Environmental Impact Of Heavy Metals Research Articles

Elution behaviour and environmental impact of heavy metals and rare-earth elements from volcanic ashes of Mt. Oyama, Miyake Island

To obtain information on the environmental impact of materials eluted from volcanic ashes of Mt. Oyama, Miyake Island, which erupted in July 2000, the dissolution behaviours of heavy metals and rare-earth elements from the volcanic ashes were examined. The most important characteristic of the Mt. Oyama eruption is that sulphur dioxide (SO2) gas has been continuously released, and all persons living on Miyake Island have been required to evacuate. To estimate in terms of the volcanic eruption using SO2 gas, the ash nature in Mt. Usu, Hokkaido, was also examined and compared with that in Mt. Oyama. When rain water mixed the ashes, the water from the ashes of Mt. Oyama became acidic because of the sulphuric acid. Therefore, SO2 gas in Mt. Oyama can accelerate the dissolution of protons and heavy metals in the ashes, whereas the rain water in Mt. Usu was not acidic and the dissolution of the heavy metals was not so evident compared with that in the case of Mt. Oyama. With this sulphuric acid, heavy metals such as As, Cd, Pb and Hg in the ashes in Mt. Oyama easily dissolved owing to the low pH. The ashes in Mt. Oyama had been released for eight years and the amount of fallen ashes was estimated to be 33 billion tons. The weights of the harmful heavy metals in the volcanic ashes, such as As, Cd, Pb and Hg, were estimated to be 3.8 × 102, 1.3 × 103, 1.1 × 103 and 29 kg, respectively, and these heavy metals were dissolved and diluted in seawater. Therefore, the concentration and species (chemical form) of these metals should be carefully monitored in the future. Moreover, SO2 gas, which has a direct effect on human health and has been monitored continuously, causes other effects, such as facilitation of metal ion elution and rock aeration.

Content, mobility and transfer behavior of heavy metals in MSWI bottom ash in Zhejiang province, China

Municipal solid waste incinerator (MSWI) bottom ash samples were taken from six cities of Zhejiang province, where 1/4 incinerators of China were located. The samples were instrumentally analyzed to detect the content of heavy metals. Sequential extraction procedure (SEP) was adopted to characterize the mobility and environmental impact of heavy metals. And the transfer coefficients of heavy metals from the input MSW to the bottom ash during the incineration were also calculated. It showed that the average content of Zn, Mn, Cu, Pb and Cr in the bottom ash exceeded 300 mg/kg, which was much higher than that in the soils. SEP results showed that although the residue fraction was the primary fraction of the heavy metals in the bottom ash, there were still 1.84 mg of Cd, 86.21 mg of Cu, 83.46 mg of Pb and 939.46 mg of Zn in 1 kg bottom ash having the potential of leaching, which indicated a great threat to the surrounding environment. The result of coefficients calculation revealed that almost all the Cu, Cr, Mn and Ni in the input MSW were transferred to the bottom ash during the incineration. Bottom ash was also the main destination of Cd, Co, As, Mo, Pb and Zn though considerable amounts of those metals were transferred to the raw gas.

Geostatistical modelling of heavy metal contamination in the topsoil of Guadiamar river margins (S Spain) using a stochastic simulation technique

This paper presents a methodology to evaluate and map environmental hazard and characterize environmental impact of heavy metals in Guadiamar river margins (South of Spain) contaminated by the Aznalcóllar mining spill. This methodology accounts for uncertainties in the mapping of the probability of soil contamination with different heavy metals and is based on a co-simulation technique using direct sequential simulation of a multivariate set of variables. Each variable is simulated based on primary data – the heavy metal concentrations in the soil – and on secondary data, consisting of a previously simulated map of one of the heavy metals. Using several realizations of the simulated multivariate set, a “hazard” index was calculated for each pixel of the study area, based on the simultaneous proportions (joint probabilities) of different levels of all metals. Finally, the intersection of the hazard map, based on the joint dispersion of all contaminants, with the environmental impact map for the different ecosystems, resulted in environmental hazard maps for the river margins. The performances of the multivariate sets of co-simulated variables were compared considering two extreme alternatives: i) the soil is considered in need of treatment if all 5 heavy metals simultaneously exceed their concentration limit value at the same location; ii) the soil is considered in need of treatment if at least one heavy metal exceeds its concentration limit at the same location.

