Formation of resistance in the Chironomus plumosus to four pesticides over 45 generations

A study was conducted on the Chironomus plumosus larvae to determine initiation of resistance to four pesticides – chlorfenvinphos, chlorpyrifos, chlorpyrifos-methyl, and malathion. First generational LC₅₀ values were well within the threshold value for chironomids based upon the literature. Subsequent LC₅₀ values were observed to increase, indicating a lessening of the toxicity of the pesticides to the chironomid. In the case of chlorfenvinphos, the 96 h LC₅₀ for generations 1–23 was 6 µg L^?1, in generations 3–7 was 8.57 µg L^?1 and 11.14 µg L^?1 for generations 8–9. Generations 10–12 had an LC₅₀ value of 22.58 µg L^?1 and generation 13 had an LC₅₀ value of 35.08 µg L^?1. Generation 14 had an LC₅₀ value of 47.58 µg L^?1. Generations 15–19 and 20–24 had 96 h LC₅₀ values of 60.68 µg L^?1, 72.58 µg L^?1, 85.08 µg L^?1, 97.58 µg L^?1 and 110.08 µg L^?1, respectively. Generations 25, 26 to 30, 31 to 38 and 39 to 45 had 96 h LC₅₀ values of 160.42 µg L^?1, 210.7 µg L^?1, 262.24 µg L^?1 and 274.36 µg L^?1, respectively. The variation between LC₅₀ values was found to be statistically significant. This was observed for most pesticides tested. Larval size and life cycle duration was observed to change from generation to generation with the body size decreasing markedly from 1 to 0.3 cm with life cycle increasing from 7 to 39 days.     

The role of root organic acids in the tolerance of Festuca rubra to zinc,lead and cadmium

Abstract

Festuca rubra L. plants are pseudometallophytes colonizing abandoned Pb/Zn mine areas, successfully employed in phytostabilization. To study the contribution of low-molecular weight organic acids to metal tolerance, F. rubra plants were grown for three months in hydroponics with Cd (1.8, 18 and 36 µmol?L^?1), Pb (50, 250 and 500?µmol?L^?1) and Zn (0.3, 3 and 6?mmol?L^?1), separately, and in ternary combination (18?µmol?L^?1 Cd + 250?µmol?L^?1 Pb + 0.3?mmol?L^?1 Zn). The roots retained most of the metals but their distribution from shoot to root was altered when the plants were treated with the ternary combination. The main organic acids in roots were citrate and malate. At the lowest concentrations, the metals caused small reductions in biomass, had no effects on photosynthetic pigments nor on malondialdehyde, but led to increases in root organic acids. At higher concentrations, phytotoxic responses were observed, associated with a decline of citrate and malate in the roots.     

Arsenic in freshwater ecosystems of the Bengal delta: status,sources and seasonal variability

The study aimed to examine the contamination status of arsenic (As) in excavated small water bodies, commonly known as ponds – the integral part of daily life in the arsenic-affected rural areas of West Bengal, India in comparison to the unaffected areas. The ponds of the contaminated area had higher levels of As: water 2–174 µg L^?1 (mean 31 ± 2 µg L^?1) and sediment 1.3–37.3 mg kg^?1 (mean 10.3 ± 0.4 mg kg^?1), than those from the unaffected area: water 1–8 µg L^?1 (mean 4 ± 0 µg L^?1) and sediment 1.4–5.3 mg kg^?1 (mean 3.0 ± 0.1 mg kg^?1). A moderate positive correlation was observed between the water and sediment arsenic content of the ponds of the arsenic-affected region (r = 0.688, n = 277, p < 0.0001). Contaminated ground water, either as direct input or through agricultural washings, was found to be the major contributor of arsenic pollution to these ecosystems. Seasonal variations were not prominent. This study emphasized the beneficial role of using the studied ecosystems over the highly contaminated ground water for various livelihood activities in the Gangetic delta region.     

