Environmental exposure to lead and its correlation with biochemical indices in children

Lead is a global concern because of its ubiquity in the environment and known to be associated with abnormal neurobehavioral and cognitive development of young children. There is no study from India to describe a composite profile of blood lead and its biochemical influences in children. The present study was aimed at determining the proportion of children with >10 mug/dL blood lead levels (BLLs), association between BLLs, and sociodemographic characteristics, if any, and alterations in biochemical indices in the blood as an underlying mechanism of lead intoxication. A total of 62 children (4--12 y) of Lucknow and nearby areas were recruited to determine BLLs, delta-amimolevulinic acid dehydratase (delta-ALAD) activity, catalase (CAT) activity, and malondialdehyde (MDA) and glutathione (GSH) levels in the blood. Mean level of blood lead was 7.47+/-3.06 microg/dL (2.78--15.0) and 29%-exceeded 10 microg/dL, CDC intervention level. The BLLs were found to be significantly influenced by social status, area of residence, source of water supply, maternal educational status (p<0.001), type of house, and proximity to traffic density (p<0.01). delta-ALAD was significantly lower in the group of children with BLLs 11.39+/-1.39 microg/dL when compared to children with BLLs 7.11+/-1.25 microg/dL and 3.93+/-0.61 microg/dL (p=0.0007, 0.0005, respectively). However, CAT activity was higher in the groups of children with higher blood levels than with lower BLLs (p=0.0159, 0.0001, respectively). There was an increase in MDA level with a concomitant decrease of GSH in children with BLLs 11.39+/-1.39 microg/dL compared with those of children with BLLs 7.11+/-1.25 microg/dL and 3.93+/-0.61 microg/dL (p=0.0001, 0.0002, and p=0.0001, respectively). There was statistically significant correlation of BLLs with delta-ALAD (r=-0.44, p=0.00035), MDA (r=0.46, p=0.00018), GSH (r=-0.62, p=0.00001), and CAT (r=0.44, p=0.00035). Significantly, CAT activity, MDA, and GSH levels were in turn, found to be correlated with delta-ALAD (r=-0.45, p=0.00024; r=-0.43, p=0.00053; r=0.43, p=0.00053, respectively). Results of the present study indicate a declining trend of BLLs in children when compared with those reported from metropolitan cities of India when leaded gasoline was in practice and that the BLLs were significantly associated with biochemical indices in the blood which have the potential to be used as biomarkers of lead intoxication.     

Microbial activity and distribution during enhanced contaminant dissolution from a NAPL source zone

Laboratory experiments were conducted to assess microbial reductive dechlorination in one-dimensional sand columns containing a 10 cm long source zone of uniformly distributed residual tetrachloroethene (PCE) nonaqueous phase liquid (NAPL), a 10 cm long transition zone directly down-gradient of the source zone containing some nonuniformly distributed NAPL ganglia, and a 40 cm long plume region down-gradient of the transition zone. The activity and distribution of Sulfurospirillum multivorans, a PCE-to-1,2-cis-dichloroethene (cis-DCE) dechlorinating bacterium, was evaluated in columns containing either a mixed-NAPL (0.25 mol/mol PCE in hexadecane) or pure PCE-NAPL. Significant dechlorination of PCE to cis-DCE was observed in the mixed-NAPL column, resulting in 53% PCE-NAPL mass recovery in the effluent with PCE-NAPL dissolution enhanced by up to 13.6-fold (maximum) and 4.6-fold (cumulative) relative to abiotic dissolution. Quantitative real-time PCR targeting pceA, the PCE reductive dehalogenase gene of S. multivorans, revealed that S. multivorans cells were present in the NAPL source zone, and increased in numbers (i.e., grew) throughout the source and transition zones. In contrast, minimal reductive dechlorination and microbial growth were observed in the column containing pure PCE-NAPL, where aqueous-phase PCE concentrations reached saturation. These results demonstrate that microbial growth within NAPL source zones is possible, provided that contaminant concentrations remain below levels toxic to the dechlorinating organisms, and that microbial growth can result in significant bioenhanced NAPL dissolution.     

