Study of heat exposure in the work environment in Jeddah

The present work was conducted to define the magnitude of the problem of heat exposure in Jeddah and the role of both the climatic and the industrial factors on the total heat load. Indoor heat exposure was studied in an industrial complex of 5 plants for cables' manufacturing. Outdoor heat exposure was studied in shaded and unshaded operations in Jeddah Islamic Port (JIP). The heat exposure parameters, including air temperature (Ta), wet bulb temperature (Tw), and globe temperature (Tg), as well as the wet bulb globe temperature (WBGT) heat stress index, the relative humidity and the air velocity, were assessed at representative locations. Results of the study indicated that:

Chlorobiphenyl contaminants at Pladda and Garroch Head in the Firth of Clyde in relation to sewage sludge input

Sewage sludge dumped at Garroch Head in the Firth of Clyde contains significant quantities of chlorinated hydrocarbons, such as polychlorinated biphenyls (CBs). These compounds are lipophilic and resistant to degradation. They accumulate in the biota either from the water column or through the food chain, particularly in tissue with a high lipid content. Bottom dwelling fish, such as plaice, in the vicinity of the dump site will accumulate CBs from their environment. Eighteen of the 209 CBs were measured in plaice livers from the Garroch Head dump site and from Pladda, a site reasonably remote from the dump site but also in the Clyde, over a 7 year period prior to the cessation of dumping in December 1998. Concentrations of the congeners in the liver of fish caught at the dump site were, in general, higher than those in the liver of fish caught at Pladda. Concentrations in the plaice livers for the sum of 18 CBs ranged from 1611 to 8471 micrograms kg-1 lipid for Garroch Head samples and from 336.9 to 2635 micrograms kg-1 lipid for samples from Pladda. The data were evaluated using principal component analysis (PCA). Pattern analysis was undertaken by normalising to the recalcitrant CB 153. Livers from the dump site were found to have a higher proportion of the lower chlorinated CBs. CB patterns were similar at the Garroch Head dump site from year to year, but multivariate techniques showed that there were differences in pattern when normalised to CB 153.     

Preliminary studies of a fast screening method for polycyclic aromatic hydrocarbons in soil by using solvent microextraction-gas chromatography

Solvent microextraction (SME) was applied to the extraction of polycyclic aromatic hydrocarbons (PAHs) from spiked and real environmental soil samples with different matrices. Soil sample was mixed with 7 mL of acetone and 14 mL of water to allow partitioning of the PAHs from the soil to the liquid phase. A 2 microL octane drop suspended from a microsyringe needle tip was then immersed into the stirred solution-soil mixture for extraction. After an 11 min extraction, the octane drop was withdrawn into the syringe and injected directly into the GC for identification and quantification. The whole analysis procedure took 27 min, with an extraction time of 11 min, and a GC separation time of 16 min. A second extraction could be undertaken whilst the GC is running, hence the GC run time currently limits the sample throughput. In this method, a small amount of organic solvent was used for the extraction process, which produced little waste. The limits of detection for lower molecular weight (< 230) PAHs range from 0.13 to 0.36 mg kg-1, and for higher molecular weight (> 250) PAHs are estimated to be between 0.5 and 1.0 mg kg-1, with RSD values generally under 20%. Due to the small volumes of organic solvent used, the consumable cost per extraction is only US$ 0.12. This is the first report of the application of SME to solid samples, and the first report of the use of SME for the analysis of PAHs.     

Study of the relationships between bone lead levels and its variation with time and the cumulative blood lead index, in a repeated bone lead survey

The study aims were to: (i) investigate long term human lead metabolism by measuring the change of lead concentration in the tibia and calcaneus; and (ii) assess whether improved industrial hygiene was resulting in a slow accumulation of lead in an exposed workforce. 109Cd excited K X-ray fluorescence was used to measure tibia lead and calcaneus lead concentrations in 101 workers in a secondary lead smelter. 51 subjects had had similar bone lead measurements 5 years previously. Most of the other subjects had been hired since the first survey. Measurements of whole blood lead were available for the large majority of subjects. Tibia lead concentrations fell significantly (p<0.001) in the 51 subjects with repeated bone lead measurements, from a mean of 39 microg Pb (g bone mineral)(-1) to 33 microg Pb (g bone mineral)(-1). The change correlated negatively with the initial tibia lead concentration, producing an estimate for an overall half-life of 15 years, with a 95% confidence interval of 9 to 55 years. Adding continuing lead exposure and recirculation of bone lead stores to the regression models produced half-life estimates of 12 and 9 years, respectively, for release of lead from the tibia. The repeat subjects showed no net change in calcaneus lead (64 microg Pb (g bone mineral)(-1) initially, 65 microg Pb (g bone mineral)(-1) 5 years later). Subjects not measured previously had average lead concentrations of 15 microg Pb (g bone mincral)(-1) in the tibia and 13 microg Pb (g bone mineral)(-1) in the calcaneus. The rate of clearance of lead from the tibia (9 to 15 years) is towards the more rapid end of previous estimates. The lack of a significant fall in the calcaneus lead was surprising. Attempts should be made to repeat this observation. If confirmed, it would have implications for models of lead metabolism. The relatively low lead concentrations in the non-repeat subjects are reassuring. However, observation after a longer period of employment would be desirable.     

