Elements uptake, histological distributions as well as mycorrhizal and physiological statuses of Atriplex halimus were determined on trace metal and metalloid polluted soils from the surrounding spray zones of a former lead smelter in the South-East coast of Marseille (France). Analyses of heavy metal and arsenic distribution in soil and plant organs showed that A. halimus tolerance is largely due to exclusion mechanisms. No specific heavy metal concentration in leaf or root tissues was observed. However, accumulation of salts (NaCl, KCl, Mg and Ca salts) on leaf bladders and peripheral tissues of roots was observed and may compete with metal element absorption. Occurrence of endomycorrhizal structures was detected in roots and may contribute to lower element transfer from root into the aerial parts of plants. The non-destructive measurements of leaf epidermal chlorophylls, flavonols and phenols showed a healthy state of the A. halimus population on the metal and metalloid polluted sites. Considering the low metal bioaccumulation and translocation factors along with a reduced metal stress diagnosis, A. halimus appeared as a good candidate for phytostabilization of trace metals and metalloids and notably arsenic in contaminated soils of the Mediterranean spray zone. However, its invasive potential has to be determined before an intensive in situ use.

This study examined the transport behavior of nano zero-valent iron (NZVI) coated with three types of stabilizers (i.e., polyacrylic acid, Tween-20, and starch) in saturated sand- and soil-packed columns under varying geochemical conditions. The cations or ionic strength and humic acid (HA) affected the transport of NZVI in varying degrees for different types of surface-modified NZVI (SM-NZVI). The effects of HA on the transport of SM-NZVI were different in sand- and soil-packed columns. In the sand-packed column, the presence of HA exerted an effect on the particle–particle interaction (i.e., aggregation), resulting in either enhanced or decreased transport of SM-NZVI. However, in the soil-packed column, the HA not only influenced the particle–particle interaction but also exerted an effect on the particle–soil grain interaction (i.e., deposition). Additionally, a significant enhancement in the transport of SM-NZVI in the soil-packed column was observed with increasing particle concentration. Moreover, the adsorption of arsenic on the surface of SM-NZVI exhibited insignificant effect on the transport of SM-NZVI. The release of arsenic from the arsenic-loaded SM-NZVI was detected when subjected to flushing with phosphate-containing groundwater. This fundamental understanding of the subsurface transport of SM-NZVI is of critical importance for the benign use and risk management of SM-NZVI.

Washing-down parlours and standing areas, following milking on dairy farms, produce dairy soiled water (DSW) that contains variable concentrations of nutrients. Aerobic woodchip filters can remove organic matter, nutrients and suspended solids (SS) in DSW, but the effluent exiting the filters may have to be further treated before it is suitable for re-use for washing yard areas. The performance of a single-layer sand filter (SF) and a stratified SF, loaded at 20 L m⁻² day⁻¹, to polish effluent from a woodchip filter was investigated over 82 days. Average influent unfiltered chemical oxygen demand (CODT), total nitrogen (TN), ammonium–N (NH₄–N), ortho-phosphorus (PO₄–P) and SS concentrations of 1,991 ± 296, 163 ± 40, 42.3 ± 16.9, 27.2 ± 6.9 and 84 ± 30 mg L⁻¹ were recorded. The single-layer SF decreased the influent concentration of CODT, TN, NH₄–N, PO₄–P and SS by 39, 36, 34, 58 and 52 %, respectively. Influent concentrations of CODT, TNT, NH₄–N, PO₄–P and SS were decreased by 56, 57, 41, 74 and 62 % in the stratified SF. The single-layer SF and the stratified SF were capable of reducing the influent concentration of total coliforms by 96 and 95 %, respectively. Although a limited amount of biomass accumulated in the uppermost layers of both SFs, organic and particulate matter deposition within both filters affected rates of nitrification. Both types of SFs produced final water quality in excess of the standards for re-use in the washing of milking parlours.

We present the study of atrazine, the pesticide separation using the typical thin film composite (TFC) membranes, made up of polyamide formation between m-phenylenediamine (MPDA) and trimesoyl chloride (TMC) on the polysulfone membrane matrix. The unreacted acyl moieties in TFC membranes are chiefly responsible for the preferential rejection of bivalent counter ion (SO₄ ⁼) due to their residual charges compared to monovalent (Cl⁻) ion. These two low-pressure-driven membranes show the similar trend as salt and organic markers. Changing the feed matrix is also an interesting direction to improve the performance apart from choosing the membrane. This approach sheds light on the separation behaviour with the addition of biosurfactant. Biosurfactant-mediated filtration showed better performance of the membranes, though it depends on the nature of membranes. The membranes having more porous (in terms of organic markers) structure showed improvement in separation of atrazine. The increase in separation 20.29 % is observed for 200 mg/L biosurfactant for Memb-I, whereas 13.81 % increase is observed for Memb-II.

Laoyingshan town lead zinc mine is one of the important zinc production centers in Guizhou province, China. The cadmium (Cd) is one of the mineral resources associated of lead zinc mine. The exploitation and uses of lead zinc mine would lead to Cd pollution to the environment. Soil Cd concentrations in this area are elevated by 30–50 times compared to the national background value in soil which is 0.279 mg kg⁻¹. In situ air Cd concentrations air/soil Cd fluxes were measured at 26 sampling sites in Laoyingshan town by moss bag from Jan. to Sep. 2005. The results showed that the average Cd concentration of total suspended particulates (TSP) and soil were 5.3 and 4.6 times higher than those measured at downwind direction 10 km due to a large amount of Cd emission from traditional melting. The results showed a clear decreasing trend along with the distance increasing from the pollution source for all the study parameters, namely cadmium contents in soil and TSP and deposition rate determined using moss-bag method. The results are consistent with the studied results previously. The correlations between Cd fluxes and soil show the relationship between the content in atmospheric TSP and spatial distribution of deposited heavy metal. The authors found that air spread is the major route of Cd pollution.

