Chemical processes in the rhizosphere play a major role in the availability of metals to plants. The objective of this study was to assess the potential of white lupin (Lupinus albus L.) for the phytoimmobilisation of heavy metals in a calcareous soil with high levels of Zn and Pb (2,058 and 2,947 μg g⁻¹, respectively) by evaluating the chemical changes in the rhizosphere, relative to bulk soil, which modify the solubility of heavy metals. Plants were cultivated for 74 days in specially designed pots (rhizopots) in which rhizosphere was sampled easily under controlled conditions. White lupin accumulated high concentrations of Mn in the shoots (average of 4,960 μg g⁻¹), well above the normal concentration in plants (300 μg g⁻¹). But the metal concentrations found in shoots were not at toxic levels. Rhizosphere soil showed a significantly greater redox potential (245 mV) and water-soluble organic carbon content (34.6 μg C g⁻¹) than bulk soil (227 mV; 27.6 μg C g⁻¹). Root activity decreased EDTA-extractable Pb, Zn and Fe and promoted their precipitation as insoluble compounds in the residual fraction (acid digestion), hardly available to plants. These results indicate the suitability of this annual N₂-fixing species for the initial phytoimmobilisation of heavy metals in contaminated soils.

About 170 million tons of phosphogypsum (PG) are annually generated worldwide as a by-product of phosphoric acid factories. Agricultural uses of PG could become the main sink for this waste, which usually contains significant radionuclide (from the ²³⁸U-series) and toxic metals concentrations. To study PG effects on pollutant uptake by crops, a completely randomised greenhouse experiment was carried out growing Lycopersicum esculentum Mill L. on a reclaimed marsh soil amended with three PG rates (treatments), corresponding to zero (control without PG application), one, three and ten times the typical PG rates used in SW Spain (20 Mg ha⁻¹). The concentrations of Cd, Pb, U (by inductively coupled plasma mass spectroscopy) and ²²⁶Ra and ²¹⁰Po (by γ-spectrometry and α-counting, respectively) were determined in soil, vegetal tissue and draining water. Cadmium concentrations in fruit increased with PG rates, reaching 44 ± 7 μg kg⁻¹ formula weight with ten PG rates (being 50 μg kg⁻¹ the maximum allowed concentration by EC 1881/2006 regulation). Cd transfer factors in non-edible parts were as high as 4.8 ± 0.5 (dry weight (d.w.)), two orders of magnitude higher than values found for lead, lead, uranium and radium concentrations in fruit remained below the corresponding detection limits--0.5 and 0.25 mg kg⁻¹ and 0.6 mBq kg⁻¹, respectively (in a d.w. basis). ²³⁸U (up to 7 μg kg⁻¹ d.w.) and ²¹⁰Po (up to 0.74 Bq kg⁻¹ d.w.) could be measured in some fruit samples by α-spectrometry. Overall, the concentrations of these metals and radionuclides in the draining water accounted for less than 1% of the amount applied with PG.

The concentrations of Cd, Cu, Fe, Ni, Pb and Zn in the different parts of six bivalves species were determined. From the study conducted, it was found that the byssus of Perna viridis, Scpharca broughtonii and Trisidos kiyonoi; the gill of Polymesoda erosa and Donax faba; and the foot of Gelonia expansa were highly accumulative of Cu. High levels of Cd were found in the gills of Scpharca broughtonii and the byssus of Trisidos kiyonoi; and also the shells of the four remaining bivalve species. As for Zn, the mantles of P. erosa and T. kiyonoi, and the gills of D. faba, G. expansa and S. broughtonii were highly accumulative of Zn. High level of Pb and Ni were found in the shells of all the species which indicated that the shells of the bivalves were highly accumulative of Pb and Ni. Elevated levels of Fe however were found in the different parts of the bivalve since Fe is an essential metal in metabolic activities and an abundant element in nature. The heavy metals in the total tissues and the different soft tissues of the bivalves were compared with the maximum permissible limits set by five different countries. From the comparison, it was found that most of the bivalves contained metal concentrations which were below the maximum permissible limits and should pose no toxicological risk to consumers.

