Rapid flameless atomic absorption analysis of the metallic content of sewage sludges I. Lead,cadmium and copper

The application of flameless atomic absorption analysis to the determination of cadmium, copper and lead in sewage sludges is described. The technique is sensitive and very rapid, since the normal lengthy sample pre-treatment has been virtually eliminated. The method can be potentially extended to a large range of metals in all types of sludges.     

Rapid flameless atomic absorption analysis of the metallic content of sewage sludges II. Chromium,nickel and zinc

The development of a new rapid flameless atomic absorption procedure for the analysis of chromium, nickel and zinc in sewage sludges is described. The technique has previously been found suitable for the analysis of lead, cadmium and copper. Sample preparation has been minimised and multi-elemental analysis of a single sample is possible.     

Flameless atomic absorption analyses of mercury in model aquatic systems

Chemical models of freshwater and seawater (34‰ S) have been used to examine the effect of humic material on the analysis of mercury by flameless atomic absorption spectrometry. Solutions containing mercuric chloride (1 μg Hg 1⁻¹) and various concentrations of humic material were allowed to attain equilibrium under carefully controlled conditions. In both media, association between the inorganic and organic entities took place within 90 min at pH ≥ 7 and the organically bound mercury was not detected by an analytical method designed for inorganic mercury. The amount of detectable mercury was related to the quantity of humic material added to the solutions.In experiments involving changes of pH the model solutions showed three characteristics: (1) a flat response in the neutral and alkaline pH range, where the humates are apparently stable; (2) a minima in the pH range 2–4 where the formation of an acid flocculent appears to remove additional mercury from solution: (3) at pH = 1, some release of mercury occurs from the organic precipitate.Photolysis studies using the model freshwater solutions showed that total mercury measurements could be made after 2 h irradiation at pH = 1. Using the same technique methylmercury chloride and diphenylmercury decomposed within 1 h. These results are relevant to routine and analyses of total mercury in natural waters.     

Electrochemical speciation of trace metals in sea water

Various approaches, such as bioassays, computer-assisted modelling and direct measurement following physical separation are currently being used to investigate the speciation of trace metals in sea water. The electrochemical techniques used successfully as a necessary prerequisite for the experiments involved include conventional polarography, anodic stripping voltammetry (ASV) and potentiometry. Differential pulse anodic stripping voltammetry (DPASV) using mercury film electrodes enables direct studies in ultratrace levels present in non-contaminated ocean waters.By varying the conditions of the sample chemistry and electroanalysis it is possible to characterize metal-organic interactions. This is demonstrated in the case of natural sea water samples subjected to ASV diagnosis. Differences in the Pb and Cu values yielded for Baltic waters by two methods based on DPASV and AAS are discussed with regard to speciation.An analysis of the existing literature is used to briefly summarize the needs of future research. Important problems requiring a more precise quantitative analysis include the adsorption of organics on electrodes and the kinetics and thermodynamic constants of chelates with special regard to the physico-chemical nature of metal-humic substances. The introduction of new and improved electroanalytical techniques and equipment for speciation studies is strongly recommended.     

Movement of heavy metals into a shallow aquifer by leakage from sewage oxidation ponds

The concentrations of Mn, Ni, Cu, Cd and Cr were measured in a shallow perched groundwater aquifer which underlies the Dan Region Sewage Reclamation Project (Israel). The contribution of effluents to the groundwaters has been evaluated on the basis of chloride concentration. Groundwater which are estimated to contain more than 60% effluents showed a hundred-fold decrease in Cu and Mn at a distance of 650 m away from the ponds, as compared with the near ponds samples. Ni and Cd showed only a small decrease in concentration over a distance of 150 m, and then stayed constant. The concentrations of Cu and particularly of Mn in the groundwaters near the oxidation ponds is equivalent to or greater than in the ponds themselves. It is suggested that Cu and Mn are mobilized from the precipitated sludge into the interstitial waters. They percolate into the groundwater near the ponds and then are precipitated by increasing aeration during the movement of the water away from the pond area. Cd and Ni form stable soluble organic chelates which are only slightly removed by interaction with the sandy soil of the aquifer.     

