Assessment of deposition of MEMC (seed dressing fungicide) in exposed rice grain through study of seedling growth parameters

Rice seed grains exposed to 240 ppm of seed dressing fungicide, MEMC showed increase in deposition of mercury with increase in period of observation (0h to 48h) in 765+/-5 mg of intact endosperm. The gradual increase in mercury deposition in intact endosperm caused simultaneous decrease in mercury content of the seed coat. Exposure periods of 5 to 20 min with 240 ppm of MEMC showed 5.5 to 8.72 microg of mercury deposition in 765+/-5 mg of intact endosperm. Increase in period of exposure (3 to 20 min) to 240 ppm of MEMC and also increase in chronic treatment to lower concentrations (1.5 ppm to 24 ppm) to seed grains have shown similar results in seedling growth parameters. Lower period of exposure or exposure to lower concentrations, both showed a significant inhibition of root growth, however the shoot growth showed stimulation. But higher exposure period or exposure to higher concentrations brought inhibition of both root and shoot growth. The exposure period showing 50% of root growth inhibition of 72h old seedling was calculated to be 10 min So also the chronic treatment showing the 50% of root growth inhibition was calculated to be 9 ppm. Ten min exposure of rice grain to 240 ppm of MEMC showed deposition of 7.11 microg of mercury in 765+/-5 mg of intact endosperm at 48h of observation (optimal phase of germinating process). Regression analysis indicated that by the time of 72h the intact endosperm and developing seedling might have acquired with a minimum amount of 10.23 microg of mercury from the seed coat. Finally it can be said that 10.23 microg of MEMC might be bringing 50% root growth inhibition in 72h old seedlings and 16.71 microg of mercury causing 50% inhibition of both root and shoot growth of 120h old seedlings.     

Chromium in tannery industry effluent and its effect on plant metabolism and growth

Different dilution levels of tannery treated effluent and their corresponding concentration of chromium (Cr6+) were studied in a petridish culture experiment on seed germination and seedling growth in radish (Raphanus sativus L). The different concentrations of Cr6+ (2, 5 and 10 ppm) and treated tannery effluent (10, 25 and 50%) showed reduction in seedling growth and related enzymatic activities with increase in concentration of Cr6+ in treatments and effluent both. The low concentration of chromium (2 ppm) and effluent dilution (10%) showed significant growth reduction separately. At this concentration of chromium and effluent dilution chlorophyll content, amylase, catalase and protein contents remained unchanged while with increase in Cr6+ concentration (>2ppm) and effluent dilution (> 10%) in treatments showed growth inhibitory effects.     

Monitoring toxicity of an azo dye methyl red and a heavy metal Cu,using plant and animal bioassays

Toxicities of an azo dye methyl red and a heavy metal copper (Cu) were quantified, using growth and mortality as end points, in four plant species and three animal species by subjecting them to short-term (4 days for animals, 10 days for plants) static bioassays. Lemna aequinoctialis Welwitch (EC₅₀: 7–16 ppm) was found to be the most sensitive species for methyl red, Ceratophyllum demersum L. (EC₅₀: 25 ppm) and Lactuca sativa L. (EC₅₀: 56 ppm) were intermediate, while Oryza sativa L. shows reduction in seedling vigor (9–27%) of <50%, being the least sensitive amongst the tested plant species. Methyl red toxicity is almost 3–5-fold higher in growing medium (pH = 5.8–6.0), even at high nutrient levels, while Cu toxicity is higher in nutrient-poor alkaline medium at alkaline pH (8.3–8.7; EC₅₀: Ceratophyllum = 104–200 ppb; Lemna = 100–170 ppb) compared to nutrient-rich acidic medium (pH = 5.4–5.7; EC₅₀: Ceratophyllum = 2600–3175 ppb; Lemna = 4350–4715 ppb). Rice tolerance (EC₅₀: 6500 ppb) was found to be higher than hydrophytes while lettuce was most tolerant to Cu. Fish sensitivity toward the test chemicals was almost parallel to Ceratophyllum and Lemna [Gambusia affinis Baird and Gerard (LC₅₀: 250 ppb for Cu) and Poecilia reticulata Peters (LC₅₀: 24 ppm for methyl red)]. Similar to the plants, dye toxicity increased markedly (LC₅₀: 7 ppm) in the acidic medium (pH = 6.0). Amongst the tested organisms, Daphnia was found to be most sensitive to methyl red (EC₅₀: 6 ppm) while its sensitivity to Cu (EC₅₀: 230 ppb) was similar to hydrophytes and fish. Initially, the combination of dye and Cu (at their sublethal concentrations) had additive effects in duckweed, while dye concentration ruled afterward. These results indicate that hydrophytes and animals are equally sensitive toward the test chemicals. Dye toxicity in hydrophytes and fish was pH dependent, while in the case of Cu, it is related to the nutrient status of the growth medium of plants.     

