Bush bean (Phaseolus vulgaris) was exposed to atmospheric deposition of As, Cd and Pb in a polluted and a reference area. The atmospheric deposition of these elements was significantly related to the concentrations in leaves, stems and pods at green harvest. Surprisingly there was also a clear relation for As and Pb in the seeds at dry harvest, even though these seeds were covered by the husks. Root uptake of accumulated atmospheric deposits was not likely in such a short term experiment, as confirmed by the fact that soil pore water analysis did not reveal significant differences in trace element concentrations in the different exposure areas. For biomonitoring purposes, the leaves of bush bean are the most suitable, but also washed or unwashed pods can be used. This means that the obtained relationships are suitable to estimate the transfer of airborne trace elements in the food chain via bush bean.

We describe an innovative method of planting Zostera marina (eelgrass) seeds in which hessian bags filled with high-silted sediments are used as a seed protecting device. Here, we evaluated the effectiveness of the method through a field seed-sowing experiment over a three year period. The suitable seed planting density required by the seeds of Z. marina in this method was also investigated. In the spring following seed distribution, seedling establishment rate of Z. marina subjected to different seed densities of 200–500seedsbag−1 ranged from 16% to 26%. New eelgrass patches from seed were fully developed and well maintained after 2–3years following distribution. The seed planting density of 400seedsbag−1 may be the most suitable for the establishment of new eelgrass patches. Our results demonstrate that seed-based restoration can be an effective restoration tool and the technique presented should be considered for future large-scale Z. marina restoration projects.

Spartina maritima is a native endangered heavy metal rhizoaccumulator cordgrass naturally growing in southwest coasts of Spain, where is used as a biotool to rehabilitate degraded salt marshes. Fifteen bacterial strains were isolated from the rhizosphere of S. maritima growing in the estuary of the Tinto River, one of the most polluted areas in the world. A high proportion of bacteria were resistant towards several heavy metals. They also exhibited multiple plant growth promoting (PGP) properties, in the absence and the presence of Cu. Bacillus methylotrophicus SMT38, Bacillusaryabhattai SMT48, B. aryabhattai SMT50 and Bacilluslicheniformis SMT51 were selected as the best performing strains. In a gnobiotic assay, inoculation of Medicago sativa seeds with the selected isolates induced higher root elongation. The inoculation of S. maritima with these indigenous metal-resistant PGP rhizobacteria could be an efficient method to increase plant adaptation and growth in contaminated estuaries during restoration programs.

Many products contain dyes, such as fabrics. However, most of the industry-generated waste is improperly handled, which causes serious environmental problems for the bodies of water that receive textile effluents. This study aimed to analyze the effect of biosorbents and biosorption techniques on decolorizing the textile azo dye Acid Blue 29 in an aqueous solution employing pine sawdust. Pine sawdust is low-cost substrate with minor environmental impact. A toxicity test was performed with Lactuca sativa seeds to determine the LC₅₀ of the dye. Subsequently, a biosorption test was performed to determine the toxicity of the resulting solutions. We observed that biosorption is a very feasible technique for the discoloration of the solutions and promotes reduction in their toxicity.

The feasibility of date seeds as a new low-cost natural adsorbent for the removal of dissolved organic carbon (DOC) from oily produced water was investigated. The aim of this study was to elucidate the mechanism associated with the removal of DOC and to find the best equilibrium isotherms and kinetic models for DOC removal in batch adsorption experiments. The effect of various physicochemical parameters such as initial DOC concentration (18.5–93.5 mg/L), solution pH (4–9), temperature (25–45 °C), and date seeds dosages (0.5–2.0 g) was evaluated. The equilibrium stage was attained after a contact time of 120 min. The maximum DOC removal was 82 % for 93.5 mg/L of DOC concentration. The equilibrium data were well represented by the Langmuir isotherm. The maximum monolayer adsorption capacity of date seeds was found to be 74.62 mg/g. The separation factor, R L, from the Langmuir equation and the Freundlich constant, n, indicated a favorable adsorption. The kinetic studies indicated that the adsorption process follows the pseudo-second-order kinetics. The adsorption of DOC is governed by both surface and pore diffusion. The results revealed that the DOC uptake decreases when temperature and pH increases. The adsorption process has been found exothermic in nature, and the thermodynamic parameters were determined. The Langmuir isotherm model equation was adopted to design a single-stage batch absorber for DOC adsorption onto date seeds. The study demonstrated that date seeds can be considered as a promising low-cost adsorbent for the removal of DOC from oily produced water.

