A greenhouse experiment using soil was conducted to investigate the effects of the addition of different forms of either nickel or lead, together with an acidifying agent, on the distribution of Ni, Pb, Zn, Cu and Mn in wheat plants, and on the post-harvest extractability of these elements in the soil. Two treatments consisting of soil alone or soil mixed with sewage sludge at a rate of 200 Mg ha⁻¹ were used as controls. Nickel (400 mg kg⁻¹) or lead (1600 mg kg⁻¹) was added to the soil as an inorganic salt or mixed previously with sewage sludge. Six further treatments including an acidifying agent (wastewater from olive oil processing: alpechin) were also prepared. Wheat (Triticum aestivum L. var. Mesa) plants were harvested 75 d after germination. Dry matter yield of wheat was increased by the addition of sewage sludge. No reductions in yield were observed after the addition of nickel or lead. Nickel concentration and uptake by wheat, and extractability from soil, were higher when the sewage sludge enriched in nickel was added to soil. This effect was enhanced when the acidifying agent was also added. In contrast, lead availability was higher after the addition of inorganic Pb to soil. The addition of both forms of Ni enhanced Zn, Cu and Mn uptake by the plant, whereas the addition of lead increased Zn and Cu. After harvesting, increases in extractable Zn and Cu in the soil were observed only in treatments with sewage sludge, and not after the addition of Ni or Pb, or after the addition of the acidifying agent. Decreasing the pH of the soil with the acidifying agent tended to increase Mn uptake by wheat, and Mn extractability from the soil after harvesting.

A new plastic-lined high-pressure squeezing device has been developed for the extraction of soil pore solutions. At a maximum pressure of 1100 kg cm⁻² the water recovery ranged between 30 and 55% of the total water content. Pressure dependent squeezing experiments showed a general increase in Si, Mn, Mg, Ca, K, Na, Al, Fe, Cd, and Zn concentrations with progressive pore water extraction and increasing pressure, indicating that micro pore solutes have the highest concentrations of solutes. Soil samples with moisture contents of more than about 15% generally provided enough water for major and trace element analyses. The data do not reveal any contamination of the pore fluids from the squeezing device. An advantage of this method is that the solution could be closely related to a specific soil horizon on a cm scale and also to the time of sampling. A further application of this squeezing method is the possibility of pressure dependent sequential squeezing to obtain fluids from different pore spaces.

The discharge of acidic mine drainage waters onto a hillslope in Dalarna, central Sweden, has lead to the contamination of the podzol soils with Cu, Fe, Ni, Pb, Zn and sulfate. Samples from contaminated and reference soils have been collected for chemical and mineralogical analyses. Jarosite is identified by x-ray diffraction analysis as a precipitate in the upper horizons (A, E, B) of the contaminated soils, where the soil acidity (pHKCₗ ∼ 2.6) promotes jarosite stability. The sequential chemical extraction of soil samples indicates that, in the reference A horizon, Cu, Pb, Ni and Zn are bound primarily to cation exchange sites and organic matter. In the A horizon of the contaminated soils closest to the rock dump, metal partitioning is dominated by the Fe oxide fractions, despite the high organic matter content; Pb is almost completely bound to crystalline Fe oxides, possibly adsorbed to Fe oxides or occuring in a jarosite solid solution. In the reference B and C horizons, Cu, Ni and Zn are primarily adsorbed/coprecipitated in the Fe oxide fractions, while Pb remains with a large fraction bound to organic matter. In the Fe-rich B horizon of the contaminated soils, the partitioning of the metals in cation exchange sites and to organic matter has greatly increased relative to the reference soils, resulting from the mobilization of organo-metal complexes down the profile.

The effects of chemical speciation on mineralization of organic compounds was studied using citric acid as a model substance. The degradation of ¹⁴C-labeled Al-, Co-, Cu-, and Zn-citrate was followed in chemically well-defined media inoculated with mixed cultures of microorganisms (soil extracts from two soils). The degradation of citrate was completely inhibited when the acid was bound to Zn, Cu, or Co and partly inhibited when bound to Al. The mineralization of citrate as well as histidine was also followed by incubation of the complexes (Cu, Zn, Al) in the two soils. No effect of metals on the degradation of histidine was seen. The degradation of citrate in soils was also unaffected when complexed to Cu and Zn, whereas Al exerted an inhibited decomposition in both soils.

In the late 1980s, citrus plantations in the area of Villarreal (Spain) showed injuries similar to those previously reported for boron and fluorine toxicity. The area was affected by the disposal of industrial wastewater, mainly from ceramic industries. Conjunctive uses of surface water, groundwater and wastewater for irrigation had taken place. A survey was conducted at 25 orchards to assess leaves and soil for their boron, fluorine, lead, nickel and zinc contents. Wastewater and groundwater were also analyzed to corroborate the presence of these pollutants. The results showed that both boron and fluorine contents were greater than those reported as excess at the most part of the orchards included in the study. Heavy metals toxicity effects were not confirmed. Boron pollution was attributed to industrial wastewater spills and fluorine contamination from atmospheric pollution.