Effect of phytohormones on the growth dynamics and macromolecular contents of two extreme halophilic Cyanobacteria (Phormidium sps)

Two non-heterocystous, filamentous solar saltern extreme halophilic cyanobacteria viz., Phormidium tenue and Phormidium fragile were allowed to grow in different concentrations of phytohormones. Among the phytohormones, Indole-3 acetic acid and Indole-3-butyric acid at 0. l ppm concentration enhanced the growth, pigments and carbohydrate content in P. fragile. The phycobiliprotein production was found higher at 0. l ppm concentration of Indole-3-acetic acid in P. tenue, whereas Indole-3-butyric acid at 50 ppm and 0. 1 ppm concentrations proved to be inhibitory in the protein and carbohydrate contents in P. tenue.     

Acclimation and tolerance of Artemia salina to copper salts

The brine shrimp Artemia salina L. was acclimated in sea water with cupric chloride, acetate, carbonate, and sulphate, each at concentrations of 0.1, 0.05 and 0.025 ppm Cu⁺⁺, together with sea water controls. Growth inhibition was observed in all four compounds, generally in direct relationship to the concentration. It was least in sulphate, and increased progressively in chloride, acetate and carbonate in that order. No inhibition however was observed in carbonate at 0.025 ppm Cu⁺⁺. In toxicity tests, 2-week old larvae from each solution were exposed to concentrations of 10, 7.5, 5, 2.5 and 1 ppm Cu⁺⁺ of the same compounds, together with unacclimated larvae of the same age. Similar tests were held with 6-week old adults acclimated (a) in 0.1 ppm Cu⁺⁺ (chloride, acetate and sulphate) using the same concentrations and (b) in 0.5 ppm Cu⁺⁺ (carbonate), using 150, 125, 100, 75, and 50 ppm Cu⁺⁺. Toxicity to unacclimated larvae and adults differed with the compounds, carbonate being the least toxic, followed by sulphate, chloride and acetate in increasing order. Larvae acclimated in chloride (0.025 ppm Cu⁺⁺) and sulphate (0.1 and 0.5 ppm Cu⁺⁺) showed an increased tolerance to 1 and 2.5 ppm Cu⁺⁺ compared to untreated controls. Tolerance was not enhanced from 5 ppm Cu⁺⁺ upwards. In both compounds, adults acclimated in 0.1 ppm Cu⁺⁺ showed an increased tolerance to concentrations between 1 and 7.5 ppm Cu⁺⁺ compared to controls. Larval mortality in carbonate was below 50% in all test solutions. Adults acclimated at 0.5 ppm Cu⁺⁺ showed an increased tolerance to 50 ppm Cu⁺⁺ compared to controls. Considerable precipitation occurred with the high levels of this compound, thus effecting the final concentrations. No acclimation effect was observed in acetate for either larvae or adults. It is suggested that in A. salina, copper toxicity depends on the particular form of the metal, and that this difference is also evident in growth inhibition and in the potential acquisition of increased tolerance through exposure to low concentrations.     

Mikrobielle Transformation vono-Nitroanilin undp-Nitrophenol

Strains ofPseudomonas putida, Ps. fluorescens, Arthrobacter hydrocarboglutamicus andNocardia sp. tolerateo-nitroaniline andp-nitrophenol in concentrations up to 50 ppm without growth inhibition. Total growth inhibition occurs at concentrations of 200 ppm and more. OnlyNocardia sp. can transform both compounds, to a certain extent. The two metabolites 4-hydroxy-2-nitroaniline and 4-nitrobrenzcatechol are not further degraded by this organism.     

