Regulatory influence of light and temperature on petroleum toxicity to Anabaena doliolum

Effects of light and temperature, the most important variables in natural environments, on the toxicity of Assam crude oil extract were examined. Illumination of oil extract increased the degree of inhibition of growth, photosynthesis, and respiration of Anabaena doliolum. Higher light intensities were more effective in inhibiting the test organism. This may result from the formation of highly toxic photooxidation products. The toxicity of oil extract also showed an increase with increase in temperature, even though it might be envisioned that elevated temperature would facilitate the loss of highly toxic volatile fractions. It is possible, therefore, that the toxic effects of petroleum might be more severe in tropical than in temperate climates.     

Toxicity to mice and sheep of a bloom of the cyanobacterium (blue-green alga) Anabaena circinalis

A bloom of Anabaena circinalis shown to be lethal to mice (i.p. LD50 17.0 +/- 0.6 mg/kg) was tested for lethal potency when given orally to mice and intraruminally and intraperitoneally to sheep. The lethal oral dose in mice was at least 170 times the parenteral dose. The bloom was lethal when given i.p. to sheep but lethality was not observed when given intraruminally in doses up to 1710 mg/kg, equivalent to drinking 8.5 litres of thick algal bloom, a volume far in excess of that likely to be consumed naturally. In vivo testing of lethal potency by i.p. inoculation of mice is therefore an unreliable method for judging potential oral toxicity in livestock of blooms of Anabaena.     

Growth and heavy metals removal efficiency of Nostoc muscorum and Anabaena subcylindrica in sewage and industrial wastewater effluents

The growth of Nostoc muscorum and Anabaena subcylindrica in sterilized sewage wastewater and N. muscorum in sterilized wastewater of El-Soda Company was higher than those grown in Allen synthetic medium. Whereas, the growth of A. subcylindrica in El-Soda Company sterilized wastewater and N. muscorum as well as A. subcylindrica grown in Verta Company sterilized wastewater was slightly lower than that grown in the standard synthetic medium. The contents of chlorophyll a, carotenoids and protein of N. muscorum and A. subcylindrica grown in sterilized sewage wastewater were higher than those grown in the standard medium. Similarly, N. muscorum and the bio-mixture of N. muscorum and A. subcylindrica grown in the sterilized wastewater of El-Soda Company showed high pigments and protein contents more than those reared in Allen medium. On the other hand, the bio-mixture of N. muscorum and A. subcylindrica grown in the sterilized sewage wastewater, A. subcylindrica grown in El-Soda Company and Verta Company sterilized wastewater showed lower contents of pigments and protein compared to synthetic medium. Heavy metals, copper, cobalt, lead and manganese were removed by 12.5-81.8, 11.8-33.7, 26.4-100 and 32.7-100%, respectively, from wastewater by using cyanobacterial cultures. The metal sorption efficiency depended on the type of biosorbent, the physiological state of the cells, availability of heavy metal, concentration of heavy metal and chemical composition of wastewater. It was observed also that the single cultures in most cases was better than the mixed cultures in heavy metal removal, this may be due to the cyanobacterial competition for nutrients in mixed cultures.     

Effects of heavy metals on corticosteroid production in cultured rat adrenocortical cells

Application of 10(-4) M Zn, 10(-5) M Ba, 10(-6) M Se, 10(-6) M Cd, 10(-6) M Hg, and 10(-6) M Mn did not affect the adrenocorticotrophic hormone (ACTH)-induced steroid production in cultured adrenocortical cells. The application of 10(-5) M Pb significantly reduced the ACTH-induced steroid production in cultured cells. However, Pb did not reduce the steroidogenesis induced by dibutyryl cyclic AMP (Dbc-AMP), suggesting that the plasma membrane is the site where Pb interferes with steroid production. The morphological changes induced by the addition of ACTH or Dbc-AMP plus the test metals were similar to those induced by ACTH or Dbc-AMP alone.     

