A comparison of results from two test methods for assessing the toxicity of aminotriazole to Selenastrum capricornutum

Two different test methods for assessing the toxicity of aminotriazole to Selenastrum capricornutum are compared. Growth medium composition is demonstrated to have a significant effect on the toxicity of aminotriazole.     

Effects of heavy metal contamination on macronutrient availability and acidification parameters in forest soil in the vicinity of the Harjavalta Cu-Ni smelter, SW Finland

Four experiments were established (1992) in Scots pine stands at distances of 0.5, 2, 4 and 8 km along a line running to the SE of the Cu-Ni smelter at Harjavalta, SW Finland, in order to investigate the effects of Cu and Ni emissions on macronutrient availability and estimates of cation exchange capacity (CEC) and base saturation (BS). The accumulation of Cu and Ni (total, exchangeable) in forest soil close to the smelter has resulted in a deficit of base cations (exchangeable Ca, Mg, K and BS) in the organic layer caused by inhibition of mineralisation and the displacement of base cations from cation exchange sites by Cu and Ni cations. No signs of soil acidification were found in the topmost layers of the soil measured as a change in pH, exchangeable acidity and Al. The determination of CEC by the summation method in heavy-metal polluted forest soils is not recommended unless heavy metal cations are also included in the calculations.     

Octachlorodibenzo-p-dioxin in wood treatment materials and treated wood

The octachlorodibenzo-p-dioxin (OCDD) concentrations have been determined in aged samples of commercial pentachlorophenol (PCP), in wood protection formulations containing PCP and in wood treated with PCP as a preservative or as an anti-sapstain treatment. The concentrations of OCDD found in the various samples are within the range expected from the amount of commercial PCP initially present in the samples. In view of the known stability of OCDD the results are interpreted as indicating that the formulation, treatment and ageing processes have not led to any substantial conversion of PCP to OCDD; although one result indicates that outdoor exposure of treated samples increased the OCDD concentration by a factor of approximately 2 after $\text{3}\text{1}\text{2}$ years. Analysis of aged samples of treated wood indicate that OCDD is lost much less rapidly from the wood than PCP.     

PCB contaminated dust on indoor surfaces--health risks and acceptable surface concentrations in residential and occupational settings

Polychlorinated biphenyls (PCBs) have been used in diverse purposes such as indoor paints. Removal of these paints with dust creating techniques, like sandblasting, will result in contamination of building surfaces with PCB-containing dust. Objectives of this study was to analyze the PCB concentrations on surfaces after sandblasting with silica using wipe samples and estimate the resulting health risks and further calculate the risk based acceptable PCB surface concentrations that do not cause incremental lifetime cancer risk higher that 10(-5) or does not cause immunosupression effects in residential use or in occupational settings. Both deterministic and probabilistic approaches were used. The total PCB concentrations on surfaces ranged from 10 to 1100 microg/m(2). Estimated cancer risk was 1.2 x 10(-4) for childhood exposure, 1.3 x 10(-5) for adult residents and 1.5 x 10(-5) for occupational exposure. Probabilistic risk assessment revealed that point estimates were quite reasonable and located between 45th and 79th percentiles on probabilistic distribution of risk. The noncancer risks were calculated as hazard quotients (HQ) which ranged from 3.3 to 35 depending on the exposure scenario. Acceptable surface concentrations based on noncancer effects that are protective for 95% of exposed population were 7 microg/m(2) for residential use, 65 microg/m(2) for residential use if only adults will be exposed and 140 microg/m(2) for occupational use. Preliminary cleanup experiment revealed that when contaminated dust was carefully removed with industrial vacuum cleaner and further washed with terpene containing liquid the surface concentration dropped below the acceptable levels calculated in this study.     

Soil Acidity Parameters and Defoliation Degree in Six Norway Spruce Stands in Finland

Soil acidity parameters (pH, basesaturation, exchangeable Al) in the organic and mineralsoil layers and in soil water (pH, dissolved organiccarbon, total Al, Al³⁺ and molar Ca/Al ratios) insix Norway spruce stands in different parts of Finlandwere compared. An attempt was also made to relate thedegree of defoliation in the tree stand to N and Sdeposition and soil parameters. No relationship was foundbetween soil acidity parameters and defoliation in thesix stands. Defoliation was positively correlated withstand age and the C/N ratio of the organic layer, andnegatively with the cation exchange capacity. The plotlocated on a so-called sulphate soil on the west coast ofFinland had very low soil pH values, and extremely highAl and SO₄ ^2- concentrations and molar Ca/Alratios of well below 1.0 in soil water. Despite the highnatural acidity in the soil on this plot, defoliation inthe spruce stand was the lowest (mean 8.6%) of all sixplots. The results of this study indicate that soilacidity is not a major factor affecting stand conditionin these spruce stands, and that the variation in soilacidity parameters is closely related to climatic factorsand natural soil formation processes.     

Analysis of polychlorobiphenyls from used transformers for polychlorodibenzofurans

The results of analyses for polychlorodibenzofuran (PCDF) content in two samples of polychlorobiphenyl (PCB) from used electrical transformers are presented and discussed. In neither sample was there evidence for enhanced PCDF concentrations even though one of them had been subjected to overheating while in service.     

Polychlorodibenzo-p-dioxins and dibenzofurans in technical pentachlorophenol - results of a collaborative analytical exercise

Results of analyses of eight samples of technical pentachlorophenol conducted by three different analytical methods are presented and discussed.