) producing gut bacteria (Bacillus licheniformis strain KX657843) was isolated and identified based on 16S rRNA sequencing and phylogenetic analysis. The strain showed maximum tolerance of 8 and 6 mM for Cu(II) and Zn(II) respectively. It removed 34.5% of Cu(II) and 54.4% of Zn(II) at 25 mg L-1 after 72 and 96 h incubation respectively. The bacteria possessed a great potential to produce indole acetic acid (38.49 µg mL-1) at 5 mg mL-1 L-tryptophan following 12 days incubation. The sterilized seeds of mung beans (Vigna radiata) displayed greater germination and growth under bacterium enriched condition. We observed that the bacterial strain phosphate solubilization ability with a maximum of 204.2 mg L-1 in absence of Cu(II) and Zn(II). Endowed with biosurfactant property the bacterium exhibited 24% emulsification index. The bacterium offered significant potential of plant growth promotion, Cu(II) and Zn(II) removal, and as such this study is the first report on EPS producing B. licheniformis KX657843 from earthworm which can be applied as powerful tool in remediation programs of Cu(II) and Zn(II) contaminated sites.

Deposition, acute toxicity, and bioaccumulation of nickel in some freshwater organisms with best-fit functions modeling.

Although nickel (Ni) frequently enters into water, documents on speciation of the metal and its toxicity to freshwater organisms are scanty. Laboratory experiments, made in this study, with 1.0-5.0 mg/L of Ni revealed that Ni was not quickly removed from water. Application of cubic regression followed by classical optimization technique showed that maximum reduction time (T) of Ni in water ranged between 60 to 65 h. Ninety-six hours of LC50 value of Ni to crustacean Diaptomus forbesi, fish Cyprinus carpio, and worm Branchiura sowerbyi was respectively 5.43, 14.70, and 19.73 mg/L. Normalizing the lethal values and plotting them against time, it was observed that C. carpio was more sensitive than D. forbesi, which was not reflected in the 96-h LC50 values. However, sensitivity of these organisms to Ni was better explained by power regression equation (M = aNib), which exhibited that mortality (M) of D. forbesi and B. sowerbyi increased slowly between 24 to 72 h, increasing sharply at 96 h, while mortality of C. carpio increased steadily every 24 till 96 h. Experiment with 1.0 mg/L of Ni in outdoor vats showed that crustacean zooplankton and worms accumulated high concentration of Ni, while only gut and liver tissues of fish C. carpio accumulated trace and moderately high concentration of Ni, respectively. It is assumed that toxicity of Ni to fish is mediated primarily through gill.

Kinetics of Deposition, Acute Toxicity and Bioaccumulation of Copper in some Freshwater Organisms.

Experiments with environmentally relevant concentrations of Cu in glass aquaria revealed that Cu was quickly removed from water. Cubic regression of Cu concentration against time showed that maximum rate of removal was around 69.34-72.11 h irrespective of treatment. The 96 h LC50 value of Cu was respectively 0.18, 0.19 and 0.35 mg/L for fish Cyprinus carpio, crustacean Diaptomus forbesi and worm Branchiura sowerbyi. Normalizing the lethal values and plotting them against time it was observed that there was sharp differences in mortality over time between the organisms and 96 h lethal values could misrepresent susceptibility of the organisms to Cu. Treatment of 0.1 mg/L of Cu in water resulted in accumulation of 10.57, 4.38, 1.46 and 2.44 µg/g of Cu, respectively in sediment, worm, crustacean zooplankton and whole body of fish. But, Cu deposited in high concentrations in gut and liver of fish indicating that Cu was principally accumulated through food.

Deposition of chromium in aquatic ecosystem from effluents of handloom textile industries in Ranaghat-Fulia region of West Bengal, India.

Accumulation of chromium (Cr) was determined in water, sediment, aquatic plants, invertebrates and fish in aquatic ecosystems receiving effluents from handloom textile industries in Ranaghat-Fulia region of West Bengal in India. Cr was determined in the samples by atomic absorption spectrophotometer and data were analyzed functionally by Genetic Algorithm to determine trend of depositions of Cr in the sediment and water. Area plot curve was used to represent accumulation of Cr in biota. The results indicate that the aquatic ecosystems receiving the effluents from handloom textile factories are heavily contaminated by Cr. The contamination is hardly reflected in the concentration of Cr in water, but sediment exhibits seasonal fluctuation in deposition of Cr, concentration reaching to as high as 451.0 µg g(-1) during the peak production period. There is a clear trend of gradual increase in the deposition of Cr in the sediment. Aquatic weed, insect and mollusk specimens collected from both closed water bodies (S1 & S2) and riverine resources (S3 & S4) showed high rate of accumulation of Cr. Maximum concentration of Cr was detected in roots of aquatic weeds (877.5 µg g(-1)). Fish specimens collected from the polluted sites (S3 & S4) of river Churni showed moderate to high concentration of Cr in different tissues. Maximum concentration was detected in the liver of Glossogobius giuris (679.7 µg g(-1)) during monsoon followed by gill of Mystus bleekeri (190.0 µg g(-1)) and gut of G. giuris (123.7 µg g(-1)) during summer. Eutropiichthys vacha showed moderately high concentration of Cr in different tissues (65-99 µg g(-1)) while Puntius sarana showed relatively low concentration of Cr (below detection limit to 18.0 µg g(-1)) in different tissues except in gill (64.4 µg g(-1)).