The characterisation of friction stir welding process effects on stiffened panel buckling performance

The introduction of advanced welding methods as an alternative joining process to riveting in the manufacture of primary aircraft structure has the potential to realise reductions in both manufacturing costs and structural weight. However, welding processes can introduce undesirable residual stresses and distortions in the final fabricated components, as well as localised loss of mechanical properties at the weld joints. The aim of this research is to determine and characterise the key process effects of friction stir welding assembly methods on stiffened panel static strength performance. Utilising experimentally validated finite element modelling methods, it is demonstrated that welding induced residual stresses have a significant influence, and that collapse behaviour is less sensitive to advanced process effects and process effect magnitudes than panel initial buckling behaviour.     

Radionuclide contamination of foods imported into Iraq following the Chernobyl nuclear reactor accident

Since early 1986, a monitoring program for radionuclides in imported foods has been carried out by the Iraqi Atomic Energy Commission. After the Chernobyl nuclear reactor accident in the Soviet Union, the program was expanded; our laboratory was officially designated by the Iraqi Government to measure radionuclide activity concentrations in foodstuff imported from countries known to be severely contaminated by Chernobyl radioactive fallout. Gamma-spectrometric analysis was used. Food items such as powdered milk, lamb meat, poultry, cereals and grains imported into Iraq before the Chernobyl accident did not contain any detectable fission products. However, all lamb meat, 81% of the lentil, 44% of the powdered milk and chick-pea, and 17% of the roast beef samples were contaminated with 137Cs or 134Cs and 137Cs. The highest 137Cs contamination levels found were 82, 147, 420, 6 and 4 Bq kg-1, respectively. Contamination by 134Cs was approximately 50% of the values given above.     

The acute effect of bunker C oil and an oil dispersant on: 1 Serum glucose, serum sodium and gill morphology in both freshwater and seawater acclimated rainbow trout (Salmo gairdneri)

Bunker C oil and an oil dispersant were tested for physiological stress on both freshwater and saltwater acclimated rainbow trout. Both compounds tended to reduce serum glucose levels with Bunker C causing the more significant decrease (P < 0.08), indicating a possible dysfunction of the kidney. The freshwater treatment group showed a significant decrease in sodium levels (P < 0.01) when treated with a dispersant, while under similar conditions, saltwater acclimated fish show a very marked increase in serum sodium concentrations (P < 0.025). Those fluctuations in sodium levels are resultant from direct interference with the energy activated sodium transport systems of the gills. Microphotographs of gill filaments and lamellae show severe damage caused by the dispersant and dispersant/oil mixture with less impairment resultant from Bunker C exposure.     

Organochlorine insecticides and PCB'S in sediments of Lake St. Claire (1970 and 1974) and Lake Erie (1971).

Sediments were collected on a grid from Lake St. Clair in 1970 and 1974 and from Lake Erie in 1971 and analysed for organochlorine insecticides and PCBs. Suspended solids were centrifuged from pumped water in the Detroit River in 1974. Residues of DDE, TDE and DDT were highest in sediment from the Western Basin (70.3 ppb) Lake Erie and lowest in sediment from Lake St. Clair (6.6 ppb in 1970 and 2.6 ppb in 1974). The Central and Eastern Basins of Lake Erie contained residues that fell about mid-way between these means. TDE was the predominant component of ΣDDT and was followed by DDE at approximately half this residue. While DDT represented the lowest component in lake sediments, it was the highest component in suspended solids from the Detroit River.HEOD was present in the entire lake system but at only a fraction of the level of ΣDDT. The mean residue in Lake St. Clair was only 0.1 ppb while Lake Erie sediments contained 1–2 ppb. The highest mean residue (3.6 ppb) was in suspended solids in the Detroit River. Other organochlorine insecticides were only occasionally identified.PCB residues in sediment were approximately 3 times higher than the total organochlorine insecticide residue, being highest in the Western Basin (252 ppb) and lowest in Lake St. Clair (19 ppb in 1970 and 10 ppb in 1974). The Detroit River and Central and Eastern Basins of Lake Erie had intermediate residues.Residues in Lake St. Clair indicated a decline in ΣDDT, HEOD, and PCB residues between 1970 and 1974, and this coincided with the restrictions on the materials. A core sample from the Western Basin of Lake Erie indicated that ΣDDT, HEOD and PCB began to accumulate in sediments in 1958, 1953, and 1956, respectively. This appeared to indicate a lag period of 2–5 years after wide-spread use occurred.     

