Environmental Pollution Series A, Ecological and Biological最新文献

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.

Moles from within 1 km of the reduction plant had a mean bone fluoride content of 7740 μg g⁻¹ (range 5160-11 100 μg g⁻¹); elsewhere on the island the overall mean was 1294 μg g⁻¹ (range 42 to 3125 μg g⁻¹). With the exception of animals within 1 km of the reduction plant, bone fluoride in moles showed no relationship to distance from the plant along either transect (P > 0·7 at least). Moles from areas more than 15 km from the reduction plant had a mean bone fluoride concentration of 971 μg g⁻¹ (range 40 to 2200 μg g⁻¹). Tooth wear index in this sample was only half that found in moles from within 15 km of the reduction plant (P < 0·001).

Common shrews had an overall mean bone fluoride concentration of 1404 μg g⁻¹ (range 82 to 8600 μg g⁻¹). Concentrations decreased with distance from the reduction plant, consistent with airbone carriage of fluoride from the stack at the plant (P < 0·05).

Apart from the immediate vicinity of the reduction plant, total fluoride concentration in earthworms showed no relationship to distance from the plant. Their fluoride content was considered to be largely due to soil contained in the gut.

Soybeans (Glycine max (L.) Merr. cv Hodgson) were exposed in the field to seasonal 7-h average concentrations of 0·017, 0·035, 0·060, 0·084 and 0·122 μl litre⁻¹ ozone using open-top chambers and ambient plots. Dose-response studies were conducted on growth and yield. Negative linear relationships were found between both growth and yield and ozone exposure. The regression equation: yield= 12·82 − (48·17 × O₃), with yield in grams per plant and O₃ as the seasonal 7-h average, expresses one relationship. Compared with the yield in charcoal filtered air (0·017 μl litre⁻¹), losses ranged from 8% in the 0·035 μl litre⁻¹ treatment to 41% in the 0·122 μl litre⁻¹ treatment.

Aboveground biomass was a good indicator of ozone stress; five weeks after the ozone treatments were initiated, a negative linear relationship was found between ozone exposure and aboveground biomass. In contrast, the percentage of biomass allocated to leaves, stems and pods did not change until after 6 to 7 weeks of exposure to ozone. The change in allocation of biomass was the result of accelerated senescence of older leaves. At final harvest, a lower percentage of aboveground biomass was found in pods and seeds of plants exposed to higher ozone concentrations.

Exhaust emissions from automobiles have been frequently connected with a new type of forest disease which is described for conifers and, more recently, also for deciduous trees. The use of the catalytic converter for pollution control and, consequently, as a remedy for forest decline, has been extensively advocated. No data are yet available on the efficiency of catalytic devices with respect to the toxicity of exhaust emissions. We have therefore studied this question in Norway spruce Picea abies (L.) Karst. under defined conditions. The efficiency of the catalyst was tested with concentrations of exhaust emissions which produced significant injuries within a limited period of time. A fast reduction of photosynthetic capacity and impairment of stomatal regulation was observed after a fumigation of only 15 min without a catalytic converter, followed by changes in colour and, finally, by needle dropping. During the early stages, buds were not injured and developed into healthy shoots. Consequently, symptoms of an inner browning and needle dropping could be mimicked. In the presence of a catalytic converter, essentially no damage to spruce could be observed under analogous conditions.

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.

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.

Comparisons of the SC with the minimum allowable levels of the corresponding metals in drinking water, effluents, irrigation water and fisheries revealed that, except for a few cases, the existing national and international water quality standards for various water uses are higher than the SC. The disparity between the SC and the permitted levels of zinc and cadmium was especially noteworthy, indicating the need for a thorough re-evaluation of the toxicity and safe levels of these metals.

Two-day-old plants of spring barley Hordeum vulgare cv Patty were exposed to 100 nl litre⁻¹ SO₂ and 100 nl litre⁻¹ NO₂ singly and in combination for 20 days. Exposure to SO₂ was found to reduce the root dry weight significantly but total shoot weight was relatively less affected. NO₂ applied on its own had very little effect on growth, but in combination with SO₂ it caused highly significant reductions in almost all the growth parameters measured. In another study plants of the same age were exposed for 2 weeks to mixtures of SO₂ and NO₂, ranging in concentration from 40 to 140 nl litre⁻¹ of each gas, and growth inhibitions were found to increase with increasing dose. It is concluded that the effects of SO₂ and No₂ applied together are greater than would be predicted from their individual effects and that the dose-response curve could be used in a predictive manner for a given set of conditions.

The environmental effects of airborne fluorides emanating from a large aluminium smelter built in a rural area were monitored during its operational life of 11 years. A zone of severe injury to epiphytic lichens developed which coincided closely with the area over which damaging fluorosis to livestock occurred. Alterations in farming practice helped limit the effects on cattle. The impact on commercial forestry and amenity trees was minor and mostly of a temporary nature. The environment started to recover very soon after the factory closed.