Surface sediment samples (n = 18) were collected from the Algerian Mediterranean coasts and analyzed for seven metals using inductively coupled plasma-optical emission spectrometry in order to asses the distribution and bioavailability of metals and to study the anthropogenic factors affecting their concentrations. Sediment samples were size-fractionated into three sizes: 1,080-500 (coarse), 500-250 (medium), and fine > coarse for all the metals. The average total extractable metal concentrations for Cd, Cr, Cu, Fe, Ni, Pb, and Zn were 1.1, 8.8, 4.7, 1,291.3, 13.9, 5.7 and 20.4 mug/g, respectively. The northeastern shelf had the lowest metal levels while the highest were in northwestern part mainly due to the significant tourism activities in the northwestern part. Comparison of our results to Earth's crust values and to previous studies points out that our samples were relatively unpolluted with respect to the heavy metals investigated; most of the metals are not from anthropogenic sources. Enrichment factors as the criteria for examining the impact of the anthropogenic sources of heavy metals were calculated, and it was observed that the investigated samples were not contaminated with Cr, Cu, and Fe, moderately contaminated with Ni, Pb, and Cd, and contaminated with Cd in some sites. The P5 phase had the highest percents of Cr, Cu, Fe, Ni, and Zn. Cadmium and lead were predominant in the P4 phase, while Cu, Fe and Zn were distributed in the order P5 > P3 > P4 > P2 > P1. The following order of bioavailability was found with the heavy metals Pb > Cr > Cd > Ni > Zn > Cu > Fe.

Determination of heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, Zn) by ICP-OES and their speciation in Algerian Mediterranean Sea sediments after a five-stage sequential extraction procedure

Heavy metals in soils are of great environmental concern, in order to evaluate heavy metal contents and their relationships in the surface soil of industrial area of Baoji city, and also to investigate their influence on the soils. Soil samples were collected from 50 sites, and the concentration of Pb, Zn, Cu, Cr, Ni heavy metals and the contents of characteristics in soil from industrial area of Baoji city were determined with X-ray fluorescence method. The concentrations of Pb, Zn, Cu, Cr and Ni in the investigated soils reached the amount of 2,682.00–76,979.42, 169.30–8,288.58, 62.24–242.36, 91.96–110.54 and 36.14–179.28 mg kg−1, respectively. The major element Pb contents of the topsoils were determined. to highlight the influence of ‘anthropic’ features on the heavy metal concentrations and their distributions. To compare, all values of elements were much higher than those of unpolluted soils in the middle of Shaanxi province that average 16.0–26.5, 67.1–120.0, 17.8–57.0, 46.9–65.6 and 24.7–34.6 mg kg−1 for Pb, Zn, Cu, Cr and Ni, respectively. An ensemble of basic and relativity analysis was performed to reduce the precipitate of Pb in soil was extremely high and greatly relativity with other elements. Meanwhile, Pb, Zn, Cu, Cr, Ni heavy metals were typical elements of anthropic activities sources, so it was easy to infer to the tracers of anthropic pollutions from the factorial analysis, which was coming from the storage battery manufactory pollutions. The pollutant distributions were constructed for the urban area which identified storage battery manufactory soot precipitate as the main source of diffuse pollution and also showed the contribution of the topsoils of industrial area of Baoji city as the source point of pollution. Consequently, the impact of heavy metals on soil was proposed and discussed. These results highlight the need for instituting a systematic and continuous monitoring of heavy metals and other forms of pollutants in Baoji city to ensure that pollution does not become a serious problem in the future.

Environment impact of heavy metals on urban soil in the vicinity of industrial area of Baoji city, P.R. China

The Oued Mellègue: Mining activity, stream sediments and dispersion of base metals in natural environments, North-western Tunisia

Heavy metals as indicators for Holocene sediment provenance in a semi-arid Mediterranean catchment in northern Tunisia

Over several decades, the mouth of the Mejerda River (northern Tunisia) has received large amounts of mining tailings mainly containing Pb, Zn and Ba. We have measured the concentrations of major and trace elements (Al, Ti, P, K, Mg, Na, Ca, S, Fe, Cl, V, Cr, Co, Ni, Cu, Zn, Ga, Br, Rb, Sr, Y, Zr, Nb, I, Ba and Pb) in three different fractions of 45 surficial sediments using wavelength dispersive X-ray fluorescence. The size distribution of fine particles (<2 μm, 2–20 μm, 20–63 μm) revealed that clay and silt compounds were predominant (75–95%) in the deeper estuarine region. These condensed clay phases were mainly dioctahedral smectite, illite and kaolinite. The total organic carbon (TOC) concentration varies from 0.08 to 1.37 %. The C:N ratio varies from 1 to 17 indicating that the organic matter has a mixed marine and continental origin principal component analysis was used to determine the associations of trace elements with organic and/or inorganic phases of the sediment fractions. The correl...

Trace elements in different marine sediment fractions of the Gulf of Tunis (Central Mediterranean Sea)

In the Fej Hcine mining area of north-west Tunisia, the Medjerda River and its principal tributary, El Melah, are polluted by heavy metals and arsenic. The geochemical studies undertaken have indicated pronounced falls in the concentrations of metals since the mining activities ceased, although the river sediments still contain higher levels than the local host rocks, particularly arsenic and zinc. At the Tunisia/Algeria border, arsenic concentrations in the Medjerda waters can exceed 1 mg/l. Leaching tests on samples of ore, flotation tailings and an arseniferous mass indicate that whilst Zn, Pb, Cu and Cd concentrations do not exceed 1 mg/l in the leachate solutions, arsenic levels reach 5, 344 and 9,400 mg/l respectively. The study has shown that the pollution originates not only from the mining activities but also from the mineral occurrences present in the mining district and from another source within Algeria.

S. Kamoun

Papers

Environmental impact of mining activity on the pollution of the Medjerda River, north-west Tunisia