Presence Of Heavy Metal Contaminants Research Articles

The chemical composition and heavy metal content of sesame oil produced by different methods: A risk assessment study.

The oil was extracted from sesame seed with two extraction methods. Traditional (Ardeh oil) and industrial method (cold pressing method: virgin and refined sesame oil) oil extraction was studied to compare the quality and heavy metal content of extracted oils. The chemical properties (fatty acid composition, peroxide, anisidine, acid values, and TOTOX) and heavy metal contents were investigated. The Hazard Quotient (HQ) and Hazard Index (HI) of heavy metal intakes were calculated. The results demonstrated that the predominant fatty acid in oil samples was oleic, linoleic, palmitic, and stearic acids. It was indicated the peroxide, anisidine, acid values, and TOTOX of oil samples were as the order of Ardeh oil > virgin sesame oil > refined sesame oil. The reduction pattern of Pb > Zn >Cu > Cd >As was reported in sesame seed. Although the oil refining had been greatly reduced the Pb of oil sample, but it had yet been much higher than the permissible levels set by Codex Alimentarius. The HQ and HI of all heavy metals were less than one, but they were higher in Ardeh oil compared to others. It is necessary to monitor the presence of heavy metal contaminants and the quality of imported sesame seeds prior to oil preparation.

Ground Water Contamination: Effects and Remedies

Studies on “ground water contamination : effects and remedies” have been conducted, in the light of these, field work studies in Obudu and Obanliku local Government Areas of Cross River State, South Eastern Nigeria, was conducted. Fifteen (15) locations of water for drinking and other domestic uses were carefully studied in the area, with their surface to water depth values recorded. Five(5) of the locations were at surface saturated water depressions(SWD), seven(7) were Hand dug wells(well), while three(3) were bore holes(BH). The physiochemical composition data compared with world Health Organization (WHO) standard shows that, the bore water was safer for drinking than the hand dug wells and surface water in saturated water depressions. Coliform count unite per 100ml of water, were detected in most of the locations in the saturated water depressions and hand dug wells, showing evidence of biogenic interference with the water. Coliform count unite per 100ml of water was not detected in any of the three bore holes, probably due to their depth distance from Biogenic activities. Phosphate and Nitrate levels were significantly above WHO standard in saturated water depressions and Hand dug wells, probably due to erosional and leaching actions of inorganic fertilizers from farm lands and waste from near dump site. It is important to note that most water borne diseases are as a result of ground water communication with contaminant, such as heavy metals, leachate from dump sites, pollutants from inorganic fertilizers, pith toilets sea water intrusion etc., most boreholes are contaminated by these processes. This is one of the reasons for the increase in the rate of cancer in most developing countries. Hence, heavy metals are known to be carcinogenic to the human cells, and also can cause mutation. The remedies to these include:
 
 The process of exploiting and storing ground water should be done with all safety precautions, such as making sure biochemical parameters in water are in line with WHO standard
 Thorough biochemical analysis and test for the presence of heavy metal contamination and coliform count and other contaminants should be done on ground water, before use for domestic and industrial purposes.
 Surface depth measurement of recharge zones in boreholes should be carried out to ensure that borehole water is from confined aquifers that are safe for domestic and industrial uses.
 Proper waste disposing system such as engineered toilet pits, engineered dump sites and effective management of electronic waste should be monitored and implemented
 Where the purity of the water is not satisfactory, such water should be properly treated before used for drinking and other domestic purposes.

Heavy metals pollution of Kotlin Island in the Gulf of Finland

The current environmental state of Kotlin Island and coastal areas reflects the negative impact of industry, transport and urban utilities that has lead to increased heavy metal content in soils, in terrestrial and aquatic vegetation and in the water of the Gulf of Finland. Based on the analysis of pollutant metals in roots and shoots of native plants grown on Kotlin Island, species with high metal-accumulating capacity have been identified. Of these, there were dandelion and coltsfoot demonstrating high mobility in heavy metals Zn especially upward transfer. These could therefore be promising as bioindicators and phytoremediators of polluted areas pointing to origins of contamination. The presence of heavy metal contamination in the coastal waters of the gulf and its variability along the coastline is regarded as dependent on multiple sources of pollution associated with Kotlin Island, namely industrial and municipal waste waters, ship and vehicle traffic, aerosol deposits, contamination by dredging activity in a new port as well as the result of metals leaching from the soils of the island (Zn, Cu, Ni). Metal-accumulating coastal plants such as cane can be a source of secondary pollution of the gulf waters during their seasonal decomposition. The data showed significantly elevated concentrations of Ni, Zn and Cd in the hair of children living in the town of Kronstadt located on Kotlin Island that confirms the adequacy of the proposed indicating methodology and shows the unfavorable environmental situation in the region.

Analisis Lingkungan Sekitar Tambang Nikel Terhadap Kualitas Ternak Sapi Pedaging di Kabupaten Halamahera Timur

Continuous activity in nickel mining has resulted in steadily growing numbers of contaminants which influence the environment. Cattle rising nickel mining in East Halmahera are exposed to high contamination. This study was conducted to assess the presence of heavy metal contamination on soil, water, grass and animal products such as liver and meet. The method used were survey and case study. The parameters measured were the heavy metal content (Pb), Cadmium (Cd), Arsenic (As) and Mercury (Hg) in soil, water, grass and sample of cattle liver and meat. The samples were analyzed using AAS (Atomic Absorption Spectrophotometry) method. Thedata obtained were analyzed descriptively and t-test was used to asses the difference results of all parameters measured from two locations. The results showed that Pb in water and outside mining location were 0.1367 and 0.0770 ppm, respectively. Hg concentration in soil, water, grass, liver and meet callte raised around mining location were 17.8725, 0.0447, 6.6925, 7.4910 and 4.7210 ppb, respectively. The water around mining was contaminated with Pb. The contaminanion of Hg on soil, water and grass around mining areas, and also the liver and meat samples of cattle were exceeded the maximum standard that could be tolerated. Keywords: heavymetal,mining nickel,contamination, beef cattle.