Distributions of Mn, Zn, Cu, Ni, Cr, Pb, As, and Cd in Finnish surface waters were studied by comparing two data sets: samples from 154 headwater lakes collected by the Water and Environment Administration in 1992 and samples from 1165 headwater streams collected during the environmental geochemical mapping program of the Geological Survey of Finland in 1990. It was expected that headwater lakes with catchments smaller than 1 km²; and high lake percentage (ratio of lake area to catchment size) would be more influenced by atmospheric trace metal deposition than the streams, with average catchment size of 30 km²;.The lakes with highest arsenic concentrations lie in an area with greenstones and arsenic-rich black schists. The same lakes have high copper concentrations, which evidently are derived from the Cu-rich greenstones of the catchment. The high copper concentrations of streams and lakes in the industrialized region of the southwest coast are due to several anthropogenic sources.The highest concentrations of chromium occur in brown stream and lake waters rich in humic matter, while manganese and zinc concentrations, which are controlled by acidity, tend to be elevated in low-pH waters. The high nickel concentrations in lakes in southwestern Finland probably are due to anthropogenic input, while Ni anomalies in stream and lake water in eastern Finland are correlated with high Ni contents of glacial till. The lead concentrations in lakes are mainly of airborne anthropogenic origin.The pattern of atmospheric deposition is reflected in the concentrations of Cd, As, Cu, Zn, and Ni in headwater lakes, but land-use, the natural distribution of metals in the overburden, water acidity, and the amount of humic substances influence the distribution of trace metals in both lakes and streams. Thus the trace metal distribution in headwater lakes cannot be used alone to estimate the contribution of anthropogenic atmospheric deposition to metal anomalies in Finnish surface waters.

Sandy soils, in the border area of Belgium and the Netherlands (the Kempen region), are heavily contaminated by atmospheric deposition of cadmium and zinc from nearby smelters. Groundwater contamination by leaching from these low retention soils is subject of study. There are reports of high cadmium and zinc concentrations in groundwater in the area, but in most cases the direct sources are unknown. In an attempt to predict present or future risk of groundwater contamination by soil leaching, metal binding processes (retardation) were studied that are specific for these soil types under the existing acidifying conditions. From four fields nine contaminated profiles were sampled and analyzed for cadmium and zinc. Average concentrations of 131μg g⁻¹ zinc and 1.6μg g⁻¹ cadmium with maximum values of 2989μg g⁻¹ respectively 16.3μg g⁻¹ were found. In addition pH and contents of organic matter, aluminium, iron, and manganese were determined. The relative importance of these soil parameters for metal retardation is derived from the profiles. The data show that organic matter is the most important soil component for binding cadmium and zinc. Adsorption of cadmium and zinc on aluminium, iron and manganese (hydr) oxides appears to be of minor importance at low pH (<5.5).

Combined effects of organic or inorganic pollutants on soil microbial activities were investigated in field plots grown with four types of covering plants. It was derived from this study that combined effects were dependent not only on the type and dose of pollutants, addition of soda lime, plant type and season variation, but also on test parameters. When jointly added, higher doses of Cd, Cu, Pb, Zn and As caused significant inhibition. Addition of soda lime could even enhance inhibition. Joint effects of phenanthrene, MET (active ingredient: paclobutrazol) and 1,2,4-trichlorobenzene were not significant, and may be covered by other biotic or abiotic factors. Compared with other two parameters (respiration and microbial biomass), dehydrogenase activity appeared to be more sensitive for evaluating the toxicity of anthropogenic pollutants in soil. Soil samples collected in summer often had higher microbial activities than those in fall. The microbial activity in soil decreased with covering vegetation in the order alfalfa > pine > poplar and maize, albeit some exceptions were observed.

Groundwater in the Rio de las Avenidas sub-basin corresponds to the bicarbonate-sodium and bicarbonate-calcium hydrochemical facies, which result from the mineralization of water passing through alkaline rocks (andesites) which prevail in this basin. However, the presence of high concentrations of Na⁺ and K⁺ reveals the existence of an external inflow of these elements: the registered mean values are respectively 94.3 and 19.0 ppm, with the Tèllez and Tizayuca areas standing out with reported values of up to 142 ppm. As for the concentration of soluble water cations, we find in decreasing order: Na⁺, Ca²⁺, Mg²⁺, K⁺, along with the anions HCO₃ ⁻, Cl⁻, SO₄ ²⁻, CO₃ ⁻, which combine to form the NaHCO₃, NaCl, Ca(HCO₃)₂, MgSO₄ and KCl salts. The presence of biological contaminants, P and detergents in the groundwater indicates that it may have been contaminated by waste water. In addition to the contaminants mentioned above, large quantities of Pb, B, Zn, Fe, Mn, Cr, Co were detected and although Fe, Pb, Zn, B, and Mn are closely related to the local lithology, the high concentrations of these elements along with the occurrence of Co, Cr, Cd, and Ni confirm the gradual degradation of the aquifers in the sub-basin. The water temperature indicates the existence of low temperature thermal processes in the area.