Effect of rubber factory effluent on seed germination and seedling growth of Vigna radiatus L

Physico-chemical analysis of the rubber factory effluents revealed high amounts of total suspended and dissolved solids. Sulphate, phosphate, total nitrogen were also present in significant amounts. At higher concentration (above 50%) of effluent, the seed germination percentage was retarded. Diluted effluent (upto 50%) favoured seedling growth. Length of root system, shoot system and number of lateral roots were increased by low concentrations of effluent.     

Cadmium toxicity induced changes in plant water relations and oxidative metabolism of Brassica juncea L. plants

Excess of cadmium (Cd) induced changes in oxidative scenario and water status of plants viz.., total water content, specific water content, water saturation deficit (WSD) and transpiration of Brassica juncea plants grown in soil pot culture. Although lower and marginal levels of excess cadmium (100 and 250 ppm) improved growth but higher levels (500 ppm) caused significant suppression. Significant accumulation of proline, an indicator of water stress, occurred at higher level of Cd. Gradual increases in activities of certain antioxidant enzymes such as catalase and peroxidase along with increased lipid peroxidation are suggestive of disturbed oxidative metabolism. Taking together, the deleterious effects of Cd and its effects on oxidative metabolism clearly indicate enhanced generation of reactive oxygen species (ROS) to be instrumental in producing toxic effects of Cd. The excess levels of Cd also decreased the concentrations of soluble protein and chlorophylls and increased the ratio of chlorophyll a/b.     

Toxicity assessment of heavy metals with Nostoc muscorum L

Heavy metals in aquatic ecosystem (Mn, Ni, Zn, Cu) were tested for their toxicity against Nostoc muscorum L., a common fresh water phytoplankton, with respect to chlorophyll, protein, total carbohydrate and starch contents along with growth (OD). Mn showed stimulatory effect up to 1.5 ppm for all the observed parameters. However, Ni, Zn and Cu (0.1, 0.2, 0.3, 0.4 and 0.5 ppm) showed adverse effects even at 0.1 ppm. Chlorophyll was most sensitive parameter followed by carbohydrate, protein and starch. Ni was most toxic to N. muscorum followed by Cu and Zn. The IC50 for Ni was 0.1 ppm for growth, chlorophyll and protein, while total carbohydrate and starch showed IC50 at 0.3 and 0.4 ppm, respectively. The IC50 for Cu was recorded at 0.2 ppm for all the parameters. Zn showed IC50 at 0.3 ppm for growth, chlorophyll, protein and starch at 0.4 ppm for carbohydrate. This study can be applied as bioassay using cyanobacteria for toxicity assessment of various industrial wastes in aquatic ecosystem.     

Effects of ammonia, nitrite and nitrate on hemoglobin content and oxygen consumption of freshwater fish, Cyprinus carpio (Linnaeus)

Lethal effects of nitrogenous compounds ammonia, nitrite and nitrate on freshwater fish Cyprinus carpio were studied and the static LC50 values obtained for these 3 toxicants for 24 hr were 0.80 ppb, 171.36 ppm; 1075.10 ppm and continuous flowthrough LC50 values for 24 hr were 0.72 ppb, 154.31 ppm; 967.63 ppm respectively. The fish were exposed to lethal concentrations to study the changes in hematological parameters and the rate of oxygen consumption. During the period of exposure general decline in the content of hemoglobin was observed. Methemoglobin content increased in case of nitrite exposure consequently the hemoglobin levels decreased drastically. It is also observed that rate of oxygen consumption decreased progressively with the increase of toxicant concentration and duration of the exposure.     

The toxicity of heavy metals to embryos of the American oyster Crassostrea virginica

The acute toxicity of 11 heavy metals to embryos of the American oyster Crassostrea virginica was studied and the concentrations at which 50% of the embryos did not develop were determined. The most toxic metals and their LC₅₀ values were mercury (0.0056 ppm), silver (0.0058 ppm), copper (0.103 ppm) and zinc (0.31 ppm). Those metals that were not as toxic and their LC₅₀ values were nickel (1.18 ppm), lead (2.45 ppm) and cadmium (3.80 ppm). Those metals that were relatively non-toxic and their LC₅₀ values were arsenic (7.5 ppm), chromium (10.3 ppm) and manganese (16.0 ppm). Aluminum was non-toxic at 7.5 ppm, the highest concentration tested.     

