Dinoflagellate cysts and hydrographical change in Gullmar Fjord, west coast of Sweden

This high-resolution study of the latest Holocene dinoflagellate cyst record from Gullmar Fjord, on the west coast of Sweden, provides evidence for the recognition of two major dinoflagellate communities within the fjord over the last 85 years. These communities may have their origins with the history of cultural eutrophication within the region, but are more likely to be associated with the wider phenomenon of the North Atlantic Oscillation and/or the complex hydrographical response of the fjord to various changing climatic environments between 1915 and 1999. The changing dinoflagellate cyst populations are compared in detail with the many hydrographical parameters available from this well studied fjord with its long instrumental records. Indeed the dinoflagellate cysts fail to demonstrate a convincing ongoing eutrophication record for the fjord but do show a major change in the cyst assemblages at about 1969/1970 at a time when the NAO was changing from a negative phase to the present-day positive phase. Gullmar Fjord is important in the history of dinoflagellate cyst studies, being the site of the 1954 study by Erdtman in which viable cysts, produced within the phytoplankton, were first documented within the water column.     

Analysis of foundation installation for old buildings in downtown Saint Petersburg

Basic types of foundations supporting old buildings in Saint Petersburg are reviewed. Fundamental relationships between the width and depth of embedment of the foundations and the number of stories are analyzed on the basis of field observations. Average pressures against the lower surfaces of the foundations are compared with design strengths adopted from modern standards for bed soils.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 13–15, September–October, 2004.     

Particle-size distribution and phosphorus levels in soil, sediment, and urban dust and dirt samples from the Menomonee River Watershed, Wisconsin, U.S.A.

Soil, bottom sediment, suspended sediment, and urban street dust and dirt samples from the Menomonee River Watershed, Wisconsin, were dispersed by ultrasound, fractionated and analyzed for the P content of each of three particle-size fractions. The major soil types in the watershed were used as a reference for comparing particle-size distribution and P content in urban street dust and dirt, and in sediments.Phosphorus level was found to be greater in the clay-sized particles than in the sand- or silt-sized particles of urban street dust and dirt samples, but 48% of the P was in the sand-sized fraction because of the predominance of sand-sized particles in these samples. The highest P level in the clay-sized fraction of the bottom sediments occurred at the site below a sanitary treatment plant (STP) outfall with secondary treatment capability. The P level found below a tertiary STP outfall was equal to the level found in agricultural areas. When using P level in sediment for locating areas of possible P input to the river, the clay-sized fraction of bottom sediments was more precise than P levels in unfractionated samples.     

Enhanced adsorption of Cd (II) on a hydrous Al (III) floc in the presence of a modified form of polyethylenimine

A polymer modified with succinic anhydride has been investigated for the adsorption of cadmium (II) on a freshly precipitated aluminium (III) hydroxide floc. The proportion of chelate attached to the polymer is varied to determine the relationship between carboxyl and amino groups on the polyelectrolyte, in terms of enhanced adsorption of cadmium (II) on a hydrous aluminium floc. The presence of polyelectrolyte enhanced the adsorption of 3.3 ppm Cd (II) on a 333 ppm Al (III) floc at every concentration of polyelectrolyte investigated. The proportion of succinic anhydride attached to the polymer had an impact on the increased adsorption of Cd (II) on an Al (III) floc observed. A decreasing proportion of succinic anhydride to polymer resulted in a decrease in the amount of cadmium adsorbed on the floc. Above pH 8, a decrease in the % Cd (II) adsorbed on the floc and % Al (III) retained within the floc decreases with the presence of polyelectrolyte as a result of the formation of soluble Cd-Polyethylenimine-succinic acid (PEISA) complexes. When the Al-PEISA combination was applied to a complex matrix where Cd (II), Cu (II) and Ni (II) ions competed for adsorption, enhanced adsorption was observed for Cd (II) and Ni (II). At pH 7, dissolution of the floc observed with the addition of discrete chelates was not observed with the addition of polyelectrolytes.     

Semi-volatile organic compounds in the Campaspe River system (Victoria, Australia)

The levels of semi-volatile organic compounds (SVOCs) in the Campaspe River system, North Central Victoria, Australia, were monitored from January to September 1995, and the environmental trends and sources of these compounds were determined. The land use within particular catchments dictated the complexity of the SVOCs in run-off water. Run-off from native forest contained the greatest number of SVOCs. Soil and ground litter were shown to contain the greatest complexity of SVOCs, mostly terpenes. However, only a small proportion were leached by run-off with the remainder being tightly bound to the soil or volatilizing to the atmosphere. Under the prevailing drought of early 1995, the rivers contained no detectable SVOCs until the first catchment run-off after significant rainfall in May. The maximum complexity and concentration of the SVOCs coincided with extensive run-off after heavy rainfall in June, effecting a surge of SVOCs with the flood peak. Fatty acids, their amides and hydrocarbons made up the majority of the compounds identified and were in the 1-39 micrograms/l concentration range. The levels then diminished as the catchment was flushed by continual run-off. These results support Lake's 1967 hypothesis that natural floodwaters contain a signature of SVOCs entering from the catchment. The downstream passage of these compounds was obstructed by a man-made storage, Lake Eppalock, with only low concentrations of SVOCs (1-3 micrograms/l) in the outflow, displaying no correlation to run-off.     

