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.     

Effect of methyl mercuric chloride treatment on haematological characteristics and erythrocyte morphology of Swiss mice

Effects of methyl mercuric chloride (MMC) on the blood parameters of Swiss mice (Mus musculus) were studied. The mice received an initial dose of MMC (24 mg kg(-1) body wt) as intraperitoneal injection followed by a second similar dose on the 14th day of the first dose administration. Significant (p < or = 0.001) decreases in haemoglobin content, red blood cell (RBC) count and haematocrit value were observed in the MMC injected mice when compared to the control mice. The effect of the second dose was severe, after which no significant recovery in the values of these parameters was observed. The result also showed a high degree of mercury accumulation in the blood of the MMC exposed mice. Interesting features were marked in the erythrocyte morphology of the exposed mice. An initial shrinkage followed by swelling of the cells was observed after each injection. The outline of the exposed cells was irregular with beak like or small finger like projections. Rupturing and disintegration of the erythrocyte membrane, leading to erythrolysis, were also noticed.     

Dry aerial fallout of organochlorine insecticide residues in Delhi, India

Monitoring of airborne dust in Delhi during May to July 1985 revealed residues of DDT varying from 1.3 to 7.14 ng mg(-1) (4.06-22.31 ng m(-2) day(-1)) with an average of 3.32 ng mg(-1) (10.38 ng m(-2) day(-1)), and HCH which ranged from 0.46 to 2.35 ng mg(-1) (1.44-7.34 ng m(-2) day(-1)) with a mean of 1.16 ng mg(-1) (3.63 ng m(-2) day(-1)). The concentration of total DDT was almost 3 times greater than that of HCH.     

Reversibility of stemflow-induced soil acidification in Swedish beech forest

Stemwater running down the trunks of beech (Fagus sylvatica L.) has an acidifying effect on soil near the stem. The deposition of acidifying substances may be two to four times higher close to the stem compared to in the stand in general. To study reversibility of soil acidification, 72 stumps of beech trees were chosen from five different year classes of felling (3, 6, 9, 14-15, 25-30), representing the years when stemflow ceased to affect the soil. The H(+) concentration (pH KCl) in the topsoil (0-5 cm) differed between the distances 10-30 cm and 230-250 cm from the stumps, the soil close to the stem being more acid. The longer the time since felling the smaller the differences in H(+) concentration became. This reduction in soil acidity amounted to ca. 50% after 15 years, and only small further changes occurred over the next ten years. This indicates that soil may not recover fully from acidification, or does so at a rather slow rate after the initial 15 years of recovery.     

Impact of repeated application on the binding and persistence of [14C]-DDT and [14C]-HCH in a tropical soil

An Indian sandy loam soil was initially treated with 1 kg a.i. ha(-1) of either [(14)C]-p,p'-DDT or [(14)C]-gamma-HCH during winter. DDT concentration after 30 days declined to 75.3%, which included 2.1% soil-bound residues. After 150 days, DDT levels further decreased to 42.4% with a concomitant increase in bound residues amounting to 5.9%. Identical treatment with HCH caused the residue levels to be reduced to 67.4 and 23.6%, after 30 and 150 days, respectively. During this period, the soil-bound residues of HCH increased from 5.2 to 12.8%. Repeat application to pre-treated soils in summer and subsequent field exposure for 30 days reduced the concentration of DDT to 52.1% and that of HCH to 42.4% of the total concentration following the second treatment. In parallel control experiments, which received only a single treatment, DDT levels declined to 61.3%, while HCH slumped to 45.3%, indicating a slower dissipation rate than in the corresponding repeated treatments. In repeat experiments, the soil-bound residues of DDT and HCH showed only a 1.07 to 1.08-fold increase in 30 days, as compared to three to ten-times increase in the control experiments. The results amply demonstrate that pre-treatment of tropical soils with DDT or HCH enhances their rate of dissipation and significantly reduce the formation of their soil-bound residues.     

