Environmental Pollution Series A, Ecological and Biological最新文献

The effect of monocrotophos and quinalphos, applied at rates ranging from 0·5 to 5 kg ha⁻¹, on algal populations was determined in a soil by following the mean probable number (MPN) method. Single or two successive additions of monocrotrophos to the soil had no inhibitory effect on the algal flora. Only two successive additions of quinalphos, even at close to field application rates (0·5 to 2 kg ha⁻¹), were significantly toxic to the algae, but not a single application.

The Upper Medway Estuary is considered as the narrow, funnel-shaped channel from the tidal limit at Allington downstream to Lower Upnor. Mathematical models are used to predict the depletion of dissolved oxygen resulting from organic waste inputs to the upper estuary. Surveys of the soft sediment fauna together with sediment redox potentials, organic carbon and cellulose content showed that conditions were generally poor and that faunal diversity was low, although a few surviving oligochaetes proliferated in the absence of predation and competition, with numbers in excess of 1·0 × 10⁶ individuals per m² of sediment being recorded. The bottom sediments were relatively mobile, although a combination of sediment organic content and redox potential profiles clearly demonstrated the occurrence of reduced sediment conditions at depths below 6 cm at some sites in the upper estuary, with the greatest effect at sites downstream of the paper mill discharges. A significant reduction in the amount of organic waste discharged to the upper estuary should increase faunal diversity, although high species richness is considered unlikely given the naturally harsh conditions.

During exposure of the freshwater fish, tilapia, Oreochromis (Sarotherodon) mossambicus, to heavy metals (mercury and copper), organochlorine insecticides (DDT and endosulfan) and aromatic hydrocarbons (napthalene and phenol) for up to 96 h, the lethal concentrations of all pollutants caused a substantial loss of liver and muscle glycogen. This was accompanied by a considerable rise in the plasma glucose levels. Although the sublethal concentrations generally failed to affect the tissue glycogen levels, the stress produced hyperglycaemia, especially towards the end of the exposure period. The most extensive effects were produced by the aromatic hydrocarbons which, at their lethal concentrations, also caused a reduction in the liver weight by 96 h exposure.

The quantitative differences in effects of the three types of pollutants are discussed in relation to differences in the capacity of fish tissues to metabolise these hazardous chemicals and also the physical activity responses of the stressed fish.

The relationships between levels of several biomolecules and survival and reproduction were investigated in Daphnia magna exposed for 21 days to chlordecone concentrations ranging from zero to 60 μg litre⁻¹. Biomolecules, which included total protein, ribonucleic acid, deoxyribonucleic acid, adenosine diphosphate and adenosine triphosphate, were monitored on days 7 and 21. The highest no observable effect concentration (NOEC) based on survival and reproduction was 11·2 μg litre⁻¹ chlordecone. Although the level of each biomolecule per individual daphnid was decreased in a concentration-dependent manner by exposure to chlordecone, protein was most sensitive and had the same NOEC as survival and reproduction. The relative sensitivity of these three parameters when expressed as percent of control was survival > reproduction > protein. RNA/DNA and ADP/ATP ratios were not significantly affected by chlordecone exposure; however, ratios of protein/RNA/DNA and ATP/DNA were significantly increased in daphnia exposed to 48·4 μg litre⁻¹ chlordecone.

Little dose-response information exists on the effects of chronic ozone (O₃) and intermittent sulphur dioxide (SO₂) exposures on the yield of important agricultural crops. Such information is needed for the refinement of estimates of air pollution-induced crop losses. Field-grown plants of two soybean cultivars (Glycine max L. Merr, ‘Amsoy-71’ and ‘Corsoy-79’) were exposed to incremental chronic doses of O₃ for 7 h a day and/or intermittent SO₂ fumigations (4 h a day, 3 days a week) from shortly after emergence until maturity. The O₃ was removed by charcoal filtration or applied by addition of various constant amounts of O₃ to the ambient O₃ present in non-filtered-air open-top chambers. There were no cultivar differences in yield response to either O₃ or SO₂. There also was no indication of an O₃ × SO₂ interaction. The data suggest yield losses of 5–15% at ambient O₃ concentrations (0·045-0·065 μl litre⁻¹) and about 7% yield loss due to 0·10 μl litre⁻¹ of SO₂ in intermittent exposures. These loss estimates for O₃ or SO₂ were similar to those of previously published studies from different areas of the United States utilising different soybean cultivars.

Eggs of pheasant Phasianus colchicus, mallard Anas platyrhynchos, goldeneye Bucephala clangula and black-headed gull Larus ridibundus were injected with 3,3′,4,4′-tetrachlorobiphenyl (TCB) into the yolks. The highest dose given was 0·1 mg per kilogram of egg (mallard) or 1·0 mg per kilogram of egg (pheasant, goldeneye and black-headed gull). Only in the pheasants' eggs was any effect on hatchability noted. Injection of 1·0 mg TCB per kilogram of egg resulted in the death of all the pheasant embryos, but no decrease in the hatching rate occurred when 0·1 mg TCB per kilogram was injected. Embryos of the species studied appear to be considerably less sensitive than chick embryos to the toxic action of TCB. The concentration of TCB in the embryos of some of the injected eggs was determined in chickens, pheasants and goldeneyes. No difference was found in the concentration of TCB in the embryos to explain the difference in effect on hatchability.

It is generally accepted that p,p′-DDE causes many species of bird to lay eggs with thinner shells, but the published evidence for this proposition is ambiguous. Data on egg size (measured by maximum length), shape (measured by the ratio of maximum breadth to maximum length), shell thickness (measured indirectly by Ratcliffe's index, I) and p,p′-DDE content (log μg g ⁻¹ fresh weight) were therefore examined in samples of eggs taken from three species: two samples from the gannet Sula bassana L., three samples from the shag Phalacrocorax aristotelis L. and six samples from the heron Ardea cinerea L. The value of I is virtually unaffected by changes of egg size but is affected by egg shape, and this variable bias in Ratcliffe's index did in some instances materially affect the conclusions to be drawn from the data. A revised index (J), derived from the prolate spheroid, was therefore developed. The value of J is virtually unaffected by changes of egg size and shape, and yields a much more accurate estimate of the product of the mean shell density and thickness.

The conventional negative linear regression of Ratcliffe's index on p,p′-DDE content occurred in many, but not all, of the egg samples that had at least a 10-fold range of p,p′-DDE concentrations. Two other samples both contained two eggs with p,p′-DDE concentrations of not more than 0·1 μg g⁻¹ fresh weight. The shell index I increased, or at least did not decrease, until the p,p′-DDE content exceeded about 0·1–0·2 μg g⁻¹. We suggest that a curvilinear relationship with a maximum turning point is probably a common physiological response to pollutants.

In Solanum melongena var. Pusa Purple Long, the density of stomata, the stomatal index and the size of stomatal pore and epidermal cells all decrease on long-term exposure to coal-smoke pollutants, while the frequencies of epidermal cells and trichomes increase. Trichome length decreases on the upper surface, but increases on the lower surface of leaves. Considerable variations of trichome type, frequency and distribution were observed on both the leaf surfaces of S. melongena grown near the Thermal Power Plant Complex of Kasimpur, West Uttar Pradesh, India.

The relationship between the quantity of undigested sewage sludge applied to agricultural land and the number of coliform and faecal streptococcal organisms transported from the sludge into the subsoil, ground water or to various parts of selected crops was investigated. Bacterial numbers transported to 15 cm depth in the plot that received the highest amount of sludge showed some correlation with the amount of sludge applied.

Bacterial numbers in other plots, in the leachate and on the crops have also been discussed.