Environmental pollution is one of the most serious causes of degradation of Mediterranean wetlands. Mercury (Hg) and cadmium (Cd) are of particular concern due to biomagnification. Here, we used red swamp crayfish (Procambarus clarkii) to monitor the spatial and temporal patterns of these two metals in a Portuguese rice field system. We sampled the crayfish in three different sites and three different time periods in the Sado River Basin (Portugal). We measured temperature, pH, total dissolved solids and conductivity in the water. Hg and Cd were measured in the crayfish abdominal muscle tissue and exoskeleton. In muscle, a spatial pattern was found for the accumulation of Cd while for Hg, only a temporal pattern emerged. The spatial pattern for Cd seemed to reflect the mining history of the sites, whereas the temporal pattern for Hg seemed related to the flooding of rice fields. We suggest that this flooding process increases Hg bioavailability.

Urban stormwater runoff is contaminated by nutrients that wash off of roadways, parking lots and lawns during storms. In-ground permeable filter systems that consist of carefully selected filter material have the potential to remove these nutrients from the run-off. In this paper, four filter materials, calcite, zeolite, sand and iron filings, were investigated using laboratory batch tests to evaluate their efficiency in the removal of nitrate and phosphate from the simulated stormwater at different initial concentrations under the same 24-h exposure time period. The range of removal for nitrate was from 39 % to 65 % for calcite, from 42 % to 77 % for zeolite, from 40 % to 70 % for sand, and from 74 % to 100 % for iron filings. The removal of phosphate ranged from 35 % to 41 % for calcite, 59 % to 100 % for zeolite, 49 % to 100 % for sand, and 73 % to 100 % for iron filings. The removal of nitrate is mainly attributed to electrostatic adsorption, except when iron filings were used as a filter material where additional processes such as electrochemical reduction, ligand complexation and precipitation may have contributed to the higher nitrate removal. Phosphate removal is also attributed to electrostatic adsorption in all filter materials; however, at higher phosphate concentrations, the precipitation process may be the dominant process for all of the filter materials except calcite. The Langmuir and Freundlich isotherms fitted the observed nonlinear adsorption results, but the mechanism of removal of phosphate changed from adsorption to precipitation at concentrations higher than 1 mg/l in zeolite, sand, and iron filings; therefore, the adsorption models are valid below this concentration limit. A typical application of these batch adsorption test results is presented in the design of a field in-ground permeable filter system.

The purposes of this research were (1) to compare level of uptake and accumulation of Eu and Ce by wheat and rye seedlings grown in soil spiked with these metals, (2) to estimate short-term variations of Eu and Ce in soil and in plants and (3) to study effects of Eu and Ce accumulation on concentrations of other macro- and trace elements in the plants. The experiments were performed in a naturally illuminated greenhouse. Instrumental neutron activation analysis was used to determine concentrations of rare earth elements and essential nutrients and trace elements in the plants and soil. The experimental results indicate that addition of Eu and Ce to soil can lead to enhanced uptake of the trace elements by plants. Plants more easily accumulated Eu than Ce. Moreover, for rye, differences between amounts of Ce in the seedlings grown in Ce-spiked soil and in Ce-free soil were statistically insignificant. During the first hours after transfer of seedlings to soil spiked with Eu, concentration of Eu in the roots of both plant species increased significantly. An increase of leaf Eu concentration was also observed, however, these variations were not as marked as those in roots. During the following 10-day growth in the Eu-spiked soil, concentration of Eu in plants constantly increased. The bioaccumulation of Eu resulted in certain decrease of Eu in the rhizosphere soil. However, no variations in soil Ce concentrations were found. The accumulation of Eu and Ce in rye and wheat seedlings did not significantly affect concentrations of essential plant nutrients and other REEs.

Recently, the World Health Organization’s International Association for Research on Cancer classified outdoor air pollution as carcinogenic to humans and puts air pollution in the same category as tobacco smoke, UV radiation, and plutonium. The ambient air is polluted by emissions from motor vehicles, industrial processes, power generation, household combustion of solid fuel, and other sources. Dust storms lead to particulate levels that exceed internationally recommended levels, especially near the Sahara. However, this source of air pollution appears to be under-studied, particularly in the literature devoted to human health impacts in West Africa. More than 50 % of the total dust emitted into the atmosphere comes from the Sahara. These aerosols contribute to increase the concentrations of particles smaller than 10 μm (PM₁₀), which are breathable particles. This study is the first designed to assess the real impact of Saharan dust on air quality and respiratory health of children in a region of West Africa. Dust events having affected the Northern Benin during the dry seasons between 2003 and 2007 were determined. The analyzed health data are the monthly rates of acute lower respiratory infections (ALRI). Over the entire study period, 61 days of dust events were observed in the region. They recorded on average a daily PM₁₀concentration of 1017 μg m⁻³, more than 18 times higher than that calculated on all days without dust events. The study also highlighted a mean increase of 12.5 % of ALRI rates during the months recording dust events. The use of daily health data should help to refine these initial results in the future.

The composition of zooplankton, benthic macroinvertebrate (BMI) and forage fish communities of 20 lakes in and near Kejimkujik National Park and National Historic Site were evaluated as part of Environment Canada’s Acid Rain Biomonitoring Program. The pH of study lakes ranged from 4.3 to 6.6. Lake pH was positively correlated with alkalinity, calcium and magnesium concentrations and negatively correlated with colour, aluminium, total organic carbon and nitrogen. Gradients in overall BMI community composition and total BMI richness were strongly related to the gradient in pH, but the composition of zooplankton and forage fish communities were more strongly related to other environmental parameters such as elevation. Potential indicator species for future acid rain monitoring included Daphnia catawba, the amphipod Hyalella azteca, pill/pea clams Pisidium casertanum and Pisidium ferrugineum and larval water scavenger beetle Berosus. These chemical and biological data provide a baseline for future evaluation of the continued effects of anthropogenic deposition to this acid-sensitive region of Atlantic Canada.

