This study investigated the relationship between contaminant body burden and the oxidative stress status of the gills and livers of two wild fish species in the Furnas Hydroelectric Power Station (HPS) reservoir (Minas Gerais, Brazil). Gills and livers presented similar pathways of metals and organochlorine bioaccumulation. During June, organochlorines were associated with lipid peroxidation (LPO), indicating oxidative stress due to the inhibition of the antioxidant enzymes superoxide dismutase and glutathione peroxidase. In the most polluted areas, metal concentrations in the liver were associated with metallothionein. During December, contaminants in the gills and liver were associated with catalase activity and LPO. Aldrin/dieldrin was the contaminant most associated with oxidative damage in the livers of both species. This integrated approach shed light on the relationship between adverse biological effects and bioaccumulation of contaminants inputted by intensive agricultural practices and proved to be a suitable tool for assessing the environmental quality of man-made reservoirs.

The objective of this study was to assess potential toxic effects of simulated urban runoff on Carassius auratus using oxidative stress biomarkers. The activity of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and the content of malondialdehyde (MDA) in the liver of C. auratus were analyzed after a 7-, 14- and 21-day exposure to simulated urban runoff containing galaxolide (HHCB) and cadmium (Cd). The results showed that the activity of antioxidant enzymes and the content of MDA increased significantly exposed to the simulated urban runoff containing HHCB alone or mixture of HHCB and Cd. The activity of the investigated enzymes and the content of MDA then returned to the blank level over a longer period of exposure. The oxidative stress could be obviously caused in the liver of C. auratus under the experimental conditions. This could provide useful information for toxic risk assessment of urban runoff.

Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O₃) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O₃ fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O₃ fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O₃, determined from the mRNA levels of the major allergens. We conclude that O₃ can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase.

Because of its toxicity and its ubiquity within aquatic compartments, uranium (U) represents a significant hazard to aquatic species such as fish. In a previous study, we investigated some biological responses in zebrafish either exposed to depleted or to enriched U (i.e., to different radiological activities). However, results required further experiments to better understand biological responses. Moreover, we failed to clearly demonstrate a significant relationship between biological effects and U radiological activity. We therefore chose to herein examine U bioaccumulation and induced effects in zebrafish according to a chemical dose–response approach. Results showed that U is highly bioconcentrated in fish, according to a time- and concentration-dependent model. Additionally, hepatic antioxidant defenses, red blood cells DNA integrity and brain acetylcholinesterase activity were found to be significantly altered. Generally, the higher the U concentration, the sooner and/or the greater the effect, suggesting a close relationship between accumulation and effect.

For phytoremediation of organic contaminants, plants have to host an efficiently degrading microflora. To assess the role of endophytes in alkane degradation, Italian ryegrass was grown in sterile soil with 0, 1 or 2% diesel and inoculated either with an alkane degrading bacterial strain originally derived from the rhizosphere of Italian ryegrass or with an endophyte. We studied plant colonization of these strains as well as the abundance and expression of alkane monooxygenase (alkB) genes in the rhizosphere, shoot and root interior. Results showed that the endophyte strain better colonized the plant, particularly the plant interior, and also showed higher expression of alkB genes suggesting a more efficient degradation of the pollutant. Furthermore, plants inoculated with the endophyte were better able to grow in the presence of diesel. The rhizosphere strain colonized primarily the rhizosphere and showed low alkB gene expression in the plant interior. Bacterial alkane degradation genes are expressed in the rhizosphere and in the plant interior.

Aquatic macrophytes were found to be the potential scavengers of heavy metals from aquatic environment. In this study, several physiological responses of Alternanthera philoxeroides (Mart.) Griseb leaves to elevated concentrations of cadmium (up to 10 mM) were investigated. It was found that A. philoxeroides was able to accumulate cadmium in its leaves. The pigment contents decreased with the increase of the Cd concentrations. The Cd could induce rise of the activity of peroxidase (POD) at lower concentration (<5 mM), however, when the concentration of Cd rose up to 10 mM, the POD activity declined. The changes of superoxide dismutase (SOD) and Catalase (CAT) activities were exactly opposite to that of POD. In the leaves of Cd-treated fronds, the amounts of three polypeptides with apparent molecular weights 80, 39 and 28 kDa, respectively, were became visible in SDS-PAGE. The nature of these polypeptides remains to be determined. Cd modified a number of physiological processes and particularly chlorophyll degradation.

The use of a vegetation cover for the management of heavy metal contaminated soils needs prior investigations on the plant species the best sustainable. In this work, behaviors of Trifolium repens and Lolium perenne, growing in a metal-polluted field located near a closed lead smelter, were investigated through Cd, Pb and Zn-plant metal concentrations and their phytotoxicity. In these plant species, metals were preferentially accumulated in roots than in shoots, as follow: Cd > Zn > Pb. Plant exposure to such metals induced oxidative stress in the considered organs as revealed by the variations in malondialdehyde levels and superoxide dismutase activities. These oxidative changes were closely related to metal levels, plant species and organs. Accordingly, L. perenne seemed to be more affected by metal-induced oxidative stress than T. repens. Taken together, these findings allow us to conclude that both the plant species could be suitable for the phytomanagement of metal-polluted soils. Usefulness of Trifolium repens and Lolium perenne for the phytomanagement of heavy metal-contaminated soils.

To validate the outcome of the national regulation on dioxins emission implemented in 1999, this study investigated temporal trends of chlorinated dioxins and related compounds (DRCs) in liver of common cormorants (Phalacrocorax carbo) collected from Lake Biwa, Japan between 2001 and 2008, as a part of the “Survey on the State of Dioxins Accumulation in Wildlife” conducted by the Ministry of the Environment, Japan. We also measured a biomarker of DRCs exposure, the cytochrome P450 1A (CYP1A)-dependent O-dealkylation activity of alkoxyresorufins (AROD), including methoxy-, ethoxy-, pentoxy- and benzyloxy-resorufins in the samples over 2001–2007. Neither TEQ nor AROD activity showed any clear declining trend over the time period, although the emission of DRCs during the corresponding period was estimated to be apparently decreasing. Our data indicate that the concentration of recalcitrant DRCs in the cormorant during 2001–2008 was scarcely affected by the national regulation on dioxins emission.