Environmental Pollution Series B, Chemical and Physical最新文献

Levels of mercury and persistent chlorinated hydrocarbons were determined in the liver of dead birds of prey (n = 568) and owls (n = 310) collected in Norway in 1965–1983. The highest levels of mercury were found in osprey and white-tailed eagle, with median concentrations of 4·7 and 2·4 μg Hg g⁻¹ liver respectively. The levels of DDE and PCB varied considerably, the highest levels of DDE being detected in white-tailed eagle and goshawk which had a median concentration of 2·0 and 1·9 μg DDE g⁻¹ liver respectively. Highest levels of PCB were detected in osprey, gyr falcon and white-tailed eagle (5·0 μg PCB g⁻¹). With a few exceptions the levels of HCB, γ-BHC and dieldrin detected were low. Mercury and organochlorine levels were also determined in unhatched eggs (n = 159) of raptorial birds collected in the same period. The levels of mercury were, with a few exceptions, low. The highest levels of DDE were found in eggs of merlin and sparrow hawk with median concentrations of 30 and 19 μg g⁻¹ respectively, while the highest levels of PCB were found in eggs of white-tailed eagle and goshawk, with median concentrations of 13·9 and 12·3 μg PCB⁻¹, respectively. It was not possible, from the present material, to demonstrate significant changes in contaminant levels over time. Nor was it possible to detect significant geographical differences. Although a very few samples of liver and eggs contained levels of mercury or organochlorines that might be considered toxic, the greater proportion of samples contained levels far below accepted critical limits.

A study of nine different washing procedures using Alconox, HCl and Na₂ EDTA for use on Ailanthus altissima leaves in particulate pollutant analyses was conducted. Leaf mineral analyses of washed and unwashed samples were carried out for Ca, Mg, K, Na, Fe, Zn, Cu and Mn by atomic absorption spectrometry, for Cl by a specific ion electrode and for Ti by a spectrophotometric procedure. The data showed that a procedure consisting of washing by hand with 1% Alconox, followed by 0·01m Na₂ EDTA, was most effective in removing surface Fe, Cu, Zn and Ti and led to little change in leaf K or Cl.

Methodological investigations were undertaken to ascertain the appropriate length of exposure in a Scottish industrial town for the transplanted low technology samplers selected for use—spherical moss bags, the lichen Hypogymnia physodes and tak samplers.

The appropriate length of exposure for the accumulation of most metals was determined by the following criteria: detectable accumulated concentrations, reliable values (i.e. high replicability) and an exposure time within the limits of practical considerations.

Because samplers gave concentrations of most metals which were high and most replicable when exposures were between 8 and 9 weeks, an exposure of 2 months was selected for the main monitoring survey.

Soil column studies were undertaken to determine the mobility of nitrilotriacetic acid (NTA) in agricultural topsoil and its effect on the solubility of Cd, Cu, Mn, Ni, Pb and Zn following land application of sludge containing NTA. The total weight of NTA retained on the columns was >99% of that applied, with the levels of leached NTA becoming undetectable after 56 days. The presence of NTA increased the solubility of all six metals studied, although the degree of solubilisation varied with the individual metal, NTA dose and sludge application rate. Such an effect may result in greater metal mobility in sludge-amended soils, with possible changes in availability to plants and/or groundwater contamination.

A study of the chemical characteristics of wet precipitation was carried out in central Switzerland. Wet-only samples were collected weekly at three sites during 1983 and 1984. The results were examined for spatial and temporal variations in the concentrations of major cations and anions and also compared with similar results from two other Swiss stations, one in the eastern part of the country and one at an alpine location. At the sites not under the direct influence of urban emissions, concentrations of sulphate, nitrate and chloride were very similar at altitudes of 515 and 950 m above sea level. Volume-weighted average concentrations observed were lower than at most other European sites used for comparison. Between 950 and 3500 m above sea level, concentrations decreased, but much less in the case of sulphate than in the case of nitrate. At sites surrounded by agriculture, most nitrate and sulphate was associated with ammonium, and not with hydrogen, ions. Anion acids were enriched in precipitation collected downwind of urban areas. The temporal variation in the concentration of sulphate and nitrate did not depend on location. It was determined by precipitation volume and seasonal factors; for instance, the increase in air temperature in spring, which was associated with an increase in sulphate. The most acidic events occurred during spring and summer months. They were characterised by an increase in the nitric acid content. Possible relationships between the variation in precipitation acidity and meteorological conditions are discussed.

Samples of bark of 29 trees of five different species were obtained from different locations in Benin City, Nigeria, where a traffic census was also conducted. The samples were analysed for trace heavy metals, lead, zinc, cadmium and copper. Rind or skin of some fruits obtained from the trees was also analysed for the metals. Levels of lead deposits in all cases, and zinc in a number of cases, were found to vary according to traffic volume; high levels (58·3–143·5 μg g^dash1 Pb, 26·8−102·7 μg g⁻¹ Zn) were recorded for areas of very high traffic volume and low levels (15·2−15·8 μg g⁻¹ Pb, 5·8−6·9 μg g⁻¹ Zn) for areas of low traffic volume. It was found that the rougher the tree bark, the higher the deposit for each species. There was no definite correlation between traffic volume and level of cadmium and copper deposits on the tree bark.

The relations were studied between concentrations of 20 trace elements in epiphytic lichens and in the substrate (bark). The bark was separated into two fractions: a 2 mm thick outer layer and the inner layer, not exposed directly to the atmosphere. For most elements a significant correlation was found between the concentrations in the lichen and the concentrations in the outer and inner bark. In general the element concentrations in the inner bark were appreciably lower than those in the outer bark and lichen. For some elements, including Zn and Cd, the concentrations in the inner bark were relatively high, indicating that for those elements the possibility of uptake from the substrate has to be seriously considered.

About 90 Glasglow surface soil samples (0–5 cm) were subjected to a six-step sequential chemical extraction procedure designed to establish the partitioning, mobility and availability of heavy metals lead, zinc, copper and cadmium in soils from a typical contaminated urban environment. The six fractions corresponding to the selected extractants were termed exchangeable, carbonate-bound, easily reducible, moderately reducible, organic and residual. Significant features of the average partitioning patterns were the association of 32% of cadmium (for total concentrations ≥ 0·6 mg kg⁻¹) with the exchangeable + carbonate fractions, 51% of lead with the moderately reducible fraction and 41% of copper and 29% of zinc with the organic fraction. Only 17% of lead, compared with 42–46% of the other three elements, remained in the residual fraction. While total concentrations for the heavy metals suggested an order of contamination, lead > zinc > copper > cadmium, in Glasgow soils, the detailed sequential extraction data indicated an order of release or mobility of cadmium ⪢ lead > zinc > copper and an order of environmental concern, with respect to availability, of lead > cadmium > copper > zinc.

A modified version of the ATDL urban dispersion model was applied to estimate annual SO₂ and suspended particulate concentrations in the Golden Horn region of Istanbul. The emissions were categorised as area sources (residential and commercial districts or small industries) and point sources (power plants and large industries). The area sources were distributed into a 3 km square grid pattern. The concentrations predicted from the model were compared with the observed concentrations, the correlation coefficient being 0·874.

The model is used to estimate the effect of various control strategies on the reduction of SO₂ and suspended particulate levels, and the comparison of these strategies discussed.