Estuaries are subjected to continual environmental impacts from activities in the catchment areas. This research assessed the quality of two estuarine habitats located in Ilha do Maranhão, Brazil, through histological and genotoxic biomarkers in Centropomus undecimalis, comparing the data obtained to metal, physical, and chemical concentrations of water samples. The gill histological alterations were analyzed by the histological alteration index and genotoxic lesions in erythrocytes were detected by the Micronucleus Test. The analysis of metals revealed that all water samples contained at least two elements with concentrations higher than that allowed by the current Brazilian law. For gill histological analysis, snook of both areas assessed exhibited moderate lesions, indicating that the local fish are affected by environmental stress. Micronucleus analysis of snook showed that the Bacanga river basin is the most affected. In addition to assessing the health of commercial fish populations, the information about the biomarkers used for the species can serve to contribute to the preparation and/or application of health assessment models and implementation of environmental recovery policies for coastal aquatic environments.

Methylation and demethylation represent major transformation pathways regulating the net production of methylmercury (MMHg). Very few studies have documented Hg reactivity and transformation in extreme high-altitude lake ecosystems. Mercury (Hg) species concentrations (IHg, MMHg, Hg°, and DMHg) and in situ Hg methylation (M) and MMHg demethylation (D) potentials were determined in water, sediment, floating organic aggregates, and periphyton compartments of a shallow productive Lake of the Bolivian Altiplano (Uru Uru Lake, 3686 m). Samples were collected during late dry season (October 2010) and late wet season (May 2011) at a north (NS) and a south (SS) site of the lake, respectively. Mercury species concentrations exhibited significant diurnal variability as influenced by the strong diurnal biogeochemical gradients. Particularly high methylated mercury concentrations (0.2 to 4.5 ng L⁻¹ for MMHgT) were determined in the water column evidencing important Hg methylation in this ecosystem. Methylation and D potentials range were, respectively, <0.1–16.5 and <0.2–68.3 % day⁻¹ and were highly variable among compartments of the lake, but always higher during the dry season. Net Hg M indicates that the influence of urban and mining effluent (NS) promotes MMHg production in both water (up to 0.45 ng MMHg L⁻¹ day⁻¹) and sediment compartments (2.0 to 19.7 ng MMHg g⁻¹ day⁻¹). While the sediment compartment appears to represent a major source of MMHg in this shallow ecosystem, floating organic aggregates (dry season, SS) and Totora’s periphyton (wet season, NS) were found to act as a significant source (5.8 ng MMHg g⁻¹ day⁻¹) and a sink (−2.1 ng MMHg g⁻¹ day⁻¹) of MMHg, respectively. This work demonstrates that high-altitude productive lake ecosystems can promote MMHg formation in various compartments supporting recent observations of high Hg contents in fish and water birds.

Sediment bacterial communities are sensitive to water conditions in river ecosystems. The objective of this study was to compare the influences of different pollution sources, including urban areas, wastewater treatment plants (WWTPs), suburban areas, and agricultural areas, on sediment bacterial communities along a typical tributary of Taihu Lake, China. The dominant composition of the sediment bacterial community was determined using a combination of terminal restriction fragment length polymorphism (T-RFLP) and a 16S rRNA clone library. The results showed that the sediment bacterial communities were distinctly affected by the four pollution sources. Alphaproteobacteria, Betaproteobacteria, and Actinobacteria (>50 % in total) were the predominant bacterial taxa across the sediment samples. Apart from those, the sediment bacterial community composition (BCC) affected by WWTP effluent was subsequently dominated by Nitrospira (12.4 %) and Bacteroidetes (11.5 %), agriculture was dominated by Firmicutes (13.2 %) and Deltaproteobacteria (7.2 %), while urban and suburban were dominated by Bacteroidetes (7.6 and 7.9 %, respectively) and Deltaproteobacteria (7.9 and 7.6 %, respectively). Cluster analysis indicated that the BCC affected by WWTP effluent was distinct from the BCC in urban, suburban, and agricultural areas. In addition, the bacterial community richness and evenness affected by WWTP effluent were much less than those by the other pollution sources. Redundancy analysis (RDA) indicated that the variation in BCC across the sediment samples was significantly associated with ammonium (17 %), organic matter (12 %), and cadmium (3 %) (p < 0.01). Overall, the results indicated that the four different pollution sources (WWTP, urban, suburban, and agriculture) have dissimilar impacts on the sediment BCC in the tributary of Taihu Lake, while WWTPs exhibited the greatest potential to lead to biotic homogenization in river sediments.