This paper investigates the pollution load of selected trace elements in 32 soil samples collected around 21 different mining areas of the Iberian Pyrite Belt (Southwest Spain), integrating chemical data with soil parameters to help understand the partitioning and mobility of pollutants. The minesoils are depleted in acid neutralising minerals and show limiting physicochemical properties, including low pH values and very high anomalies of potentially hazardous metals. The total concentrations of As (up to 1,560 mg kg⁻¹) and certain heavy metals (up to 2,874 mg kg⁻¹ Cu, 6,500 mg kg⁻¹ Pb, 6,890 mg kg⁻¹ Zn, 62 mg kg⁻¹ Hg and 22 mg kg⁻¹ Cd) are two orders of magnitude above the soil background values. The close association of Cd and Zn with the carbonate content in lime-amended minesoils suggests metal immobilisation through adsorption and/or co-precipitation mechanisms, after acid neutralisation, whereas As and Pb are similarly partitioned into the soil and mostly associated with iron oxy-hydroxides.

The paper presents results of a preliminary study on mercury concentration in the air carried out in the period of October 2006 to April 2007 at sampling sites located in the cities of Gliwice and Zabrze in the region of Upper Silesia--Poland's largest urban and industrial agglomeration. The study comprised physical (particulate matter-gaseous phase) and chemical speciation of gaseous mercury. Mercury concentration data related with two fractions of particulate matter: PM2.5 and PM10 are reported. The performed measurements indicated that the average monthly concentrations of the total mercury were in the range of 4.1 to 9.1 ng m⁻³. The highest mercury concentration was observed in winter, especially in periods of low precipitation. The investigation of ambient mercury distribution indicated that 4.6% to 9.8% of the total mercury present in the air was bound to particulate matter. It has been also observed that 77% of mercury in PM10 was bound to the respirable PM2.5 fraction. Chemical speciation analysis showed that elemental mercury presented 96.1% up to 99.3% of the total gaseous mercury concentration in the air.

This study was performed on 21 soils with the aim of establishing whether Pb and Ni adsorption/desorption parameters could be considered as good indicators of the risk of groundwater pollution. Results showed that high pH values in soil caused a totally irreversible Pb adsorption, thus excluding any risk of Pb groundwater pollution. Sorption/desorption studies, quantified by the desorption index (DI), showed that Ni retention was only partly affected by the basic pH values but it was also due to the electrostatic attraction processes occurring on soil surfaces, as demonstrated by the partial reversibility of the Ni sorbed. This justifies possible risks of Ni groundwater pollution. The results of a monitoring research confirmed these findings. Results suggested that the adsorption/desorption parameters, namely DI, are promising indicators to predict the risk of groundwater pollution from metals in calcareous soils.

For bioremediation of copper-contaminated soils, it is essential to understand copper adsorption and chemical forms in soils related to microbes. In this study, a Penicillium strain, which can tolerate high copper concentrations up to 150 mmol l⁻¹ Cu²⁺, was isolated from a copper mining area. The objective was to study effects of this fungus on copper adsorptions in solutions and chemical forms in soils. Results from lab experiments showed the maximum biosorptions occurred at 360 min with 6.15 and 15.08 mg g⁻¹ biomass from the media with Cu²⁺ of 50 and 500 mg l⁻¹, respectively. The copper was quickly adsorbed by the fungus within the contact time of the first 60 min. To characterize the adsorption process of copper, four types of kinetics models were used to fit the copper adsorption data vs. time. Among the kinetics models, the two-constant equation gave the best results, as indicated by the high coefficients of determination (R ² = 0.89) and high significance (p < 0.01). The addition of the fungal strain to autoclaved soil facilitated increases in concentrations of acid-soluble copper, copper bound to oxides, and of copper bound to organic matter (p < 0.05). However, the inoculation of Penicillium sp. A1 led to a decrease of water-soluble copper in the soil. The results suggested that Penicillium sp. A1 has the potential for bioremediation of copper-contaminated soils.

