Response of thermal stressed bobwhite to organophosphorus exposure

Constant and intermittent cold stressed juvenile northern bobwhite (Colinus virginianus) were exposed to chlorpyrifos, an organophosphorus insecticide, following avian dietary LC(50) test procedures. Chlorpyrifos concentrations ranged from 100 to 1000 ppm; ambient temperatures (T(a)) included 35.0 (control), 32.5, 30.0 and 27.5 degrees C. Survival decreased significantly under constant cold conditions. Non-survivors averaged 33% weight loss, but survivor weight dropped with increasing dose and decreasing T(a). Control quail at all temperatures maintained a constant body temperature (T(b)); however, T(b) of dosed quail fell with increasing dose and decreasing T(a). Non-surviving cold stressed quail had higher cholinesterase (ChE) activity that non-survivors at 35 degrees C; in addition, dead quail failed to average the 50% inhibition of ChE used to implicate a ChE depressant in death. Daily exposure of quail to 12 h of warmth increased survival. Survivors of intermittent cold stress experienced less weight loss than constant cold survivors due to reduced metabolic costs. Synergistic effects were evident in juvenile northern bobwhite exposed simultaneously to chlorpyrifos and cold stress; however, mortality and certain sublethal effects were mitigated when cold exposure was intermittent.     

The total carbohydrate: organic carbon ratio as an indicator of sewage-derived organic matter in Burbo Bight sediments, Liverpool Bay, UK

Sediments from the Burbo Bight, Liverpool Bay, were analysed for their total carbohydrate (TCH) and organic carbon (TOC) contents, and the TCH:TOC ratio (when the TCH is expressed as a percentage of the TOC) was used to give an indication of the amount of sewage-derived organic matter in the sediments. The %TCH values found ranged from 17-68 with an average of 40, indicating that sewage-derived organic matter constituted a significant fraction of the organic matter in the sediment. This appears likely to have been derived mainly from the Mersey Estuary outflow and the sewage sludge dumped in Liverpool Bay, but these two sources cannot be distinguished using this technique. It is suggested that further studies are required on the carbohydrates in sewage sludge and coastal sediments to satisfactorily establish this technique.     

Secondary effects of air pollution: ozone decreases brown rust disease potential in wheat

Young wheat plants were fumigated with 170 microg m(-3) ozone for 3 days, or with 210 microg m(-3) ozone for 7 days, for 7 hours a day. At the end of the fumigation period the plants were inoculated with brown rust (Puccinia recondita f. sp. tritici) uredospores. The development of new uredospore pustules on fumigated and control plants was evaluated as a measure of rust disease potential. The number of pustules on the ozone fumigated plants was greatly reduced in comparison with the number of plants treated with charcoal-filtered air.     

Studies on water hyacinth as a biological filtre for treating contaminants from agricultural wastes and industrial effluents

The aquatic weed--water hyacinth [Eichhornia crassipes (Mart) Solms] showed a remarkable capacity to withstand the effects of pH changes ranging from 5 to 8 in the aquatic environment. Growth continued to be normal except when placed for longer periods in medium containing iron ions at pH 3.3. The ability of this plant to neutralize some very acid solutions of heavy metals such as salts of copper, cadmium and zinc individually and in combinations, is being reported. Plants placed in pure acid and alkali solutions were also able to neutralize the medium. Calcium appears to play an important role in the mechanism involved in the adaptability of these plants to such environments.     

Effect of methyl mercuric chloride treatment on haematological characteristics and erythrocyte morphology of Swiss mice

Effects of methyl mercuric chloride (MMC) on the blood parameters of Swiss mice (Mus musculus) were studied. The mice received an initial dose of MMC (24 mg kg(-1) body wt) as intraperitoneal injection followed by a second similar dose on the 14th day of the first dose administration. Significant (p < or = 0.001) decreases in haemoglobin content, red blood cell (RBC) count and haematocrit value were observed in the MMC injected mice when compared to the control mice. The effect of the second dose was severe, after which no significant recovery in the values of these parameters was observed. The result also showed a high degree of mercury accumulation in the blood of the MMC exposed mice. Interesting features were marked in the erythrocyte morphology of the exposed mice. An initial shrinkage followed by swelling of the cells was observed after each injection. The outline of the exposed cells was irregular with beak like or small finger like projections. Rupturing and disintegration of the erythrocyte membrane, leading to erythrolysis, were also noticed.     