The pharmacology of anatoxin-a(s), a neurotoxin produced by the freshwater cyanobacterium Anabaena flos-aquae NRC 525-17

N. A. Mahmood and W. W. Carmichael. The pharmacology of anatoxin-a(s), a neurotoxin produced by the freshwater cyanobacterium Anabaena flos-aquae NRC 525-17. Toxicon24, 425 – 434, 1986. — Anatoxin-a(s) [antx-a(s)] is produced by Anabaena flos-aquae clone NRC 525-17 and is different from anatoxin-a, a known depolarizing agent produced by A. flos-aquae NRC 44-1. Purification of antx-a(s) from lyophilized cells involved extraction with 1.0 M acetic acid: ethanol (80:20), column chromatography (Sephadex G-15 and CM-Sephadex C-25) and high performance liquid chromatography. Purified toxin has an ld₅₀ (i.p., mouse) of approximately 50 μg/kg. Gross pharmacological tests of antx-a(s) on isolated chick biventer cervicis and frog rectus abdominis muscles showed no direct agonistic effect. Instead, antx-a(s) augments the acetylcholine response and antagonizes the actions of d-tubocurarine. Twitch potentiation and tetanic fade were observed on isolated rat phrenic nerve - diaphragm muscle when stimulated indirectly at different frequencies. In acute toxicity tests with mice and rats the signs of poisoning were indicative of excessive cholinergic stimulation. Mice pretreated with atropine sulfate showed longer survival times and no parasympathomimetic signs of toxicity. The mice still died of respiratory arrest with convulsions, which indicated that toxicity is due to more than just the peripheral muscarinic action of antx-a(s). Assays of serum cholinesterase of rats in acute toxicity tests showed complete inactivation of the enzyme at doses of 350 and 600 μg/kg. It was concluded that antx-a(s) may be acting as an anticholinesterase, thereby causing toxicity.     

关于含矿物中成药中总重金属和酸可溶性重金属含量的比较研究

目的：研究比较含矿物中成药中总重金属和酸可溶性重金属的含量。方法：选用3种含矿物药的中成药，用电感耦合等离子体质谱法在1350W功率下，以全定量模式进行了含量测定。结果：同批样品中酸可溶性重金属含量低于其所含的总重金属含量。结论：酸可溶性重金属含量限度可作为药物质控指标之一。     

黄芪中重金属超临界CO_2净化技术研究

目的利用超临界CO2 萃取技术净化黄芪中重金属。方法a 以二乙基二硫代氨基甲酸钠(DDTC)为金属络合剂 ,用超临界流体萃取技术净化药材中的重金属 ,并对萃取方案进行最优化。b 选择不同的混酸消化液完全消解药材后 ,以空气 乙炔火焰AAS法和氢化物发生AAS法分别测定其中的铅 (Pb)、镉 (Cd) ,以及砷 (As)、汞 (Hg)。c 采用UCTRONVX -ODS(2 5 0mm×4 6mm ,5 μm)色谱柱 ,以乙腈 水 (V∶V =30∶70 )为流动相 ,检测波长为 2 0 3nm ,卡马西平为内标 ,测定黄芪中黄芪甲苷的含量。结果与结论a 确定了药材中重金属的最佳萃取条件。在最佳萃取条件下 ,重金属净化率达到 85 %以上 ;同时 ,中药材中的有效成分损失低于 5 %。b 建立了药材中金属元素和有效成分的含量测定方法 ,为正确评价中药材的质量奠定了基础 ,可用于正确评价净化前后药材的质量变化     

Effects of heavy metals on water hyacinths (Eichhornia crassipes (Mart.) Solms)

Water hyacinths (Eichhornia crassipes (Mart.) Solms) were exposed for 6 wk to solutions containing 0–5 mg/1 Ph, Cd or Cu. The metal concentrations and metal accumulations within plant tissues increased linearly with solution concentration in the order leaves < stems < roots. The order of increasing mobility at solution concentrations ≥ 1.0 mg/l was Pb < Cu < Cd. There was no apparent effect of Pb on plant growth, but both Cd and Cu were toxic and caused substantial reductions in growth. The threshold toxicity of Cd was approximately 0.5 mg/l, whereas that for Cu was between 1.0 and 2.0 mg/l. Concentrations of Cd and Cu beyond the threshold toxicity produced chlorosis, suppressed development of new roots, and reduced relative growth rates to about ten percent of those of either the controls or plants exposed to Pb. These studies indicate that caution should be exercised when using results of short-term laboratory studies in combination with data on biomass production under optimum field conditions to predict the ability of plants to absorb toxic substances from waste water.     