Analysis of two-way layout of count data with negative binomial variation

A number of methods has been proposed for dealing with single-factor or factorial experiments when the requirements for performing the normal theory analysis of variance procedure are not satisfied. This paper suggests the use of the likelihood ratio statistic for testing the main effects and the interaction between the factors in two-way layout of count data following negative binomial distributions with a common dispersion parameter. The likelihood ratio statistic for testing the equality of the dispersion parameters of several groups of count data is also derived. The methods is illustrated by an example concerning the study of spatial and temporal variation of bacterial counts.     

Spatial analysis and mapping the annual mean concentrations of acidity and major ions in precipitation over the United Kingdom in 1986

The composition of precipitation is being monitored in collectors sited throughout the United Kingdom. In the first year, 1986, hydrogen ion, nitrate, ammonium and non-marine sulphate were measured in samples from 47 sites and annual mean concentrations determined. Spatial analysis based on Regionalized Variable Theory revealed autocorrelation in all four ions and reasonable bounded models were fitted to the sample variogram of all four. These were then used to estimate values of a fine mesh grid by simple kriging, and the estimates were then contoured. The estimation errors were similarly mapped, and both sets of maps are presented. The maps show that concentrations of these ions are greatest in eastern parts of the country, as expected from consideration of European emissions and weather patterns. For the first time estimation errors were also mapped and show how the network could be improved.     

Exploring data quality for some inorganic and organic constituents of inhalable particulate matter (PM10)

Quality assurance (QA) assessments of air pollution data sets provide a basis for evaluating the significance of various substances in the atmosphere. For non-criteria pollutants, QA results are seldom reported in the technical literature and are often difficult to estimate. The present report provides a summary of QA results such as recovery, precision and accuracy data. Of the six trace elements and nine organic constituents compared in detail, recoveries, laboratory precision and laboratory accuracy values were 100%, ±3% to ±19% and-2 to-13% for the former group and 69% to 98%, ±7% to 23% and-15 to-34% for the later group. System precision varied from ±22% to ±47% for the trace elements and ±42% to ±83% for the organic constituents. Limitations in the interpretation of non-criteria particulate-phase pollutant data bases are discussed with some emphasis placed on receptor-modelling and risk assessment applications. Finally, the relevance of NBS certified materials for QA estimates in non-criteria air pollutant studies is also reviewed.     

Environmental audits: Proposed terminology

This paper presents a review of the fast developing subject of environmental auditing with the authors proposing a series of definitions. Of particular concern is a move towards the development of an accepted vocabulary for environmental impact assessment, even though the international dimension of the subject makes this a difficult task. Use of the word audit has become an accepted part of EIA vocabulary, however there are several types of audits being undertaken today. Presently, there are no commonly accepted definitions, consequently this paper will attempts to address this issue. Definitions for seven types of environmental audits are suggested, derived from the experience of the authors and from a review of the current literature. It is hoped that by the presentation of these definitions that such terms will be advocated for future EIA work, and thereby reducing confusion that otherwise may occur. The paper concludes with a brief review of the status of auditing.     

Changes in levels of organochlorines in woodcock wings from 1971 to 1975

Wings from woodcock (Philohela minor) were first monitored for organochlorine pesticides and polychlorinated biphenyls (PCBs) in the eastern U.S. in 1971. Regional differences in these compounds were clearly demonstrated and baseline residue levels were obtained for later comparisons. An expanded sampling of wings in 1972 revealed that residues in wings of adult woodcock may differ significantly from those in immatures, and that residues of several important agricultural insecticides and PCBs had declined significantly. More extensive sampling was undertaken in 1975 to determine if changes in residue levels had taken place in the intervening years. PCBs, mirex, and heptachlor epoxide increased significantly between 1972 and 1975 in adult woodcock wings. In immature woodcock wings mirex, dieldrin, and PCBs increased significantly between 1972 and 1975, but DDT residues decreased significantly.