Metal reference values established in Brazilian legislation for terrestrial disposal of dredged sediments and soil quality were derived for temperate regions. To evaluate the adequacy of such metal reference values to tropical soils, the ecotoxicity of a dredged sediment (from the Guanabara bay, Rio de Janeiro, Brazil) was investigated in two local soils (ferralsol and chernosol) by performing avoidance and reproduction tests using Folsomia candida and Enchytraeus crypticus. Test doses consisted of 0 %, 1.25 %, 2.5 %, 5, 10 %, and 20 %. Total and potentially bioavailable metal concentrations were determined in the test mixtures. Although the chernosol mixtures had the highest total metal concentrations, the influence of the expansive clay minerals (with high ability to adsorb metals) and the high contents of nutrients typical from this type of soils, seem to reduce the ecotoxicity. Collembolan avoidance behavior was the least sensitive endpoint. The lowest sediment doses increased the reproduction of F. candida in ferralsol mixtures. E. crypticus reproduction in the ferralsol mixtures were more pronounced at lower concentrations than in chernosol mixtures. Possibly the low nutrient content of the ferralsols, in connection with the addition of small amounts of sediment, created particular conditions that promoted reproduction of the test species. Data obtained in the ecotoxicological tests may support the establishment of a “safe” ecological dose of dredged sediments to be applied in tropical soils, supporting decision-makers in programs of environmental management.

The increasing sludge generated in wastewater treatment plants poses a threat to the environment. Based on the traditional processes, sludge dewatered by usual methods was further dewatered by hydraulic compression and the filtrate released was treated by anaerobic fermentation. The difficulties in sludge dewatering were associated with the existence of sludge flocs or colloidal materials. A suitable CaO dosage of 125 mg/g dry sludge (DS) could further decrease the moisture content of sludge from 82.4 to 50.9 %. The filtrate from the dewatering procedure was a potential substrate for biohydrogen production. Adding zero-valent iron (ZVI) into the anaerobic system improved the biohydrogen yield by 20 %, and the COD removal rate was lifted by 10 % as well. Meanwhile, the sludge morphology and microbial community were altered. The novel method could greatly reduce the sludge volume and successfully treated filtrate along with the conversion of organics into biohydrogen.

Cu, Zn, Pb, and Cd concentrations in a soil plant (Lactuca sativa) continuum were measured after sewage sludge amendment. The effects of sewage sludge on growth and trace metal bioaccumulation in snails (Cantareus aspersus) were investigated in a laboratory experiment specifically designed to identify contamination sources (e.g., soil and leaves). Application of sewage sludge increased trace metal concentrations in topsoil. However, except Zn, metal concentrations in lettuce leaves did not reflect those in soil. Lettuce leaves were the main source of Zn, Cu, and Cd in exposed snails. Bioaccumulation of Pb suggested its immediate transfer to snails via the soil. No apparent toxic effects of trace metal accumulation were observed in snails. Moreover, snail growth was significantly stimulated at high rates of sludge application. This hormesis effect may be due to the enhanced nutritional content of lettuce leaves exposed to sewage sludge.

In this study, we determined the abundance of 8 antibiotics (3 tetracyclines, 4 sulfonamides, and 1 trimethoprim), 12 antibiotic-resistant genes (10 tet, 2 sul), 4 antibiotic-resistant bacteria (tetracycline, sulfamethoxazole, and combined resistance), and class 1 integron integrase gene (intI1) in the effluent of residential areas, hospitals, and municipal wastewater treatment plant (WWTP) systems. The concentrations of total/individual targets (antibiotics, genes, and bacteria) varied remarkably among different samples, but the hospital samples generally had a lower abundance than the residential area samples. The WWTP demonstrated removal efficiencies of 50.8 % tetracyclines, 66.8 % sulfonamides, 0.5 logs to 2.5 logs tet genes, and less than 1 log of sul and intI1 genes, as well as 0.5 log to 1 log removal for target bacteria. Except for the total tetracycline concentration and the proportion of tetracycline-resistant bacteria (R² = 0.330, P < 0.05), there was no significant correlation between antibiotics and the corresponding resistant bacteria (P > 0.05). In contrast, various relationships were identified between antibiotics and antibiotic resistance genes (P < 0.05). Tet (A) and tet (B) displayed noticeable relationships with both tetracycline and combined antibiotic-resistant bacteria (P < 0.01).

