The numbers of bacteria (total coliforms (TC), faecal coliforms (FC) and total aerobic bacteria (TAB) and nutrients (NH4+, NO3− and PO4−) in ponds receiving runoff from point and non-point sources were monitored at different seasons. Turbidity, BOD, pH and dissolved solids were measured. Neutral pH range (6·0–8·0) was observed in all the samples. In both ponds available nitrogen and phosphorus concentrations were significantly (p<0·05) higher in sediment than in water. Lower temperatures in the winter correlated significantly (p<0·05) with TAB, TC and FC bacteria. Nitrogen, especially NO3, was also correlated (p<0·05) with all bacterial (TAB, TC and FC) counts. However, PO4 correlated negatively with the TC and FC in sediments and TC in surface water of both ponds. Faecal coliform numbers in the winter exceeded the recommended water quality standards.
Changes in the radiation balance (albedo) of maize polluted with cement dust were measured at the Agrometeorological Research Station, Keszthely, Hungary, during 1982–1984. The radiation intake of polluted plants was increased, and this increased plant temperature and evapo-transpiration. Higher radiation values did not have a positive effect on dry matter production; in fact, fertilisation was found to deteriorate and yields on average decreased by 16·2% during the three years.
Static bioassay tests were conducted with three oil dispersants at two salinities (32·0 ± 2 g litre−1 and 16·0 ± g litre−1) using fingerlings of the mullet Mugil sp. and hermit crabs Clibinarius africanus as test animals. The acute toxicity was estimated both by graphical interpolation and the approximate nomographic method of Litchfield & Wilcoxon (1949) and is reported as the 24 h, 48 h and 96 h LC(1)50 Lloyd & Tooby, 1979) values. Conco-K was the most toxic, and BP 1,100X the least toxic, to the two test organisms at the two test salinities. Simple observations were made on the behavioural responses of the test animals. The rôle of acute toxicity data in ecological predictions is briefly discussed.
The acute toxicity of nickel to first and second instars of Chironomus riparis was determined using larvae from a laboratory culture. First instar larvae were found to be significantly more sensitive to nickel than second instars with 48h LC50 values of 79·5 ± 3·7 mg litre −1 Ni and 169 ± 10 mg litre−1, respectively.
Bacterial densities of sewage from five hospitals in Baghdad city from September 1983 to August 1984 were measured.
SEM studies were made of the effects of SO2 and NO2 pollution on the leaves of Commelina communis. Plants at the two-leaf stage were exposed to a mixture of 100 nl litre−1 SO2 and 100 nl litre−1 NO2 for 10 days in recycling-type fumigation chambers. The first visible symptoms of injury appeared after 4 days on the abaxial surface of the oldest leaf in the form of glazed light brown patches along the margins. These symptoms also became visible on the adaxial leaf surface by the seventh day of exposure. SEM analysis of leaf epidermis showed that control plants had evenly distributed surface waxes while fumigated plants had wax accumulated in small heaps with large denuded areas. The palisade cells in fumigated leaves became flaccid due to loss of turgidity and there was a complete collapse of spongy tissue. Commelina communis thus appears to be extremely sensitive to an environment containing SO2 + NO2.
A group of New Zealand rabbits was exposed to environmental metal pollutants for 6 months via the respiratory route at the biomonitoring station near a nickel refinery dump. The count of alveolar macrophages (AM) and the lysosomal enzyme activities (acid phosphatase and β-glucuronidase) were significant reduction was found in the antibody-mediated rosette formation by AM in the exposed rabbits. In the in vitro system a dose-dependent inhibition of Fc receptor activity was detected in rabbit AM pretreated with a metal particle suspension at three concentrations (200, 400 and 600 μg ml−1). The inhibitory effect of metal particle ingestion on the AM plasma membrane Fc receptor activity revealed the possible adverse effect of long-term exposure in a polluted area on the immune function of alveolar macrophages. Antibody-mediated rosette formation by AM may be a suitable assay for risk assessment of toxic pollutants in the ambient air.
As a continuation of our earlier studies on the impact of heavy metals on aquatic organisms (Abbasi & Soni, 1984), the behavioural responses and survival of the teleost Nuria denricus exposed to different levels of zinc (II), cadmium (II) and lead (II) were studied. Safe concentration (SC) values of the metals were determined with the help of computer-aided long-term bioassays.
The considerable logistical problems involved in large-scale monitoring networks could be overcome in part by establishing a biological water quality network of stations, operated by high schools. Measurement of benthic invertebrate community structure obtained in a pilot project involving five schools produced results that were reliable with regard to collecting and identification efficiency. Early results from a network that includes more than 20 teachers and 500 students at 12 schools show an ability to identify changes in stream water quality.
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.
Metal (Cu, Ni, Fe, Co, Zn, Pb) and Ra-226 levels were compared in several tissues of meadow voles Microtus pennsylvanicus of both sexes and differing age groups, collected seasonally on Ni and U mine tailings and at a control site. Seasonal variation of Cu levels in liver and Fe levels in kidney was observed at all sites (Fe in liver also varied seasonally at the Ni mine site). No variation by season in metal content of muscle was observed. Small sample size from the Ni mine location did not permit a firm conclusion to be drawn regarding sex and age effects on accumulation of these metals in soft tissues. Although Co and Pb in bone did not vary by sex or age group, Pb varied seasonally. Ra-226 concentrations in bone varied by age and season but not by sex.
