Environmental Pollution Series B, Chemical and Physical最新文献

A sediment core from Milwaukee Harbour was dated by the Pb-210 and Cs-137 methods and analysed for polychlorinated biphenyls (PCBs). The mass sedimentation rate of 1·10 g cm⁻² year⁻¹ was significantly higher than for Lake Michigan. The Cs-137 inventory of 162·9 dpm cm⁻² was 11·7 times higher than that calculated from atmospheric deposition data. There was a significant degree of PCB pollution in the sediments, as evidenced by the fact that the PCB flux was 596 times higher than the average atmospheric input to Lake Michigan. The vertical distribution of PCBs in the relatively undisturbed core followed the available national sales records (1957–1974) remarkably well. In addition, there was a sharp drop in layers from the late 1970s which would be expected in view of the recent curtailment of PCB usage and production. Relatively high levels of Aroclor 1254 point to local electrical component manufacturers. Several users of hydraulic fluids and lubricants containing PCBs have probably also contributed to the increased levels in the harbour sediments.

A 75 litre sample of Illinois River water was taken on 6 December 1982 for comparison with deionised water to test metal toxicity to duckweed. Barium, cadmium and chromium (VI) were tested.

There were three different types of results. Ba is moderately toxic in deionised water and non-toxic in river water. Cd is extremely toxic in deionised water and also substantially toxic, though somewhat less so, in river water. Cr(VI) toxicity in river water is more or less identical to that in deionised water. These results point out the importance of natural water in regulating heavy metal toxicity.

Laboratory experiments were performed to investigate the behaviour of six phenols: 4-chloro-m-cresol, 2,4-dimethylphenol, 2,4-dinitrophenol, 4-nitrophenol, pentachlorophenol, and 2,4,6-trichlorophenol, in dolomite aquifers. The phenols are toxic, persistent in aquatic environments, and used widely in the chemical and manufacturing industry. Dolomite aquifers are common sources of water in many parts of the country.

The experimental results are that, with the exception of the chlorinated phenols, little, if any, of the phenols adsorb onto dolomite at temperatures of 5° and 22°C and at concentrations from 0·1 to 10 mg litre⁻¹. Pentachlorophenol adsorbs most strongly, with as much as 22% adsorbing from groundwater onto dolomite. No processes of phenol degradation were detected in the experiments, with some experiments lasting 21 days. Thus, phenols dispersed in an area where they can leach and contaminate dolomite groundwater aquifers would pose a threat to human health and the environment. In contrast to dolomite, chemical sorbents strongly adsorb the phenols and could be used for groundwater cleanup.

Distribution coefficients (K_d) indicate the capability of a soil to retain a solute and also the extent of its movement in a solution phase. The purpose of the study was to determine K_d values for the heavy metals Ni and Zn in soils, in order to evaluate the ability of different soils to retain the metals. Batch equilibrium experiments on Ni and Zn were conducted to obtain adsorption isotherms, K_d values and distribution curves for Ni and Zn, with six concentrations of test solutions and three soils. Ni and Zn adsorption increased significantly as the concentration of the cation increased in the test solution. The range of K_d values for Zn and Ni was 140–684 and 152–388 ml g⁻¹, respectively, for the soils investigated. The Mecklenburg clay, with high cation-exchange capacity (CEC), gave high K_d values for both Ni and Zn. There was no consistent relationship between the K_d values and soil pH and organic matter. The distribution curves for Ni and Zn showed negative correlation between solution concentration of Ni and Zn and K_d values. The results of this study indicate better retardation of Zn as compared to Ni by the soils.

This paper deals with certain physico-chemical properties of fly ash collected from a coal-fired power plant at Kanpur (26° 26′ N latitude and 80° 22′ E longitude), India. Textural analysis reveals that a major fraction of fly ash mass (65%) is composed of silt-sized particles (0·02 to 0·002 mm). Sand-sized particles (2·0 to 0·02 mm) represented 25%, while clay-sized particles (<0·002 mm) represented only 10%. The bulk density and optimum moisture content of freshly collected fly ash samples were measured, being 1·02 g cm⁻³ and 2·1%, respectively. Water extracts from fly ash were alkaline and contained excessive amounts of soluble salts.