Development and growth of eggs and larvae of Mytilus edulis exposed to a linear dodecylbenzenesulphonate,LAS

The fertilization and growth of eggs and larvae of Mytilus edulis L. were studied under the influence of an important ingredient in washing powders, linear dodecylbenzenesulphonate (LAS). Observable effects occurred in concentrations as low as 0.05 ppm. The length attained by the larvae was affected even by concentrations of 0.1 ppm. The possible ecological consequences of these effects are discussed.     

Tertiary-butyl acetate metabolism,toxicity, and human health considerations

Tertiary-butyl acetate (TBAC) (CAS No. 540-88-5) is an organic solvent with a potential for occupational and environmental exposure as a result of its use in industrial coatings, adhesives, inks, and degreasers. The objective of these studies was to extend the toxicological database upon which health hazard and risk assessments of TBAC can be made. The metabolism of TBAC was studied in rats exposed by inhalation for 6?h to concentrations of 100 or 1000?ppm. There was an evidence of partial saturation of TBAC absorption and metabolism at some concentration below 1000?ppm. Approximately 5% of the low dose and 26% of the high dose was expired without change within 12?h, while the retained material was rapidly metabolised and excreted, mostly in the urine, within 24?h. Very little radioactivity remained in the tissues after day 7. The metabolism of TBAC appears to follow two major routes: hydroxylation of the tertiary-butyl moiety to form 2-hydroxymethylisopropyl acetate and ester hydrolysis to form tertiary-butyl alcohol (TBA). A minor route involves oxidation of the acetate moiety. Based on the proportion of metabolites that can clearly be assigned to one or the other major pathway, hydroxylation of the tertiary-butyl moiety prevails at 100?ppm, while hydrolysis of the ester bond predominates at 1000?ppm.

Based on nose-only inhalation exposure of rats to TBAC for 6?h, the LC50 for males and females combined is approximately 4200?ppm. Clinical signs included exaggerated breathing, staggering, tremors, and lethargy approximately 1?h after the exposure, but all surviving rats appeared normal from 24?h until the end of the 14?day observation period. An LC₅₀ was not identified for mice. After exposure of whole body for 6?h to 3000?ppm, the highest concentration tested, all mice were prostrate for most of the exposure time, but there were no deaths.

Groups of five male and five female Sprague-Dawley rats were exposed nose-only to 0, 100, 400, or 1600?ppm TBAC 6?h?day^?1 5 days?wk^?1 for 2?weeks. There were no effects on body weight, feed or water consumption, or necropsy findings. Male rats exposed to 1600?ppm had increased liver weights and hypertrophy of centrilobular hepatocytes. An increased proportion of cortical tubule cells with hyaline droplet accumulation was observed in all treated groups of males. Groups of five male and five female CD-1 mice were exposed whole body to 0, 190, 375, 750, or 1500?ppm TBAC 6?h?day^?1 for 14 consecutive days. There were no effects on body weight, feed consumption, or necropsy findings. Liver weights were increased in female mice at 750 and 1500?ppm. Minimal hypertrophy of centrilobular hepatocytes was found in female mice at 375, 750, and 1500?ppm and in male mice at 1500?ppm TBAC.

TBAC did not induce gene mutations in bacterial tests with strains of S. typhimurium and E. coli. Further, there was no evidence of clastogenic activity from tests either for the induction of chromosomal aberrations in human lymphocytes in vitro in the presence or absence of S9 mix or for the induction of micronuclei in bone marrow cells of rats exposed by inhalation for 6?h to 1600?ppm TBAC.

These results are relevant to human health risk assessment and are discussed in the context of previous studies. The weight of the scientific evidence supports the conclusion that TBAC has lower acute toxicity than previously suggested, that it is rapidly excreted when inhaled, and that neither TBAC nor its TBA metabolite are genotoxic or potential human carcinogens.     

Acute toxicity evaluation of copper,arsenic and HCH to paddy field crab,Paratelphusa hydrodromus (Herb.)