Equilibrium chemical modelling of heavy metals in activated sludge

A chemical speciation distribution model of heavy metals, previously developed by Nelson et al. (J. Wat. Pollut. Control Fed. 53, 1323, 1981), was applied to cadmium in activated sludge from a full-scale wastewater treatment plant. In the model, cadmium adsorption to bacterial solids was quantified by the determination of conditional formation constants based on TOC. Adsorption of cadmium strongly pH-dependent. Soluble cadmium speciation was dominated by the free cadmium ion below pH 6, by cadmium-organic ligand complexation at pH 6 and 7 and by inorganic species at pH 8 and 9. Cadmium adsorbed by bacterial solids increased greatly with pH from near 30% at pH 4 to near 90% at pH 9. Cadmium speciation and distribution was also modelled in an indifferent electrolyte suspension of bacterial solids and in activated sludge using adsorption constants from the indifferent electrolyte medium.     

DNA damage by benzo[a]pyrene in the liver of mosquito fish Gambusia affinis

Exposure of Gambusia affinis to water containing different concentrations of benzo[a]pyrene (BaP) causes an increase in benzo[a]pyrene monooxygenase (BPMO) activity which reaches a maximum on the second day. Concomitantly, the DNA is altered in such a way that nuclease S1-sensitive sites (SSS) become measurable. The size distribution of liver DNA treated with nuclease S1 in control fish shows two populations of DNA by length, with means of 30 X 10(6) and 60 X 10(6) Daltons, respectively. In fish treated with 100 ppb BaP, the population with longer molecules of DNA disappears and shorter molecules increase in number. This may be explained in terms of the introduction of an additional 0.31-0.46 DNA nicks per control DNA molecule caused by metabolically activated BaP derivatives.     

Activity of benzo[a]pyrene monooxygenase in fish from the Sava River, Yugoslavia: correlation with pollution

Benzo[a]pyrene monooxygenase (B[a]PMO) activity in non-migratory fish from a given river segment is highly correlated to the recent pollutional history of that part of the river. The enzyme activity level can serve as a relevant measure for the harmful pollutant potential in aquatic ecosystems. Caged experimental fish exposed for about 10 days in river segments show BaPMO activity changes with the same predictive validity as that of the natural population.     

Determination of methyl chrysenes in a coal liquefaction product

Analysis of carcinogenic methyl chrysenes in a complex sample matrix requires a combination of liquid-liquid partition and column chromatography to obtain a chrysene subfraction. Analytically interfering alkyl benzanthracenes are removed by a combination of a selective Diels-Alder reaction and column chromatography. Application to a coal-liquefaction product revealed 98 ppm of chrysene and 106 ppm of 3-methyl, 102 ppm of the 2-methyl, 64 ppm of the 6-methyl, and possibly 19 ppm of the 4- plus 5-methyl chrysenes.     

The balance of heavy metals through a sewage treatment works I. Lead,cadmium and copper

Concentrations of lead, cadmium and copper have been determined in the sewage sludges, sewages and effluent of a sewage treatment works. Treatment at this works is by primary sedimentation prior to biological treatment in a diffused air activated sludge plant. By analysis of composite samples corresponding to a 24-h input of raw sewage to the works, a mass balance of metals through the works has been estimated. The partition of the metals from raw sewage into the settled sewage and primary sludge, and from the settled sewage into the activated sludge and final effluent has been quantified.     

