Cadmium is a toxic element for living organisms. This metal causes different damages to the cell, generating oxidative stress. In order to elucidate cadmium tolerance mechanism and increase tomato plant tolerance by inoculating a Cd-tolerant Burkholderia strain, we analyzed malondialdehyde, hydrogen peroxide content, and the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione S-transferase of two strains, one isolated from a soil contaminated with Cd (strain SCMS54) and the other from a soil without Cd (strain SNMS32). Strains SNMS32 and SCMS54 exhibited different SOD, CAT, and GR isoenzyme profiles in non-denaturing polyacrylamide gel electrophoresis analysis, with strain SCMS54 exhibiting an extra isoenzyme for all enzymes (Mn-SOD, CAT I, and GR IV, respectively). Despite accumulating more Cd, strain SCMS54 did not increase peroxide hydrogen and presented a fast antioxidant response (increasing SOD and CAT after 5 h of Cd exposure). In this way, strain SCMS54 exhibited a higher metabolic diversity and plasticity when compared to strain SNMS32, so it was selected for Cd–Burkholderia–tomato interaction studies. Inoculated tomato plants in the presence of Cd grew more than non-inoculated plants with Cd indicating that the SCMS54 increased tomato Cd tolerance. It appears that the strain isolated from Cd-contaminated soil (SCMS54) triggers a global stress response in tomato increasing plant tolerance, which may enable plants to be cultivated in Cd-contaminated soils.

Seedlings of Cosmos bipinnatus were cultured in vitro for 30 days on modified Murashige–Skoog medium supplemented with four different concentrations of hexavalent chromium (Cr(VI); 0.0–2.0 mM). Seed germination occurred after 7 days of culture, but was significantly lower when cultured in 2.0 mM Cr(VI) than when cultured without Cr(VI) in the medium. Seedlings were able to survive heavy metal stress condition, irrespectively of the Cr(VI) concentration used. The seedlings showed two metal tolerance mechanisms that were dependent on chromium concentration: (1) metal exclusion at 0.0–0.5 mM and (2) metal accumulation at 1.0–2.0 mM. Regarding the latter mechanism, seedlings showed metal accumulation values considered as characteristic of hyperaccumulator species. The highest bioaccumulation in dry tissue was of 5443 mg Cr kg⁻¹in shoot and 4767 mg Cr kg⁻¹in root for seedlings cultured with 2.0 mM of Cr(VI). These results indicated that substantial Cr translocation from the roots unto shoots took place (translocation factor > 1.14) associated to a bioaccumulation factor for Cr(VI) greater than 98.

Recent evidence suggests that microplastic pollution is widespread in every oceanic basin; however, there is limited data available for the tropical South Atlantic Ocean. The purpose of this study was to examine the distribution, density and characteristics of plastic particles in plankton samples collected in the western tropical Atlantic Ocean. Neustonic tows (N = 160) were conducted near three important insular environments (Fernando de Noronha, Abrolhos and Trindade), and the presence of microplastics in the ocean surface of these areas was confirmed for the first time. The collected microplastic particles included hard plastic fragments, plastic films, paint chips and fibres and strands, which were classified as a secondary source of microplastics. The stock of plastic originates from both land-based and marine-based sources. This type of marine pollution in the tropical Atlantic Ocean is a potential threat to important ecological species.

Nuisance odors generation from waste and wastewater treatment plants are a cause of public discomfort and complaints. This situation impairs the air quality and represents a growing social and public health problem, especially in developing countries. Several modeling approaches have been developed and successfully implemented in the frame of a wastewater treatment plant for both the biological treatment and physicochemical processes. The mathematical modeling of the odor generation process is still considered a quite complex issue, mainly due to the fact that olfactory nuisance can be caused by many different chemical compounds and the perception of odors is influenced by subjective thresholds. Moreover, the impact of odor sources on air quality is highly conditioned by complex atmospheric dispersion processes. This review presents a critical state-of-art and assessment where information related to odor emissions impact studies as well as modeling applications are compiled and discussed.

A granular media synthesized using iron oxide nanoparticle-coated alumina (IONA) has been demonstrated as an effective solid catalyst in the heterogeneous catalytic ozonation of para-chlorobenzoic acid (pCBA). TEM analysis showed that iron oxide nanoparticles with an average size of 5–20 nm were well-coated onto an alumina surface. It was determined that the iron oxide nanoparticle coating increased the specific surface area by 54 times and the functional group density by 1.5 times. During catalytic ozonation at acidic pH levels, it was clearly observed that IONA increased the degradation of pCBA (98 %) through effective hydroxyl radical formation compared to bare alumina (9 %) under continuous ozonation processes. In comparing the Rcₜvalue, which represents the ratio of ozone exposure to hydroxyl radical exposure, the Rcₜof IONA was approximately four times higher than for bare alumina. In addition, IONA showed good stability for catalytic ozonation of pCBA in the reusability tests.

Water samples collected in 1995 and 2007 from the Shinano and Agano rivers were examined to determine the types and concentrations of pesticides and their effects on tap water in typical rice production areas of Japan. Tap water originating from the Shinano River was also sampled in 2007, in Niigata City, Japan. Pesticides were present in the river and tap water throughout the year. Comparison of 13 pesticides common to both 1995 and 2007 series revealed that the frequency of individual pesticide occurrence and concentrations were decreasing. Riverine pesticides were classified into five groups according to the period of their appearance and changes in concentration. Pesticides were detected at the time of application to, and drainage from, paddy fields. Pesticide concentrations in tap water showed notable decline following rapid sand-filtration combined with granular activated carbon. The detection index (DI) for tap water and Shinano River water did not exceed a value of 1. Herbicides contributed most to the DI.