Choosing native vascular plants as nutrient and toxic element accumulators for passive biomonitoring of urban river quality is not an easy task in Mediterranean rivers, due to the particular climate determining high variations in river hydrology. To identify potential biomonitors for this area, the roots of seven species (Angelica sylvestris, Apium nodiflorum, Tradescantia fluminensis, Nasturtium officinale, Persicaria lapathifolia, Arctium lappa, Typha latifolia), growing in seven sites along the River Irno (Southern Italy), were collected in July 2010 and analyzed regarding their capability to accumulate Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, V, and Zn through atomic absorption spectrometry. Notwithstanding the expected different accumulation degree among the species, they highlighted similar spatial contamination gradients, and all of them appeared suitable, alone or in combination, for river passive biomonitoring. A. nodiflorum, in particular, appeared the best biomonitor for the River Irno, where severe anthropogenic impacts were detected: high Cu and Cd contamination from vine cultivation in the upper stretch, and Pb, Zn, and Mn contamination in the medium stretch from airborne dusts coming from a cast iron foundry.

Amethopterin is used as a chemotherapeutic agent, and its antioxidant activity is used to treat many cancer types. This study aimed to study the ameliorating effect of L-carnitine against amethopterin-induced cardiac injury and oxidative stress in male rats. Sixty male albino rats were equally divided into six groups; the first and second groups were the control and L-carnitine groups, respectively, while the third group was treated with amethopterin rat group; the fourth and fifth groups were co-treated and post-treated with amethopterin rat with L-carnitine, respectively, and the sixth group was self-treated with amethopterin rat group. Cholesterol, triglycerides, low-density lipoprotein (LDL), glutathione, and total protein levels in amethopterin group showed a significant decrease when compared with control group, while high-density lipoprotein (HDL), glutamic oxaloacetic transaminase (GOT), malondialdehyde (MDA), catalase, and nitric oxide (NO) levels in amethopterin group showed a significant increase when compared with control group. Cholesterol, triglycerides, LDL, GOT, MDA, and catalase levels in the self-treated group showed a significant increase when compared with amethopterin group, while glutathione, total protein, and NO levels in the self-treated group showed significant decrease when compared with amethopterin group. Many of abnormalities as moderate hydrophobic changes of myofibrillar structure with striations, myocardial atrophy, cytoplasmic vacuoles, edema, and leukocyte infiltration were detected in cardiac tissues in amethopterin rat group. A significant increase of the apoptotic protein p53 and CD68 immunoreactivity, despite a significant decrease in the antiapoptotic Bcl–2 proteins after amethopterin injection when compared with control group, was observed. Treatment (co and post) with L-carnitine improved the biochemical, histopathological, and immunohistochemical alterations in the heart treated with amethopterin.

A mixture of urban and hospital effluents (50 % v/v) was evaluated for ecotoxicity with an advanced bioassay battery. Mixed effluents were tested before any treatment, after biological treatment alone, and after biological treatment followed by a tertiary ozonation (15 mg O₃/L). Laying a high value on the continuance of organisms’ fitness, essential to preserve a healthy receiving ecosystem, the main objective of this study was to combine normalized bioassays with newly developed in vivo and in vitro tests in order to assess alteration of embryo development, growth and reproduction, as well as genotoxic effects in aquatic organisms exposed to complex wastewater effluents. Comparison of the bioassays sensitivity was considered. Contrary to the lack of toxicity observed with normalized ecotoxicity tests, endpoints measured on zebrafish embryos such as developmental abnormalities and genotoxicity demonstrated a residual toxicity in wastewater both after a biological treatment followed or not by a tertiary O₃ treatment. However, the ozonation step allowed to alleviate the residual endocrine disrupting potential measure in the biologically treated effluent. This study shows that normalized bioassays are not sensitive enough for the ecotoxicological evaluation of wastewaters and that there is a great need for the development of suitable sensitive bioassays in order to characterize properly the possible residual toxicity of treated effluents.

