Mercury toxicity induces oxidative stress in growing cucumber seedlings

In this study, the effects of exogenous mercury (HgCl(2)) on time-dependent changes in the activities of antioxidant enzymes (catalase and ascorbate peroxidase), lipid peroxidation, chlorophyll content and protein oxidation in cucumber seedlings (Cucumis sativus L.) were investigated. Cucumber seedlings were exposed to from 0 to 500microM of HgCl(2) during 10 and 15 days. Hg was readily absorbed by growing seedlings, and its content was greater in the roots than the in shoot. Time and concentration-dependent reduction in root and shoot length was observed at all concentrations tested, equally in the roots and shoot, at both 10 and 15 days. At 50microM HgCl(2), root fresh weight of 15-day-old seedlings increased, and at other concentrations, it reduced. For 10-day-old seedlings, reduction in root and shoot fresh biomass was observed. At 15 days, only at 50microM HgCl(2) was there no observed reduction in shoot fresh biomass. Dry weight of roots increased at 500microM both at 10 and 15 days, though at 250microM HgCl(2) there was only an increase at 15 days. There was a significant effect on shoot dry weight at all concentrations tested. Hg-treated seedlings showed elevated levels of lipid peroxides with a concomitant increase in protein oxidation levels, and decreased chlorophyll content when exposed to between 250 and 500microM of HgCl(2). At 10 days, catalase activity increased in seedlings at a moderately toxic level of Hg, whereas at the higher concentration (500microM), there was a marked inhibition. Taken together, our results suggest that Hg induces oxidative stress in cucumber, resulting in plant injury.     

Zinc accumulation in Solanum nigrum is enhanced by different arbuscular mycorrhizal fungi

Solanum nigrum was found to proliferate in sediments with high levels of metal pollution. The effect of Zn on plant growth and tissue metal accumulation was assessed. The response of the plant to the inoculation with four different isolates of arbuscular mycorrhizal fungi (AMF) (Glomus sp. BEG140, Glomus claroideum, Glomus mosseae and Glomus intraradices) was studied. While the isolates of AMF did not have a significant (P<0.05) influence on mycorrhizal colonisation, increasing Zn concentration to high levels (500 and 1000 mgkg(-1)) induced significant (P<0.05) decrease of the AMF colonisation. In general, the presence of AMF did not affect the growth and biomass of S. nigrum individuals. However, the level of metal in the matrix affected S. nigrum growth; plants grown at 100 mgkg(-1) had significantly (P<0.05) lower leaf, stem, root and total biomass than control ones and plants growing at 500 and 1000 mgkg(-1) had the significantly (P<0.05) lowest biomass. Plants inoculated with the AMF G. claroideum and G. intraradices presented significantly (P<0.05) higher Zn accumulation in all plant tissues. In general, the stem tissues had the higher Zn content while the leaves registered the lowest values, which indicate a high translocation of the metal. AMF inoculation had no significant (P<0.05) influence on the metal translocation within the plant. This study suggests that inoculation with the AMF G. claroideum or G. intraradices, can enhance the Zn accumulation in the tissues of S. nigrum, not affecting the plant translocation capacities.     

Arabica-coffee and teobroma-cocoa agro-industrial waste biosorbents,for Pb(II) removal in aqueous solutions

Environmental Science and Pollution Research - Agro-industrial waste biosorbents of arabica–coffee (WCA) and theobroma–cocoa (WCT) have been characterized and tested to remove Pb(II)...     

