Lead,cadmium, and arsenic residues in animal tissues in relation to those in their surrounding habitat

The relationships of the residues of lead, cadmium, and arsenic in animal tissues to those in surrounding vegetation and soil were determined in a natural habitat representing a wide range of such residues. The samples studied were selected from 18 different locations. Analyses were performed on a total of 113 animals, 332 plant specimens (representing 33 species), and 408 soil samples (taken at different depths). For the purpose of evaluating relationships, the samples from each location were averaged and reported as parts per million on a dry weight basis. The average lead residues from different locations ranged from 1.4–9.2 ppm in the liver, 45–195 in bones, 4–283 in vegetation, and 15–1399 in soil samples. The cadmium contents ranged from 1–27 ppm in the liver, 3–77 in bones, 0.5–5 in vegetation, and 1–10 in soil. The arsenic contents in different components of the ecosystem varied with an average of 1–9 ppm in liver, 0.6–94 in vegetation, and 7–655 in soil samples. The soil residues varied considerably according to the depth of sampling. Little variation was noted in different species of vegetation or in soil and vegetation samples according to the time and year of sampling.Statistical analyses performed on the averages indicated a significant correlation between vegetation and soil residues for all three elements, and also between animal to vegetation and animal to soil cadmium residues. Multiple linear correlations for all elements in soil, vegetation, and animal tissues were determined. The results indicated a possibility of an increase in cadmium in animal tissues depending upon the increased residues of this metal in the environment.     

The effect of temperature on the removal of non-ionic surfactants during small-scale activated-sludge sewage treatment—I. Comparison of alcohol ethoxylates with a branched-chain alkyl phenol ethoxylate

The degree of biodegradability of three non-ionic surfactants has been assessed using small-scale activated-sludge sewage treatment plants. The effect of temperature on biodegradability was studied by operation at 15°, 11° and 8°C.The two alcohol ethoxylate surfactants tested were well degraded at all three operating temperatures. The alkyl phenol ethoxylate surfactant tested was well degraded at 15°C but at lower temperatures the biodegradability was dependent on concentration. At 5 mg 1⁻¹, greater than 90 per cent removal was achieved but at 20 mg 1⁻¹ the degree of removal fluctuated between 40 and 95 per cent at 11°C and between 20 and 80 per cent at 8°C.The present results have been compared with those obtained using the same surfactants in community trials at a small sewage works employing biological filtration. Although a similar temperature effect was observed with the alkyl phenol ethoxylate, the biodegradabilities obtained in the laboratory were consistently greater than those obtained at the sewage works, perhaps because of the constant conditions of the laboratory test.     

Interstitial inorganic phosphorus concentrations in lakes Mendota and Wingra

Interstitial P levels in Lake Mendota and Lake Wingra were evaluated as a function of season and water column and sediment depth. Interstitial water was obtained by the centrifugation-filtration method. Temporal variations were observed over the entire 15 cm sediment depth interval examined in all four locations evaluated. Interstitial reactive P (IRP) levels in Lake Mendota ranged from 0.014–1.67 mg l⁻¹ at the 5–6 m water column depth and from 1.20–5.75 mg l⁻¹ at the 18–19.5 m depth. IRP levels in Lake Wingra ranged from 0.029–2.15 mg l⁻¹ at 3.5 m and from 0.191–3.96 mg l⁻¹ at 2 m. Variations in interstitial P were attributed to variations in oxidation state of Fe as influenced by oxygen transport and reduction rates.     

Oscillations of Foundations Installed on the Ground and Cast-in-Place Piles Subject to Kinematic Effects

Results are presented for experimental investigations on the traffic-induced oscillations of two full-scale foundations of a metallic tunnel, one of which is installed directly on the ground, and the other on cast-in-place piles. The foundations are close to one another with respect to mass and the load applied to them. Differences are revealed between the parameters of the actual oscillations of these foundations and their computed values.     

Features of disinfection kinetics of water containing <Emphasis Type="Italic">Escherichia Coli</Emphasis> in conditions of hydrodynamic cavitation

The paper has investigated the disinfecting effect of hydrodynamic cavitation on the microorganisms of E. coli in water. It has been found that disinfection kinetics depend on the intensity of the hydrodynamic cavitation field, the microbial load, and gas content. We have studied structure and morphology variation of the E. coli bacteria. It has been demonstrated that the antimicrobial effect is achieved owing to the physicochemical effects of the cavitation field, under whose influence there occurs mechanical destruction of cells and chemical disinfection by the radicals of hydroxyl and hydrogen peroxide.     

