Environmental Pollution (1970)最新文献

Sewage sludge and a kind of seaweed, Ulva sp., were used as supplementary feed for chicks. Different diets were prepared by mixing the two supplementary feeding stuffs separately with the control diet (5%, 15%, 25% w/w). These diets were fed continuously for 35 days to chicks from the age of 53 days. No significant differences in growth rate were found between the chicks fed Ulva sp. and the control group. The sludge was inferior for feeding chicks, as shown by their lower growth rates. However, the growth rate on the lower gortion of sludge (5%) was similar to that of the control group.

The contents of crude protein, crude fat and available carbohydrate and the metabolisable energy of the supplementary feeds used in the present study were similar to those of the control diet. Although no visual gross histopathological symptoms in liver and kidney of chicks were observed, further study should be made of the potential hazard of the various heavy metals present in the sewage sludge.

Observations at Long Island seabird colonies during the period 1969 to 1978 revealed a more or less constant prevalence of oiling of less than 1% for adult common terns and nearly 2% for adult black skimmers. Oiling was usually light (1–2 on a scale of 5) and very few heavily oiled birds were seen either at the colonies or elsewhere on Long Island's beaches. Currently oiling of seabirds on the Atlantic Coast of North America is not a widespread or serious problem compared with its prevalence on parts of the Pacific and Gulf Coasts of North America and in Europe. Data presented here provide a baseline for comparison with future years, since oil exploration began off Long Island during 1978 and large-scale exploitation is planned.

Fertilised eggs at various stages of development and newly hatched fry of medaka Oryzias latipes were exposed to a series of concentrations of the water-soluble extract of toluene. Static bioassays were conducted and TL₅₀ calculations made. In addition, the embryos were examined for the presence of developmental anomalies. The mean 96 h TL₅₀ for eggs was 54 mg/litre. The early (<3·5h) and late (>192 h) stages were more sensitive than the average. The newly hatched fry were not as sensitive to toluene as were the embryos.

In addition to acute toxicity effects, concentrations of toluene as low as 41 mg/litre produced teratogenic effects in susceptible embryos. We propose that the observation of these defects in the transparent eggs constitutes a simple and rapid tool for the estimation of Maximum Acceptable Toxicant Concentration (MATC) for fish.

The decomposition rates of a grass/clover mixture buried in revegetated china clay sand wastes of varying age and management were compared. Rates of weight loss compared favourably with those obtained by other workers on litter decomposition and were generally negatively related to C:N ratio and positively related to organic matter and total nitrogen concentration.

The decomposition rates of grass and clover shoots and roots were compared in the field and in laboratory incubation experiments. Clover shoots and roots decomposed at a significantly faster rate in the field than grass shoots and roots. Net nitrogen release was detected only from clover shoots and roots in the laboratory.

The lack of nitrogen accumulation in the sand waste was attributed to the removal of shoot material from exposed sand tips and the rapid leaching of inorganic nitrogen.