Reduction in the concentration of pharmaceuticals present in wastewater has been attributed to sorption and biodegradation. However, the contribution of these processes has not been fully characterized. Previous studies have reported varying effects of solution pH and concentration on sorption behavior of pharmaceuticals in different absorbents including activated carbon waste and zeolites. Here we report the pH and concentration effect on sorption of two common anti-inflammatory drugs, viz., ibuprofen and naproxen, on suspended solids in simulated domestic wastewater (SDWW). Batch experiments were conducted at various pH levels, viz., 3.5, 6.5, 7.5, and 8.5, and concentration, viz., 125, 250, 500, 750, and 1,000 μg L⁻¹. The results showed that both ibuprofen and naproxen have higher sorption at lower pH values and at higher concentration. It was found that the data were comparatively well fitted to the Redlich–Peterson isotherm. The study revealed that both ibuprofen and naproxen can be removed from wastewater by the sorption process achieved by lowering the pH to values lower than pKₐand maintaining the concentration at an optimal value.

The scope of this study was to investigate the uptake of chromium and nickel by onions (Allium cepa) and potatoes (Solanum tuberosum) and their impact on plant enzymes catalase (CAT, E.C. 1.11.1.6) and peroxidase (POX, E.C. 1.11.1.7). A greenhouse experiment was conducted, simulating the irrigating conditions existing in the two biggest tuber-producing regions of Greece (Asopos and Messapia). Plants were cultivated for 4 months in six irrigation lines, each one supplied by an aqueous solution, containing levels of Cr(VI) and Ni(II) ranging from 0 μg/L (control) to 1,000 μg/L. Significant statistical correlations were observed between (i) the levels of heavy metals in plants, (ii) the levels of heavy metals in plants and in irrigation water, and (iii) the levels of heavy metals and the enzymatic activities in plants. The existing EU legislation has no legal limits for Ni and Cr in food, and the nutritional implications of this study are discussed.

Mineral dissolution plays an essential role in controlling geogenic arsenic (As) contamination in groundwater. Although reductive dissolution of Fe oxyhydroxides is generally considered a key As release mechanism in many aquifers, some recent studies argue that silicate minerals, normally considered “inert” in As release, are the primary source of As contamination under certain conditions. The objective of this study is to determine As distribution in different minerals in a natural sediment and identify As release mechanisms and the role of silicate minerals in As release. A sediment sample was collected, characterized, and tested using leaching experiments at a range of pH and redox potentials. Our results showed that silicate minerals, which make up the bulk of the sediment, are the main As reservoir, containing 75 % of As. Fe–Mn oxyhydroxides, which are minor components in the sediment, are the second largest As reservoir and hold 16 % of As. Leaching experiments showed that silicate mineral dissolution is an important As-releasing mechanism and that high pH and low redox potential promoted silicate mineral dissolution and As release.

Recycling irrigation water is a common practice at ornamental plant nurseries for conserving water; however, it poses the risk of sourcing and dispersing waterborne plant pathogens, especially species of Phytophthora. Slow sand filtration is a water treatment process that can remove pathogens from water, but the slow rate of water treatment may limit its application at nursery operations. In this study, four novel substrates (crushed brick, calcined clay, polyethylene beads, and Kaldnes® medium) in addition to sand were examined to determine how effective each substrate was at removing zoospores of Phytophthora nicotianae from water. The effects of substrate physical parameters, substrate depths (0, 5, 10, 20, 40, and 60 cm), and microbe density (after nursery effluent was recirculated through each substrate for 21 days) on zoospore removal by each substrate were quantified. Sand was the most effective physical filter and supported development of the best biological filter for removing zoospores. Sand columns 40 and 60 cm deep removed zoospores completely using physical filtration alone, and zoospore removal by sand at 10- and 20-cm depths was increased with the addition of biological filtration. Kaldnes® medium and polyethylene beads were the least effective filtration substrates under all conditions tested. After 21 days of recirculating nursery effluent through substrate columns, microbe density in and zoospore removal by all substrates increased. With further optimization, crushed brick may have potential to be utilized as a recycled material for a slow filtration system focused on removing plant pathogens from irrigation water.

The extent of endosulfan sulfate removal from soils by different planting pattern with sweet corn (Zea mays), cowpea (Vigna sinensis), and cucumber (Cucumis sativus) either cultivated alone or together was investigated in pot experiments. Endosulfan sulfate was removed to the greatest extent in the treatment in which sweet corn was grown alone; only 11.3 and 27.2 % of the initial endosulfan sulfate remained in rhizospheric and bulk soil, respectively, of sweet corn grown alone at day 60. Endosulfan sulfate was also removed from soil to a great extent in treatments where cucumber or cowpea was grown alone; only 30.3 and 38.8 % of endosulfan sulfate remained in their respective rhizospheric soil after 45 days. However, cucumber did not tolerate the toxicity of endosulfan sulfate well and died around 50–55 days when it was cultivated either alone or together with another plant. Cultivation of sweet corn and cowpea together was less effective in removing endosulfan sulfate from soil; about 41.7 and 52.3 % of endosulfan sulfate remained in their respective rhizospheric soils after 60 days. The results showed that single cultivation of the plants was the most efficient way to remediate endosulfan sulfate-contaminated soil in this study. Endosulfan sulfate was detected in both the root and shoot of plants but given the low levels found, bioaccumulation was judged to be a relatively minor factor in endosulfan sulfate removal from soil.