A verity of human activities i.e. urbanization and industrialization have been resulted serious environmental contaminations by heavy metals in all over the world. The settlement of populations in urban and nearby industrial areas for economic development has significant share in their exposure to these metallic contaminants. Depending on the nature and type of the pollutants, targeted urban-industrial environments can have harmful and chronic health risk impacts on exposed local inhabitants and may require detoxification, healing and remedial therapy. Consequently, environmental monitoring as well as human health risk assessments of urban environments under industrial influence are key dominant features. We believe this work will provide new insights into the studies of metals exposure and associated health risks in emerging industrials cities of developing countries. Present study aimed to study the bioavailability of metals, quantify the changeability in soil and vegetable metal concentrations and estimation of human health risks via dietary exposure, focusing on urban-industrial environment. Soil and vegetable samples were collected in six random sites within the urban, periurban and industrial areas and analyzed for metal concentrations. In addition, risk assessment model proposed by US-EPA was employed to estimate the potential health risk of heavy metals via dietary intake. Results indicated that the heavy metal concentrations were noteworthy in periurban and urban-industrial areas. However, contamination levels varied with the type of vegetable, and the point source pollution such as traffic, urban wastes and industrial effluent. According to the estimated THQ and HI values for non-carcinogenic risk, little or no negative impact of heavy metals was observed on local inhabitants. However, the concentrations of Cr, Cd, Pb and Ni were nearly closed to the permissible limits described by US-EPA in urban-industrial areas. Conclusively, some efficient remedial strategies should be focus to overcome the increasing levels of Cr, Cd, Pb and Ni in this study area to protect the health of local inhabitants.

The scarcity of freshwater resources is a serious problem in arid regions, such as Tunisia, and marginal quality water is gradually being used in agriculture. This study aims to study the impact of treated urban wastewater for reuse in agriculture on the health of soil and food crops. The key findings are that the effluents of Sfax wastewater treatment plant (WWTP) did not meet the relevant guidelines, therefore emitting a range of organic (e.g., up to 90 mg L⁻¹ COD and 30 mg L⁻¹ BOD₅) and inorganic pollutants (e.g., up to 0.5 mg L⁻¹ Cu and 0.1 mg L⁻¹ Cd) in the receiving aquatic environments. Greenhouse experiments examining the effects of wastewater reuse on food plants such as tomato, lettuce, and radish showed that the treated effluent adversely affected plant growth, photosynthesis, and antioxidant enzyme contents. However, the pollution burden and biological effects on plants were substantially reduced by using a 50 % dilution of treated sewage effluent, suggesting the potential of reusing treated effluent in agriculture so long as appropriate monitoring and control is in place.

Greenhouse hydroponic experiments were carried out using three different heavy metal accumulation tobacco genotypes to evaluate how different genotypes responded to chromium (Cr) toxicity in the presence of 24-epibrassinolide (EBR; a biologically active brassinosteroid). The results showed that Cr stress caused a marked reduction in plant biomass, chlorophyll content, chlorophyll fluorescence, and photosynthesis parameters but induced malondialdehyde accumulation and ultrastructure damage, with 2010-38 (L) less affected. Foliar application of 24-epibrassinolide (0.1 μM) on Cr-stressed plants greatly alleviated Cr-induced inhibition of growth and photosynthesis, oxidative stress and ultrastructure damage, decreased Cr accumulation in different parts of leaves and roots, with the exception of the upper and lower of leaves of genotype L, and maintained ion homeostasis. Regarding genotypes, L was more tolerant than M and H, as it absorbed less Cr and also performed better in all of the studied parameters. These findings suggest a potential role for 24-epibrassinolide in Cr stress alleviation and the utilization of elite genetic resources in future breeding programs to develop low Cr accumulation genotypes. These results advocate a positive role for 24-epibrassinolide in reducing pollutant residues from health point of view.