Biomarkers of type II synthetic pyrethroid pesticides in freshwater fish.

Type II synthetic pyrethroids contain an alpha-cyano group which renders them more neurotoxic than their noncyano type I counterparts. A wide array of biomarkers have been employed to delineate the toxic responses of freshwater fish to various type II synthetic pyrethroids. These include hematological, enzymatic, cytological, genetic, omic and other types of biomarkers. This review puts together the applications of different biomarkers in freshwater fish species in response to the toxicity of the major type II pyrethroid pesticides and assesses their present status, while speculating on the possible future directions.

Dietary ascorbic acid as a means to counter the stress of cypermethrin on the growth of freshwater catfish Heteropneustes fossilis.

Two months of experiments performed in outdoor vats in a 3 3 factorial design to evaluate the effects of three sublethal levels (0.0, 0.3 and 0.5 µg L(-1)) of cypermethrin on freshwater catfish Heteropneustes fossilis fed with three different levels (0.0, 0.5 and 1.0 g kg(-1)) of ascorbic acid (AA) in the diet. Even the lower sublethal level (0.3 µg L(-1)) of cypermethrin produced significant reduction in growth and deposition of protein in the body of H. fossilis. Dietary supplement of AA at 0.5 g kg(-1) failed to counter these ill effects of cypermethrin on H. fossilis, but a supplement of 1.0 g kg(-1) AA significantly increased the AA reserve in the body of the fish, and the ill effects of cypermethrin on growth were reversed. It was concluded that the catfish H. fossilis required an exogenous supply of AA to counter the stress of cypermethrin.

Effects of carbaryl, chlorpyrifos and endosulfan on growth, reproduction and respiration of tropical epigeic earthworm, Perionyx excavatus (Perrier).

Effects of sub-lethal doses of carbaryl (1-Naphthyl-methylcarbamate), chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2-pyridinyl-phosphorothioate) and endosulfan (6,7,8,9,10,10-Hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide), respectively a carbamate, an organophosphate and an organochlorine insecticide on growth, reproduction and respiration of the tropical earthworm, Perionyx excavatus (Perrier) were investigated under laboratory conditions. The results showed significant reduction in biomass, production and hatching of cocoon and production of juveniles of the worms exposed to 0.75 to 3.03 mg/kg soil of carbaryl, 0.91 to 3.65 mg/kg soil of chlorpyrifos and 3.75 to 15.0 µg/kg soil of endosulfan corresponding to 12.5 to 50 % of LC(50) value of the respective insecticide for P. excavatus. Endosulfan was found most dangerous among the three insecticides followed by carbaryl and chlorpyrifos. There was no hatching of the worms at endosulfan treatment 5.0 µg/kg soil (25 % LC(50)) or above while the highest dose of carbaryl and chlorpyrifos (50 % of LC(50)) rendered respectively 87.13 and 24.84 % reductions in hatching as compared to control. Chlorpyrifos produced no change in respiration of the worms except at the highest dose, while the worms showed an increase in evolution of CO(2) at all doses of carbaryl and endosulfan. Based on the recommended agricultural dose of each insecticide, it was concluded that application of endosulfan and carbaryl was potentially dangerous to earthworms.

Ecotoxicological assessment of cobalt used as supplement in the diet of common carp Cyprinus carpio.

Experiments were performed in the laboratory to determine if excess levels of Co used as dietary supplement (0.0, 0.05, 0.10 and 1.0%) to enhance growth of the fish Cyprinus carpio was safe for aquatic organisms. Lethal concentrations of Co for tadpole of toad Bufo melanostictus (96 h LC(50), 17.2 mg/L), oligochaet worm Branchiura sowerbyi (96 h LC(50), 179 mg/L) and crustacean zooplankton Diaptomus forbesi (96 h LC(50), 1.5 mg/L) were compared with the concentration of Co in the medium leached from the unused diets and faeces. The results indicated that the Co leached from diet containing 1.0% Co was ecotoxicologically unsafe for crustacean zooplankton.

Effects of cypermethrin on some biochemical parameters and its amelioration through dietary supplementation of ascorbic acid in freshwater catfish Heteropneustes fossilis.

