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441.
Seasonal Fluctuation in Heavy Metal Pollution in Iran´s Siahroud River - A Preliminary Study (7 pp) 总被引:1,自引:0,他引:1
Charkhabi AH Sakizadeh M Rafiee G 《Environmental science and pollution research international》2005,12(5):264-270
Background The management of its available water resources has become a key issue for Iran. During the last few decades, the water quality
of Siahroud River in the coastal plain of the Caspian Sea in Gilan Province in Northern Iran has significantly degraded. The
scarcity of water has been compounded by rapid population growth and increasing pollution from fertilizers, pesticides, and
municipal and industrial wastes. One of the sources of this degradation is the movement of heavy metals from the river's watershed
into the various water systems supported by the river, including the water system for Rasht City.
Methods To study the magnitude of heavy metal pollution in the Siahroud River, seven heavy metals including Zn, Cu, Pb, Cd, Mn, Fe,
and Ni were measured in duplicate from replicated water samples collected over five consecutive seasons and analyzed by Atomic
Absorption Spectrometry. In situ measurements of pH were taken with the samples and total organic carbon (TOC) was analyzed
by IR gas measurement.
Results The results demonstrated that four of the seven heavy metals including Pb, Fe, Cd, and Mn exceeded permissible safe levels
as established by the United States Environmental Protection Agency. Multivariate factor analysis suggested that industrial
land-use was the main contributing factor for the high levels of Fe and Mn in the Siahroud River, whereas, Cd was principly
from agricultural activities in the watershed. The data also suggested that pH and TOC had an important role in the behaviour
of Pb and Mn, and that the elevated levels of these two heavy metals in Siahroud River was the consequence of other anthropogenic
sources. Only negligible levels of Zn, Cu and Ni were detected. Finally, all the sampling stations were subjected to cluster
analysis. The results indicated that three different zones could be distinguished according to the levels of pollution. In
addition, it was shown that the urban areas did not have a significant impact on the heavy metal pollution in the river. This
observation stems from the fact that the data from the sampling stations before and after Rasht City were not significantly
different.
Recommendation . Preventive measures need to be undertaken in the land-use systems and watersheds of the Siahroud River to reduce the pollution
levels of Pb, Cd, Mn and Fe. 相似文献
442.
Guy Mercier Patrick Drogui Jean-Fran?ois Blais Myriam Chartier 《Water environment research》2006,78(8):872-879
The objective of this research was to investigate the performance of the ferrous sulfate bioleaching (FSBL) process in a pilot plant for decontamination and stabilization of wastewater sludge. Batch and continuous experiments, conducted with two 4-m3 bioreactors using indigenous iron-oxidizing bacteria (20% v/v of inoculum) with addition of 4.0 g ferrous sulfate heptahydrate per liter of sludge initially acidified to pH 4.0, were sufficient for effective heavy metal (cadmium, copper, manganese, zinc, and lead) removal yields. The average metal removal yields during the FSBL process were as follows: cadmium (69 to 75%), copper (68 to 70%), manganese (72 to 73%), zinc (65 to 66%), and lead (16%). The FSBL process was also found to be effective in removing both fecal and total coliforms (abatement > 5 to 6 log units). The nutrients content (nitrogen, phosphorus, and magnesium) were also preserved in decontaminated sludge. 相似文献
443.
444.
Aqueous solutions of methamidophos (O,S-dimethyl phosphoramidothioato) are mineralised in sunlight in the presence of dispersed particles of TiO2 in a pre-industrial pilot plant. A commercial pesticide (Tamaron 50, 50% Methamidophos) is used as a model to demonstrate the application of the treatment. Total Organic Carbon (TOC) and PO4(3-) are analysed to confirm the mineralization of the contaminants. The concentration of organics in water was set at TOC approximately 100 mg/L, but with only illuminated TiO2, mineralization was slow. Oxidation of the organics present in the formulation is enhanced 18 times by use of an appropriate electron scavenger (peroxydisulphate) compared to TiO2 alone. 相似文献
445.