Routine static tests were conducted for determining the median lethal tolerance limit of paddy field crab, Paratelphusa hydrodromus exposed to Copper, Arsenic and HCH at different time intervals of 24, 48, 72 and 96 hour. The LC50 values for Copper came to be 28.00, 22.00, 18.20 and 15.70 ppm; Arsenic 136.00, 128.00, 121.500 and 114.00 ppm and HCH 10.00, 8.80, 7.00 and 6.00 ppm, respectively. The safe concentration, application factor and safe application rate were also calculated. They were for, Copper: 5.56, 1.59 and 3.26 ppm, Arsenic: 38.53, 11.40 and 76.00 and HCH : 4.07, 0.06 and 1.28 ppm. Animals exposed to different concentrations of test chemicals (Copper, Arsenic and HCH) showed prominent behavioural/morphological alterations viz., coughing, redness on the ventral side, paralysis and disorientation in scaphognathite activity. Animals exposed to high concentrations showed an avoidance behaviour by keeping away from the direct contact with the toxic solution either by climbing on the wall of aquarium or by mounting over the weak individual and forming a type of pyramid.     

Developmental arrest in Japanese medaka (Oryzias latipes) embryos exposed to sublethal concentrations of atrazine and arsenic trioxide

Embryos of the Japanese medaka (Oryzias latipes) were exposed to serial concentrations of atrazine (0, 25, 50, and 100 ppm) and arsenic trioxide (0, 0.025, 0.05, 0.1 ppm) until hatching. Stasis of circulation, blood islands, titanic convulsions, tube heart and mortality were observed in atrazine-treated embryos. Each endpoint exhibited a concentration-response relationship. Only 4% of the embryos hatched in the 25 ppm, and none in the 50 and 100 ppm, probably due to cell death attributed to the embryos' inability to break from the chorion. With arsenic exposure, hatching was inversely correlated to chemical concentration: 86%, 75% and 54% for 0.025, 0.05 and 0.1 ppm, respectively. Hatching periods were also reduced from 7-13 days in controls to 7-11 days in arsenic-treated embryos. This observation was more pronounced with the 0.05 ppm concentration, showing a reduction of about 4 days. Despite this shortage in hatching time, there were no observable morphological abnormalities, as seen with atrazine. The ecological significance of these findings and implications for the development of sublethal toxicity tests using Japanese medaka embryos are important.     

La对Pb伤害大豆幼苗的影响

以盆载法研究了Ｐｂ对大豆幼苗的伤害及Ｌａ对Ｐｂ伤害的生态生理效应．结果显示,１０００ｍｇＬ－１ＰｂＡｃ２能严重抑制大豆幼苗代谢与生长,叶面喷布３０ｍｇＬ－１ＬａＣｌ３１次,能减轻Ｐｂ造成的毒害．实验证明,此与Ｌａ能增加大豆幼苗光合速率,提高叶绿素含量与硝酸还原酶活性,降低细胞质膜透性与体内Ｐｂ含量,维持ＴＴＣ还原力等多种作用相关     

Toxicity of four oil dispersants to some animals from the Baltic Sea

Four oil dispersants of interest for practical use in the Baltic Sea were tested as regards toxicity to animals from the littoral zone of the same area. The dispersants tested were Corexit 7664, Berol TL-188, Berol TL-198, all water-base dispersants, and BP 1100-X, an oil-base dispersant. Two species of fish, two species of bivalves and two species of crustaceans were tested. Significant differences in toxicity were found between the water-base dispersants at concentrations above 1700 ppm. Below this concentration there were no significant differences. The dispersants contain similar surfactants in similar concentrations, but differ with respect to types and amount of solvent. The observed differences at high concentrations are, therefore, argued to be connected chiefly to differences between these solvents. Differences in toxicity to different animal types were found between the water-base dispersants and the oil-base dispersants. The toxicity of Corexit 7664 was (96h LC₅₀ approximate values): fish, 1000 ppm; bivalves, 2000 ppm; crustaceans, 10,000 ppm. The toxicity order was strikingly reversed for BP 1100-X: crustanceans, 150 ppm; bivalves, 2000 ppm; fish, 10,000 ppm. This difference in toxicity for different animal types is suggested to be connected mainly to differences in the chemical character of the outer layer of the body surface of the animals.     