Contamination Levels and Preliminary Assessment of the Technical Feasibility of Employing Natural Attenuation in 5 Priority Areas of Presidente Bernardes Refinery in Cubatão, São Paulo, Brazil

Five priority areas of potential impact by contaminants (API) were investigated at the Presidente Bernardes Refinery in Cubatão, São Paulo, Brazil with the following aims: (i) to identify both organic and inorganic contaminants present in soil and groundwater; (ii) to define the environmental conditions relevant for microbial activity at the site and (iii) to evaluate the feasibility of employing natural attenuation for treatment of the hydrocarbon contamination. One area (API 1) was an uncontrolled landfill, where waste materials from the refinery were deposited between 1954 and 1986, and four areas (API 4, 5, 7 and 11) were located in the operational section of the refinery. Soil contamination by regulated BTEX compounds (benzene, toluene, total xylenes) was restricted to two samples from API 1. Nonregulated ethylbenzene was detected in one soil sample from API 4, one from API 5 and two from API 1. No soil contained regulated PAH above threshold levels. Several nonregulated PAHs were found in 6 soil samples from API 1, 3 soil samples from API 4 and 1 soil sample from API 5. Site soils contained very high aluminium concentrations, but metal contamination was restricted to one soil sample from API 1, which contained nickel above threshold limits. BTEX contamination of groundwater was due mostly to benzene. Of the 17 PAH molecules tested, only naphthalene and 2-methylnaphthalene occurred in groundwater. The sum of total BTEX and total PAH exceeded 200 μg/L in only a few monitoring wells in API 4, 5 and 11 and was always below 2.640 μg/L. Be, Cd, Cr, Cu, Hg, Ni, Se, Ag, Tl and Zn were not detected in groundwater, which was contaminated in a few locations by aluminium (mostly below 1 mg/L), lead (<0.066 mg/L) and arsenic (<0.056 mg/L). S, K, Ca, Mg and Fe were present in groundwater in excess of physiological requirements for microbial growth, but low concentrations of N and P could become growth limiting. However, BTEX were efficiently degraded in saturated and unsaturated zone microcosms and nutrient amendments did not stimulate biodegradation rates measurably. The inorganic carbon pool in groundwater was up to one order of magnitude larger than the organic carbon pool. Total inorganic carbon (TIC) in API groundwater exceeded TIC of clean groundwater by factors of 2 (API 4), 6 (API 5, 7 and 11) or 10 (API 1). Most of the inorganic carbon incorporated into groundwater beneath the refinery originated from biodegradation in the unsaturated soil, which contained a microbiota (10⁶ cells/g on average) capable of growth with most of the pure (benzene, toluene, ethylbenzene and xylene) and mixed hydrocarbons tested (diesel oil, gasoline, naphtha, condensate, aromatic residue and fuel oil). A viscous hydrocarbon paste uncovered in API 1 was insoluble in water but dissolved in dichloromethane. Many organic components of this paste were biodegradable as evidenced by weight reduction of the hydrocarbon paste and by the growth of suspended and attached biomass in saturated zone microcosms, where the paste was the only carbon source. This study indicates that monitored natural attenuation may be a technically feasible and efficient means for plume control in API 1, 4 and 5, provided the plumes in API 4 and 5 are not expanding. This technique is not suitable for contaminant reduction in API 11.     

Differential aggregation of polystyrene and titanium dioxide nanoparticles under various salinity conditions and against multiple proteins types