Environmental impact of heavy metals from dredged and resuspended sediments on phytoplankton and bacteria assessed in in situ mesocosms

Past and on-going reclamation, dredging, construction and shipping activities impact Ponggol Estuary, located on the northeastern coast of Singapore. Tin, lead, nickel, cadmium, and copper in particulate and dissolved fractions and sediments ranged from ND (undetectable)–92ppm, ND–303.2ppm, ND–2818.4ppm, ND–74.4ppm and ND–1117.7ppm, respectively. Intensive dredging activity during the monitoring period may have led to the resuspension and bioavailability of particulate metals. This was tested by the exposure of phytoplankton and bacteria in mesocosms to previously measured environmental levels of heavy metals and the contaminated sediments with the highest heavy metal concentrations from one of the impacted sites. The results showed significant copper toxicity to phytoplankton and autotrophic bacteria, followed by nickel and lead at all concentrations tested. Enhanced rates of heterotrophic bacterial production and total bacterial abundance were observed in treatments with higher metal concentrations. Among the various treatments, particulate and sediment metal concentrations were significantly different from those of the control. Mesocosms using contaminated sediments with the highest metal concentrations compared with the control showed a bioavailability of metals that resulted in the inhibition of phytoplankton and autotrophic bacteria. High concentrations of copper (5.52–11.35mgL−1) and nickel (2.42–2.71mgL−1) observed in the aqueous phase of treatment mesocosms, and attributed to release from the contaminated sediments could account for the toxicity to phytoplankton and autotrophic bacteria.

The environmental impact of heavy metals from sewage sludge in ferralsols (São Paulo, Brazil)

The spreading of sewage sludge on acidic ferralsol soil was simulated in a column experiment in order to estimate the potential impact on water and soil quality. Drainage and runoff water were sampled daily over a 2-month experiment and analysed for Fe, Ni, Cu, Pb and DOC. Results show a clear influence of the sludge on the water quality, especially at the start of the experiment, increasing the export of Cu, Ni, Pb and in DOC from the soil, mainly in dissolved form. Nickel was usually the most mobile element in the sludge and in the soil. In the soil, Pb mobility was complex and increased drastically with time compared to the other elements. No significant increase in soil heavy metal content due to the sludge spreading was recorded on this time scale.

Environmental impact of heavy metals (Fe, Ni, Cr, Co) in soils waters and plants of triada in euboea from ultrabasic rocks and nickeliferous mineralisation

Soil, water and vegetation samples were collected from the Triada area of Central Euboea and analysed for heavy metals in order to evaluate their environmental impact. The geology of the area studied includes ultrabasic rocks that are overlaid by Upper Cretaceous limestones whereas Fe–Ni mineralisation is intercalated between either the ultrabasic parent rocks or the karstified Jurassic/Triassic carbonates and the transgessive Upper Cretaceous limestones. All the samples were analysed for heavy metals by using atomic absorption spectroscopy. The heavy metal ranges (in μg g−1) for soils samples are: Ni 480–4000, Cr 240–2720, Co 40–208, Fe 24,000–380,000, Mn 46–1680, Pb 16–56, Zn 40–144, Cu 2–82. The values of soil samples of the Triada area are much higher than the values found for Ni, Cr, Co and Fe, in normal soils of the world. The heavy metal ranges (in μg L−1) for water samples are: Ni 19–24, Cr 19–476, Co <5, Fe <100, Mn <100, Mg 5.7–220.5, As 30–69, Cd <2, Pd <10, Zn 5–11, Cu 2–7. The water samples of the Triada area have Cr and Mg concentrations higher than the permittable values. The heavy metal ranges (in μg g−1) for vegetation samples are: Ni 1–135, Cr 0–24, Co 1–21.5, Fe 20–680, Mn 10–206, Cd 0–10, Pb 0–14, Zn 14–70, Cu 0–10.5. The vegetation samples of the Triada area have so high values of Ni, Cr and Co that are considered toxic. The intercorrelated elements Fe, Ni, Cr, Co of the Triada soils, waters and vegetation reflect their association with the ultrabasic rocks and with the Fe–Ni mineralisation.

