Toshio Takeshita

Bioaccumulation of Arsenic by Freshwater Algae and the Application to the Removal of Inorganic Arsenic from an Aqueous Phase. Part II. By Chlorella vulgaris Isolated from Arsenic-Polluted Environment

Abstract Green algae, Chlorella vulgaris Beijerinck var. vulgaris, isolated from an arsenicpolluted environment, was examined for the effects of arsenic levels, arsenic valence, temperature, illumination intensity, phosphate levels, metabolism inhibitors, heat treatment on the growth, and arsenic bioaccumulation. The following conclusions were reached from the experimental results: (a) The growth of the cell increased with an increase of arsenic(V) levels of the medium up to 2,000 ppm, and the cell survived even at 10,000 ppm; (b) The arsenic bioaccumulation increased with an increase of the arsenic level. The maximum accumulation of arsenic was about 50,000 μg As/g dry cell; (c) The growth decreased with an increase of the arsenic(III) level and the cell was cytolyzed at levels higher than 40 ppm; (d) No arsenic(V) was bioaccumulated by a cell which had been pretreated with dinitrophenol (respiratory inhibitor) or with heat. Little effect of NaN3 (photosynthesis inhibitor) on the bioaccumulation was obse...

Synthesis of EDTA-monoalkylamide chelates and evaluation of the surface-active properties

ABSTRACTNew chelating agents were synthesized from long-chain amines and ethylenediaminetetraacetic acid (EDTA) monoanhydride which was prepared by partial hydrolysis of EDTA anhydride. The equivalent reactions between the chelating agents and several metal ions gave the corresponding 1:1 metal chelates in good yield. These chelates and the sodium salts of the chelating agents were found to have good surface active properties, especially dispersing power and emul-sifying power.

Arsenic metabolism in a freshwater food chain

Abstract Accumulation and the biotransformation of arsenic were investigated in a three-step freshwater food chain consisting of an autotroph ( Chlorella sp.), a grazer ( Moina sp.) and a carnivore ( Carassius sp.). The grazer and carnivore survived in arsenic-containing water below 3 and 25 mg As(V) L −1 , respectively. These organisms also accumulated arsenic(V) from water and methylated part of it. The arsenic-accumulation from food decreased one order of magnitude and the biomethylation of the arsenic increased, successively with an elevation in the trophic level.

Bioaccumulation of zinc and cadmium in freshwater alga, Chlorella vulgaris. Part I. Toxicity and accumulation

Abstract The essential trace metallic element, zinc, and the non-essential metal, cadmium, were investigated for toxicity and accumulation in a freshwater alga, Chlorella vulgaris , which has been isolated from natural water and which has a very large resistance to arsenic. Above 80 mg Zn L−1 in medium, the lag phase in the growth curve appeared, but the growth was recovered in a few days. Above 25 mg Cd L−1 in medium, the cells were killed. Zinc and cadmium were accumulated by the cells from the aqueous medium containing 100 and 10 mg metal L−1, to the extents of 35 × 104 mg Zn and 1.8 × 104 mg Cd kg−1 of dry cells, respectively. Accumulation of zinc by the cells was affected by NaN3 (photosynthesis inhibitor) treatment. Accumulation of cadmium was affected both by NaN3 and dinitrophenol (respiratory inhibitor). Zinc and cadmium were predominantly accumulated by biological processes and physicochemical processes, respectively.

Bioaccumulation of Arsenic by Freshwater Algae and the Application to the Removal of Inorganic Arsenic from an Aqueous Phase. Part I. Screening of Freshwater Algae Having High Resistance to Inorganic Arsenic

Abstract Several freshwater alga having resistance to arsenic were screened from microorganisms which had been sampled at sites polluted with arsenic from a geothermal electric power plant and old mines and smelters of arsenic ores. The alga thus screened could grow in the liquid medium (Modified-Detmer culture medium) containing sodium arsenate at levels up to 2000 ppm as elemental arsenic concentration. Some mixed systems of alga grew rapidly in the media at the higher levels of arsenic ranging from 50 to 2000 ppm. The mixed systems of alga screened included predominantly blue-green algae, green algae, and diatom, and also included protozoa, rotifera, and bacteria as minor components. One pure algal culture was obtained by means of an agar plate culture, and the algae isolated was identified as Chlorella vulgaris Beijerinck var. vulgaris. The growth of C. vulgaris in a pure culture was unaffected by 100 ppm of arsenic.