Reductions in inactivation rates of bacteriophages by clay minerals in lake water

Differences were noted in the rate of inactivation of bacteriophages in natural lake water, with the sequence of lability being φ11M15 of Staphylococcus aureus RN450, Qβ of Escherichia coli K-38 > 80α of S. aureus RN450 > P1 of E. coli B > T1 of E. coli B. The survival of φ11M15 in lake water was unaffected by autoclaving, filtration, or amendment with particulate humic acids or heat-killed cells of Erwinia herbicola, Sarcina lutea, and Saccharomyces cerevisiae. However, in the presence of attapulgite and vermiculite and, to a lesser extent, montmorillonite and kaolinite, the rate of inactivation of φ11M15 in natural, autoclaved, or filtered lake water was greatly reduced.     

The balance of heavy metals through a sewage treatment works II. Chromium,nickel and zinc

Concentrations of chromium, nickel and zinc have been determined in the sewage sludges, sewages and effluent of a sewage-treatment works. Treatment at this works is by primary sedimentation prior to biological treatment in a diffused air activated sludge plant. By analysis of composite samples corresponding to a 24-h input of raw sewage to the works, a mass balance of these metals through the works has been estimated. The partition of these metals from raw sewage into settled sewage and primary sludge, and from the settled sewage into the activated sludge and final effluent has been quantified.     

Nitrosamines in tap water after concentration by a carbonaceous adsorbent

Ambersorb XE-340 carbonaceous adsorbent removed trace levels of volatile nitrosamines (NAs) that were added to the influent water. Recovery of seven added NAs was between 58–99% as determined by a gas-liquid chromatograph interfaced with a Thermal Energy Analyzer (GLC-TEA). When municipal (tap) water (10–42 l.) was passed through the Ambersorb XE-340 column. N-nitrosodimethylamine (NDMA; 0.003–0.006 μg 1⁻¹) and -morpholine (NMOR; 0.006–0.018 μg 1⁻¹) were the principal NAs found. All of the NDMA and 18 of 20 NMOR samples were confirmed by high resolution mass spectrometry. Secondary amines added to tap water at levels of 1 mg 1⁻¹ and 10 μg 1⁻¹ formed apparent NAs, suggesting a possible component(s) in the water that caused NA formation. Low levels of volatile NAs were detected by GLC-TEA in commercial, pure, adsorbents (activated carbon). NAs were confirmed by high resolution mass spectrometry except where concentrations were too low. In the latter case, the apparent NAs were found to be photolabile when subjected to u.v. light (365 nm) and were reanalyzed by GLC-TEA thus providing additional evidence that the TEA responsive compounds were NAs.     

Natural and acquired resistance of mice to infection by airborne Klebsiella pneumoniae after subchronic intoxication by cadmium administered orally

Mice daily ingested about 22 mg of cadmium per kg of body weight in drinking water for 30 days. On the 30th day, the liver and kidneys of the mice contained about 18 μg of Cd²⁺ perg of fresh organ. A group of these mice was immunized against Klebsiella pneumoniae using two injections of vaccine, the first on the 7th day and the second on the 14th day of intoxication. On the 28th day, the non-immunized and the immunized mice were infected via a respiratory route by one lethal dose 50% of K. pneumoniae (the LD₅₀ for the immunized mice was 2.4 times higher than the LD₅₀ for the non-immunized mice). Comparison with the non-intoxicated control mice showed that the ingestion of Cd²⁺ did not significantly modify the natural resistance or the acquired resistance of the mice to the infection by airborne K. pneumoniae.     

A rapid routine method for quantitative determination of benzo(a)pyrene in water by low-temperature spectrofluorimetry

Some limitations of the analytical method for the determination of polynuclear aromatic hydrocarbons (PAH) in water have led the authors to study the quantitative application of low-temperature spectrofluorimetry as a rapid routine method for the screening of benzo(a)pyrene (BaP) in the aquatic environment. Experiments on the technique of recovery of BaP from distilled water samples utilizing liquid-liquid extraction have given good results; trials concerned with evaluation of any quenching effects on BaP by other PAH and with the applicability to real water samples (river, rain and drinking waters) have shown the promise of this method for screening analysis of environmental waters. The reproducibility of the method is adequate and the required time of total analysis is very short, especially for drinking water samples.     

