Prediction of ecotoxicological behaviour of chemicals: Relationship between physico-chemical properties and bioaccumulation of organic chemicals in the mussel Mytilus edulis

The analysis presented in this paper shows that water solubility as well as the n-octanol/water partition coefficient are useful indicators of the tendency of organic chemicals to bioaccumulate. It is suggested that these physico-chemical data be used as screening test for organic chemical bioaccumulation in aquatic organisms, such as the mussel $\text{Mytilus edulis}$.     

The effects of organic environmental chemicals on the growth of the alga Scenedesmus subspicatus: A contribution to environmental biology

The effective concentrations of 15 chemicals, inhibiting the cell growth of the alga $\text{Scenedesmus subspicatus}$ by 10 % and 50 % during 96 hours, have been investigated in a static test under controlled laboratory conditions.     

Uptake and bioaccumulation of three PCBs by Chlorellafusca

This paper reports the bioaccumulation of three PCBs (2,4′-dichlorobiphenyl, 2,4,6,2′-tetrachlorobiphenyl and 2,4,6,2′,4′-pentachlorobiphenyl) by the green alga $\text{Chlorella}$$\text{fusca}$ under various conditions. A probable pattern of the bioconcentration mechanism is suggested. No metabolites were extracted from algae or water 6 days after incubation with PCBs.     

Bioaccumulation of pentachlorophenol by killifish (Fundulussimilus)

Killifish ($\text{Fundulus}$$\text{similis}$) were exposed in the laboratory to pentachlorophenol (PCP) at concentrations of 57 to 610 μg PCP/L. Bioaccumulation reached a plateau value of about 53 by 168 hrs and remained at this level for at least 72 hrs. One-half the plateau value was reached in about 25 hrs. Following exposure, fish placed in PCP-free aquaria lost PCP rather slowly ($\text{t}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{～ 4.7}\text{days}$). The depuration data were suggestive of a pool of PCP which was lost more rapidly ($\text{t}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{～ 4.2}\text{hrs}$). The results of this study are compared to similar studies in other species. The bioaccumulation factors measured in this study agree relatively well with those in other marine species, but are lower than reported for fresh water species. Possible reasons for this difference are discussed.     

Effects of selected pesticides on Rhizobiummeliloti, and on seed germination and Verticillium wilt pathogens of alfalfa

Studies on the effects of 21 fungicides and five pyrethroid insecticides on growth of $\text{Rhizobium}$$\text{meliloti}$, emergence and survival of alfalfa seed and the efficacy of the chemicals in control of Verticillium wilt pathogens were conducted.     

Effects of some pesticides on Rhizobiomjaponicum and on the seed germination and pathogens of soybean

The relative toxicity of 23 pesticides, including 21 fungicides and two pyrethroid insecticides, on $\text{Rhizobium}$$\text{japonicum}$, four soybean pathogens, $\text{Fusarium}$$\text{oxysporum}$, $\text{Phytophthora}$$\text{megasperma}$, $\text{Phytophthora}$$\text{parasitica}$ and $\text{Pythium}$$\text{ultimum}$, and germination of soybean seeds was compared with a highly toxic broad spectrum germicide, HgCl₂ under laboratory conditions.     

Effect of fungicidal seed treatments on alfalfa growth and nodulation by Rhizobiummeliloti

A study of the effect of 5 fungicide seed treatments on alfalfa ($\text{Medicago}$$\text{sativa}$ L. var. Vernal) growth and nodulation by $\text{Rhizobium}$$\text{meliloti}$ 102F66 was conducted in a growth chamber. Captan, maneb and thiram exhibited greater toxicity to $\text{R}$. $\text{meliloti}$ and alfalfa plants than that of benomyl and zineb. Recovery of the inhibitory effect was rapid.     

Biotransformation of N-phenyl-β-naphthylamine to β-naphthylamine in a laboratory sludge system

$\text{N}$-Phenyl-$\text{β}$-naphthylamine, a widely used rubber antioxidant and antiozonant, was biotransformed into $\text{β}$-naphthylamine, a potent carcinogen, in a laboratory sewage sludge system. $\text{β}$-Naphthylamine appeared to accumulate in the aqueous phase of the system while the undegraded parent compound appeared to be associated with the sludge solids.     