Bioaccumulation of zinc and cadmium in freshwater alga, Chlorella vulgaris. Part II. Association mode of the metals and cell tissue

Association mode of zinc and cadmium accumulated in Chlorella vulgaris was investigated by use of radioactive 65Zn as ZnCl2 and 115mCd as CdCl2. Whereas only 3.5% of zinc bioaccumulated by C. vulgaris was desorbed with 0.1mM EDTA when the bioaccumulation level was at 3.5 × 105 μg Zn g−1 dry weight, 81% of zinc accumulated was desorbed with 0.1mM EDTA when the bioaccumulation was at 900 μg Zn g−1 dry weight. Almost all (99.7%) of zinc accumulated was associated with the residue of solvent extraction with CHCl3CH3OH/H2O(8:4:3). Gel filtration data showed that zinc was associated with proteins of molecular weight of 6×103, and cadmium was associated with proteins of molecular weight of 6×103 and 3×104. Cysteine content in the proteins of cadmium-binding tissue was found to be approximately ten-fold higher than that of control cell. These results lead to the conclusion that metallothionein-like proteins were inductively synthesized in C. vulgaris, when the cell was exposed to cadmium and zinc.

Selective Adsorption of Arsenic(V) lon by Use of Iron(III) Hydroxide-Loaded Coral Limestone

Abstract By use of iron(III) hydroxide-loaded coral limestone (abbreviated Fe-coral) as an adsorbent, a trace level of arsenic(V) ion in aqueous solution could be efficiently and selectively adsorbed onto the adsorbent surface. The arsenic adsorptibility of the Fe-coral depended upon the amount of iron(III) hydroxide loaded on the coral limestone. The arsenic adsorption was almost unaffected by the initial pH of the solution in the pH range 2–10, and was not practically influenced by the addition of such anions as chloride, nitrate, sulfate, perchlorate, and acetate in the aqueous solution. However, only coexisting phosphate caused a great depression in the arsenic adsorption. The arsenic absorbed onto Fe-coral was hardly desorbed in contact with an aqueous solution under a wide pH range (3.5–10). The arsenic adsorption was effectively applied to a column-type operation.

EXTRACTION OF METAL-OXALATE COMPLEXES BY DICATIONIC ANION-EXCHANGE EXTRACTANTS

ABSTRACT The extraction of oxalate complexes of divalent metal ions (Zn2+, Cd2+ ) by dicationic anion-exchange extractants, polymethylenebis(trioctylphosphonium)s (abbreviated as CnBP), was studied. The shorter the length of methylene-chain connecting two cationic centers within an extractant molecule, the higher was the extractant capability, i. e., the extraction ability of extractants decreased in the order: C2- > C3- > C4- > C5- > C6- > C8- > C10- > C12BP. The entirely inverse order was obtained in the extraction of metal-halide complexes (MIICl4 2-) and metal-cyanide complexes (M II(CN) 4 2-). The extraction abilities of monocationic extractants were inferior to even that of the least efficient one among the dicationic extractants. The extraction equilibrium was also studied.

N-lauroyl-ethylenediamine chelates: Preparation and evaluation of surface tension and dispersant properties

A chelate surfactant was synthesized having a hydrophobic alkyl group and hydrophilic metal ion bonded to the former in the chelate configuration, and its properties were investigated. N-lauroyl-ethylenediamine (LEDA) was used as the hydrophobic chelating agent and salts of some transitional metals (e.g. iron, cobalt, nickel, copper and chromium) were reacted therewith. The reaction of LEDA with ferric sulfate on 1:1 equivalent reaction ratio afforded [Fe(LEDA) (H2O)4]3/2SO4. In other reactions pure chelates were not obtained, but the products showed good surface activity.

Low viscosity COM (coal oil mixture) using tall-oil as an additive

Abstract Tall oil, an inexpensive by-product from pulp manufacturing (about one-tenth of the cost to those of ordinary surfactants), was found as an effective additive for COM (coal oil mixture) to provide good stability and low viscosity. The viscosity of COM (coal concentration: 50%) was as low as 2 Pa at 70 °C after 25 day-storage by addition of only 1% of tall-oil to COM. Tall-oil supported an increase in concentration of coal from 46% to 52.5%, maintaining usable viscosity. Structural viscosity (SV) of COM was proposed by the authors and defined as follows: SV = η (2.2)− η (22); where η(2.2) and η(22) are the viscosities at low shear rate (2.2 s −1 ) and high shear rate (22 s −1 ), respectively. The SV was found to be a good parameter for predicting the sedimentation stability and the viscosity of COM after long-term storage in the case of Miike-COM.