The fluoride pathway from an aluminium reduction plant was investigated by examining fluoride accumulation in the species of many invertebrate groups. Previous workers had examined only a few groups. All groups showed increasing accumulation from control to medium exposure to high exposure zones. In the high exposure zone, the scavengers, millipedes and woodlice, had the greatest mean accumulation of approximately 1100 μg Fg−1. The predatory spiders (393 μg Fg−1) and harvestmen (258 μg Fg−1) were next. These were followed by slugs and snails (190 μg Fg−1) feeding on decaying and fresh plant material, earthworms (184 μg Fg−1) feeding on organic material in the soil, the omnivorous beetles (50 μg Fg−1) and the predatory centipedes (48 μg Fg−1). The herbivorous grasshoppers contained least (20 μg Fg−1). The overall sequence of increasing fluoride was: herbivores—omnivores—predators—scavengers. In some groups, such as beetles, the levels were comparatively low, but the same sequence occurred. The fluoride content of each species is important in the transfer of fluorides to predators, but does not necessarily reflect the level of involvement in the fluoride pathway through the ecosystem.
Male specimens of H. fossilis were exposed to a concentration of 8 mg litre−1 of malathion in their aquarium water for 16 days during the early post-spawning phase. Its effects on glycogen of liver, testes and muscle, glucose and free fatty acids (FFA) in plasma, spleeno-somatic index (SSI), red blood corpuscle (RBC) and haemoglobin (Hb) were examined. Reduced levels of liver and muscle glycogen, associated with increasing plasma glucose, were noticed after 4 and 8 days of treatment but, after 16 days, a recovery was observed. Testicular glycogen did not respond to malathion exposure. Plasma FFA was also unchanged for 4 and 8 days of treatment but a higher level was recorded after 16 days' exposure. RBC and Hb were reduced following the 4-day exposure; however, no apparent change in their level was observed after 8 and 16 days' exposure. The SSI was also reduced during the 4- and 8-day treatments but 16 days' exposure caused the level to return to normal. Thus, this study demonstrates that, after prolonged exposure, H. fossilis develops a tolerance and partially recovers from the stress condition. In the initial stages carbohydrate was used as an energy source to meet the stress situation, while, in the later phase of exposure, FFA served as the major source of energy.
Concentrations of heavy metals were determined in tits collected in three polluted forest sites in southern Poland and in a relatively unpolluted site at Białowież Forest. Cadmium, lead, zinc, copper and iron contents were determined by AAS in the liver, femur bones, feathers and carcasses. In all these organs and in the caracasses the concentrations of cadmium and lead attained higher levels in birds from polluted regions than in the control birds. The concentrations of copper, zinc and iron did not differ significantly. The adult birds living in polluted forests are regarded as the group most endangered by heavy metal pollution. The danger comes mainly from cadmium and lead ingested with contaminated food.
Moles (Talpa europaea) and common shrews (Sorex araneus) were trapped in 1977 at three 5 km intervals on two transects radiating NE and SE from an aluminium reduction plant on the island of Anglesey, North Wales. Earthworms (Lumbricidae) were collected from the same transect locations. Materials were also obtained from elsewhere for comparison. For all materials, highest fluoride concentrations were found within 1 km radius of the reduction plant.
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 effect of O3 and SO2 on leaf diffusive resistance (LDR) of yellow poplar seedlings was studied at 40% and 80% humidity. LDR was measured at 0800, 0900, 1100, 1400 and 1600 h on seedlings fumigated from 0900 h until 1400 h each day for five consecutive days. Fumigation treatments were control, 0·15 μl litre−1 O3, 0·25 μl litre−1 SO2 and 0·15 μl litre−1 O3 + 0·25 μl litre−1 SO2. No change in daily LDR response was observed for the seedlings at 40% humidity. At 80% humidity, daily LDR response of seedlings in all four treatments changed significantly over the 5 days of the experiment. The range of the LDR values and the daily response curves both changed. The higher humidity apparently caused the stomata to open so that more pollutants could enter the leaves. The pollutants then interacted with the leaf cells and modified the stomatal response.
Sediments from the highly mercury-contaminated Berry's Creek in the Hackensack Meadowlands of New Jersey were brought into the laboratory to investigate the effects of different environmental factors on their release of mercury and its uptake by Fundulus heteroclitus. Sediments were placed in 16 aquaria in which conditions of pH (6 vs 8), salinity (0·3% vs 1·2%), aeration (aerated or unaerated) and stirring (stirred or not stirred) were varied. Mercury analysis was performed on Fundulus heteroclitus from the aquaria. Condition factor of the fish was also monitored. Low oxygen was associated with higher levels of mercury in the fish and with poorer condition. Stirring the sediment did not decrease fish condition, and was associated with lower Hg uptake. The concentration of mercury in the sediments in individual tanks was not related to the uptake by the fish. Monitoring of mercury levels of fish collected from Berry's Creek throughout the year revealed a 5-fold increase during the summer months.
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.
Plants of maize Zea mays L. and soybean Glycine max L. were treated with fly ash, a waste product of coal-fired electric generating plants, at the rates of 2, 4 and 8 g m−2 day−1 for 30 consecutive days between 15 and 46 days of plant age. At the lower two rates, both crops showed an increase in plant height, metabolic rate, content of photosynthetic pigment and all dry weight fractions measured. This response was, in part, due to correction of boron deficiency by fly ash deposition. The highest dusting rates, however, caused reductions in pigment content and dry matter production. Reduction in plant growth at the highest dusting rate was attributed chiefly to the excessive uptake and accumulation of boron, and alkalinity caused by excessive soluble salts on the leaf surface.
