Effect of gamma-irradiated sludge on the growth and yield of rice (Oryza sativa L. var. GR-3)

The effects of gamma-irradiated sludge on the growth and yield of rice (Oryza sativa L. var. GR-3) in pot cultures have been studied. Compared to plants grown only in soil, shoot length, root length, fresh weight, dry weight, total proteins, total soluble sugars, starch and chlorophyll content of plants grown in soil supplemented with unirradiated or gamma-irradiated sludge were found to be significantly increased. Irradiation of sludge significantly stimulated the linear growth of shoot and root systems as well as fresh and dry weights of plants, compared to those grown in soil containing unirradiated sludge. There was also an improvement in the grain yield (weight of seed) when plants were grown in soil supplemented with irradiated sludge. The results obtained suggest that the gamma-irradiated sewage sludge can be beneficially recycled for agricultural uses.     

Tidal and diurnal influence on food consumption of a salt marsh killifish Fundulus heteroclitus

Feeding patterns during four 24-h periods, sampled at 3-h intervals, were investigated for the mummichog Fundulus heteroclitus, in a Delaware, USA tidal marsh. Two factors potentially influencing feeding patterns, time of day and tide height, were examined. On 2 of the sampling periods a low tide occurred in the morning, while on the other 2 sampling periods a high tide occurred in the morning. Results are reported as g-dry wt. of food per g-dry wt. of fish. F. heteroclitus is primarily a daytime feeder that most actively feeds at high tide, regardless of whether or not the high tide inundates marsh surface areas. When tide height was sufficient to inundate the marsh surface, fish invaded these areas and consumed prey characteristic of the marsh surface. F. heteroclitus is an important link in energy transfers between the marsh surface and subtidal systems, enhancing its own energy supplies by consuming marsh surface prey whenever available.     

Non-carcinogenic effects of inorganic arsenic

This review will focus primarily on ohe effects of the inorganic arsenicals (arsenate and arsenite forms) that are present in drinking water. They are acutely toxic to both humans and animals, an effect that may be related to their bioavailibility. In humans, arsenicals have been reported to cause dermatitis and mucous membrane irritation upon exposure. They have also been reported to cause skin lesions and peripheral neurotoxicity in smelter workers and in patients treated with Fowler's Solution. When humans are exposed to arsenic in drinking water, effects such as hyperkeratosis, electromyographic abnormalities and vascular effects have been reported. In experimental animals, arsenic has been demonstrated to affect the liver and kidneys. In mice, arsenic has also been reported to decrease the animal's resistance to certain viral infections. The arsenite (+3) and arsenate (+5) forms have different modes of action. Arsenite binds to sulphhydryl groups and has been reported to inhibit over 100 different enzymes, while the arsenate can substitute for phosphate in various high energy intermediates, resulting in arsenolysis. In addition, when arsenate is reduced to arsenite in the body, it can also cause toxicity as that species.     

The Contribution by the Study of the Algae Forms (Phytoplankton and Periphyton) as Integrators of Physicochemical and Microbiological Data in the Varenna Stream

Physico-chemical, microbiological, ichthyotoxicological conditions and microalgae of Varenna stream were studied in samples taken in 12 collecting stations. The data reported indicate a marked deterioration proceeding downstream e.g. an increase of bacterial population, concentration of suspended solids, COD and variations in the composition and abundance of phytoplankton and periphyton.     

Acute toxicity of two insecticides to tubificid worms, Tubifex tubifex and Limnodrilus hoffmeisteri

Acute toxicity and presumable harmless concentration of two commercial insecticides, Furadan 3G and Malataf 50E were reported for tubificid worms, Tubifex tubifex and Limnodrilus hoffmeisteri. L. hoffmeisteri were found more susceptible to both the insecticides; the Furadan was found to be more toxic than Malataf to tubificid worms. Analysis of variants showed a significant difference between safe concentrations of the same insecticide to different species.