Cryptosporidium parvum oocysts may reach soil through direct deposition of human or animal fecal material, irrigation with raw wastewater or untreated effluents, and contaminated runoff. Examination of soil samples for oocyst presence is of primary importance in order to prevent secondary contamination of crops and groundwater. Several methods were proposed for oocyst recovery from soil samples; however, their efficiency was very low. In the present study, four known methods used to recover oocysts from water and fecal samples (sedimentation, sedimentation with reduced water content, sucrose floatation, water-ether separation) were compared to a method used in the past to recover bacterial spores from bottom sediments (two-phase separation). The two-phase separation technique proved to be the best method of choice resulting in a recovery average of 61.2 ± 15.6%. According to this method, the lowest and highest recoveries were 37% to 95%, respectively. Two other important outcomes were observed with the soil experimental set-up: (1) recovery efficiency is influenced by oocyst viability (high viability was directly correlated with increased recovery efficiency) and (2) high sand content of soil samples reduced oocyst recovery by its detrimental effect on oocyst viability.

The use of enhanced-flushing technologies has emerged as a promising technique for the remediation of sites contaminated with immiscible liquids. An important aspect for the effective remediation of these sites depends on the physical heterogeneity of the subsurface and the related distribution of immiscible liquid present within porous media. Recent interest has developed in using mass flux-based approaches to evaluate remediation success and performance for immiscible liquid-contaminated sites. The unique focus of these experiments was to evaluate trichloroethene (TCE) mass flux behavior and mass removal effectiveness for various solubilization agents when the distribution of immiscible liquid is uniform. In order to accurately compare the performance of each enhanced-solubilization agent, the distribution of immiscible liquid must be consistent and uniform. Previous dissolution experiments have typically relied upon injecting immiscible liquid into the porous media which can result in nonuniform immiscible liquid distribution causing nonideal dissolution and mass flux behavior (i.e., immiscible liquid fingering and bypass flow). Homogeneous 20/30 quartz sand was thoroughly mixed with a predetermined amount of immiscible liquid TCE and packed into columns to ensure that uniform distributions of residually saturated TCE (S N = 8-11%) were created. These columns were then flushed with a specific enhanced-solubilization flushing agent to initiate dissolution. Of the four enhanced-solubilization used, the lower solubilization power flushing agents (i.e., cyclodextrins) resulted in more ideal TCE mass flux behavior in which mass flux is maximized and maintained during the majority of the flushing experiment. A strong positive correlation (R ² = 0.92) exists between enhancement factor and mass flux ideality which may suggest that these systems were in fact uniformly distributed with immiscible liquid. In order to appropriately evaluate and compare the effectiveness of specific solubilization agents, it is important to consider mass flux behavior in conjunction with elution behavior and mass removal efficiency.

A pot experiment was conducted to study the effect of 7 intercrops on Cd uptake by maize. The intercrops included cowpea (V. unguiculata (L.) Walp.), purple haricot (L. purpureus (L.) Sweet.), chickpea (C. arietinum L.), alfalfa (M. sativa L.), teosinte (E. mexicana Schrad.), amaranth (A. paniculatus L.) and rape (B. napus L.). The results showed that most legumes substantially increased Cd uptake by maize during vegetative growth. Leaf tissue of maize grown with legumes averaged 5.05 mg kg⁻¹ higher Cd than that grown with nonlegumes, or 2.42 mg kg⁻¹ higher than the control. However, the effect of intercrops on Cd uptake by maize became small during reproductive growth. Since chickpea resulted in a relatively large maize bioconcentration factor of 2.0 and large transfer factor of 0.55, it is regarded as the most valuable intercrop for enhancing Cd extraction from soil by maize. The results suggest that intercropping might be a feasible practice in facilitating phytoremediation.

In Tabasco the petroleum industry pollutes soil recurrently by oil spills. We analysed Pb, V, Ni and Cr concentrations in water samples, and total metal contents and metal fractions in soil samples of contaminated and non-contaminated soils and in sediments. Besides, we determined Eh, pH, DOC and major ions in water and Eh, pH, Corg in soils and sediments. Sediments contained considerably larger heavy metal (HM) concentrations than soils. Local background concentrations of V, Ni and Cr in soils are larger than global means and oil spillages have not added these metals in quantities that exceed the natural variation. Spillage of formation water increases Pb concentrations in soils, particularly in mobile fractions. The contribution of the oil industry to HM loads is diluted by large fluvial water and sediment discharges and difficult to assess by comparison of total metal contents. Therefore, easily mobile metal fractions are much better indicators.

The effect of aluminium on histopathological and behavioral changes in the planarian Polycelis felina (Daly.) in laboratory conditions was studied. The planarians were treated with seven concentrations of aluminium sulfate for five days and compared to three control groups of animals. Microscopical, histological and morphometric methods were used. The results showed distinguished morphological changes on the planarian body as well as behavioral changes: various depigmentations, disordered locomotion, twisting of the body parts, hardly reacting to the mechanical stimuli, body contractions, deformations and mortality. Histomorphometric analyses showed changes in the size and number of neoblasts and reticular cells. Changes in epithelial cells and segments, parenchyma and muscular layer were also noticed. Concentrations of 600 and 1100 mg/L caused most distinct changes in behavior, morphological and histological structure of planarians. The highest concentrations caused irreversible changes. Considering high LC₅₀ (1100 mg/L), the used concentrations of aluminium presented no actual environmental threat to planarian populations in nature, but showed the extent of damages in a possible concentrated aluminium environment.

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.

Mobilization of arsenic (As) in the subsurface environment can result in elevated concentrations of As in groundwater and potential human exposure and adverse health effects. Natural attenuation (i.e., sequestration) of As may, under appropriate geochemical conditions, serve to limit human exposure to As. The effectiveness of As sequestration by sorption, co-precipitation, and/or precipitation can be strongly influenced by redox conditions, which can control the solubility of sorbent phases and the stability of As-containing solids. The redox transformation of As between the +III and +V oxidation states can also affect the extent of As sorption. The effect of amendment with synthetic manganese (Mn) oxide birnessite (nominally MnO₂) on As sequestration in a sediment suspension was examined in the absence and presence of iron (Fe) added as Fe(II). In the absence of Fe(II), the extent of As(III) oxidation to As(V) increased with increasing birnessite amendment, but As sequestration was not increased. In the presence of Fe(II), however, As sequestration did increase with increasing birnessite amendment. Concurrently, Fe(II) was also sequestered, and the Fe(III) content of the solid phase was observed to increase, suggesting that the oxidative precipitation of an Fe(III) oxyhydroxide phase plays an important role in As sequestration. These results suggest that amendment with Mn(III, IV) oxides could be an effective way to augment natural attenuation of As in cases where As-contaminated groundwater also contains elevated concentrations of Fe(II).

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.

Fecal pollution from human and natural sources enters soil or watercourses, mixes, then reemerges as a nuisance of unknown origin. Before remediation is attempted, the sources and identities of pollution must be identified. Previous microbial source tracking studies have relied on traditional methods of microbiology such as selective media and biochemical characteristics to quantify fecal bacteria in water samples. This is successful when single sources are responsible for pollution. However, when multiple sources are present, numbers must be subdivided into categories of pollution to define relative importance and select appropriate methods of remediation which are very different for examples such as humans and avifauna pollution. Rather than depending on a single method, we recommend a tiered approach which takes advantage of ecological parameters and conventional microbiology to provide context for more precise DNA data and related statistics.

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.