Differential effects of UV-B radiation fluence rates on growth,photosynthesis, and phosphate metabolism in two cyanobacteria under copper toxicity

This work was undertaken to ascertain the impact of different fluence rates of ultraviolet-B (UV-B) radiation on two cyanobacterial biofertilizers, Phormidium foveolarum and Nostoc muscorum, growing under copper toxicity. Copper (2 and 5?µmol?L^?1) and high UV-B fluence rate (UV-B_H; 1.0?µmol?m^?2?s^?1) decreased the growth, pigment content, photosynthetic oxygen yield, phosphate uptake, and acid phosphatase activity in both the strains analyzed after 24 and 72?h of experiments, and combined exposure further enhanced the toxic effects. Respiration and alkaline phosphatase activities were stimulated appreciably. The damaging effect was shown on the order on pigments: phycocyanin?>?chlorophyll a?>?carotenoids, and on photosystems: whole chain photosynthetic reaction?>?photosystem II?>?photosystem I. Partial recovery in the photosystem II activity in the presence of artificial electron donors; diphenyl carbazide (DPC), hydroxylamine (NH₂OH), and manganese chloride (MnCl₂) pointed out the interruption of electron flow on the oxidation side of photosystem II. Unlike UV-B_H, low UV-B fluence rate (UV-B_L; 0.1?µmol?m^?2?s^?1), rather than causing damaging effect partially, alleviated the toxic effects of Cu. This study suggests that the cyanobacterium P. foveolarum is less sensitive against UV-B_H and excess Cu (2 and 5?µmol?L^?1), thus P. foveolarum may be used as a biofertilizer for sustainable agriculture.     

Effects of bisphenol A on Gammarus fossarum and Lumbriculus variegatus in artificial indoor streams

The impact of bisphenol A (BPA) on Gammarus fossarum and Lumbriculus variegatus was studied in four artificial indoor streams (0, 5, 50 and 500?µg?L^?1 BPA, nominal) over 103 days in a pulse–dose exposure scenario (weekly BPA application). For G. fossarum populations at day 103, the proportions of juveniles and of breeding females from the highest BPA treatment were in tendency reduced. For individually exposed gammarid pairs an EC₁₀ of 17?µg?L^?1 BPA (nominal) for the proportion of reproductive females in the fourth brood was determined. During the first three broods, the largest brood size occurred at the highest BPA concentration, whereas in the fourth brood it decreased concentration-dependently (fourth brood EC₁₀?=?5?µg?L^?1 BPA, nominal). Effects on L. variegatus were a reduced population growth (103?d-EC₁₀ of 2?µg?L^?1 BPA, nominal) and an increase in dry weight and the number of segments in large, complete worms.     

Larvicidal potential of different solvent extracts and oleanolic acid derivative from Coccinia indica against vector mosquitoes

The mosquito larvicidal activities of different solvent extracts (chloroform, ethyl acetate, and methanol) from the leaves of Coccinia indica were studied. Among the extracts tested, the methanol extract showed the highest larvicidal activity against early fourth instar larvae of Culex quinquefasciatus (LC₅₀?=?142?mg?L^?1), Aedes aegypti (LC₅₀?=?158?mg?L^?1) and Anopheles stephensi (LC₅₀?=?161?mg?L^?1) after 24?h of exposure period. The lowest larval mortality was observed with the ethyl acetate extract with the LC₅₀ values of 927, 872, and 730?mg?L^?1 against Cx. quinquefasciatus, Ae. aegypti, and An. stephensi, respectively. The chloroform extract showed the moderate larvicidal activity against the mosquito species tested with the LC₅₀ values from 446 to 546?mg?L^?1. A new triterpene was isolated from the methanol extract using bio-assay guided separation and identified as an oleanolic acid derivative by NMR, IR and mass spectral studies. The compound showed prominent larvicidal activity against Cx. quinquefasciatus, Ae. aegypti and An. stephensi with the LC₅₀ values of 5.6, 5.0, and 4.8?mg?L^?1, respectively. The results of the present investigation offer an opportunity for developing alternatives to rather expensive and environmentally hazardous organic insecticides.     

Acute toxicity of waterborne manganese to Rutilus caspicus (Yakovlev, 1870) – gill histopathology,immune indices,oxidative condition,and saltwater resistance

The acute toxicity of manganese (Mn) in Caspian roach Rutilus caspicus was determined. The 96 h-LC₅₀ was calculated to be 300 (240–360) mg L^?1. Then, fish were exposed for 96 h to 300 (96 h-LC₅₀), 150 (50% of 96 h-LC₅₀), 60 (20% of 96 h-LC₅₀), and 0 (control group) mg L^?1 Mn. Exposure to all Mn concentrations led to fish gill damages, including epithelial lifting, hyperplasia, lamellar fusion, aneurism, and lamellar curling. Also, the fish exposed to all Mn concentrations showed decreased plasma alternative complement and lysozyme activity. Whole body superoxide dismutase, catalase, and malondialdehyde showed significant increases in the Mn-exposed fish which also exhibited lower tolerance to saltwater than the control group.     