Effects of industrial effluents,heavy metals,and organic solvents on mallard embryo development

Mallard eggs were externally exposed at 3 and 8 days of incubation to 7 different industrial effluents and to 7 different heavy metal, organic solvent, and petroleum solutions to screen for potential embryo-toxic effects. This route of exposure was chosen in order to simulate the transfer of pollutant from the plumage of aquatic birds to their eggs. Five of the effluents including mineral pigment, scouring effluent, sludge, and tannery effluent resulted in small but significant reductions in embryonic growth. Treatment with methyl mercury chloride solution of 50 ppm (Hg) impaired embryonic growth but much higher concentrations were required to affect survival and cause teratogenic effects. Oil used to suppress road dust was the most toxic of the pollutants tested and only 0.5 $\text{μl}\text{egg}$ caused 60% mortality by 18 days of development.These findings, in combination with other studies suggest that petroleum pollutants, or effluents in combination with petroleum, may pose a hazard to birds' eggs when exposure is by this route.     

A review of the effects of heavy metals on freshwater mussels

The widespread recent decline in the species diversity and population density of freshwater mussels in North America may be partly related to chronic, low-level exposure to toxic metals. As benthic filter-feeding organisms, freshwater mussels are exposed to metals that are dissolved in water, associated with suspended particles and deposited in bottom sediments. Thus, freshwater mussels can bioaccumulate certain metals to concentrations that greatly exceed those dissolved in water. In adult mussels, the most common site of metal uptake is the gill, followed by the mantle and the kidney. The toxic effects of metals on freshwater mussels have been examined in a few acute toxicity tests, but the sublethal effects of long-term exposure to low environmental concentrations are little understood. Sublethal exposure to metals can alter growth, filtration efficiency, enzyme activity and behaviour. Sublethal effects are frequently observed at concentrations that are only half the lethal concentrations. However, few toxicity tests have used environmentally realistic exposure concentrations. Total concentrations of Cd, Cu, Hg and Zn in many oxic surface waters are in the ngl^-1 range, yet many toxicity studies have exposed mussels to concentrations in the gl^-1 or even the mgl^-1 range. An understanding of the processes by which metals affect freshwater mussels would provide insights on the ecotoxicological significance of metal contamination to natural mussel populations and aid in the development of water-quality criteria that adequately protect mussels.     

Cyanobacteria as a biosorbent of heavy metals in sewage water

The effect of sewage water on some physiological activities of cyanobacteria was studied. Metal-tolerant cyanobacterium (Nostoc linckia) and metal-sensitive (Nostoc rivularis) were grown at three levels of sewage water (25, 50 and 75%). The growth rate showed significant stimulation in low and moderate levels (50% for N. linckia and 25% for N. rivularis). Not only the number of cells was elevated but also, the time required to reach the exponential and the stationary phases was reduced. Also, low levels of sewage water increased chl.a content, photosynthetic O(2)-evolution, respiration and protein content. Similarly, heterocyst frequency as well as nitrogenase activity were increased in cyanobacteria grown at low and moderate levels (25 and 50% sewage). On the other hand, the high level of waste (75%) reduced growth and metabolic activities of the two species. N. linckia accumulated about 30-fold of Zn and ten-fold of Cd than those of growth medium (50% sewage water). Also, N. rivularis accumulated about ten-fold of Zn and two-fold of Cd. The distribution of Cd and Zn in cells were investigated. About 65-60% of Cd or Zn were found in pellets (sediment) as insoluble form in the two species. The soluble form (cytosolic fraction) after being fractionated on sephadex G-(75-100) revealed two peaks with molecular weights of 70-75 and 40-45 kDa. These peaks were in coincidence with Cd and Zn maxima. Nostoc rivulais showed more sensitivity to heavy metals than N. linckia, and accumulated less amount of metal-binding proteins. Nostoc linckia seems to be tolerant to heavy metals (Zn and Cd) and is able to accumulate this metal by adsorption on the pellets (cell surface) and/or through sequestration via metal-binding protein. Therefore it can be recommended it to be employed in the purification of waste contaminated with these heavy metals.     

Effects of heavy metals on alpha-fetoprotein in maternal sera and amniotic fluid of pregnant mice.

This report describes the effects of low levels of copper, nickel and lead salts on the concentrations of alpha-fetoprotein (AFP) in the sera and amniotic fluid of pregnant Nylar mice. During the early and mid-gestation (9-17 days), pregnant mice were injected intraperitoneally twice with heavy-metal salt solutions and were autopsied two days following the second injection. Maternal sera and amniotic fluid (AF) were collected and AFP levels were quantified by radial immunodiffusion. Metal levels determined by X-ray fluorescence spectroscopy in individual samples confirmed the presence of trace metals in the fetus. Low doses of nickel and copper were associated with elevated AFP levels in amniotic fluid in 15-17 day pregnant animals, while maternal serum AFP levels mostly remained unchanged. Decreased concentrations of maternal serum AFP occurred with increased doses of copper and lead in contrast to elevated concentrations of AFP in amniotic fluid. Furthermore, there was an increase in fetal wastage when higher doses of copper and lead were administered. A reduction of secondary litter size (F1 generation) with low dosage levels of lead was also observed. These results imply that the fetal-maternal transfer of AFP may either be impaired or reflect increased leakage or decreased placental permeability in the presence of sublethal doses of copper and lead. These findings suggest that the parallel measurements of AFP concentrations in sera and amniotic fluid might be employed for assessment of embryo- and fetotoxicity when heavy metal intake is suspected during pregnancy.     

