Environmental Pollution Series A, Ecological and Biological最新文献

A field study was conducted to monitor changes in diflubenzuron (DFB) and a degradation product, 4-chlorophenylurea (CPU) in water and sediment collected from a supratidal mosquito breeding lagoon. Three applications of a 0·4% sand granule followed by three applications of a 25% wettable powder formulation were made to the site. Substantial differences in the dynamics of both DFB and CPU concentrations in water were noted among applications. Non-linearity of the logarithm of DFB concentrations in water as a function of time was also evident in some applications. In such cases, the half-life parameter does not characterise the dynamics of the process and is of questionable value.

For four of the six applications, there was strong evidence of a decrease in DFB concentration in water. However, there was not significant evidence of a decrease in DFB concentrations in sediment, which appeared to be a major site for DFB adsorption. Water concentrations for each analyte (DFB, CPU) were negatively correlated with sediment concentrations for the same analyte, suggesting that an exchange of both analytes occurs across the water/sedimetn interface. Also, positive correlations were noted between DFB and CPU in both water and sediment. These correlation findings are counter-intuitive, if it is assumed that changes in DFB and CPU concentrations are mainly due to degradation of the former to the latter.

While DFB concentrations in the supratidal lagoon water tended to remain above 0·4 μg litre⁻¹ for 7 days post application, it seems unlikely that this toxic concentration would affect planktonic larval crustaceans in adjacent estuaries if DFB entered these waters via runoff or by flooding of supratidal areas. The persistent DFB concentrations in the water and sediment (∼100 μgkg⁻¹), however, could be detrimental to detrialfeeding populations of marsh crustaceans (e.g. Uca).

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.

Levels of Ni, Co and Pb in soft tissues were below detection limits in most cases and firm conclusions on site effect could not be drawn. No site variation was observed in soft tissue levels of Cu. The Fe levels of liver and kidney tissue, in summer-captured voles from tailings high in Fe, were higher than those in animals from other sites. Lowest Zn levels were seen in kidneys of voles from the site with the lowest environmental levels of the metal.

Bone content of Co did not vary by site. Skeletal Pb was highest during the summer and autumn on the uranium mine tailings while skeletal Ra-226 was highest for voles from that site during all seasons. Internal dose rate due to Ra-226 and cumulative dose at capture were calculated as 0·04 rad day⁻¹ and 2·5 rad for animals captured in the spring, 0·009 rad day⁻¹ and 0·6 rad for summer captures and 0·005 rad day⁻¹ and 0·3 rad for those taken in the autumn.

Long-term sampling of a small stream revealed changes up to 6 years after completion of a major highway crossing. Suspended solids and rates of sedimentation declined below the construction site as silt was flushed downstream. Upstream conditions were not re-established for 5 years; incomplete recovery occurred downstream.

Complex changes in invertebrate communities occurred; for $\text{2}\text{1}\text{2}$ years after construction, populations increased downstream, and diversity declined. Trichoptera and Diptera proliferated, while Plecoptera and Ephemeroptera remained unchanged, or declined. Five years after construction diversity had rebounded, as flushing of silt allowed repopulation, and silt-tolerant Diptera declined. Few species were lost or gained, but a restructuring of invertebrate communities was evident, especially among the Trichoptera.

Blacknose dace and creek chub increased disproportionately for 2 years, but bottom-feeding species rebounded when sedimentation rates declined. The creek is apparently still changing in response to nutrients and sediments introduced by erosion, and elevated production appears to be relatively persistent.

Bleached kraft mill effluent (BKME) from a Finnish kraft pulp mill with a full bleaching system was aged under laboratory conditions. The ageing solutions were prepared in nutrient solution and three types of lake water. The changes in acute toxicity of the BKME were studied by Selenastrum algal assays and degradation of chlorinated phenolics. Chlorinated phenolic compounds were analysed with a gas chromatograph from the subsamples taken from the ageing solutions on the following days: 0, 4 and 7 or 8. The toxicity of the ageing solutions was bioassayed on the same days using Selenastrum capricornutum as a test organism. The response of the test algae to ageing solutions was measured by cell counting after 72 and 96 h.

During the ageing period the amounts of chlorinated phenolics decreased in the following order: (1) chlorocatechols, (2) chlorophenols and (3) chloroguaiacols. After the ageing period the EC₅₀ values of BKME ageing solutions to Selenastrum algae ranged from 6% to 10% (v/v) depending on the test medium and the effluent sample used. The correlation between the EC₅₀ values and total chlorinated phenolics was not statistically significant, so it seemed that, in these studies, chlorinated phenolics were not the primary reason for the acute toxicity of the BKME to Selenastrum algae.

Subcutaneous fat (SCF) and abdominal fat (AF) of ten Adelie penguins (five male and five female) and the muscle, liver, bone and brain samples from three male specimens, collected during different days of starvation in a breeding season, were analysed for concentrations of PCBs and p,p′-DDE. All the specimens analysed contained detectable levels of PCBs and DDE and both compounds were found to be highly concentrated in the fat-rich tissues, to the extent that the SCF burdens of both compounds can be considered as the total body burdens. On starvation during breeding, the concentrations of both compounds increased simultaneously in the declining fat reserves, as well as in other organs. Some redistribution of organochlorines to other tissues from the fat reserves was also noticed during starvation. The bioconcentration factor for DDE was found to be higher than for PCBs in all the levels of the Antarctic food chain and also the DDE/PCB ratio increased with increase in trophic levels, both indicating the high residual potentiality of DDT compounds in higher animals.

The effects of increasing zinc concentration on germination, survival and growth of birch seed collected from sites showing varying degrees of zinc contamination were investigated. Germination decreased with elevated zinc levels but differences between different seedlots were not found. Distinct differences were found for percentage survival and growth. Radicle elongation was more adversely affected than hypocotyl extension. The nutrient status of the culture media influenced the toxicity of zinc. Tolerance indices at different developmental stages are compared.

Grass cultures can be used for the biological monitoring of mercury pollution in ambient air, because the measured mercury accumulation in grass cultures gives a reliable indication of the average concentrations found in leafy vegetables. However, for washed leafy vegetables, the concentrations are usually lower than those found in grass.

The mercury accumulation found in herbs, especially in perennials, is far higher than that in grasses and leafy vegetables. There is apparently a long-term accumulation similar to the pattern found in oak leaves at the end of the growing season. Nevertheless, there exists a clear relationship between the concentrations found in herbs and those in grass cultures.

No such relationship could be detected for roots, tubers, bulbs, fruits or leguminous vegetables.

The fairly low concentrations found in roots, tubers and bulbs (ten times less accumulation than grass in containers) and in fruits and leguminous vegetables (factor 25 less) apparently result from an accumulation from the soil and less from a direct deposition of airborne mercury.

The simple technique of permanent grass cultures sampled every 28 days is very useful for a general survey of atmospheric pollution. Shorter integration periods are necessary to monitor the fluctuations in mercury pollution and alternating grass cultures (14-day exposure) are preferred. There exists a clear relationship between these two biomonitoring techniques.