Tropospheric ozone (O₃) has long been documented to cause an injury to plants, but a plants’ protectant, widely applicable in agronomical practice, does not exist. We evaluated the potential antiozonate efficacy of the antitranspirant di-1-p-menthene (Vapor Gard) compared with ethylenediurea (EDU) on Bel-W3 tobacco plants. Plants were treated either with water, or by EDU (10, 100, and 500 mg dm⁻³), or by vapor (1, 5, 10, and 50 ml dm⁻³) and were exposed either to O₃-enriched (90 ppb) or O₃-free air, for 12 days and 8 h day⁻¹. EDU when applied at 10 mg dm⁻³did not protect the plants against O₃, but when applied at 100 and 500 mg dm⁻³offered a significant protection to the plants. Vapor, when applied at 1 ml dm⁻³did not protect the plants against O₃, neither by terms of foliar visible injury nor by terms of aboveground biomass. In addition, when applied at 10 and 50 ml dm⁻³caused phytotoxicity to all the plants, which it was expressed as necrotic spots on the leaves’ surface, misshaping of the leaves, or short plants' height.It is obvious that vapor does not protect Bel-W3 tobacco plants against O₃. The antiozonate role of di-1-p-menthene is species-specific and probably occurs only under short-term exposures.

A laboratory-scale study was conducted to test whether biochar from cow dung as a soil amendment can reduce nutrient leaching from soil irrigated with biogas slurry. Polyvinyl chloride (PVC) columns were packed with soils containing 0, 20, and 40 g kg⁻¹of biochar. The biogas slurry was applied at 0, 200, and 400 ml per column, equivalent to 0, 130, and 260 kg N ha⁻¹. The biogas slurry was diluted to 1,500 ml with water and then applied five times every 6 days at 300 ml each time. All leached solutions were collected separately. Results showed that soil available phosphorus (P) and potassium (K) increased significantly with increased biogas slurry rates and biochar rates. The concentrations of total N, P, and K in leached solutions increased significantly as biogas slurry rates increased. Biochar significantly increased the concentrations of total and available P, total K, and electric conductance in leached solution. Contributions of biochar and biogas slurry treatments to the net amount of N, P, and K in leached solution increased with increased biochar and biogas slurry rates except at 4 % biochar rate where total N was decreased. Nutrient removal rate of biochar was over 10.6 % for total N and negative for total K at 2 % biochar rate. Nutrient removal rate of biochar was over 7.19 % for total P and negative for total N and total K at 4 % biochar rate. It is suggested that both biogas slurry and biochar have the potential to pollute water when leaching happens although biochar has the ability to adsorb N and P from biogas slurry.

The effects of municipal-treated wastewater on growth and gas exchange characteristics were studied in eucalyptus plants cultivated in a greenhouse under continuous sub irrigation with 70 % Long Ashton solution as a control, 100 % treated wastewater, and treated wastewater diluted 50 % with tap water. Irrigation with wastewater resulted in a reduction of total dry matter per plant and the shoot-to-root ratio and increased specific leaf mass, irrespective of the dilution. The gas exchange characteristics were adversely affected by the irrigation with wastewater, with photosynthetic rates been negatively affected. Total chlorophyll and carotenoids content were reduced in plants grown under treated wastewater. The results demonstrated that when the eucalyptus plants were grown under treated wastewater as the only source of mineral nutrients they were able to produce nearly 50 % of the dry matter produced by the plants grown under appropriate mineral nutrient supply, irrespective of the dilution. Therefore, the contribution of mineral nutrients and organic matter from the treated wastewater used as agricultural irrigation will be significant in lower the fertilizer rates without reducing dry matter production per plant.

Spatial and seasonal mobilization trends of metals in surface water were evaluated in the US–Mexico San Pedro River (SPR). Water samples were collected at five sampling stations for the analysis of dissolved oxygen, pH, electric conductivity, sulfates, and metals (Cd, Cu, Fe, Mn, Pb, and Zn). Quality of the water was characterized through Ecological Criteria of Water Quality (ECWQ) established in Mexico and Water Quality Criteria (Environmental Protection Agency (EPA)). High total metal concentrations were detected as follows: Fe > Cu > Mn > Zn > Pb > Cd. Metal concentrations were slightly higher in dry season than in rainy season: Cd (below detection limit (BDL)–0.21 mg L⁻¹), Cu (BDL–13 mg L⁻¹), Fe (0.16–345 mg L⁻¹), Mn (0.12–52 mg L⁻¹), Pb (BDL–0.48 mg L⁻¹), and Zn (0.03–17.8 mg L⁻¹). Low pH and dissolved oxygen values as well as high sulfate content were detected in both seasons. High values of metals (Cd, Cu, Fe, Mn, Pb, Zn) were detected at station E1 representing pollution source, as well as at stations E2 (Cd, Cu, Fe, Mn), E3 (Fe, Mn, Pb), and E4 and E5 (Fe, Mn). Detected concentrations exceeded maximum permissible established in ECWQ and Water Quality Criteria (EPA). Efflorescence salts on sediments in the dry season could increase levels of metals in water column. This study provides valuable information on the potential mobility of metals in surface water of SPR located in an arid environment where transport processes are strongly linked to climate. The information derived from this study should help the regional and national authorities to address present environmental regulations.