Interaction of higher marine fungi with the herbicide atrazine. III. Adsorption of atrazine to the marine fungus Dendryphiellasalina

The adsorption of the herbicide ¹⁴C-atrazine to the marine fungus $\text{Dendryphiella}$$\text{salina}$ was studied using sodium azide as an inhibitor of active uptake. Adsorption of atrazine (94 ppb) was found to reach equilibrium within six hours. Adsorption as a function of concentration (9.4 to 468 ppb) conformed to the empirically derived Freundlich equation giving a K value of 6.2. Atrazine on the fungal cell surface was easily desorbed by successive artificial seawater washes indicating a relatively loose binding. The ability of the marine fungus $\text{D.}$$\text{salina}$ to remove ¹⁴C-atrazine from an artificial seawater medium suggests an environmental role in the transport and redistribution of atrazine in estuaries.     

Metabolites of diisopropylnaphthalene in carp Part 2. Invitro experiment

This study described an $\text{in}$$\text{vitro}$ experiment on biotransformation of 2,6-DIPN in carp hepatopancreas. It has already been revealed by the previous $\text{in}$$\text{vivo}$ studies to be metabolized with enzymatic oxidation in the liver and been postulated a metabolic pathway. These results were confirmed by means of incubation with 2,6-DIPN in carp hepatic microsome preparation with NADPH, and G-6-P as co-factor. It was suggested that DIPN may be mainly metabolized in the hepatic cytochrome P-450 in the microsomes system. The kinetic parameters i.e. apparent Michaelis constant (Km) and maximum velocity (Vmax), in the metabolites formation were also calculated.     

Chlordane compounds residues in Weddell seals (Leptonychotesweddelli) from the Antarctic

Weddell seal samples taken from the Antarctic have been found to be contaminated with chlordane compounds. ΣChlordane ($\text{cis}\text{-chlordane}\text{+}\text{cis}\text{-nonachlor}\text{+}\text{trans}\text{-nonachlor}\text{+}\text{oxychlordane}$) was present in blubber of seals at the range of 12 - 62 ng/g fresh weight. The order of chlordane compound concentrations was $\text{trans}\text{-nonachlor}\text{>}\text{oxychlordane}\text{>}\text{cis}\text{-nonachlor}\text{>}\text{cis}\text{-chlordane}$. Relative aboundance of $\text{cis}$-chlordane in Σchlordane is higher than that in humans. A probable explanation for their occurrence in the Antarctic is an airborne transport.     

The effect of cadmium ion on the growth,photosynthesis, and nitrogenase activity of Anabaenainaequalis

The growth of $\text{Anabaena}$$\text{inaequalis}$ was significantly inhibited by Cd²⁺ concentrations greater than 0.02 ppm (μg/ml) and completely inhibited at 0.06 ppm (Day 12). Cadmium had no significant effect upon the lag phase of growth or the culture doubling time, but caused the retardation phase to arrive sooner. One ppm Cd²⁺ significantly inhibited the rates of both photosynthesis and acetylene reduction, by $\text{A}$. $\text{inaequalis}$, with complete inhibition at 4 and 20 ppm respectively. Cell sensitivity increased directly with exposure time. Cadmium caused some cell lysis of $\text{A}$. $\text{inaequalis}$ and induced an increase in filament length, heterocyst frequency, and a loss of cellular contents from filament apical cells. The cellular abnormalities observed and the fact that toxicity increased with longer exposure times, suggested that metal toxicity resulted from effects of Cd²⁺ taken up by cells rather than Cd²⁺ at the cell surface.     

Effect of cadmium and zinc on intestinal absorption of xylose and tryptophan in the fresh water teleost fish, Heteropneustesfossilis

The effect of cadmium and of zinc on the rate of uptake of a pentose sugar xylose and an aminoacid tryptophan by the intestine of a teleost fish, $\text{Heteropneustes}$$\text{fossilis}$ was studied under two experimental conditions. In the first, four concentrations of cadmium or zinc (1.0 mM, 0.1 mM, 0.01 mM and 0.001 mM) mixed with the nutrient solution were filled in the intestinal sacs, and the rate of absorption was recorded after 1 h at 23°C. In the second experiment fish were exposed by bath to a sublethal concentration of cadmium (0.26 mg/1) or zinc (4 mg/1) for 15 and 30 days and the rate of absorption of the two nutrients was measured. The activity of intestinal Na⁺, K⁺ activated adenosine triphosphatase was also assayed. The two heavy metals at all the four concentrations decreased the rate of intestinal transport of nutrients. Increase in the concentration of each of the heavy metals decreased the uptake of nutrients, but the decreases were not linear. The rate of intestinal absorption of the two nutrients was also reduced by exposure of fish to the heavy metals $\text{in}$$\text{vivo}$. The activity of Na⁺, K⁺ ATPase decreased $\text{in}$$\text{vitro}$ with all four concentrations of cadmium and zinc and was diminished in fish exposed for 15 and 30 days. Of the two heavy metals, cadmium was more effective in reducing the rate of transport of xylose and tryptophan.     