Samples of each fraction of fly ash (sand, silt and clay) were analysed for concentrations of four macro-elements (N, P, K and Ca) and four trace elements (B, Cu, Mn and Zn). Except for N, fly ash contained higher concentrations of all elements than normally found in soil.

Shag and cormorant eggs were collected from three sites off the east, south-east and south coasts of Ireland and the pesticide and PCB levels determined by gas chromatography.

Of the pesticides, pp-DDT, pp-DDE, op-DDE, lindane, dieldrin, endrin, α-BHC, α-chlordane, oxychlordane, heptachlor, hept-epoxide and quintogen were detected, while op-DDT, op-DDD, aldrin, endosulphan-1, endosulphan-2, endosulphate, methoxychlor, β-BHC and γ-chlordane were not found. PCB levels were an order of magnitude greater than those of the pesticides, but levels of all substances were, in general, rather low, and it is concluded that organochlorine contamination is not at present a serious problem in the Irish marine environment.

There were few interspecific differences in concentrations of individual pesticides, and there was no significant difference in levels of total pesticides or total organochlorines.

In general, the highest levels were found at the site off the east coast, and there was a significant inter-site difference in total pesticides, while the difference in PCBs was very close to significance at P = 0·05.

The overall evidence suggested that these levels did not cause either lethal or sublethal (egg-shell thinning) effects.

Methodological investigations were undertaken to determine the replicability of the concentrations of metals in a number of low technology samplers. Most of these samplers were subsequently used for the main monitoring survey of atmospheric metal pollution in Armadale, an industrial town in central Scotland. The indigenous samplers included Hypnum (moss), Lecanora (lichen), Agropyron (grass) and surface soils. The transplanted samplers included spherical moss bags (acid washed), Hypogymnia (lichen) and tak (synthetic fabric). Other samplers were added for purposes of comparison: translated flat moss bags (acid washed), another two types of spherical moss bag (fresh moss and water washed), dead Hypogymnia and a fruticose lichen.

Of the low technology samplers selected for use in the main monitoring survey, all except the surface soils gave concentrations of most metals that were well within an acceptable range of variability. However, metals such as Cr and Ni, which were present in low concentrations, showed values which were significantly less replicable than those of the other metals.

Of the comparison samplers, the flat moss bags, water-washed spherical moss bags and the dead Hypogymnia gave very replicable concentrations of metals; the fresh moss bags and the fruticose lichens gave the least consistent metal values.

A marked increase in the concentration of LiCl-extractable sulphate occurred when samples of two acid brown earth soils (one from a site exposed to heavy atmospheric pollution and the other from a relatively unpolluted site) were waterlogged in the laboratory with either deionized water, dilute sulphuric acid (pH 4·0) or acid rain (pH 3·8). The greatest increases in sulphate concentration occurred in the heavily polluted soils. However, no similar increases were found when two neutral loam soils were waterlogged. The pH of the brown earths increased on waterlogging, while soil Eh fell, but only slowly. Sulphate reduction eventually occurred in the brown earths following most treatments, resulting in a decrease in sulphate concentration. No free H₂S was evolved under these conditions, however. The acid rain treatment had the same effect as dilute sulphuric acid and deionized water on sulphate transformations in these woodland soils. The increases in the concentration of LiCl-extractable sulphate which occur when brown earths are waterlogged appear to result from a combination of organic sulphur mineralisation and increased desorption of adsorbed sulphate.

Spatial and seasonal variation of lead concentrations were investigated in the Cairo atmosphere. It was found that the annual mean lead concentrations in the central and densely populated parts of Cairo exceeded the 2μm⁻³ recommended limit. In sharp contrast to data for European cities, summer lead concentrations were higher than those detected during winter. Calculated settling velocities of lead particles show that in the central urban district lead particles can stay suspended for long periods, and so are available for inhalation, as compared with particles found in the atmosphere of other parts of the city.

The lead levels in the river sediments of two small rivers draining the city of Christchurch, New Zealand, reflect nearby inputs from a lead accumulator battery factory and street dust carried into the river. The high levels found in the river sediments are not reflected in the levels in the sediments of the rivers' estuary. The lead species: PbCO₃, PbSO₄, PbS and Pb metal were found to exist in a sediment profile, the carbonate dominating near the top and sulphide near the bottom of the profile. Only a small fraction of the lead is held by sorption on to the sediments.