Relationships between ambient geochemistry, watershed land-use and trace metal concentrations in aquatic invertebrates living in stormwater treatment ponds

Stormwater treatment ponds receive elevated levels of metals from urban runoff, but the effects of these pollutants on organisms residing in the ponds are unknown. We investigated the accumulation of Cu, Zn, and Pb by macroinvertebrates collected from stormwater treatment ponds in Maryland serving commercial, highway, residential and open-space watersheds, and determined whether watershed land-use classification influences metal concentrations in macroinvertebrates, sediments, and water. Three types of invertebrate samples were analyzed--molluscs, odonates, and composite. Zn concentrations in odonates from ponds draining watersheds with commercial development (mean = 113.82 micrograms g-1) were significantly higher than concentrations in the other land-use categories. Similarly, Cu levels in odonates from commercial ponds (mean = 27.12 micrograms g-1) were significantly higher than from highway (mean = 20.23 micrograms g-1) and open space (mean = 17.79 micrograms g-1) ponds. However, metal concentrations in sediments and water did not differ significantly among land-uses. The results suggest that despite the high variation in ambient metal concentrations within each land-use category, macroinvertebrates in ponds serving commercial watersheds accumulate higher levels of Cu and Zn. The levels of Cu, Zn, and Pb in invertebrates from all ponds were less than dietary concentrations considered toxic to fish.     

Factor analysis of essential and toxic elements in human placentas from deliveries in arctic and subarctic areas of Russia and Norway

Concentrations in human placenta of 11 essential elements (P, Ca, Mg, Cu, S, Na, Fe, Zn, K, Se, Mn) and 5 toxic elements (Ba, Sr, Pb, Ni, Cd) are compared for each of two arctic communities in eastern Norway and western Russia, and for another in each country located at more southerly latitudes. All but Mg, Fe, P and K were present in higher concentrations in the Russian study group. The observed inter-element correlations are reflected by the four major factors identified in a principal component analysis. The total variation explained was 67.3%, of which more than half (35.3%) was contributed by Factor 1. P, Ca, Mg, Ba, Sr, Pb, and Ni were major contributors to this factor. The placental concentrations of these elements depended strongly on gestational age, increasing from about week 35 and peaking near weeks 39 and 40, and exhibited skewed frequency distributions and a dependence on maternal smoking. The gestational-dependent mineralization of the placenta is interpreted to reflect the deposition of metal phosphates coinciding with smoking-induced tissue damage. The loadings of the remaining three factors are reviewed in the context of common uptake mechanisms, similar biochemistries and unique transport pathways. The inter-element relationships and grouping of the elements observed should constitute a scientific base for the use of placenta composition in environmental monitoring and epidemiological studies.     

Radionuclide fluxes at a plant manufacturing dicalcium phosphate for domestic animals

We have studied a phosphate rock plant which produces dicalcium phosphate (DCP), used as a source of calcium and phosphorus for domestic animals. A by-product in the manufacturing process is calcium chloride which is used in the oil industry, the food industry and as road-salt. The objectives of our study were to describe the fluxes of radionuclides from the 238U decay series and to estimate the radiation doses to workers at the plant. The radionuclides in the phosphate rock were found to be in secular radioactive equilibrium with 238U, with an average activity concentration of 837 Bq kg-1. Separation and concentration processes were observed at different stages in the plant. Most of the 226Ra was found in the calcium chloride, while the major part of the 238U, about 950 Bq kg-1, was found in the dicalcium phosphate. The annual occupational effective dose to the workers was found to be below the 1 mSv limit recommended by ICRP (1991a) for the public. This study has shown a good example of an important non-nuclear industry with a high input of natural radionuclides with several conceivable pathways to man.     