Static bioassays were made to evaluate efficiency of dietary supplementation of ascorbic acid to counter stress exerted by the pyrethroid pesticide, cypermethrin on freshwater catfish Heteropneustes fossilis. Three levels, a control and two sub-lethal concentrations (0.3 and 0.5 microg L(-1)) of cypermethrin were tested. Stress on H. fossilis was evident from the rise of plasma glucose level and reduction in the level of liver glycogen after 4 h of cypermethrin treatment. Acid and alkaline phosphatase activities of liver and ascorbic acid level of blood, liver and kidney also decreased significantly in H. fossilis exposed to cypermethrin as compared with control. Fish previously fed for 60 d with a diet supplemented by high level of ascorbic acid (1.0 g kg(-1)) could significantly reverse these effects. Fish fed a low level of dietary ascorbic acid (0.5 g kg(-1)) failed to counter the stress of cypermethrin.

Toxicity of the pyrethroid pesticide fenvalerate to freshwater catfish Clarias gariepinus: lethality, biochemical effects and role of dietary ascorbic acid.

Static bioassays were made in the laboratory to determine lethal concentration of the pyrethroid pesticide fenvalerate [(RS)-alpha-cyano-3-phenoxybenzyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate] for the freshwater catfish Clarias gariepinus and effects of sublethal concentrations of the pesticide on some biochemical parameters of the fish. For exposure periods of 24 to 96 h, LC(50) values of fenvalerate ranged from 5.83-4.76 micro g/L and 4.24-2.94 micro g/L, respectively for water and acetone soluble fenvalerate. Two sublethal concentrations of fenvalerate were used in the bioassays for biochemical parameters: 2.1 micro g/L for 24 h and 1.4 micro g/L for 96 h exposure, both concentrations representing 50% of LC(50) value of acetone soluble fenvalerate for the respective exposure period. Hepatosomatic index, liver glycogen, alkaline phosphatase of liver and ascorbic acid of blood, liver, and kidney decreased while haemoglobin (Hb) %, plasma glucose levels and acid phosphatase level of liver increased after 24 h exposure to 2.1 micro g/L fenvalerate. Longer exposure (96 h) to even a lower concentration (1.4 micro g/L) of fenvalerate resulted in reduction of all the parameters (except Hb %) tested as compared with control. Fish previously fed for 60 days with a diet supplemented by a high level of ascorbic acid (100 mg/100 g diet) could reverse most of the effects caused by 24 h exposure to 2.1 micro g/L fenvalerate. A lower level of ascorbic acid (50 mg/ 100 g diet) supplement could not influence these effects of fenvalerate. Even the higher dose of ascorbic acid supplementation (100 mg/100 g diet) could not relieve the stress parameters, except for Hb% and HSI, when the pesticide was applied at 1.4 micro g/L for a longer time period (96 h).

Ecotoxicological effects of jute retting on the survival of two freshwater fish and two invertebrates.

Severe deterioration of water quality occurs during jute retting in ponds, canals, floodplain lakes, and other inland water bodies in the rural areas of West Bengal in India. Attempts were made to evaluate changes in the physicochemical parameters of water caused by jute retting, and their impact on the survival of two species of freshwater fish (Labeo rohita and Hypophthalmicthys molitrix) and two species of freshwater invertebrate (Daphnia magna, a Cladocera, and Branchiura sowerbyi, an Oligochaeta). Results showed that jute retting in a pond for 30 days resulted in a sharp increase in the BOD (>1,000 times) and COD (>25 times) of the water, along with a sharp decrease in dissolved oxygen (DO). Free CO(2), total ammonia, and nitrate nitrogen also increased (three to five times) in water as a result of jute retting. Ninety-six-hour static bioassays performed in the laboratory with different dilutions of jute-retting water (JRW) revealed that D. magna and B. sowerbyi were not susceptible to even the raw JRW whereas fingerlings of both species of fish were highly susceptible, L. rohita being more sensitive (96 h LC(50) 37.55% JRW) than H. molitrix (96 h LC(50) 57.54% JRW). Mortality of fish was significantly correlated with the percentage of JRW.

Acute toxicity of synthetic pyrethroid cypermethrin to some freshwater organisms.

Ninety-six hours static bioassays were made in the laboratory to determine acute toxicity of cypermethrin to five non-target freshwater organisms belonging to different taxa and niche. Susceptibility of the organisms to cypermethrin was in the order: the crustacean Diaptomus forbesi > the aquatic insect Ranatra filiformis > the freshwater carp Cyprinus carpio > the tadpole larva of the toad Bufo melanostictus > the oligochaet worm Branchiura sowerbyi. Ninety-six hours LC50 values of aqueous cypermethrin ranged from 0.03 microg/L for the crustacean to 9.0 microg/L for the tadpole larva. The value was very high (71.12 microg/L) for the oligochaet worm. LC50 values changed with hours of exposure till 72 h after which cypermethrin became inactive in both aqueous and acetone solution. Acetone solution of cypermethrin was more toxic to B. sowerbyi, C. carpio and the tadpole larva. There was no significant difference in susceptibility of any other test organism between aqueous and acetone solution of cypermethrin.