Mobilization of lead from human bone tissue during pregnancy and lactation--a summary of long-term research

The skeleton is potential endogenous source of lead during pregnancy and lactation. We have undertaken a longitudinal investigation into the mobilization of lead from the human maternal skeleton to determine whether lead is mobilized from the maternal skeleton during pregnancy and lactation, and if so, when and how much is released. Subjects in the study were migrants to Australia (n=15) whose skeletal lead isotopic composition (endogenous lead) was different to that prevailing in the Australian environment (exogenous lead). This migrant cohort was compared with 6 multi-generational Australian controls. Biological and environmental samples were taken pre-pregnancy where possible, throughout pregnancy and postpartum for at least 6 months. Newly-born infants of the migrant and Australian mothers were monitored for 6 months. Blood lead concentrations for the migrant mothers ranged from 1.5 to 20 microg/dl (geometric mean 2.8) and for Australian mothers ranged from 1.9 to 4.3 microg/dl (geometric mean 2.9). There was minimal change in lead isotopic composition of the Australian pregnant controls although there were increases of approximately 40% in blood lead concentration in 3 of 6 cases during the postpartum period and from 0 to 12% in the other 3. In the migrant pregnant subjects, the geometric mean skeletal lead contribution to blood lead using the isotopic composition was approximately 33% (range 10-88%) for 14 subjects using a revised estimate for exogenous lead. Skeletal contribution to blood lead during the postpartum period was significantly greater than during pregnancy (P<0.001). The skeletal contributions to blood lead are higher and the changes are more consistent in those subjects who conceived within 100 days of arrival in Australia compared with those who conceived longer than 100 days. In the migrant subjects, changes in blood lead concentration during pregnancy and postpartum varied from subject to subject with an overall 20% increase; the increases during the postpartum period were greater than during pregnancy (P<0.001). It was estimated that the amount of maternal skeletal lead mobilized during pregnancy and transferred to the infant via cord blood averaged approximately 79%. The increased skeletal contribution to blood lead is attributed to a low daily calcium intake of approximately 500 mgCa/day, a condition which was present in both migrant and Australian subjects. An ongoing clinical trial is providing a new cohort with calcium supplements. A summary of other aspects of the study is included and covers: additional flux released from the skeleton during pregnancy and postpartum; XRF bone lead results; urinary excretion of lead during pregnancy and postpartum; dietary contribution to blood lead in female adults and children; comparison of rates of exchange of lead in blood of newly-born infants and mothers; relationships of lead in breast milk to lead in blood, urine and diet of the infant and mother; changes in blood lead after cessation of breastfeeding; urinary lead isotopes during pregnancy and postpartum indicate no preferential partitioning of endogenous lead into plasma; a comparison of some aspects of the nonhuman primate and human pregnancy studies.     

ASSESSING AND MANAGING THE RISKS OF PATHOGEN TRANSFER FROM LIVESTOCK MANURES INTO THE FOOD CHAIN

A review was undertaken of (a) the levels and prevalence of Salmonella spp., Campylobacter spp., Listeria monocytogenes, Escherichia coli 0157. Cryptosporidium parvum and Giardia intestinalis in livestock manure, and (b) factors which affect their survival during storage and following land application. Pathogens are commonly present in livestock manures and can survive in soil for several months or years after spreading or excretion onto land. Temperature was identified as being the most important factor influencing pathogen survival, although pH, UV light and drying were also important. Various practical measures to minimise the risk of pathogen transfer into the food chain were identified, including treatment, extended storage and no/harvest periods following land spreading. Guidelines are being developed on managing farm manures to minimise the risks of microbiological contamination of ready-to-eat crops.     

Full scale fire tests for ship accommodation quarters

Ten full-scale test fires were conducted in a chamber simulating a three person ship accommodation quarter. The test fires used three different ventilation conditions, two types of bunks and furnishings with either polyurethane foam or chloroprene foam. The chamber was instrumented to follow the development of the fire.The furnishings with polyurethane foam were readily ignited and produced an intense fire within 2 to 4 minutes. The furnishings with chloroprene foam ignited but burned slowly with a small flame or in smoldering combustion.The ventilation conditions had a significant effect on the development and intensity of the fire as the test fires were burning under oxygen-limiting conditions.The solid pan bunks retarded the early development of the fire compared to open bunks for polyurethane furnishings. However, once the mattresses on the three bunks were ignited the intensity of the test fires was similar for both types of bunks.