Dry aerial fallout of organochlorine insecticide residues in Delhi, India

Monitoring of airborne dust in Delhi during May to July 1985 revealed residues of DDT varying from 1.3 to 7.14 ng mg(-1) (4.06-22.31 ng m(-2) day(-1)) with an average of 3.32 ng mg(-1) (10.38 ng m(-2) day(-1)), and HCH which ranged from 0.46 to 2.35 ng mg(-1) (1.44-7.34 ng m(-2) day(-1)) with a mean of 1.16 ng mg(-1) (3.63 ng m(-2) day(-1)). The concentration of total DDT was almost 3 times greater than that of HCH.     

Radionuclides and the birds at Ravenglass

Since 1983, concern has been expressed about the apparent decline in numbers of birds in the Ravenglass estuary in west Cumbria, particularly of the black-headed gull colony on the Drigg dunes, and suggestions have been made that this decline might be due to excessive radiation in the birds' food and their general environment. Twelve species of marine invertebrates from Ravenglass, most of them known to be important foods for birds, were analysed, and further samples were taken from sites along the west Cumbrian coast. None of these samples showed excessive contamination with any of the radionuclides analysed. Analysis of a sample of bird carcasses from the areas showed oystercatchers (Haematopus ostralegus) and shelduck (Tadorna tadorna) to have some of the highest concentrations of (137)Cs in their tissues; yet their breeding success and populations were not affected. Black-headed gulls, on the other hand, were found to be feeding mainly inland, and were the least contaminated with radionuclides of all the birds at Ravenglass, yet this species and its breeding success were in decline. Calculations of the total dose equivalent rate to the whole body of the most contaminated black-headed gull amounted to 9.8 x 10(-4) mSvh(-1) (approximately equal to 8.4 x 10(-4) mGy h(-1), whole body absorbed dose rate), and the background exposure dose was of the order of 8.3 x 10(-4) mGy h(-1). As a minimum chronic dose of 1000 mGy day(-1) has been found necessary to retard growth of nestling birds, and 9600 mGy over 20 days of incubation to cause the death of 50% of embryos in black-headed gulls' eggs, the concentrations of radionuclides in the foods, body tissues and general environment were at least three orders of magnitude too low to have had any effect. The more likely cause of the desertion of the gullery was the combination of an uncontrolled fox population, the severest outbreak of myxomatosis amongst the rabbits since 1954 and the driest May-July period on record, all in the same year (1984).     

Effects of elevated CO2 concentration on the polyamine levels of field-grown soybean at three O3 regimes

Effects of increased ozone (O3) and carbon dioxide (CO2) on polyamine levels were determined in soybean (Glycine max L. Merr. cv. Clark) grown in open-top field chambers. The chamber treatments consisted of three O3 regimes equal to charcoal filtered (CF), non-filtered (NF), and non-filtered plus 40 nl litre(-1) O3 and CO2 treatments equal to 350, 400 and 500 microl litre(-1) for a total of nine treatments. Leaf samples were taken at three different times during the growing season. Examination of growth and physiological characteristics, such as photosynthesis, stomatal resistance, and shoot weight, revealed that increasing CO2 ameliorated the deleterious effects of increased O3. Results from the initial harvest, at the pre-flowering growth stage (23 days of treatment), showed that increasing O3 at ambient CO2 caused increases in putrescine (Put) and spermidine (Spd) of up to six-fold. These effects were lessened with increased CO2. Elevated CO2 increased polyamines in plants treated with CF air, but had no effect in the presence of ambient or enhanced O3 levels. Leaves harvested during peak flowering (37 days of treatment) showed O3-induced increases in Put and Spd at ambient CO2 concentrations. However, increased CO2 levels inhibited this response by blocking the O3-induced polyamine increase. Leaves harvested during the pod fill stage (57 days of treatment) showed no significant O3 or CO2 effects on polyamine levels. Our results demonstrate that current ambient O3 levels induce the accumulation of Put and Spd early in the growing season and that further increases in O3 could result in even greater polyamine increases. These results are consistent with a possible antiozonant function for polyamines. The ability of increased CO2 to protect soybeans from O3 damage, however, does not appear to involve polyamine accumulation.