Naturally occurring soil organic compounds stabilize potentially toxic elements (PTEs) such as Cu, Cd, Pb, and Mn. The hypothesis of this work was that an insoluble glycoprotein, glomalin, produced in copious amounts on hyphae of arbuscular mycorrhizal fungi (AMF) sequesters PTEs. Glomalin can be extracted from laboratory cultures of AMF and from soils. Three different experiments were conducted. Experiment 1 showed that glomalin extracted from two polluted soils contained 1.6-4.3 mg Cu, 0.02-0.08 mg Cd, and 0.62-1.12 mg Pb/g glomalin. Experiment 2 showed that glomalin from hyphae of an isolate of Gigaspora rosea sequestered up to 28 mg Cu/g in vitro. Experiment 3 tested in vivo differences in Cu sequestration by Cu-tolerant and non-tolerant isolates of Glomus mosseae colonizing sorghum. Plants were fed with nutrient solution containing 0.5, 10 or 20 μM of Cu. Although no differences between isolates were detected, mean values for the 20 μM Cu level were 1.6, 0.4, and 0.3 mg Cu/g for glomalin extracted from hyphae, from sand after removal of hyphae and from hyphae attached to roots, respectively. Glomalin should be considered for biostabilization leading to remediation of polluted soils.

Eighty soil cores were collected from a residential area adjacent to an automobile battery manufacturing facility to determine the level and variability of lead concentrations in the soil. Results of ICP-MS on HNO₃ digestions showed lead concentrations in the residential soil as high as 2760 mg kg⁻¹. High variability of lead concentrations of two to three times over short distances, less than a meter, indicated the necessity of remediating the entire soil area based on a clean-up level of 400 mg kg⁻¹. To delineate areas of soil requiring no remediation at a high level of confidence would have required a more extensive soil sampling survey. High lead concentrations in the residential soil to a depth of approximately 15 cm indicated remediationof residential soil to at least this depth may be necessary. Overall, the high variability of lead concentrations in the residential soil was consistent with a soil having been disturbed by residential activity and illustrated the difficulty in using a single sample per residentialyard for making correct remediation decisions.

Bulk rainfalls were sampled during ten months in the Eastern Channel (Northern France). Chloride and sodium are the heavily loaded major ions in wet deposition, indicating a high influence of seasalt. However, the presence of heavy metals is independent of seasalt emissions and various anthropogenic sources should have an impact on their atmospheric concentrations.The comparison between heavy metals concentrations, always ranked as [Zn] ≫ [Pb] > [Cu] ≫ [Cd], with other values obtained during the same period on European coastal or on urban sites, confirms that ourwestern European station is in a semi-rural area where no local source strongly influences the abundance of atmospheric heavy metals. This semi-rural site could be disturbed by medium and/or long range transportepisodes.The observation of literature data confirms a decrease of Cd, Cu and Pb concentrations in rain waters from the beginning of the nineties. On the other hand, no sharp evolution has been observed for zinc concentrations.The structuring of data by clustering has permitted to extract five clusters, including four different types of origins. Two marine clusters, with relatively low levels of heavy metals, are opposite to three other clusters with higher heavy metal levels and a more important impact of continental polluted sources. In 47% of cases, the heavy metals collected at Cap Gris-Nez could originate from British Islands or north western Europe.Heavy metals fluxes show that this rural coastal European site has a level of contamination higher than those measured in remote area. The wet depositions of heavy metals to the English channel and the southern bight of the north sea are not negligible in the evaluation of global fluxes for this area, representing from 20 to 70% of the total input (riverine, direct and atmospheric inputs).

Soil remediation has been studied after a spill from a settling pond of a pyrite mine in Aznalcóllar (SW Spain). The affected area was approximately 55 km² and extended about 40 km from the spill. The Pb concentration in soils ranged from 35.8 to 3231.0 mg kg⁻¹, with a mean value of 385.8 mg kg⁻¹. The remediation techniques investigated included: manual and mechanical removal of the contaminated soil, mixing the upper part of the soils by ploughing, and addition of different amendment materials to reduce the Pb solubility, such as carbonates, zeolites, iron-rich soils, bentonites and yeasts. A combination of liming with iron-rich soils proved the most effective treatment.