Effects of copper on lipid peroxidation,glutathione, metallothionein,and antioxidative enzymes in the freshwater mussel Anodonta anatina

Copper is an essential element to all animals. At elevated concentrations, it is toxic and can participate in the formation of reactive oxygen species, leading to cellular damage. In this study, the ecotoxicological relevance of copper was investigated with freshwater mussels, Anodonta anatina. When the mussels were exposed to copper at environmentally realistic concentrations, either via the water (0.3?µmol?L^?1 Cu) or fed with Cu-loaded algae (equivalent to 0.06?µmol?L^?1 Cu), the level of thiobarbituric acid-reactive substances rose and glutathione decreased. This was associated with the induction of metallothionein and, relative to total protein, of glutathione reductase and the antioxidative enzymes superoxide dismutase, catalase, and glutathione peroxidase. But, since the overall protein-synthetic capacity was hampered by the copper insult, the activities of the enzymes relative to tissue weight and copper concentrations were depressed. During depuration, most parameters started to normalize although not returning to control values within 12 days.     

4种甲氧基丙烯酸酯类杀菌剂不同剂型对斑马鱼急性毒性效应

采用半静态法测定了4种甲氧基丙烯酸酯类杀菌剂原药及制剂对斑马鱼(Brachydonio rerio)急性毒性。结果表明,以实测浓度计,250 g·L~(-1)嘧菌酯悬浮剂对斑马鱼的96 h半数致死浓度(LC50)值为0.539 mg·L~(-1),急性毒性为高毒,95%嘧菌酯原药和50%嘧菌酯水分散粒剂对斑马鱼的LC50(96 h)值分别为1.09和1.21 mg·L~(-1),急性毒性均为中毒;98%啶氧菌酯原药和22.5%的啶氧菌酯悬浮剂对斑马鱼的LC50(96 h)值分别为0.0974和0.0972 mg·L~(-1),急性毒性均为剧毒;95%吡唑醚菌酯原药、15%吡唑醚菌酯悬浮剂和250 g·L~(-1)吡唑醚菌酯乳油对斑马鱼的LC50(96 h)值为0.0613、0.0549和0.0487 mg·L~(-1),急性毒性均为剧毒;95%醚菌酯原药和50%醚菌酯水分散粒剂对斑马鱼的LC50(96 h)值分别为0.468和0.702 mg·L~(-1),急性毒性均为高毒。这4种甲氧基丙烯酸酯类杀菌剂对斑马鱼均有较高风险,会对其他水生生物也存在潜在的风险。     

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.     

Deltamethrin-induced alterations in serum calcium and prolactin cells of a freshwater teleost,Heteropneustes fossilis

Deltamethrin, a pyrethroid insecticide widely used in many countries, causes significant adverse effects in aquatic ecosystems. The concentration of deltamethrin in water reservoirs and the run off from agricultural areas (in water) in many countries range up to 24.0?µg?L^?1 which is higher than the recommendation of the European Union standard. Hence, in this study the effects of deltamethrin were investigated, i.e. its toxic impacts on the freshwater catfish Heteropneustes fossilis in terms of serum calcium and prolactin cells (located in the rostral pars distalis region of the pituitary). The fish were subjected to deltamethrin for a short-term experiment (96?h; 1.5?µg?L^?1 e.0.8 of 96?h LC₅₀) and a long-term experiment (28 days; 0.37?µg?L^?1 e.0.2 of 96?h LC₅₀). After short-term deltamethrin exposure, serum calcium levels decrease. No histological change in prolactin cells is noticed throughout the short-term experiment. Fish exposed to deltamethrin for 7 days also exhibit a decrease in serum calcium level. This decrease persisted until the end of the experiment (28 days). Prolactin cells of fish treated for 14 days with deltamethrin exhibit increased nuclear volume and degranulation, increasing progressively from the 21st day onwards. After 28 days, a few degenerated cells are discerned. The results of this study show that deltamethrin is moderately toxic for the freshwater fish H. fossilis by producing adverse effects on serum calcium and prolactin cells. Hence, it should be used with caution in areas near fish-inhabited waters.     