Heavy metals are determinant factors in increasing environmental pollution, and chromium is considered to be of highest concern because of its genotoxicity in microorganisms, animals, and humans. Relatively few studies are focused on the injury induced in plant genetic material. Therefore, the main objective of this work was to evaluate the extent of the cytogenetic damage induced in root meristems of barley (Hordeum vulgare L.) after short-term seed exposure to 10, 100, 250, and 500 μM K₂Cr₂O₇(Cr(VI) concentration is 1.04, 10.39, 25.99, and 51.99 μg ml⁻¹) and 10, 100, 250, and 500 μM CrCl₃(Cr(III) concentration is 0.52, 5.19, 12.99, and 25.99 μg ml⁻¹). Chromium genotoxic potential was proved by significant increases in the rates of the ana-telophase chromosomal aberrations (1.3–2.3 times higher for K₂Cr₂O₇and 1.7–2.2 times higher for CrCl₃, as compared to the control; p < 0.05, p < 0.01) and of metaphase disturbances (5.0–7.5 times more numerous in chromium-treated groups than in control; p < 0.001). The pattern of the chromosomal aberrations is constituted by chromatid bridges, complex aberrations, lagging, and vagrant chromosomes, while the abnormal metaphases are c-like metaphases, sticky metaphases, and metaphases with chromosomes expulsed from equatorial plate. The mitotic indices and the growth of the barley plantlets in the early ontogeny were stimulated by chromium. The changes induced in the frequency of division stages mainly consisted in prophase and telophase accumulation and diminution of metaphase and anaphase proportion.

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.

A novel method of acid orange 7 (AO7) removal has been developed via the deposition of plasma-polymerized allylamine (ppAA) films on quartz particles. ppAA films were deposited at a power of 25 W, allylamine flow rate of 4.4 sccm and polymerization time of 5 to 60 min. Polymerization time had a significant effect on surface chemistry where the XPS nitrogen concentration, XPS C-O, C-N concentration, isoelectric point and the number of positively charged groups per nm²all increased with increasing polymerization time. Increasing polymerization time increased AO7 adsorption due to greater concentrations of positively charged amine groups on the surface. The pH and initial AO7 concentration were varied to investigate their effect on AO7 adsorption. Increasing the initial AO7 concentration increased adsorption for all polymerization times. pH had a significant effect on AO7 adsorption with maximum adsorption at pH 3 and significantly less at pH values of 5–9. Regeneration of ppAA-coated quartz particles for up to 4 cycles using pH 12 Milli-Q water resulted in only slight losses in adsorption capacities. ppAA-coated particles have shown to successfully remove AO7 dye from solution and therefore demonstrate potential for use in the treatment of industrial dye wastestreams.

In this study, the potential effects of three modified industrial by-products—modified low-grade phosphate rock with soda dregs (MP), modified flue gasses desulfurization residue (MF), and a mixture of MF and phosphoric acid (MFP)—were evaluated in the remediation of heavy metal-contaminated agricultural soil at four different treatment levels. The effects of the amendments on the extractability and phytoavailability of soil heavy metals were tested using a standardized sequential extraction test and a pakchoi pot experiment. The impacts of the three amendments on soil quality was investigated, including changes of soil pH, availability of K, Ca, Mg, Si and P, and the effects on pakchoi growth. The addition of these amendments resulted in a significant decrease of labile fraction of the heavy metals in soil (p < 0.05) and a marked decrease in heavy metal uptake by pakchoi (p < 0.05) in the pot experiment. All the amendments improved soil quality as measured by neutralization of soil acidity, increased content of mineral nutrients of soil (specifically, available K, Ca, Mg, Si, and/or P), and enhanced pakchoi growth when compared to the controls. Significant correlations (positive/negative) were observed among these factors, indicating multiple effects of the amendments on the remediation process. The increased soil pH and elevated mineral nutrients contributed to the stabilization of heavy metals, and the remediated soil conditions resulted in improved growth of pakchoi. These results suggest that all three of the modified industrial by-products could be used for the remediation and restoration of heavy metal-contaminated agricultural soil.

A column experiment was conducted to evaluate the effectiveness of nanoscale zerovalent iron (nZVI) for the in situ immobilization of Pb and Zn in an acidic soil. The impact of nZVI on soil was evaluated by monitoring the physicochemical characteristics of the leachates and their ecotoxicological effects on three species, Vibrio fischeri, Artemia franciscana, and Caenorhabditis elegans. Treatment with nZVI resulted in more effective Pb immobilization in comparison to Zn and reduced the leachability by 98 and 72 %, respectively; the immobilization was stable throughout the experiment. Leachates from nZVI-treated soils showed lower toxicity than leachates from untreated ones. The highest toxicity in treated soils was observed in the first leachate, which presented high values of electrical conductivity due to the leachability of soil ions and those provided by the commercial nanoparticle suspension (Na and Fe). V. fischeri and C. elegans were more sensitive to leachates from nZVI-treated soils polluted with Zn than those from soils polluted with Pb; A. franciscana showed the opposite trend.