The effects of pH and suspended solids in the removal of organics from waters and wastewaters by the activated carbon adsorption process

The effects of pH, inorganic suspended solids and organic suspended solids on the adsorption of organics by activated carbon were investigated using sewage effluents and selected organic compounds of varying size, structure, molecular weight and properties in model solutions. It was found that suspended solids, and in particular organic suspended solids, could interfere with the adsorption process, both in terms of adsorption capacity and adsorption rate; the effect of the solids diminished as the size of the adsorbate increased. The effect of pH variation became more significant as the acidity or basicity of the adsorbate in solution increased. Adsorption of organics from biologically treated sewage effluents was somewhat more effective in the acid and alkaline pH regions than in the neutral pH region.     

Characterization of trace metal species and measurement of trace metal stability constants by electrochemical techniques

Differential pulse polarography and differential pulse anodic stripping voltammetry were used to determine copper, lead, cadmium and zinc complexes of relevance to environmental conditions. The dependency of peak current on pH and alkalinity was interpreted in terms of the variation in the metal species present. Stability constants of copper and lead complexes with carbonate were determined from the magnitude of the shift of peak potential using the method of Lingane. Inclusion of the transfer coefficient, calculated from the peak half-width for electrochemically irreversible systems, was used to determine the stability constant. By using both electroanalytical techniques, the investigator validates the correctness of his results without needing to rely on prior determinations of the stability constant for verification.     

Interaction and mobility of cobalt-60 between water and sediments in marine environments possible effects by acid rain

In Japan, all nuclear power stations have been constructed facing sea-shores and the operating radioactive wastes have been either stored at the sites or discharged into marine environments, if permissible. The purpose of this investigation was to understand the behavior of a radioactive cobalt (⁶⁰Co), one of the typical radionuclides produced by operating nuclear reactors, in marine environments, namely cobalt interaction between water and sediments. Great emphasis was focused on demonstrating a quantitative difference in behavior of cobalt between marine and freshwater environments.Under natural conditions, cobalt remained in the water phase in marine environments more than 5 times as much as in freshwater environments. In freshwater, most cobalt (over 95%) is absorbed by and permanently retained within bed sediments under the normal environmental conditions. However, in marine environments cobalt gains mobility. Furthermore, this mobility of cobalt once established did not diminish nor disappear when surrounding conditions were changed.In short, cobalt in marine environments is generally mobile. This considerable mobility was greatly influenced by the environmental factors: (e.g. pH, the redox potential, the ionic strength, the type of sediments and the length of reaction time) but, it was primarily determined by the initial environmental conditions. The result of this experiment suggests that the treatment and the storage of radioactive cobalt waste should be done in freshwater environments rather than in a marine environment if we try to reduce the mobility. Because the mobility depends on pH, acid rain is, therefore, to be expected to strongly influence the mobility of ⁶⁰Co in aquatic environments.     

The distribution and origin of mutagens in airborne particulates, detected by the salmonella/microsome assay in relation to levels of lead, vanadium and PAH

At three stations in central Copenhagen, Denmark, samples of particulate matter were collected simultaneously with different contributions from automobile exhaust products. Samples were obtained at street level, 22 m above street level and within a hospital zone; 32 samples were analysed for levels of polycyclic aromatic hydrocarbons (PAH) and elements, as well as for mutagenicity towards S. typhimurium TA1538. Two classes of mutagens were quantified: a non-polar extract rich in PAH and, other promutagens, and a polar extract containing direct acting mutagens (not requiring microsomal activation). Covariances between lead and mutagenicity, and the varying distribution of the polar and non-polar mutagens at the stations, indicate that at all stations the mutagenicity of the non-polar extract is dominated by automobile exhaust products. The polar extract is relatively less influenced by primary traffic emissions; a considerable part of the activity of this extract is attributed to secondary emissions, transformed by atmospheric reactions, and primary emissions from stationary sources.