Application of the comet and micronucleus assays to butterfish (Pholis gunnellus) erythrocytes from the Firth of Forth, Scotland.

This report describes an investigation of genotoxic effects in an inter-tidal fish species sampled along a pollution gradient in the Firth of Forth, Scotland, UK. The comet assay is an electrophoretic technique for measuring DNA breakage in nuclei from individual cells and has only recently been applied to field investigations of genotoxicity. The measurement of nuclear anomalies (NA), such as the presence of micronuclei (MN) and 'lobes', has been successfully utilised in many field studies of genotoxic effects of contaminated sediments. These two techniques were applied to nucleated red blood cells (RBC) from the butterfish, Pholis gunnellus. The comet assay was adapted and validated for use in this species. Fish were sampled from the inner Firth of Forth, which has a legacy of industrial contamination and the outer Firth of Forth which is comparatively clean. The analysis of DNA strand breakage using this technique did not reveal any significant differences between animals sampled from inner and outer zones of the Firth. In contrast, MN and NA frequencies were elevated in the inner polluted zone of the Firth compared to the outer zone. This study suggests: (1) there are genotoxic effects associated with contaminants in the inner Firth of Forth, and (2) the comet assay may not be a suitable genotoxicity biomarker in fish.     

The Gas Supply Situation in the United States

The body of information presented in this paper is directed to those individuals who require information on the present natural gas supply and demand relationship and the prospects for future changes, including individuals concerned with air quality control and the use of natural gas for combating air pollution.

If natural gas could continue to capture large shares of the energy market, as in the past when supply was not a growth inhibiting factor, annual demand for gas is projected to increase to 34.5 and 46.4 trillion cubic feet in 1980 and 1990, respectively. Annual production levels which could be supported by presently proven reserves and anticipated future reserve additions are estimated to peak in the mid-1970’s and decline to about 18 trillion cubic feet in 1990.

When viewed from the perspective of anticipated indigenous supply deficiencies, the acquisition of supplemental sources of gas becomes of paramount importance. Pipeline imports, the only substantive supplemental source presently available, could almost double by 1980 and be about 2 trillion cubic feet annually in 1990.

Available volumes of gas from Alaska could be 0.7 trillion cubic feet in 1980 and could increase to 2.3 trillion cubic feet annually by 1990. Actual initial deliveries of gas are inextricably related to construction of an oil pipeline from Prudhoe Bay. Construction delays postpone initial delivery dates for gas as well as oil.

Advancements in cryogenic transportation and storage technologies have made the heretofore largely untapped supplies of gas from several countries with limited internal markets available to the United States as LNG. Annual LNG imports could be about 0.3 trillion cubic feet in 1975 and perhaps 2 and 4 trillion cubic feet by 1980 and 1990, respectively.

Pipeline quality gas from coal presents the prospect for a supplemental source of gaseous fuel independent of foreign sources and free from balance of payments problems. The first pipeline quality gas from coal may be expected by 1976, and by 1980 perhaps 0.3 trillion cubic feet could be provided annually from this source; in 1990, 3.3 trillion cubic feet might be available. An additional, but presently unqualified, source of synthetic gas will be the conversion of liquid hydrocarbons.

In the aggregate, supplemental gas supplies are anticipated to total about 4.6 and 11.5 trillion cubic feet annually by 1980 and 1990, respectively. While demand for gas is anticipated to increase, domestic conventional gas production is projected to peak in the mid-1970’s and decrease somewhat thereafter. As a consequence, a continuing gas supply-demand imbalance is anticipated.     

Age dependence of potentially toxic elements (Sb,Cd, Pb,Ag) in human liver tissue from paediatric subjects

Toxic elements are present at low concentrations in the environment. This work was undertaken to investigate the age dependence of the liver content of selected elements in paediatric populations, as an index of internal exposure. Liver samples were collected at autopsy from 157 subjects, aged < 1 day to 6 years, as part of investigations on a possible role of Sb compounds in sudden infant death syndrome (SIDS). In addition to Sb, the concentrations of Ag, Cd and Pb were also determined by inductively coupled plasma mass spectrometry on the remaining digest. Comparison of 95% confidence intervals of the median concentrations of the four elements suggested that there were no differences between the two categories of cause of death, SIDS or those who had died of an identified disease. Cadmium, lead and antimony median concentrations were lower than corresponding values observed in adult populations. Silver concentrations were significantly higher at birth and decreased with age. Cadmium levels were almost negligible in neonates and infants, but increased in older children. The finding of non-negligible concentrations of both Ag and Pb in neonatal liver provides further direct evidence that these elements cross the human placental barrier. The reported data, by far the largest collection observed in subjects less than 1 year old, are the result of exposure, during pregnancy and in early childhood, to present levels of these elements in the environment. They can serve as a reference to compare post-mortem values from individuals or groups of subjects in this age range when an exposure risk is suspected and to highlight trends in human exposure.     