Phytoextraction is widely used for the reclamation of degraded sites, particularly to remove trace metals from contaminated soils. Whereas this technique demonstrates several advantages, the biomass resulting from phytoextraction processes is highly enriched in metallic elements and constitutes therefore a problematic waste. We show here that this biomass can be used for the preparation of novel polymetallic extracts, with high potential as catalysts or reagents in organic synthesis. This new concept of ecocatalysis constitutes an innovative recycling of metallic elements whose current known reserves could be exhausted in the coming decades. The ecocatalysts Eco-Zn and Eco-Ni prepared respectively from Zn and Ni hyperaccumulating plants display two distinct chemical reactivities, starting from the same substrates. Eco-Zn led to the formation of esters of commercial interest for the fragrance industry, following a hydro-acyloxy-addition reaction pathway. In contrast, Eco-Ni afforded chlorinated products thank to the hydrochlorination of alkenes. Both ecocatalysts allowed the synthesis of valuable products in high yields through methodologies in line with the spirit of sustainable chemistry.

Emissions from primary lead smelters have been recognized as one of the mainly factor which has contributed to the contamination of soils by metals. Less attention has been paid to volatile metalloids such as arsenic (As) which accompanies lead (Pb) smelting activities. One of the objectives of this study was to determine the As concentrations in various extracting solutions using a collection of urban soils located no far away from two former Pb and zinc plants in the North of France. The procedure for the determination of As, Asᴵᴵᴵ, and Asⱽwith hydride vapor generator atomic absorption spectrometry was described in details. Pseudo-total concentrations of As in the studied soils ranged from 5.3 to 65.9 mg kg⁻¹. Good correlations were found between As and lead, zinc, and cadmium concentrations in soils. These depended on the soil uses and the soil distance from the source of contamination. Because the form of As may pose a health risk to human population, its speciation was determined in each urban top soils. Very good correlations were found between Asᴵᴵᴵand Asⱽversus As concentrations in soils studied, but the results did no permit to establish a relation between the location of soils and their uses. In contrast, it was shown that the highest mobility factor and lowest partitioning index values were related to the location. The mobilty of As depended on the assimilated phosphorus (P), carbonate contents, and pH. The percentages of the water-extractable As concentrations ranged from 0.3 to 3.0 % of the As concentrations in soils. Very good positive correlations between water-extractable Asᴵᴵᴵand Asⱽversus water-extractable As concentrations were obtained. It was shown that the water-extractable Asᴵᴵᴵconcentrations depended on the soil uses. The results revealed that soils for which the As was the most mobile presented the highest water-extractable As concentrations. Principal component analysis indicated that mechanisms related to the release of As depended on the physico-chemical parameters of the soils, particularly on the assimilated P, organic matter, and/or iron oxides/hydroxides contents. Finally, the glasshouse experiments using ryegrass as plant model and three soils with similar physico-chemical parameters with regard to the PCA analysis showed that the water extracting solution could be a good indicator to evaluate the As phytoavailability.