Since the last century, humanity has sought ways to minimize the impact of the industrial growth in the environment. The textile industry, as one of the major contributors to water pollution, has been dumping coloured effluents which cause great impact in water bodies. The electrolytic process not only degrades the colour of the effluent but also transforms recalcitrant substances by direct or indirect oxidation. The ecotoxicological tests are used nowadays as a way to verify the toxicity degree of water bodies polluted by industrial and farming activities. The ecotoxicological tests consist in exposing determined organisms to the samples with the intention to evaluate their toxicity by observing the organisms’ responses. This study had the objective to degrade, by electrolytic process, a simulated textile effluent containing a mixture of Acid Blue 40 and Acid Red 151 dyes and the toxicity evaluation of the treated effluent by ecotoxicological tests. The bioassays used were tests with seeds of Lactuca sativa (lettuce), Eruca sativa (rocket), and Cucumis sativus (cucumber). Tests with the micro crustaceous Artemia salina and the yeast Saccharomyces cerevisiae were also conducted. The electrolytic treatment degraded the initial colour of the textile effluent, and the ecotoxicological tests indicated low toxicity to the treatment.

The bioaccumulation efficiency of cadmium (Cd) by fenugreek (Trigonella foenum-graecum) was examined using different concentrations of CdCl₂. The germination rate was similar to control except at 10 mM Cd. However, early seedling growth was quite sensitive to the metal from the lowest Cd level. Accordingly, amylase activity was reduced substantially on treatment of seeds with 0.5, 1, and 10 mM Cd. Cadmium also affected various other plant growth parameters. Its accumulation was markedly lower in shoots as compared to roots, reducing root biomass by almost 50 %. Plants treated with 1 and 5 mM Cd presented chlorosis due to a significant reduction in chlorophyll b especially. Furthermore, at Cd concentrations greater than 0.1 mM, plants showed several signs of oxidative stress; an enhancement in root hydrogen peroxide (H₂O₂) level and in shoot malondialdehyde (MDA) content was observed. Conversely, antioxidant enzyme activities (superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT)) increased in various plant parts. Likewise, total phenolic and flavonoid contents reached their highest values in the 0.5 mM Cd treatment, consistent with their roles in quenching low concentrations of reactive oxygen species (ROS). Consequently, maintaining oxidant and antioxidant balance may permit fenugreek to hyperaccumulate Cd and allow it to be employed in extremely Cd polluted soils for detoxification purposes.

The present study was conducted to assess the impact of gibberellic acid on growth and yield of sunflower in hexavalent chromium [Cr(VI)]-contaminated soil in the presence as well as absence of pressmud. Seeds of sunflower were sown in potted soil amended with pressmud as an organic amendment and contaminated with different levels of Cr(VI) (12, 18, and 24 mg kg⁻¹) by using K₂Cr₂O₇ salt. Gibberellic acid (10⁻⁴ M) was applied at time of seedling emergence in the rhizosphere. The results showed that Cr(VI) stress significantly reduced the growth and yield of sunflower. However, application of gibberellic acid and pressmud reversed the toxic effects of Cr(VI) and improved the growth and yield of sunflower. Combined application of gibberellic acid and pressmud further improved growth and yield compared to their separate application in Cr(VI) stress. Moreover, gibberellic acid and pressmud decreased the uptake of Cr and stabilized it in the soil.

The toxicity of four zinc oxide nanoparticles (i.e., spheric ZnO-30, spheric ZnO-50, columnar ZnO-90, and hexagon rod-like ZnO-150) to the seed germination of Chinese cabbage (Brassica pekinensis L.) was investigated in this study. The results showed that zinc oxide nanoparticles (nano-ZnOs) did not affect germination rates at concentrations of 1–80 mg/L but significantly inhibited the root and shoot elongation of Chinese cabbage seedlings, with the roots being more sensitive. The inhibition was evident mainly during seed incubation rather than the seed soaking process. Both the production of free hydroxyl groups (·OH) and the Zn bioaccumulation in roots or shoots resulted in toxicity of nano-ZnOs to Chinese cabbage seedlings. The toxicity of nano-ZnOs was affected significantly by their primary particle sizes in the minimum dimensionality, but large columnar ZnO-90 and small spherical ZnO-50 had comparable toxicities. Therefore, both the particle size and morphology affected the toxicity of nano-ZnOs.

The aim of this study was to evaluate the stabilization/solidification (S/S) of trace element-contaminated soil using air pollution control residues (APCRs) prior to disposal in landfill sites. Two soil samples (with low and moderate concentrations of organic matter) were stabilized using three APCRs that originated from the incineration of municipal solid waste, bio-fuels and a mixture of coal and crushed olive kernels. Two APCR/soil mixtures were tested: 30 % APCR/70 % soil and 50 % APCR/50 % soil. A batch leaching test was used to study immobilization of As and co-occurring metals Cr, Cu, Pb and Zn. Solidification was evaluated by measuring the unconfined compression strength (UCS). Leaching of As was reduced by 39–93 % in APCR/soil mixtures and decreased with increased amounts of added APCR. Immobilization of As positively correlated with the amount of Ca in the APCR and negatively with the amount of soil organic matter. According to geochemical modelling, the precipitation of calcium arsenate (Ca₃(AsO₄)₂/4H₂O) and incorporation of As in ettringite (Ca₆Al₂(SO₄)₃(OH)₁₂ · 26H₂O) in soil/APCR mixtures might explain the reduced leaching of As. A negative effect of the treatment was an increased leaching of Cu, Cr and dissolved organic carbon. Solidification of APCR/soil was considerably weakened by soil organic matter.