Environmental Pollution Series B, Chemical and Physical最新文献

The wide-ranging applications of voltammetry to the analysis of trace metals and other ions of interest to environmental scientists are reviewed. It is concluded that the availability of modern microprocessor controlled instrumentation, capable of performing both anodic stripping and square wave voltammetry, provides a flexible and powerful technique to aid in solving analytical problems and carrying out routine analyses. The recent identification of many sensitising agents which reduce detection limits to part per thousand million level, or below, is a further exciting development in this field.

Catchment soils and surface sediments from the associated estuary in Northwest England have been analysed for total Fe, Mn, Cd, Cu, Pb and Zn and the distribution of these metals between geochemical fractions. The results indicate that metal behaviours in the soils and sediments are different, the soils showing greater leaching tendency than the sediments. For the soils, considerable variations in total metal and non-residual concentrations were found at different localities, while the same metal fractions in the sediments were uniformly distributed.

The mobility patterns of four divalent heavy metals—Zn²⁺, Cu²⁺, Pb²⁺ and Cd²⁺—were determined under varying acidities in an artificially contaminated sand and a naturally polluted soil after the addition of various organic materials—farm yard manure (FYM), peat, humic acid (HA) and tetraethylene pentamine (Tetren). Due to dissolution and decomplexation, the mobility of the heavy metals increased considerably upon progressive acidification. Metal pairs ZnCd and CuPb showed almost similar mobility patterns. In the case of artificially contaminated scand, the addition of FYM and peat enhance the mobility of heavy metals at lower pH values and decreased it at higher pHs. Humic acid and Tetren had little effect.

Eight plant species—Acacia melanoxylon, Bauhinia malabarica, Bougainvillea glabra, Calotropis procera, Catharanthus roseus, Eucalyptus globulus, Ipomoea fistulosa and Peltophorum pterocarpum—were collected from a newly established suburb colony of Lucknow city, where the major pollutant is dust, to study cleansing efficiency of the plant canopy and also to establish the correlation between the leaf morphological characteristics and their dust trapping potential. The dust load, in milligrams per square centimetre of leaf surface, was measured and related to foliar epidermal and cuticular characteristics, and morphological features.

A replicated factorial pot trial with perennial ryegrass and a sandy loam soil (pH 7·0) investigated the relative phytotoxicities of Zn, Cu and Ni, and the nature of their interaction. Sewage sludge of controlled metal content made from enriched sewage was used for the soil treatment so that each pot received the same amount of sludge dry solids whilst quantities of metals added were adjustable as required. Upper critical concentrations (total) of the three elements in soil were found to be 319 mg Znkg⁻¹, 105 mg Cukg⁻¹ and 221 mg Nikg⁻¹. The relative toxicities of Zn/Cu/Ni were 1·0/2·6/1·0 on a loading rate basis. The comparatively low toxicity of Ni was attributed to the pH value (7·0) of the soil used. At subcritical levels in the soil phytotoxic effects of mixtures of the three elements were independent but some additivity was seen when one or more element was already at a hypercritical level. At subcritical levels the element present in highest concentration relative to its critical concentration determined the phytotoxic effect on ryegrass yield of mixtures of Zn, Cu and Ni in soil. But where two or more elements exceeded their critical soil concentrations their combined phytotoxic effect could be taken as being additive. It was concluded that the three elements could be dealth with separately in guidelines for sludge utilisation on agricultural land.

The following elutriate test parameters were evaluated using sediment and water from the James River estuary to determine their effects on test results: sediment concentration (20, 5, 2·5 and 1%), mixing time (120, 30 and 5 min) and Kepone concentration in/on the sediment (0·04 and 0·02 mg kg⁻¹). A factorial analysis of variance indicates that Kepone concentration on sediment is the only factor within the above parametric ranges controlling concentrations in the elutriate water. The results agree with analyses of samples taken during a dredging operation near the site of sediment collection for the elutriate tests.

The Kepone elutriate results indicate that a relatively low sediment concentration (1%) is adequate to obtain meaningful elutriate results. This suggests that the standard elutriate test (Environmental Protection Agency, 1973) may prescribe an excessive amount of sediment (20%) which may impart an unnecessary burden on the analyst.

Two hundred birds found dead in Belgium between 1970 and 1981, and belonging to 30 species, were analysed for total mercury contamination. The contamination of aquatic birds ranged between 0·11 and 35 μg g⁻¹ wet weight. For terrestrial birds, the extreme values were: not detectable and 14 μg g⁻¹. In both cases, differences in diet can explain the differences in contamination. The order of diets associated with increasing mercury contamination for aquatic birds was invertebrates, zooplankton and garbage, and fish; and for terrestrial birds this consisted of plants, invertebrates, mammals and birds. For raptors and owls, this effect of diet includes geographical variations within species. A higher mercury contamination level in the winter and early spring was noted for two species of owls. For aquatic birds, the contamination of liver was higher than that of kidney, with ratios varying between 1·2 and 2·5. For terrestrial birds, the ratio was closer to 1. A few determinations were also made for muscle and heart, giving respectively 0·25 and 0·6 of the liver contamination. Among the birds analysed for their liver contamination, 15% showed levels higher than 3 μg g⁻¹ and could have been affected in their reproduction; 3% had levels higher than 10 μg g⁻¹, and could have died from mercury poisoning; and 6% showed an abnormally high liver: kidney ratio, which could reflect an acute intoxication.

There exists a striking parallelism between the levels of mercury and of organochlorine residues (DDT) in birds of prey, suggesting the existence of common ecotoxicological mechanisms.

Following the cessation of the use of dieldrin in 1963 and the subsequent use of Eulan WA New at the textile mill in Kinross, Scotland, the fate and distribution of the mothproofing agents in the Loch Leven environment were studied. Fish samples analysed between 1963 and 1970 showed a decline in dieldrin concentrations with a half-life of 0·56–0·82 years (r > 0·87). Samples of water, sediment, zooplankton and fish were taken for analysis during 1978–1979. About 50% of the Eulan WA New remained in the soluble ionic form and was discharged into the River Leven. Much of the remaining 50% was associated with particulate matter and sediment. Less than 10% was associated with the biota. The samples were analysed using GC-ECD and GC-MS-DS with decachlorobiphenyl as the internal standard.

A modified liquid extraction method for determining trace amounts of lower halogenated hydrocarbons in drinking water has been studied. A 45 ml sample solution containing not less than 5 μg litre⁻¹ of CHCl₃, CHCl:CCl₂, CHBrCl₂, CHClBr₂, CHBr₃ and CCl₂:CCl₂ and 0·4 μg litre⁻¹ of CCl₄ was extracted with 5 ml of xylene. The equilibrium concentrations of lower halogenated hydrocarbons in the xylene phase were determined by a gas chromatograph equipped with an electron capture detector and using a column which consists of tricresyl-phosphate (90 cm), squalane (170 cm) and silicone DC 200 (40 cm).

By means of this method, μg litre⁻¹ levels of lower halogenated hydrocarbons in drinking water were determined successfully.

The concentrations of a range of species, related to agricultural chemicals applied to the sugar cane crops, have been determined in the groundwaters of the Burdekin River Delta. Concentrations of γHCH and heptachlor, organic and inorganic mercury, nitrate, nitrite and ammonia, phosphate, sodium, potassium, chloride and fluoride are reported. The concentrations of the various species are discussed in terms of local geographic features, annual rainfall pattern and agricultural chemical usage.