Toxic effects of phosphoramidate on Paramecium sp. with special emphasis on respiratory metabolism,growth, and generation time

The toxicological impacts of the increasing number of synthetic compounds present in the aquatic environment are assessed predominantly in laboratory studies where test organisms are exposed to a range of concentrations of single compounds. Protozoan cells are often used as bioindicators for the presence of xenobiotic compounds. In this article, we describe the inhibitory effect of a synthetic phosphoramidate derivative at different concentrations (40, 60, and 80?µmol?L^?1) on Paramecium sp., affecting its growth (proliferation) in concentration-dependent manner, as well as the generation time and response percentage. The LC₅₀ value determined for these protozoa was estimated at 60?µmol?L^?1 on 24?h of exposure. The respiratory metabolism of protozoan is perturbed at three concentrations, noting that the oxygen consumption was significantly increased at high concentrations after 18?h of exposure. In addition, the data can be used as reference values in further testing with other pesticides.     

Effects of cerium oxide nanoparticles on biochemical and oxidative parameters in marigold leaves

Abstract

The effects of suspensions of cerium oxide nanoparticles sprayed onto marigold seedlings (Calendula officinalis L.) at concentrations between 50 and 3200 mg L^?1 were studied. At concentrations of 50 and 100 mg L^?1, the nanoparticles had a slight positive effect on some growth parameters, but at higher concentrations they caused severe oxidative damage. Activities of phenylalanine ammonia lyase and lipoxygenase increased from 400 mg L^?1 upward, tyrosine ammonia lyase from 1600 mg L^?1. Ascorbate and glutathione contents decreased from 400 mg L^?1 upwards.     

Effects of chronic bisphenol A exposure on hepatic antioxidant parameters in medaka (Oryzias latipes)

Bisphenol A (BPA), the plastic monomer and plasticizer with well-known endocrine-disrupting chemical properties, is widely present in the aquatic environment, but little is known regarding hepatic toxicity in fish. This study assessed the effects of chronic exposure to BPA on the antioxidant defense system of Japanese medaka liver. Fish were exposed to sub-lethal concentrations of BPA (0.1, 1, 10, 100, or 1000?µg?L^?1) for 60 days. Antioxidant parameters were determined and compared with controls. The results showed that the activities of catalase (CAT), superoxide dismutase, glutathione peroxidase, glutathione S-transferase, and the content of reduced glutathione were all induced at 10?µg?L^?1 BPA after 60 days. Further, hepatic CAT was sensitive to BPA at 1?µg?L^?1 concentration. In conclusion, CAT may serve as a potential early biomarker of BPA exposure in aquatic environment.     

In vitro kinetic characterization of inhibition of acetylcholinesterase by organophosphate and carbamate compounds in food animals

Organophosphate, dichlorvos (2,2-dichlorovinyldimethylphosphate, DDVP), and diazinon (DZN) as well as carbamates are currently found in contaminated water, dust, soil, agricultural waste, and elsewhere in the environment, and can be harmful after accidental or deliberate exposure. Intoxication by these compounds causes a generalized cholinergic crisis due to the inhibition of acetylcholinesterase (AChE), whose major physiological role in mammalian tissues is in nervous transmission. The half-maximal inhibitory concentration (IC₅₀) was found to be higher for carbaryl than DDVP and DZN, about 3–4 times in liver and about 4–6 times in muscles. The half time (t _1/2) of inhibition (8?µmol?L^?1 DDVP or DZN; 40?µmol?L^?1 carbaryl) ranged between 4 and 16?min and decreased as follows: pig?>?cattle?>?sheep for liver tissue, and cattle?>?sheep?>?pig for muscle. Rate constants of inhibition (k _i) ranged between 43?×?10^?3 and 168?×?10^?3?min^?1 for liver and from 46?×?10^?3 to 115?×?10^?3?min^?1 for muscles. Very little residual AChE activity (<6.1%) was seen in liver, but more was seen in muscle (<17%).     

Genotoxic and cytotoxic in vitro evaluation of ivermectin and its formulation ivomec® on Aedes albopictus larvae (CCL-126™) cells