Strength of lime-cement stabilized tropical lateritic clay contaminated by heavy metals

Cement and lime are considered as stabilizers of contaminated land since they can reduce the leachability of contaminants. The contaminated soils can generally have higher strength after stabilization. However, the presence of heavy metal contaminants in soil interferes with stabilizer hydration which inhibits strength development in treated soils. Stabilizing products also have different strength properties due to heavy metals that affect levels of chemical fixation in different contaminated soil mixes. This paper presents an experimental study that evaluates strength development in cement-lime stabilized/solidified soils contaminated with either copper or zinc. Unconfined compressive strength was used to determine the suitability of cement and lime stabilization of contaminated laterite clay soils. Control samples (cement-lime stabilized soils without heavy metals) were prepared for comparison. Results confirmed the interference of heavy metals in the process of cement and lime hydration as a direct reflection of varied strength developments in tested soil samples. It was found that metal concentration, stabilizer content, type of stabilizer, and heavy metal type were factors that affected stabilizer hydration and strength development. The most significant ones of these were the type of stabilizer used and heavy metal concentration.

Heavy metals contamination of Chrysichthys nigrodigitatus and Lates niloticus in Ikere Gorge, Oyo state, Nigeria

This study investigates the presence of heavy metal contamination of Chrysichthys nigrodigitatus and Lates niloticus . Adult C. nigrodigitatus and L. niloticus were obtained from fishermen in Ikere Gorge, Oyo state, Nigeria. Water samples were also collected during the wet and dry seasons of the year in the same locality. The presence of five metals were analyzed in both fish and water. Iron, copper, zinc, lead and manganese were investigated by atomic absorption spectrosocopy (AAS) in two separate experiments. In each case, four tissues; gills, bone, intestine and muscle were compared with the level of metals in the water. Lower concentrations of metals were recorded in water than in fish. Lower concentration of the metals found in fish and water was less than that recommended by the World Health Organisation (WHO) guideline for maximum concentration recorded in the tissue of the two samples. Iron was found to be dominant in the intestine of C. nigrodigitatus, while manganese was found to be highest in the bone of L. niloticus, copper recorded the least of all the metals. There is significant difference (P < 0.05) in heavy metals concentration in the gill of C. niloticus and water, as well as the concentration in the intestine of L. niloticus and water. It was concluded that though the heavy metals of interest were present in measurable quantities, they were still within safe limits for consumption. Key words : Heavy metals, fish, gorge, contamination.

Combining nutrition, food science and engineering in developing solutions to Inflammatory bowel diseases – omega-3 polyunsaturated fatty acids as an example

The Inflammatory bowel diseases, Crohn's disease and ulcerative colitis, are debilitating conditions, characterised by lifelong sensitivity to certain foods, and often a need for surgery and life-long medication. The anti-inflammatory effects of long chain omega-3 polyunsaturated acids justify their inclusion in enteral nutrition formulas that have been associated with disease remission. However, there have been variable data in clinical trials to test supplementary omega-3 polyunsaturated fatty acids in inducing or maintaining remission in these diseases. Although variability in trial design has been suggested as a major factor, we suggest that variability in processing and presentation of the products may be equally or more important. The nature of the source, and rapidity of getting the fish or other food source to processing or to market, will affect the percentage of the various fatty acids, possible presence of heavy metal contaminants and oxidation status of the various fatty acids. For dietary supplements or fortified foods, whether the product is encapsulated or not, whether storage is under nitrogen or not, and length of time between harvest, processing and marketing will again profoundly affect the properties of the final product. Clinical trials to test efficacy of these products in IBD to date have utilised the relevant skills of pharmacology and gastroenterology. We suggest that knowledge from food science, nutrition and engineering will be essential to establish the true role of this important group of compounds in these diseases.

A study of contamination and damage on Si surfaces induced by dry etching

Damage/contamination effects of dry etching in two different modes, plasma etching (PE) and reactive ion etching (RIE), on silicon surfaces just after oxide etching are discussed. The electrical measurements on aluminium Schottky diodes were used to evaluate the effect of dry processing and various postetch treatments on a Si substrate. The presence of heavy metal contamination of the Si surface as a result of dry etching was confirmed by secondary ion mass spectroscopy and SECCO etch defect decoration. C-t (minority-carrier lifetime) measurements on special guard ring devices were used as indirect evidence of heavy metal contaminants. The quality of a gate oxide grown on Si surfaces after dry-etching conditions was examined through breakdown voltage. Improved device electron mobility was observed for the RIE-exposed Si surface compared to PE, due to the smoother surface after the RIE process. >

Shifts in caddisfly species composition in Sacramento River invertebrate communities in the presence of heavy metal contamination.

The results reported in the study document a change in invertebrate species composition that may be due to exposure to increasing levels of toxic metals in the environment. This is a gradual response which could only be documented because of the long-term and extensive data base accumulated over 18 years. The study is unique in this respect and may also reveal an example of the unexpected side benefits which accrue from a monitoring program such as this. The study area was the upper Sacramento River, which extends from near Anderson, California, to the vicinity of Red Bluff, California. During a routine program conducted to monitor resident benthic invertebrate communities, unusual shifts in species composition of two indigenous caddisfly larvae were observed. These occurrences were not associated with any point source, nonpoint source, or seasonal event for which data were available. However, there is reason to suspect that heavy metals in this ecosystem had a role in the changes seen.