Accumulation of bis(tributyltin) oxide by the mud crab, Rhithropanopeusharrisii

Accumulation of ¹⁴C labelled bis(tributyltin) oxide (TBTO) by the mud crab, $\text{Rhithropanopeus}$$\text{harrisii}$, was determined through short-term exposure to labelled water and food. The potential for trophic accumulation during chronic low level exposure is emphasized.     

Environmental photochemistry of PCDDs. Part I. Kinetics and quantum yields of the photodegration of 1,2,3,4,7-penta- and 1,2,3,4,7,8-hexachlorodibenzo-p-dixin in aqueous acetontrile

For the determination of the quantum yields of 1,2,3,4,7-pentachlorodibenzo-$\text{p}$-dioxin ($\text{1}$) and 1,2,3,4,7,8-hexachlorodibenzo-$\text{p}$-dioxin ($\text{2}$), ten Pyrex glass photochemical cells were constructed and their correction factors determined. Quantum yields at 313 nm for $\text{1}$ and $\text{2}$ in aqueous acetonitrile (4:6 v/v) were (9.781 ± 2.376) 10^?5 and (1.096 ± 0.020) × 10^?4, respectively. These quantum yields and the measured absorption spectra were used to estimate the environmental phototransformation first-order rate constants and photochemical half-lives of $\text{1}$ and $\text{2}$ in water under conditions of variable sunlight intensity during various seasons from solar intensity data available in the literature. In summer, typical half-lives for the phototransformation of $\text{1}$ and $\text{2}$, respectively, near the surface of water bodies at 40° north latitude would be 364 ± 88 and 151 ± 3 h; whilst such values in winter would be 1257 ± 309 and 518 ± 10 h.     

Enumeration of 2,4-D-degrading microorganisms in soils and crop plant rhizospheres using indicator media; high populations associated with sugarcane (Saccharum officinarum)

Population of microorganisms able to degrade 2,4-D (2,4-dichlorophenoxyacetate) were estimated in 4 non-rhizosphere and 5 rhizosphere soils in Natal by a most probable number (MPN) method using 2,4-D-bromocresol purple media to show 2,4-D degradation with the formation of HC1. Confirmation of herbicide degradation in acid 2,4-D tubes was required by subculturing into fresh 2,4-D-and control indicator media. The MPN estimates of 2,4-D-degrading organisms per g of corresponding rhizosphere/control soils were 6100/212 with African clover ($\text{Trifolium africanum}$ L.) soils, and $\text{46400}\text{178}$, $\text{156000}\text{1480}$ and $\text{40700}\text{6170}$ with sugarcane ($\text{Saccharum officinarum}$ L.) soils. The high, stimulated populations of 2,4-D-degrading microorganisms in the sugarcane rhizospheres suggest the possibility of rapid degradaton in the rhizosphere as an additional mechanism for the protection of certain plants against soil-applied herbicides.     

Heavy metal pollution from a point source demonstrated by means of mussels, Mytilusedulis

Heavy metal pollution from a point source has been demonstrated by the levels of mercury in flesh of mussels, $\text{Mytilus}$$\text{edulis}$.     

The possibility of the use of nitrogenous wastewaters as a medium for Stichococcus bacillaris

The possibility of the use of nitrogenous wastewaters as a medium for $\text{Stichococcus bacillaris}$ was investigated. The strain grew equally well in nitrogenous wastewaters as in synthetic medium and its productivity was affected mainly by concentration of ammonium nitrogen. The obtained results suggest that nitrogenous wastewaters could be used for large-scale cultures of $\text{S. bacillaris}$.     

Environmentally-induced cadmium tolerance in the grass Holcuslanatus L.

This paper reports results of a study on cadmium tolerance in the grass $\text{Holcus}$$\text{lanatus}$ which suggest that tolerance is inducible and can be lost in transplanting plants to uncontaminated soils.