Genotoxic effects of ivermectin (IVM) and its commercial formulation ivomec® (IVM 1.0%) were studied on Aedes albopictus larvae (CCL-126?) cells by sister chromatid exchange (SCE) and single cell gel electrophoresis (SCGE) while cytotoxicity was determined by cell-cycle progression (CCP), proliferative rate index (PRI), mitotic index (MI), 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and neutral red (NR) endpoints within a 1–250 µg mL^?1 concentration range. While IVM and ivomec® did not markedly affect SCE frequencies, these agents induced DNA-strand breaks enhancing both slightly damaged and damaged cells at 25–50 and 5–50 µg mL^?1 IVM and ivomec®, respectively. Both compounds exerted a delay in CCP and reduction of PRI at 10 µg mL^?1. Cytotoxicity was observed at concentrations higher than 25 µg mL^?1. A marked reduction of about 98% and 94% of MI compared to controls was noted with 25 µg mL^?1 of IVM and ivomec®, respectively. NR and MTT assays revealed that both compounds induced a cell growth inhibition within the 1–250 µg mL^?1 concentration range. Data indicated that IVM and ivomec® exert both genotoxicity and cytotoxicity in insect cells in vitro, at least in A. albopictus larvae CCL-126? cells.     

21种杀菌剂对家蚕的急性毒性与风险评价

旨在为桑园及周围农田合理选择和使用农药提供科学依据,采用食下毒叶法测定了农业生产上常用的21种杀菌剂对家蚕的急性毒性,并进行了风险评价.急性毒性测定结果表明:20％苯醚甲环唑微乳剂、10％氟硅唑水乳剂、12.5％腈菌唑水乳剂、12.5％烯唑醇可湿性粉剂和70％嗯霉灵可湿性粉剂对家蚕的96 h-LC50值为46.5(41...     

Utilization of a new bdelloid rotifer (Philodina acuticornis odiosa) assay to evaluate the effect of salinity on the toxicity of chlorothalonil

Acute (24 h) toxicity tests were conducted to determine the toxicity of the fungicide chlorothalonil towards the freshwater bdelloid rotifer (Philodina acuticornis odiosa). Since rotifers are the dominant zooplankton species in many inland freshwater lakes in Australia, the influence of salinity on chlorothalonil toxicty was also assessed. The rotifers used in this study appeared to be reasonably tolerant to changes in salinity, with little mortality observed at 3760 µS cm^?1, increasing thereafter at higher salinity. The bdelloid rotifers were, however, found to be highly sensitive to chlorothalonil (24 h LC50, 3.2 µg L^?1) with results also suggesting that as salinity increases, so does toxicity (e.g., 24 h LC50 at 5000 µS cm^?1, 0.5 µg L^?1).     

Hepatic effects of yttrium oxide nanoflowers: in vitro risk evaluation

Yttrium oxide nanoflowers were prepared by a hydrothermal technique, and X-ray diffraction and scanning electron microscopy were used to determine their structures. The cytotoxic and genotoxic potentials of aqueous dispersions of the nanoflowers to cultured primary rat hepatocytes were examined at concentrations up to 500 mg L^?1 for 72 h. Cell viability was determined by monitoring the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, release of lactate dehydrogenase, and uptake of neutral red. Genotoxicity was assessed by the liver micronucleus assay. Exposure to Y₂O₃ nanoflowers at concentrations lower than 100 mg L^?1 did not lead to any cytotoxicity or genotoxicity. At higher concentrations (200, 400, and 500 mg L^?1), cell viability decreased and induction of micronuclei increased (400 and 500 mg L^?1).     

Evaluation of the toxicity of tetrabromobisphenol A and some of its oxidation products using a micro-scale algal growth inhibition test

A micro-scale algal growth inhibition (μ-AGI) test using a common micro-plate based fluorometric detection was used to demonstrate the effects of humic substances (HSs) on the toxicity of tetrabromobisphenol A (TBBPA) and its oxidative decomposition products 2,5-dibromo-1,4-benzoquinone (2,5-DBBQ), 2,5-dibromohydroquinone (2,5-DBHQ), 2,6-dibromobenzoquinone (2,6-DBBQ), and 2,6-dibromophenol (2,6-DBP) to Pseudokirchneriella subcapitata. The EC₅₀ values were: EC_50(TBBPA) = 7 mg L^?1, EC_50(2,5-DBHQ) = 7 mg L^?1, EC_50(2,5-DBBQ) = 19 mg L^?1, EC_50(2,6-DBP) = 49 mg L^?1, and EC_50(2,6-DBBQ) = 13 mg L^?1. The toxicity of the chemicals was slightly lower in the presence of HA. The toxicity of TBBPA decomposed by a biomimetic catalytic system consisting of iron (III) 5,10,15,20-tetrakis (p-sulfonatophenyl) porphyrin (Fe(III)-TPPS) and KHSO₅ was also evaluated using P. subcapitata and Chlamydomonas reinhardtii.