Environmental Pollution Series B, Chemical and Physical最新文献

The capacities of the mosses Rhacopilopsis trinitensis (C. Muell) Britt.et Dix., Stereophyllum virens Card., and Thuidium gratum (C. Muell) Jaeg. to sorb and retain Pb, Cu and Cd ions from solution were studied. All the species showed very high capacities to sorb these metal ions from single-ion as well as mixed-ion solutions. Ca and Mg ions were most readily released from the moss tissues on sorption of the metal ions. The sorbed metal ions were strongly retained in the moss tissues, but may be significantly leached out by strongly acidic solutions. The three species did not differ remarkably in their capacities to sorb and retain the metal ions.

The objective of this study was to develop a phytoassay procedure using common duckweed. The results suggest that the assay is simple, sensitive and very economical.

Those substances evaluated for relative toxicity by the phytoassay included most of the constituents listed in Illinois' general standards for water quality. Based on the duckweed assay, the maximum permissible concentrations of Ba(II), Cd(II), Fe(III), Ni(II), and Se(IV) are lower than the water quality standards. On the other hand, similar limits for B(III), Cr(VI), Cu(II), F(I), Pb(II), Mn(II), SO₄(II) and phenol are higher than those concentrations stipulated in the water quality standards. For Cl(I) and Zn(II) the limits developed by the phytoassay are equal to the standards.

The results suggest that duckweed is a promising indicator of aquatic toxicity. Duckweed assay should be further explored so that its value can be evaluated when more data are available.

Levels of four metals were measured in the shells of Elliptio complanata, collected from three localities in the Great Lakes, having widely different levels of contamination. The levels of ten metals were measured in the outermost shell and overlying periostracum, cut from each of the annual rings of two shells. Zn (unlike Pb) displayed a much greater affinity to the soft tissues than the shell. Levels of Al, Cu, Fe, Ni, Pb and Zn were significantly higher in the outer periostracum of the shell than in the inorganic prismatic shell layer. In spite of high Pb levels in industrial effluent at one of the locations, inorganic Pb was not deposited in the prismatic shell layer. Metal concentrations in the periostracum did not follow the chronological trends in the prismatic layer. Levels of Al, Fe and Mn decreased with clam age, whereas concentrations of Cu and Zn were greatest during years of fastest growth.

The amounts of zinc, cadmium, lead and copper were determined in the hepatopancreas and whole body of the woodlouse Porcellio scaber (Crustacea, Isopoda) and soil and leaf litter collected from 89 sites in the counties of Avon and Somerset, south-west England. Maps were drawn to compare the regional distribution of concentrations of metals in the samples.

The main source of zinc, cadmium, lead and copper pollution was centred on Avonmouth to the north-west of Bristol, the site of a primary zinc, lead and cadmium smelting works. Concentrations of all four metals in the hepatopancreas, whole woodlice, soil and leaf litter were above background levels over a large area on all maps which, in the case of cadmium in the hepatopancreas, extended for 25 km to the east of the smelting works.

The correlation coefficients between the concentrations of each metal in woodlice and soil, and between woodlice and leaf litter, were positive and statistically significant (P < 0·001) in all cases. At individual sites, however, particularly those associated with disused mining areas, rubbish tips or busy roads, the concentrations of zinc, cadmium, lead and copper in woodlice could not have been predicted accurately from the levels of metals in leaf litter or soil due to the large scatter of data points along the lines of ‘best fit’.

Future exercises in pollution monitoring should include analysis of at least one representative of the primary consumers of vegetation to enable the ‘availability’ of metals to the fauna to be reliably assessed. Porcellio scaber is probably the ideal ‘indicator species’ in the UK because it has a strong affinity for zinc, cadmium, lead and copper, is large enough to provide sufficient tissue for analysis, and is common in a wide range of rural and urban habitats.

Analysis of cedar bark samples and deposition samples in the Nagatsuta area, Yokohama, Japan, shows that there is contamination by heavy metals, Cr, Zn, Cu and Pb, as indicated by enrichment factor values, particularly in the parts adjacent to the highway. It is suggested that motor traffic is the major source. The soil is enriched with respect to these heavy metals by a factor of 2 to 361. It is suggested that this contamination occurs primarily by aerial deposition. A correlation between heavy metal levels and distance from the road was established and a power regression analysis, ln Y = a + B ln X, gave a fit(p < 0.001) indicating an exponential decay function.

The accumulated levels of the metals, Pb, Cd, Cu, Ni, Zn, Mn and Fe were determined in forest mosses from south-west Nigeria. Distinct gradients were observed only with Pb and Zn, and a small zone of random contamination with Cu was identified in parts of the east and the south-east. This contamination was possibly a result of the use of copper-based fungicides and pesticides in cocoa farms in the area.

The levels of the metals are compared with those in forest mosses in some other parts of the world.

This study reports an investigation into fluvial contamination by the Cwm Rheidol ZnPb mine near Aberystwyth, Wales. This mine was last worked at the end of the last century, but acidic drainage waters are still a major source of water-borne contamination to the River Rheidol, despite the installation of a static treatment plant below the mine over twenty years ago.

Acidity in the main discharge stream often approaches pH 3, causing the precipitation of hydrated ferric oxides and subsequent sorption of metals along its length. The concentrations and movement of Ag and other metals (Cd, Cu, Pb and Zn) before and after treatment are reported.

The fate of these metals after discharge into the River Rheidol was also studied, using a sequential extraction procedure performed on the sediments. Much of the discharged Cd remained ‘easily or freely leachable and exchangeable’ (Badri & Aston, 1983), non-lithogenic forms (i.e. not bound in the mineral lattice) of Ag and Cu were released from sediments by oxidation, while Cd and Zn were solubilised predominantly by an acid-reduction extraction. Studies of the distribution and partitioning of metals in sediments at and near the mine suggest similarities in the behaviour of Zn and Cd and of Ag, Cu and Pb. However, the data indicate that caution should be exercised when interpreting the chemical partitioning of elements solubilised by so-called ‘selective’ extractants.

The shellfish Chione (Austrovenus) stutchburyi has been studied as a bio-indicator for lead in an estuarine environment near Christchurch, New Zealand. Over four years the mean lead level in the soft tissue was 1·16 μg g⁻¹. The levels responded to significant rainfall events in the catchment area. Over the four years a fall in lead levels corresponded to reduced lead inputs into a river feeding the estuary. In addition to climatic and lead source changes, seasonal effects and shell size also need to be considered, as lead levels fall in the early summer and are elevated in small shellfish. The use of the shell as a bio-indicator for lead necessitates sectional and surface shell analysis rather than whole shell analysis. Both shell age and depth into the shell are variables that associate with lead.

Dutch sparrowhawk populations were seriously affected by organochlorines during the 1960s. In particular, the role of DDE in suppressing the reproductive output has been often stressed, an effect which was said to prevent sparrowhawk populations from recovering, even after bans on the use of most organochlorines had been enacted.

In the present study residue levels of DDE in eggs were monitored over the period 1975-83, during which time most sparrowhawk populations recovered. Fresh eggs were sampled in three study areas and the contents were analysed for organochlorine compounds.

Since DDE affects egg shells, Ratcliffe indices for shell thickness were measured. Egg breakage frequency was recorded from 1970 to 1983.

From 1975 to 1983 no significant trend in DDE residues, nor in egg-shell thickness, is apparent. The decline in the proportion of clutches with broken eggs suggests a decrease in contamination levels during the early 1970s.

Several causes of the continuing contamination are discussed. DDE is a very persistent compound, and it is likely that considerable amounts are still to be found in the soil and, therefore, in the food chain of the sparrowhawk.