The effect of heavy metals on vitamin A metabolism

Three kinds of divalent ions were injected subcutaneously to rats. Copper at the total dose of 6.2 mg/kg and zinc at the total dose of 12.6 mg/kg did not alter the plasma or liver vitamin A (VA) concentrations. The liver concentration of both had returned to control levels by 2 weeks after the final injection. Cadmium, at the total dose of 6.2 mg/kg, decreased significantly the plasma level of VA, although the liver VA content was not affected. This effect persisted till 2 weeks after the final injection.     

Impact of heavy metals and PCBs on marine picoplankton

Synergistic/antagonistic effects of multiple contaminants in marine environments are almost completely unexplored. In the present study, we investigated the effects of heavy metals (Zn and Pb) and PCBs on picoplankton abundance, biomass, cell size distribution, and bacterial C production. Natural picoplankton assemblages were exposed to heavy metals (Zn or Pb), organic contaminants (PCBs, Aroclor 1260), and to a mixture of different contaminants. The results of the present study indicate that Zn addition stimulated heterotrophic growth, whereas Pb has a negative impact on heterotrophic picoplankton, particularly significant in the first 24 h. Heavy metals had no effects on the autotrophic component. The addition of Aroclor 1260 had a significant impact on abundance, biomass, and cell size of autotrophic and heterotrophic picoplankton, and reduced significantly bacterial secondary production. Three weeks after PCB treatment, heterotrophic bacteria displayed a clear resilience, both in terms of abundance and biomass, reaching values comparable to those of the controls, but not in terms of bacterial C production. Our results indicate that picoplankton can be sensitive indicators of impact determined by heavy metals and PCBs in coastal marine systems.     

The evolution of the pharmacopoeial test for heavy metals

This article describes some recent improvements to simplify the test for heavy metals, avoiding loss of analytes and increasing sensitivity.     

Integrated approach to assessing the effects of soils polluted with heavy metals on a plant population

This study addresses the effects of soil polluted with more than one heavy metal in a grass species. A 16-week bioassay with Avena sativa L. was conducted in microcosms using soils from two abandoned mines in central Spain that contained levels above World Health Organization (WHO) reference limits for soils of more than three heavy metals. Pollution effects were examined at cell, tissue, organ, plant and population levels. For this purpose, dry weight, maximum height and number of leaves were determined; leaf tissues were observed by low temperature scanning electron microscopy; the metal contents of roots and shoots were determined by plasma emission spectroscopy and their distribution in different tissues was analyzed by X-ray microanalysis using an environmental scanning electron microscope. The results explain the accumulation and translocation of soil metals by this plant species; their effects in cells, tissues and growth of plants; and allow inference on population effects. The discussion of the methodological approach leads us to propose a valid protocol to assess the effects of a set of heavy metals present in the topsoil of polluted sites on a plant population. We recommend its use for an ecotoxicological diagnosis and risk analysis of similarly polluted sites.     

Cytogenetic investigations on leucocytes of cattle intoxicated with heavy metals

After an intoxication of cattle with heavy metals, resulting in the death of 6 animals, cytogenetic investigations were performed on 9 survivors. A few chromatid and chromosome breaks, one disturbance of spiralization and one cell with 3 X-chromosomes were observed in the survivors but, in general, the chromatid and chromosome aberrations recorded were essentially of the same type in controls and in intoxicated cows.     

冬虫夏草重金属化学形态的研究

目的:研究铅、砷、汞、镉4种重金属在冬虫夏草中存在的化学形态。方法:通过逐步提取法来分析冬虫夏草中铅、砷、汞、镉的化学形态。结果:化学形态分析结果表明Pb以盐酸提取态为主;As主要以残渣形式存在,其次是乙醇提取态和去离子水提取态;Hg基本为残渣态;Cd含量很低,且主要是氯化钠提取态。结论:冬虫夏草中4种重金属的主要存在形态有很大的差异。