Olive mill wastewater is considered as one of the most polluting effluents of the food industry and constitutes a source of important environmental problems. In this study, the removal of pollutants (chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), polyphenols, turbidity, color, total suspended solids (TSS), and oil and grease) from olive oil mill processing wastewater by peroxi-electrocoagulation/electrooxidation-electroflotation process with bipolar aluminum electrodes was evaluated using a pilot continuous reactor. In the electrochemical unit, aluminum (Al), stainless steel, and RuO₂/Ti plates were used. The effects of pH, hydrogen peroxide doses, current density, NaCl concentrations, and reaction times were studied. Under optimal conditions of pH 4, current density of 40 mA/m², 1000 mg/L H₂O₂, 1 g/L NaCl, and 30-min reaction time, the peroxi-electrochemical method yielded very effective removal of organic pollution from the olive mill wastewater diluted four times. The treatment process reduced COD by 96 %, BOD₅by 93.6 %, total, polyphenols by 94.4 %, color by 91.4 %, turbidity by 88.7, suspended solids by 97 % and oil and grease by 97.1 %. The biodegradability index (BOD₅/COD) increased from 0.29 to 0.46. Therefore, the peroxi-electrocoagulation/electrooxidation-electroflotation process is considered as an effective and feasible process for pre-treating olive mill wastewater, making possible a post-treatment of the effluent in a biological system.

Increasing land utilization through diverse forms of human activities, such as agriculture, forestry, urban growth, and industrial development, has led to negative impacts on the water quality of rivers. To find out how catchment attributes, such as land use, hydrologic soil groups, and lithology, can affect water quality variables (Ca²⁺, Mg²⁺, Na⁺, Cl⁻, HCO₃⁻, pH, TDS, EC, SAR), a spatio-statistical approach was applied to 23 catchments in southern basins of the Caspian Sea. All input data layers (digital maps of land use, soil, and lithology) were prepared using geographic information system (GIS) and spatial analysis. Relationships between water quality variables and catchment attributes were then examined by Spearman rank correlation tests and multiple linear regression. Stepwise approach-based multiple linear regressions were developed to examine the relationship between catchment attributes and water quality variables. The areas (%) of marl, tuff, or diorite, as well as those of good-quality rangeland and bare land had negative effects on all water quality variables, while those of basalt, forest land cover were found to contribute to improved river water quality. Moreover, lithological variables showed the greatest most potential for predicting the mean concentration values of water quality variables, and noting that measure of EC and TDS have inversely associated with area (%) of urban land use.

Identifying nitrogen (N) pollution sources is the fundamental work of non-point source pollution load reduction from watersheds, but is hard due to complex N transport and transformation within spatially heterogenized huge areas. During September 2011, we measured water characteristics and sediment N stable isotope in four tributaries of the upper reach of the Hun River, an important water source of the Dahuofang Reservoir, a large drinking water source in Northeast China. Results showed that spatial changes in SO₄²⁻and Cl⁻contents in the tributaries were consisted with the changes in density of the population living along the tributaries. Sediment δ¹⁵N from all tributaries showed a downstream increasing trend in line with the land use change, which is characterized as more farmlands and more people around the outlet area of each tributary. Principal component analysis indicated the population density had a strong impact on N in these tributaries in the low-flow period. Tributaries and villages close to the Dahuofang Reservoir should be the major N load control objects in reduction of non-point source nitrogen load from the upper reach of the Hun River.

In the Baltic Sea, high concentrations of toxic brominated aromatic compounds have been detected in all compartments of the marine food web. A growing body of evidence points towards filamentous algae as a natural producer of these chemicals. However, little is known about the effects of environmental factors and life history on algal production of brominated compounds. In this study, several congeners of methoxylated polybrominated diphenyl ethers (MeO-PBDEs), hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and brominated phenols (BPs) were identified in a naturally growing filamentous red algal species (Ceramium tenuicorne) in the Baltic Sea. The identified substances displayed large seasonal variations in the alga with a concentration peak in July. Production of MeO-/OH-PBDEs and BPs by C. tenuicorne was also established in isolated clonal material grown in a controlled laboratory setting. Based on three replicates, herbivory, as well as elevated levels of light and salinity in the culture medium, significantly increased the production of 2,4,6-tribromophenol (2,4,6-TBP). Investigation of differences in production between the isomorphic female, male and diploid clonal life stages of the alga grown in the laboratory revealed a significantly higher production of 2,4,6-TBP in the brackish water female gametophytes, compared to the corresponding marine gametophytes. Even higher concentrations of 2,4,6-TBP were produced by marine male gametophytes and sporophytes.