A digestive tract mass balance was performed on six men with high body burdens of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Intake via food was measured by analyzing duplicate portions of the food consumed by the volunteers and excretion via feces was determined by quantitative collection and analysis of the feces. Blood samples were taken to determine the current body burden. The results showed that the quantity of non-metabolized chemical excreted in the feces clearly exceeded the uptake via food for all of the 2,3,7,8-substituted PCDDs and some of the PCDFs, indicating a significant clearance across the gastrointestinal tract. The concentrations of these PCDD/F congeners in blood and feces were highly correlated (r > 0.8), demonstrating that the fecal PCDD/F content was determined by the body burden. The half lives in the test persons due to fecal clearance of non-metabolized chemical were estimated from the excretion rate and the current body burden and ranged between 10 years (Cl8DD) and 33 years (2,3,4,7,8-Cl5DF). These were compared with the overall contaminant half-lives due to all clearance processes which were calculated from the body burden and the decrease in blood concentrations measured over several years. The fecal clearance of non-metabolized PCDD/F contributed on average between 37% (2,3,7,8-Cl4DD) and 90% (Cl8DD) to the total elimination. This indicates that the gastrointestinal pathway plays a decisive role in the clearance of most 2,3,7,8-subsituted PCDD/F congeners. 相似文献
446.
447.
Fritz Nü?lein Ernst Anton Feicht Sigurd Schulte-Hostede und Antonius Kettrup 《Umweltwissenschaften und Schadstoff-Forschung》1997,9(3):136-142
Zusammenfassung Ein quecksilberkontaminierter Altstandort dient als Beispiel für eine umweltmedizinische Beurteilung der Belastung der im
Umfeld wohnenden Personen durch Quecksilberimmissionen. Dabei wird die innere Exposition für sieben verschiedene Altersgruppen
bezüglich der KontaktmedienBoden, Luft undNahrungsmittel anhand von konventionell festgelegten Szenarien abgesch?tzt und ein Vergleich mit den epidemiologischen Ergebnissen eines
Humanmonitorings angestrebt. Die standortspezifisch und pfadspezifisch durchgeführte Expositionsabsch?tzung stützt sich auf
cine Vielzahl von unterschiedlichen Probenehmern sowie auf über mehrere Jahre durchgeführte Konzentrationsmessungen in den
aufnahmerelevanten Kompartimenten. Sowohl die Berechnungen als auch die epidemiologischen Untersuchungen zeigen eine leichte
Erh?hung der Quecksilberexposition, gemessen an strengen Richtwerten.
相似文献
448.
449.
Gerrit Schüürmann Gerd Sch?dlich Ralph Kühne 《Umweltwissenschaften und Schadstoff-Forschung》1994,6(1):3-4
Die Cadmium-Belastung im Ackerboden der Region Leipzig-Halle wurde an 63 terrestrischen Standorten über einer Fl?che von etwa
7 000 km2 bestimmt. Die Verteilung der durch Normierung auf einheitlichen Gehalt an Ton und organischem Material erhaltenen effektiven
Expositionswerte wurde mit Literaturangaben über NOEC-Werte verglichen. Die Risikoanalyse ergibt, da? an 9% der untersuchten
Standorte eine potentielle Gef?hrdung der Bodenorganismen durch Cadmium vorliegt.
Cadmium contamination in the agricultural soil of the region Leipzig-Halle was determined at 63 sites covering an area of
ca. 7 000 km2. Normalization according to lutum and organic matter lead to effective exposure values; their distribution was compared with
NOEC data taken from literature. The risk analysis reveals that the soil fauna is potentially affected by cadmium contamination
at 9% of the investigated sites. 相似文献
450.
Orrù R Cincotti A Concas A Cao G 《Environmental science and pollution research international》2003,10(6):385-389
The possibility of exploiting self-propagating reactions for environmental protection is discussed in this paper. In particular, results obtained at the laboratory scale and related to the fixation and consolidation of high level radioactive wastes, the recycling of silicon sludge and aluminum dross produced by semiconductor industries and aluminum foundries, the treating and recycling of a highly toxic solid waste from electrolytic zinc plants, and the degradation of chlorinated aromatics, are examined with particular emphasis on the latter case. Specifically, the self-propagating destruction of hexachlorobenzene and 2-(2-4-dichlorophenoxy)-propanoic acid with calcium hydride as reductive substrate is demonstrated. In fact, the heat liberated by the reactions involved is large enough to guarantee the self-sustaining character of the process within a wide range of reactants compositions. Moreover, no residual chlorinated organic compounds were found in the final solid product. Some reactor engineering aspects, as well as other significant future scientific and technological issues, are also addressed in view of large-scale applicability of processes based on self-propagating reactions. To date, the batch reactor technology seems to be more easily applicable, although the use of continuous reactors is not excluded in the next future. 相似文献