The interaction of nanoplastics (NPls) and engineered nanoparticles (ENPs) with organic matter and environmental pollutants is particularly important. Therefore, their behavior should be investigated under the different salinity conditions, mimicking rivers and coastal environments, to understand this phenomenon in those areas. In this work, we analyzed the elementary characteristics of polystyrene-PS (unmodified surface and modified with amino or carboxyl groups) and titanium dioxide-TiO2 nanoparticles. The effect of salinity on their colloidal properties was studied too. Also, the interaction with different types of proteins (bovine serum albumin-BSA and tilapia proteins), as well as the formation of the BSA corona and its effect on the colloidal stability of nanoparticles, were evaluated. The morphology and dispersion of sizes were more uniform in unmodified-surface PS-NPs (70.5?±?13.7 nm) than in TiO2-NPs (131.2?±?125.6 nm). Likewise, Rama spectroscopy allowed recognizing peaks associated with the PS phenyl group aromatic ring in unmodified-surface PS-NPs (621, 1002, 1582, and 1602 cm^?1). For TiO2-NPs, the data suggest belonging to the tetragonal form, also known as rutile (445, 610 cm^?1). The elevation of salinity dose-dependently decreased NP colloid stability, with more significant variation in the PS-NPs compared to TiO2-NPs. The organic matter is also involved in this phenomenon, differentially as a function of time compared to its absence (unmodified-surface PS-NPs 30 psu/TOC 5 mgL^?1/24 h: 2876.6?±?378.03 nm; unmodified-surface PS-NPs 30 psu/24 h: 2133?±?49.57 nm). In general, the TiO2-NPs demonstrated greater affinity with all proteins tested (0.066 g/L). It was observed that morphology, size, and surface chemical modification intervene in a relevant way in the interaction of the nanoparticles with bovine serum albumin (unmodified-surface PS-NPs 298 K: 6.08E⁺⁰²; 310 K: 6.63E⁺⁰²; TiO2-NPs 298 K: 8.76E⁺⁰²; 310 K: 1.05E⁺⁰³ L mol^?1) and tilapia tissues proteins (from blood, gills, liver, and brain). Their morphology and size also determined the protein corona formation and the NPs’ agglomeration. These findings can provide references during knowledge transfer between NPls and ENPs.

     

An integrative negotiation model to deal with conflicts toward water resources management: a case study in Brazil

Environment, Development and Sustainability - An integrative negotiation model is proposed so that watershed committees (WSC) can deal better with conflicts over alternatives for protecting water...     

Human disturbance and shifts in vertebrate community composition in a biodiversity hotspot

Understanding how human modification of the landscape shapes vertebrate community composition is vital to understanding the current status and future trajectory of wildlife. Using a participatory approach, we deployed the largest camera-trap network in Mesoamerica to date to investigate how anthropogenic disturbance shapes the occupancy and co-occurrence of terrestrial vertebrate species in a tropical biodiversity hotspot: the Osa Peninsula, Costa Rica. We estimated species richness in different categories of land protection with rarefaction analysis and estimated the expected occupancy with a joint species distribution model that included covariates for anthropogenic disturbance, land protection, habitat quality, and habitat availability. Areas with the most stringent land-use protections (e.g., Corcovado National Park, 24 species [95% CI 23–25]) harbored significantly more species than unprotected areas (20 species [19.7–20.3]), mainly due to a reduced presence of large-bodied species of conservation concern in unprotected areas (e.g., jaguar Panthera onca and white-lipped peccary Tayassu pecari). Small-bodied generalist species, such as opossums (Didelphidae) and armadillos (Dasypus novemcinctus), in contrast, were more common at disturbed sites, resulting in a significant difference in vertebrate community composition between sites with low and high disturbance. Co-occurrence of species was also mainly associated with response to disturbance. Similar responses to disturbance create two groups of species, those whose site-level occupancy usually increased as anthropogenic disturbance increased and those whose estimated occupancy decreased. The absence of large-bodied species entails an important loss of ecological function in disturbed areas and can hinder forest development and maintenance. Efforts to protect and restore forested landscapes are likely having a positive effect on the abundance of some threatened species. These efforts, however, must be sustained and expanded to increase connectivity and ensure the long-term viability of the wildlife community.     

Towards a green industry through cleaner production development

Environmental Science and Pollution Research - The growth in global production and consumption rates has resulted in increased pollution generation by industrial companies. To this end, cleaner...     

Lateral flow assay applied to pesticides detection: recent trends and progress

Environmental Science and Pollution Research - Devices based on lateral flow assay (LFA) have been gaining more and more space in the detection market mainly due to their simplicity, speed, and low...     

Correction to: Briquettes of acai seeds: characterization of the biomass and influence of the parameters of production temperature and pressure in the physical-mechanical and energy quality

Environmental Science and Pollution Research - A Correction to this paper has been published: 10.1007/s11356-021-16529-z