Contamination of Austrian soil with caesium-137

Austria ranks among the countries that have been most strongly affected by the Chernobyl fallout. The mean contamination with 137Cs is 21.0 kBq/m2, of which 18.7 kBq/m2 is due to the Chernobyl accident, whereas global fallout contributes 2.3 kBq/m2. Maximum values of total 137Cs contamination are nearly 200 kBq/m2. Total deposition of Chernobyl 137Cs on Austrian territory is 1.6 PBq or a fraction of around 2% of the 137Cs released from the reactor. 2115 measurements were used to draw the Austrian "caesium map". The geographical pattern of fallout distribution shows regional differences of contamination as high as 1:100.     

Integrated measures for preservation, restoration and improvement of the environmental conditions of the Lagoon Olho d'Agua basin

The Lagoon Olho d'Agua in Pernambuco State, Northeast Brazil has received increasing environmental concern due to significant stress from pollution in the catchment. The existing environmental problems are the result of great pressure from a broad range of human activities, especially in the last 10 years. Serious pollution exists mainly from some industrial and urban activities, which increased intensively after the eighties. There is a strong social and economical pressure for housing and construction near the lagoon, due to the available land nearby beaches and estuarine zone, and recently by growing tourism activities. Uncontrolled land use by low-income communities and the pressure for construction by developers have led to landfilling and to deterioration of water quality in the lagoon catchment. Improvement of the environmental conditions in the catchment needs integrated measures. Guidelines and some specific actions involving several institutions have been established and refer to sanitation and urban infrastructure as the main priorities. A main target is the construction of low-cost sewage system with smaller and decentralised treatment plants.     

Simulation of Live and Dead Phytomass Formation and Transformation in Optimized Agrocenoses

The formation and transformation of live and dead phytomass in agrocenoses with a complex horizontal structure are described. These processes are demonstrated to be specific and to be determined by differences in the horizontal structure. Only agrocenoses of a mosaic structure (with square parcels) have optimal conditions for these processes.     

Mycotoxin production on rice, pulses and oilseeds

 Mycotoxin-producing fungi were isolated from contaminated grains of rice, pulses and oilseeds sold in the local markets of Calcutta for human consumption. It was found that aflatoxin B₁ was produced by Aspergillus flavus and Aspergillus parasiticus, aflatoxin G₁ by A. flavus, ochratoxin by Aspergillus ochraceous, sterigmatocystin by Aspergillus japonicus and citrinin by Penicillium citrinum. Aflatoxin B₁ (333–10416 μg/kg) was produced by Aspergillus spp. in rice, pulses and oilseeds. Received: 11 May 1999 / Accepted in revised form: 10 April 2000     

Effect of culture conditions on the formation of struvite by Myxococcus xanthus

The amount of struvite (MgNH₄PO₄·6H₂O) produced by Myxococcus xanthus as well as the culture parameter values (pH, total phosphorus, total Kjeldahl nitrogen) were dependent on the culture medium used. Struvite formation started during the exponential phase and the maximum concentration was observed at the beginning of stationary growth phase. The addition of each medium component to the liquid culture influenced the amount of crystal produced. This amount did not depend on the pH increase during the culture period. The moment of the bacterial growth phase, at which each medium component was added, influenced the struvite formation.     

Investigation on organic pollutants from a domestic heating system using various solid biofuels

Various herbaceous biofuels (straw, whole plant cereals and set aside hay) and spruce wood were tested for their potential to form PCDD/F, PCPh, PCBz and PAH during combustion. The trials were conducted in an automatically charged multi-fuel furnace for domestic applications (50 kWth). Both, flue gas and the different ash fractions were analysed. CO-emission results show, that combustion conditions were relatively uniform (mean CO-level: 200 mg/m3 at 13% O2 in flue gas). Likewise, the TOC- and PAH-emissions in the fuel gas remained constantly on a relatively low level. However, for the PCDD/F, PCPh and PCBz increased emissions were detected when herbacious fuels were applied. This may be attributed to their higher chlorine concentration and the high ash content, which is responsible for increased dust emissions during combustion. Similar observations were also found for the PCDD/F-concentrations in the ashes. Combustion chamber ashes usually showed a drastically reduced contamination with highly toxical compounds, compared to the ash fraction from the heat exchanger ash or to chimney soot.