Sorption of phosphorous to Filtralite-P--the effect of different scales

Sorption of P to the filter material Filtralite-P was examined at a small, medium and large scale. In the small- and meso-scale laboratory models, the sorbed amount of total phosphorus (P) was heterogeneously distributed with more P sorbed in the inlet zone and the bottom layers. The full-scale system had, on the other hand, the highest sorbed concentration in the outlet region. The overall P sorption capacity of the material was 8030, 4990 and 521 mg P kg(-1) Filtralite-P for Box 1, Box 2 and meso scale, respectively. This equals 4.4, 2.8 and 0.29 kg P m(-3) material, respectively. However, the maximum sorption capacities found were 2500, 3887 and 4500 mg P kg(-1) Filtralite-P for the two small-scale box systems and the meso-scale container, respectively. In the full-scale system the overall P sorption capacity of the material was 52 mg P kg(-1) Filtralite-P (0.029 kg P m(-3) Filtralite-P with a maximum sorbed amount of P of 249 mg P kg(-1). Results from both the small- and meso-scale system show that when a constructed wetland (CW) is saturated, i.e. when the outlet concentration has reached its maximum allowed concentration of 1.0 mg P l(-1), only parts of the filter material will have reached the sorption capacity. Sequential extractions of Filtralite-P showed that the loosely bound P, Ca-P and Al-P were the primary P sorption pools both in the small-scale models and in the full-scale CW. However, the proportion of these three fractions varied with time and change in pH. A white product precipitated in the outlet zone of both the small-scale box models as well as the onsite CW. The surface of these precipitation particles was identified by X-ray diffraction and SEM method as CaCO3 and precipitated Ca- and Mg-phosphates.     

Effects of adding organic materials to an acid sulfate soil on the growth of cocoa (Theobroma cacao L.) seedlings

Acid sulfate soils having a pH of less than 3.5 are widespread in Malaysia. Some of these soils are planted to cocoa, but the yield is reported to be low due to soil infertility related to Al toxicity. Cocoa growth is sensitive to the presence of Al in the soil. To a certain extent, Al toxicity in soils can be reduced by organic matter application and to a greater extent in iron-poor acid sulfate soil. A study was conducted to determine the efficacy of various types of organic materials easily available in the country to ameliorate acid sulfate soil infertility for growing cocoa seedlings. The treatments were control (nil), lime (3 t/ha), peat (10% w/w), peat plus green manure (10% w/w), peat plus rice straw (10% w/w), peat plus chicken dung (10% w/w) and peat plus POMS (Palm oil mill sludge) (10% w/w). The growth of cocoa seedlings was affected significantly by the presence of Al in the cocoa tissues. As the amount of Al in the leaves increased, the relative top dry weight of cocoa seedlings decreased. Likewise, the relative plant height was negatively correlated with Al in the leaves. Peat as well as peat in combination with green manure, rice straw, chicken dung or palm oil mill sludge was able to reduce Al toxicity in acid sulfate soil; the highest top dry weight of cocoa seedlings were obtained in the peat plus green manure treatment. The best cocoa seedlings root growth was found for the peat treatment alone. The relative top dry weight of cocoa seedlings was negatively correlated with Al(3+) as well as Al(3+)+Al(OH)(2+)+Al(OH)(2)(+) activity in the soil solution. The critical values for Al(3+) and the combination of Al(3+)+Al(OH)(2+)+Al(OH)(2)(+) activity in the soil solution were 10 microM and 15 microM, respectively.     

The collapse of welded aluminium plate girders—an experimental study

Twenty-two tests conducted to study the collapse behaviour of welded aluminium girders are described. The girders are of varying proportions, have transverse or longitudinal web stiffeners and are subjected to different combinations of shear and bending loads. It is observed that, although shear sway mechanisms similar to those for steel girders do develop, the webs of aluminium girders may fracture in the heat affected zones adjacent to the perimeter welds. These fractures develop at some stage during the formation of the collapse mechanism and are the consequence, rather than the cause, of failure. It is shown that the tension field theory, originally developed for steel girders, may overestimate the shear-carrying capacity of aluminium girders and it is concluded that the theory requires some modification before it can be applied with confidence to aluminium girders.