Recent studies have shown that natural perchlorate may be an important component to the general population exposure. These studies indicate that natural perchlorate is likely deposited by atmospheric deposition. Perchlorate concentration of total (dry + wet) deposition is relatively unstudied yet these measurements will aid in understanding natural levels in the environment. We sampled total deposition monthly at six sites in Suffolk County, Long Island, NY from November 30, 2005 until July 5, 2007. The mean perchlorate concentration is 0.21 ± 0.04 (standard error) μg L⁻¹ with a maximum value of 2.78 μg L⁻¹ . Here we show up to an 18-fold increase above the mean concentration in July 2006 and July 2007 samples. It appears that this increase in perchlorate in total deposition is associated with Fourth of July fireworks.

Using ICP-AES and ICP-MS, several metals were analyzed in water and suspended particulate matter (SPM) samples collected under normal turbidity conditions at various stations from Deûle river (in northern France) to assess the impact of a former smelting plant on the fate of particulate elements and on the water quality in this aquatic environment. Compared to their regional background, particulate Pb, Zn and Cd were found to be most enriched, suggesting anthropogenic inputs from bed sediments into the water column mainly due to physical disturbances induced by barges traffics. Conversely, no significant enrichments of particulate metals such as Cu, Cr and Ni were observed in Deûle SPM. Characterization of SPM with analyses of mineralogical and chemical compositions--using environmental scanning electron microscopy equipped with an energy dispersive X-ray spectrometer (ESEM/EDS)--indicated the presence of micro-specimens attributed to anthropogenic minerals, mostly PbS and ZnS. The calculated enrichment index (or the geoaccumulation index, I geo), enrichment factor (EF) and the partition coefficient (K d) confirmed that SPM was strongly polluted in cadmium, lead and zinc, moderately polluted in copper and unpolluted in chromium and nickel. Based on the analytical data obtained for SPM from the BCR (European Community Bureau of Reference) sequential extraction scheme, it was concluded that: (i) the reducible phases were largely more important for the binding of Pb and Cd than that of Zn and Ni and in a lesser extent Cu and Cr; (ii) copper was found to be mostly associated with the sulphides/organics fraction; (iii) chromium with a lithogenic origin was extracted in the largest percentage in the residual phase; and (iv) zinc was bound to the exchangeable-carbonate phase in the largest percentage in the particles analysed, followed by nickel and cadmium, suggesting that these metals might be easily remobilized if changes in environmental conditions would occur.

We assessed the potential of nitrate-nitrogen (NO₃-N) and fluoride (F) contamination in drinking groundwater of an intensively cultivated district in India as a function of its agricultural activities. Three hundred and forty two groundwater samples were collected from different types of wells with varying depths and analyzed for pH, EC, NO₃-N load and F content. Database on predominant cropping system, fertilizer and pesticide uses were also recorded for the district. The NO₃-N load in groundwater samples were low ranging from 0.01 to 5.97 mg L⁻¹ with only 6.7% of them contained greater than 3.0 mg L⁻¹. Samples from the habitational areas showed higher NO₃-N content over the agricultural fields. But all the samples contained NO₃-N below the 10 mg L⁻¹, the threshold limit fixed by WHO for drinking purpose. The content decreased with increasing depth of wells (r = -0.297, P <= 0.01) and increased with increasing rate of nitrogenous fertilizer application (r = 0.931, P <= 0.01) and was higher in areas where shallow-rather than deep-rooted crops are grown. Fluoride content in groundwater was also low (0.02 to 1.19 mg L⁻¹) with only 2.4% of them exceeding 1.0 mg L⁻¹ posing a potential threat of fluorosis in some locality. On average, its content varied little spatially and along depth of sampling aquifers indicating homogeneity in lithology of the district. The content showed a significant positive correlation (r = 0.237, P <= 0.01) with the amount of phosphatic fertilizer (single super phosphate) used for agriculture. Results thus indicated that the groundwater of the study area is presently safe for drinking purpose but some anthropogenic activities associated with intensive cultivation had a positive influence on its loading with NO₃-N and F.