Assessing the bio-psychosocial correlates of flood impacts in coastal areas of Lagos,Nigeria

This paper explores the complex heterogeneous experiences of flood impacts based on a bio-psychosocial model of socio-economic, demographic, behavioural and environmental factors. Using ordinary least squares regression on a cross-sectional survey of 1003 individuals, flood impacts in three contiguous coastal neighbourhoods in Lagos, Nigeria, were modelled. The results show that approximately 52% of the variability in flood impact was accounted for by education, age, family structure, ethnicity, personal health concern and income. While involvement in coping was not a significant predictor of flood impacts, relocation emerged as a strong predictor. The inclusion of behavioural factors did not change the magnitude and significance of the relationship between demographic factors and flood impacts. However, the effects of age, education and personal health concern disappeared when environmental factors were controlled. The overall importance of the predictors for determining flood impact in decreasing order is as follows: income > coping strategies > ethnicity = participation in community development > family structure > personal health concerns > housing quality > reasons for living in residential locality > neighbourhood vulnerability to flood > housing vulnerability to flood.     

Chemical characteristics of chromophoric dissolved organic matter in rainwater

Proton nuclear magnetic resonance (¹H-NMR), UV absorbance and excitation-emission matrix (EEM) fluorescence spectroscopy were used to define the chemical characteristics of chromophoric dissolved organic matter (CDOM) in whole and C₁₈ extracted rainwater. The average total recovery of fluorescence determined from the sum of extract and filtrate fractions relative to the whole was 86% suggesting that 14% of fluorescent CDOM in rainwater is comprised of very hydrophobic material that cannot be eluted from the column. Half the fluorescence of rainwater was recovered in the filtrate fraction which is important because it suggests that 50% of the chromophoric material present in precipitation is relatively hydrophilic. The average spectral slope coefficient was smaller in extracted samples (16.3 ± 9.0 μm^?1) relative to whole samples (18.9 ± 2.8 μm^?1) suggesting that the extracted material contains larger molecular weight material. Approximately one-third of the total dissolved organic carbon (DOC) in rainwater exists in the extract fraction suggesting that a large percentage of the uncharacterized DOC in rainwater can be accounted for by these hydrophobic macromolecular species. The fluorescence of extracted samples is strongly correlated with total NMR integration and is most sensitive to aromatic protons suggesting that molecules in this region are the most important in controlling the optical properties of rainwater. The lower removal efficiency of CDOM in rainwater relative to surface waters or the water-soluble fraction of aerosols during solid phase extraction (SPE) suggests that rainwater contains significantly more hydrophilic chromophoric compounds which are compositionally different than found in these other aquatic matrices.     

Community duplicate diet methodology: a new tool for estimating dietary exposures to pesticides

An observational field study was conducted to assess the feasibility of a community duplicate diet collection method; a dietary monitoring tool that is population-based. The purpose was to establish an alternative procedure to duplicate diet sampling that would be more efficient for a large, defined population, e.g., in the National Children's Study (NCS). Questionnaire data and food samples were collected in a residence so as not to lose the important component of storage, preparation, and handling in a contaminated microenvironment. The participants included nine Hispanic women of child bearing age living in Apopka, FL, USA. Foods highly consumed by Hispanic women were identified based on national food frequency questionnaires and prioritized by permethrin residue concentrations as measured for the Pesticide Data Program. Participants filled out questionnaires to determine if highly consumed foods were commonly eaten by them and to assess the collection protocol for the food samples. Measureable levels of permethrin were found in 54% of the samples. Questionnaire responses indicated that the collection of the community duplicate diet was feasible for a defined population.     

Influence of physico-chemical properties of soil clay fractions on the retention of dissolved organic carbon

This study investigated the effects of surface functional groups, cation exchange capacity (CEC), surface charge, sesquioxides and specific surface area (SSA) of three soil clay fractions (SCFs) (kaolinite–illite, smectite and allophane) on the retention of dissolved organic carbon (DOC) in soils. Physico-chemical properties of the SCFs before and after removing native carbon and/or sesquioxides were characterised, and the DOC adsorption–desorption tests were conducted by a batch method. Native organic carbon (OC)/sesquioxide removal treatments led to a small change in the CEC values of kaolinite–illite, but significant changes in those of smectite and allophane. The net negative surface charge increased in all samples with an increase in pH indicating their variable charge characteristics. The removal of native OC resulted in a slight increase in the net positive charge on soil clay surfaces, while sesquioxide removal increased the negative charge. Changes in the functional groups on the SCF surfaces contributed to the changes in CEC and zeta potential values. There was a strong relationship (R ² = 0.93, p < 0.05) between the Langmuir maximum DOC adsorption capacity (Q _max) and SSA. The Q _max value also showed a moderately strong relationship (R ² = 0.55, p < 0.05) with zeta potential (at pH 7). Q _max was only poorly correlated with CEC and native OC content. Therefore, along with SSA, the surface charge and functional groups of SCFs played the key role in determining the adsorption affinity and hence retention of DOC in soils.     

The natural production of organobromine compounds

Organobromine chemicals are produced naturally by an array of biological and other chemical processes in our environment. Some of these compounds are identical to man-made organobromine compounds, such as methyl bromide, bromoform, and bromophenols, but many others are entirely new moleclar entities, often possessing extraordinary and important biological properties. Although only a few natural organobromine compounds had been discovered up to 1968, this number as of early 1999 is more than 1,600, and new examples are being discovered continually. Organobromine compounds are produced naturally by marine creatures (sponges, corals, sea slugs, tunicates, sea fans) and seaweed, plants, fungi, lichen, algae, bacteria, microbes, and some mammals. Many of these organobromine compounds are used in chemical defense, to facilitate food gathering, or as hormones.