Respiratory quotient and ammonia excretion in Tilapia mossambica

Tilapia mossambica (Peters), acclimated to and tested in fresh water at 30°C, maintained a routine respiratory quotient (R Q) of about unity and an ammonia quotient (A Q) (Vol. NH₂/Vol. O₂) of about 0.2 at high ambient oxygen concentrations. At low oxygen concentrations (below 2 ppm) R Q and A Q increased sharply to values of 8 and 1, respectively (at 0.6 ppm), indicating a close relationship of increase in anaerobic energy utilization and increase in protein metabolism at inadequate oxygen concentrations. T. mossambica (8 cm), exercised continuously with intervening sampling and flushing stops for 6 h, at a swimming speed of about 2 body lengths/sec, derived some anaerobic energy throughout the exercise (R Q: 1.2), utilizing more protein the longer the exercise. The coupling of the increased protein metabolism and anaerobic energy utilization may be of advantage in preventing acidosis and also in conserving sodium (Na⁺) in fish.Part of this work was included in a paper presented at the Centennial Meeting of The American Fisheries Society, September 13–16, 1970, New York.     

诺氟沙星对芽期玉米的毒性和氧化损伤研究

畜禽养殖废弃物的农田处置,使大量抗生素进入环境,从而对环境生物产生潜在危害.为了研究诺氟沙星(norfloxacin,Nor)对玉米发芽和幼苗生长的影响,采用水培发芽实验,测定了不同浓度下,诺氟沙星对玉米种子的发芽率和玉米幼苗对诺氟沙星的吸收与传输的影响;另外还研究了诺氟沙星对玉米幼苗生物量、自由基水平、丙二醛(MDA)含量、抗氧化酶活性的影响.结果显示,诺氟沙星能被玉米根吸收并传输到地上部分.0.5mg·L-1～50mg·L-1的诺氟沙星暴露均不影响玉米的发芽率.当诺氟沙星浓度大于1mg·L-1时,幼苗的生长受到抑制,其敏感指标依次为根重>根长>芽长>芽重.诺氟沙星暴露使玉米根、芽中MDA含量明显增加,玉米根中谷胱甘肽硫转移酶(GST),过氧化物酶(POD),超氧化物歧化酶(SOD)和过氧化氢酶(CAT)等抗氧化酶的活度有显著改变,这表明诺氟沙星暴露能够引起玉米体内的氧化损伤.用电子自旋共振结合二级自由基自旋捕获技术测定了玉米根中自由基水平,发现诺氟沙星能够引起玉米根中大量羟基自由基的产生,为诺氟沙星引起玉米幼苗的氧化损伤提供了直接的证据.     

Antioxidative response of Lemna polyrrhiza L. to cadmium stress

Growth, lipid peroxidation, different antioxidative enzymes and metal accumulation were studied in Lemna polyrrhiza treated with different concentrations (1-40 ppm) of CdSO4. The growth of the plant was slightly enhanced with 1 ppm, while higher concentrations retarted growth and multiplication of fronds, the effect being concentration and dose dependant. Increase in malondialdehyde content was insignificant after the first week but a prolonged exposure led to significant (p < 0.05) increase of about 38% and 45% over the control in 20 and 30 ppm, respectively after four weeks. Catalase (EC 1.11.1.6; CAT) activity increased at low concentration, but it declined to 42% and 54% at 40 ppm after 6 and 30 days, respectively Superoxide dismutase (EC 1.15.1.1; SOD), ascorbate peroxidase (EC 1.11.1.11;APx) and glutathione reductase (EC 1.6.4.2) increased at both low as well at high concentrations, but a prolonged exposure to high concentration of Cd (40 ppm) led to significant (p < 0.05) decline in the mean activities of these antioxidant enzymes. Accumulation of Cd in biomass was concentration and time dependant However at high concentration of 40 ppm, Cd accumulation did not increase significantly (p < 0.05) with time. Increased activities of antioxidant enzymes in Cd treated plants suggest that metal tolerance in L. polyrrhiza might be associated to the changes of antioxidant enzymatic activities.