Concentration Levels Of Heavy Metals Research Articles

Composition of aerosols in an industrialized area of Northeastern China

Surface level aerosol samples were collected utilizing conventional high volume air sampler in the highly industrialized area of Shenyang, China, located in the northeastern part of the country. Sampling was conducted in the severely polluted Tiexi District area on December 25, 1995 and again from August 23–30, 1997. The average SO2 and TSP concentrations obtained during the summer was 38 ppb and 388μg/m3, respectively. SO4 2‐, NO3 ‐ and Cl‐ were the detected water‐soluble anions with respective summerconcentrations of 3.6–10.6μg/m3, 3.2–6.5μg/m3 and 4.5–7.8μg/m3. In addition, elevated levels of heavy metals such as iron, lead, and zinc in aerosols were noted, which most likely resulted from the combustion of coal and other fuels and/or emissions associated with nearby industrial facilities. As expected, concentration levels of TSP, water‐soluble ions and heavy metals were found to increase during the winter months.

The Environmental Status of Hawkesbury River Sediments

The Hawkesbury River of New South Wales, Australia is under increasing environmental stress. Pre‐anthropogenic and current levels of heavy metal concentrations have been established for bed sediments between Windsor and Broken Bay. Sediment heavy metal concentrations in the main channel of the Hawkesbury River are close to background, but are substantially elevated in the headwaters of Berowra Creek, Cowan Creek and in southeast Pittwater. The Berowra Waters area and the upper catchment contribute both heavy metals and organochlorines/pesticides to the Berowra estuary. High contaminant levels above and below the Hornsby sewage treatment plant, and above and below the Calna Creek sewage treatment plant, make an assessment of the contribution by these plants difficult. Analyses of oyster tissue from the middle and lower reaches of the estuary indicate that heavy metal contaminants are entering the food chain.

Transport Pathways of Radionuclides and Chemical Contaminants in the Kara Sea

A joint Norwegian/US field expedition to the Kara Sea was carried out in August-September 1995. The main purpose of the expedition was to monitor contamination levels in sea water and sediments, determine transport pathways of contaminants and investigate oceanographic circulation patterns. The results from this investigation corroborate earlier findings that 137 Cs and 90 Sr concentrations are not appreciably elevated above expected levels for the Kara Sea. Although the potential for sorption of 137 Cs and 90 Sr to sediments is greatest within the mixing zones of the rivers Ob and Yenisey, the observed distribution of 137 Cs and 90 Sr in the Kara Sea is primarily controlled by water mass transport processes. Influence of a 90 Sr contribution from the rivers has been detected in the Ob and Yenisey estuaries. The concentration levels of heavy metals is generally very low and the levels of PCBs were below the detection limit for all the measured samples.

Activation of in vivo metabolism of malathion in male Tilapia nilotica.

Adult T. nilotica were collected from River Nile, nearby Cairo, Egypt. Fishes weighing about 100-150 g were kept in glass aquaria (80 X 40 X 60 cm) containing river water. The general characteristics of river water are given in Table 1. The water samples were very low in heavy metals (concentration levels of Hg, Cd,Co, Cr and Pb were < 0.005 mg/L). The fish were fed twice daily a commercial diet (mixed protein and carbohydrate) and were kept at room temperature (25°C ± 2°C) for 48 hr before running the experiments. Male fishes were selected for this study to unify the specific xenobiotic enzymes liable to be involved in vivo degradation. either before or after injection with phenolbarbital.

The background levels of heavy metal concentration in sediments of the west coast of Peninsular Malaysia

The west coast of Peninsular Malaysia is exposed to several sources of pollutants, predominantly from human activities. In this study heavy metal contamination was studied in the sediments collected from sampling stations all along the west coast of Peninsular Malaysia. The results show that in general the background levels of heavy metals in the sediments in most of the stations are still within the normal levels found elsewhere. Over 70% of Fe analysed ranges between 25000–50000 μg/g, over 50% of Mn analysed ranges from 3,000 to 5,000 μg/g. The bulk of Zn (60%) analysed ranges from 600 to 900 μg/g and over 70% of Pb analysed in sediments falls within 10–30 μg/g. Cu analysed shows over 70% below 5 μg/g, while for Cd over 80% is below 1 μg/g. The usefulness of the background concentrations is justified in view of the expected increases in industrial, domestic and municipal effluents discharged as the country makes headway into diversified land-based developments, especially in the industrial sector. This is especially so along the western coasts of Peninsular Malaysia, where over 70% of the populations live. The anthropogenic input of heavy metals into the coastal environment of Peninsular Malaysia had not been adequately studied; however, there are valid reasons to suspect increasing amounts of heavy metals in the coastals sediments.

Heavy metals and sulphur in mosses from southern Spitsbergen

Concentrations of Cd, Pb. Ni, Cu. Zn and S were determined in 16 moss species collected from 9 localities in southern Spitsbergen (mostly within the Hornsund region). Two species, Sanionia uncinata and Hylocomium splendens, were objects of more thorough studies. In Sanionia uncinata the mean concentrations were (ug/g): Cd-0.59, Pb-7.07, Ni-4.25, Cu-6.01. Zn-21.13 and S- 1, 481. Hylocomium splendent accumulated similar quantities of these elements. The concentrations of metals and sulphur in mosses differed significantly {p0.05) from site to site, depending on geological and climatic conditions specific to the Arctic region. The effect of remote sources of pollution reaching Spitsbergen on the levels of heavy metal concentrations was taken into account, as well as the effect of local emissions from the Polish Polar Station. At 10-25 metre distances from the Station, the levels of heavy metals and sulphur were 3-10 times higher than at a 300-metre distance.

Heavy metals in river tees estuary sediments

Abstract A detailed survey of the River Tees estuary in the north east of England has been carried out to determine the levels of total heavy metal concentrations in its bed sediments. Samples were collected at 31 locations, 0.5 km apart between the upper dredging limit and the river mouth. Three samples of the surface sediments were taken at each location; from the north and south banks and at mid‐channel. The mean total metal concentrations after acid digestion were found to decrease in the order Zn>Mn, Pb>Cu>Cr>Ni>Cd for the sample locations. Along some locations of the estuary, the maximum and other peak metal concentrations were similar to those found in strongly polluted industrialised rivers.

Background concentration ranges of heavy metals in Swedish groundwaters from crystalline rocks: A review

Concentration levels of heavy metals (Cr, Cu, Zn, Cd, and Pb) in groundwaters, primarily from igneous crystalline bedrock, are summarized. The groundwaters were sampled from 126 stations in Sweden during 1985–87 (1–6 times per year). The observed groundwater concentrations are generally at least qualitatively related to concentration levels in the bedrock as well as to pH of the water. Background concentration ranges for unpolluted groundwaters from the present bedrock environment are suggested.