An investigation of environmental levels of cadmium and lead in airborne matter and surface soils within the locality of a municipal waste incinerator

The results of an investigation into the environmental impact of heavy metals in the airborne emissions from the Baldovie municipal waste incinerator, Scotland, are presented. A sampling network of 1-km grid squares covering a 7 × 9 km area was established over the incinerator plant and its surroundings. Surface soil core samples were collected from within each 1 km 2 and analysed for cadmium and lead content. The spatial distribution of lead levels in soils showed a marked variation downwind from the Baldovie incinerator in comparison with the background level for the area but remained well within the typical range of lead in rural, unpolluted, British soils. A comparison of the observed levels of lead in local soils, with the predicted downwind long-term ground level lead distribution in air indicates that atmospheric emissions of lead originating from the Baldovie incinerator directly determine concentrations of lead in soils within a radius of 5 km of the incinerator. An empirical relationship between the levels of lead in soils and the long-term levels in air was established. In the case of cadmium, the spatial distribution of the heavy metal showed neither a marked nor extensive contamination of the sampled area around the incinerator and remained within the typical range of cadmium levels in rural, unpolluted, British soils. The work concludes that atmospheric emissions of lead from the Baldovie incinerator significantly determines the local distribution of lead in soils within the immediate vicinity of the incinerator.

Environmental impact of mercury and other heavy metals

The environmental impact of heavy metals is reviewed. One significant source of emissions of heavy metals to air is waste incineration. Consumer batteries contributes significantly to this problem, as well as to heavy metal leakage to groundwater from landfill deposits. The situation in Sweden is used as an example to describe how the deposition from the atmosphere still is increasing the load of heavy metals, like mercury, cadmium and lead, in top soils and aquatic sediments. Critical factors and effect levels for Hg, Cd, Pb, Cu, Zn and As are discussed. Specific questions like mercury contents in present battery waste and heavy metal contents in new and future secondary batteries are addressed.

Hepatic enzyme activity after combined administration of methylmercury, lead and cadmium in the pekin duck

In order to assess adequately the environmental impact of heavy metals it is important to consider that they may occur simultaneously in the environment, where they may interact to alter their individual toxicities on living systems. Metals such as mercury (Hg), lead (Pb) and cadmium (Cd) can be found in all levels of the polluted ecosystem, and in animals inhabiting such areas. In the polluted aquatic environment waterfowl have been noted to accumulate high levels of these metals in their tissues. A major toxic manifestation of heavy metal exposure is the perturbation of a wide range of enzyme systems in virtually all subcellular compartments. With the exception of lead, little data is available on the effects of metals on avian enzyme systems. The present report describes the effects observed in vivo on acid phosphatase (AP), glutathione S-transferase (GST) and cytochrome c oxidase (cyt c ox) in the liver of pekin ducks exposed to combinations of methylmercury (MeHg), lead and cadmium.

Radiochemical Techniques Applied to Laboratory Studies of Water Leaching of Heavy Metals from Coal Fly Ash

Assessment of the potential environmental impact of heavy metals (HM) mobilized by coal-fired power plants showed that water leaching of HM from pulverized fuel ash may for certain HM constitute an important pathway to the aquatic environment. This process was therefore investigated in more detail by laboratory experiments. Batch experiments were performed in order to simulate ash pond conditions, whereas column experiments were carried out to represent water leaching from fly ash deposits. Using highly sensitive radiochemical techniques such as radioactive tracers and neutron activation of fly ash the fate of a single HM could be easily followed even in very low concentration experiments. Employing radioisotopic tracers the distribution coefficients of simple ionic forms of As, Sb, Bi, Se, Te, Cr, Mo, W, Ni, Cd in a coal fly ash/water system could be determined as a function of pH. Results obtained on the adsorption and desorption behaviour of HM on coal fly ash can be explained in part on the basis of the surface predominance and the aqueous chemistry of single ionic, mainly anionic, forms of the relative elements. But ion exchange and coprecipitation phenomena also seem to be important processes. The nature and concentration of ions contained originally in the water used (distilled water, fly ash leachate and seawater) were found to have a strong influence on the sorptive behaviour of HM on coal ashes. The high degree of applicability of radiochemical and nuclear techniques to coal ash water leaching problems has been demonstrated and further points for subsequent research in this field possibly using nuclear techniques are indicated.