Congratulations to Valerii Viktorovich Mikheev

Anniversaries and Memorable Dates

Congratulations to Valerii Viktorovich Mikheev Candidate of Technical Sciences, honorable builder of the Russian Federation, and recipient of the prize awarded by the Council of Ministers of the USSR     

The long-term evolutions and the regional characteristics of atmospheric methane concentrations in Nagoya, 1983-1997

This study provides information on the long-term evolutions of the atmospheric methane (CH4) concentrations in Nagoya City, Japan, which were analyzed by using the continuous monitoring data observed at the eight observatory stations for 1983-1997. The 15-year records of the atmospheric CH4 concentrations were examined by means of a time-series analysis using a fast Fourier transform with a low-pass filter to elucidate the seasonal cycles and the long-term trends. The annual averages of the CH4 concentrations in Nagoya were 1.85 ppmv (parts per million by volume), 1.91 ppmv, and 1.90 ppmv in 1988, 1995 and 1997, respectively. Moreover, the annual average growth rate showed a drastic decrease from 17 ppbv (parts per billion by volume) year(-1) in 1992 to 2 ppbv year(-1) in 1993, and further down to 7 ppbv year(-1) in 1997. Comparison of the atmospheric CH4 records in Nagoya with those in global air of the northern hemisphere observed at Mauna Loa observatory in Hawaii, USA, allows us to estimate the excess concentration of CH4 in the urban atmosphere of Nagoya, which was 0.17 ppmv in 1988 and 0.15 ppmv in 1997. On a local scale, the atmospheric CH4 concentrations in the northern part of Nagoya City increased until 1992 and then gradually decreased from 1993 to 1997, although those in the south-western urban areas constantly increased at the averaged growth rate of 13 ppbv year(-1) for 1988-1997. The variation of the long-term trends of the CH4 concentrations in Nagoya may be ascribed to the emission changes from the CH4 sources due to the human activities such as waste dumping and landfills.     

The uptake of chemical elements from coal ash and settling basin effluent by primary producers II. Relation between concentrations in ash deposits and tissues of grasses growing on the ash

A number of reports of biomagnification of trace metals by plants indicate that elements are selectively concentrated within certain tissues when plants grow on coal ash. This study determined the uptake by, and tissue bioaccumulation of, 15 chemical elements within broom sedge and nut grass growing in the drainage system of a coal ash basin. Biomagnification of these elements by the grasses was compared to concentrations of these elements found in duckweed within the same system.Aluminium, arsenic, barium, cadmium, cobalt, chromium, copper, iron, mercury, manganese, molybdenum, selenium, strontium, titanium, and zinc were measured by neutron activation analysis in roots, stems, leaves and fruit of the grasses which grew in sediments within the effluent. Mercury and zinc were biomagnified in both grasses and duckweed to a level exceeding the concentration in sediment. All elements were biomagnified above the water concentration in all parts of the plants. Bioaccumulation of elements in the leaves and fruit of these plants provides a concentrated source of potentially toxic chemical elements for passage to animals which may consume these plants. The mechanisms of movement of potentially toxic elements from coal ash or water into food webs need additional study as utilization of coal is increased.