Toxicological evaluation of sulfur-containing metabolites of 2,5,2′,5′-tetrachlorobiphenyl in rats

Sulfur-containing metabolites of 2,5,2′,5′-tetrachlorobiphenyl (TCB), 4-methylthio-TCB (MT-TCB), 4-methylsulfoxyl TCB (MSX-TCB) and 4-methylsulfonyl TCB (MS-TCB) were examined for their acute toxicities, hepatic enzyme inducing activities, accumulation in the liver and lung, and excretion to the feces in rats. TCB and MT-TCB suppressed body weight and recovery of body weight gain was delayed in the MT-TCB-treated rats. MT-TCB and MS-TCB caused an increase in total liver lipid and only MT-TCB brought about an atrophy of the thymus. Treatment with MT-TCB increased cytochrome P-450 content and benzphetamine N-demethylase activity. The same enzymes were also induced by treatment with MSX-TCB. Although TCB administered was excreted mostly as hydroxylated TCB, a part was excreted as unchanged and a very small portion as the sulfur-containing metabolites. MT-TCB, MSX-TCB and MS-TCB were excreted from the MT-TCB- and MSX-TCB-treated rats. The MS-TCB-treated rats excreted only MS-TCB. The same compounds as found in the feces were identified in the liver and lung of the rats treated with those compounds except in the liver of TCB-treated rats. These results indicate that sulfur-containing metabolites, especially MT-TCB, were more important than their parent compound, TCB, from a toxicological point of view.     

Comparison of two methods for the determination of total organic halogen (TOX) in receiving waters

Two methods for the determination of total organic halogen (TOX), orginating from bleaching of pulp, in receiving waters have been compared. One of the methods (AC/MC) is based on adsorption of the halogenated matter onto an activated carbon sorbent. The halogen is determined by a microcoulometric technique after combustion of the carbon. The other method (XAD/PT) uses an XAD resin as sorbent and the determination of the halogen is carried out by potentiometric titration after a schöniger combustion of the resin eluate.Both methods showed good performance for samples consisting of spent bleach liquors diluted with distilled, fresh and brackish water. The repeatability was very good with a relative standard deviation less than a few per cent. The detection limit of the AC/MC method is about 0.1 μmol/1 and for the XAD/PT method about ten times higher. The AC/MC method gave in most cases 10–20% higher TOX concentrations compared to the XAD/PT method.     

Chemical fractionation and heavy metal accumulation in the plant of Sesamum indicum (L.) var. T55 grown on soil amended with tannery sludge: Selection of single extractants

A pot experiment was carried out to study the single and sequential extractions of metals in different tannery sludge amendment and the potential of the plant of Sesamum indicum L. var. T55 (sesame) for the removal of metals from tannery waste contaminated site. The metal extraction efficiency obtained with each extractants was slightly different and follow the order; EDTA>DTPA>NH(4)NO(3)>NaNO(3)>CaCl(2). The correlation analysis between extractable metals in the different amendments of sludge and metal accumulation in the plant (lower and upper parts) showed better correlation for most of the tested metals with EDTA extraction. In this study, a sequential extraction technique was applied on different amendments of tannery sludge. The results showed that Mn, Zn, Cr and Cd were mostly associated with Fe-Mn oxide fraction in most of the amendments, K and Ni was found in residual (RES) fraction, Fe and Cu was bound with organic matter (OM) and RES fractions and Na was associated with carbonate (CAR) fraction. The metal accumulation after 60 d of growth of the plant was found in the order of K>Na>Fe>Zn>Cr>Mn>Cu>Pb>Ni>Cd and its translocation was found less in upper part. The accumulation of toxic metals (Cr, Ni and Cd) in the plants was found to increase with increase in sludge ratio, in contrast, the accumulation of Pb decreased. In view of growth parameters and metal accumulation in the plant, it was observed that lower amendments (25%) of tannery sludge were found suitable for the phytoremediation of most of the studied metals.