Ecotoxicological assessment of TiO2 byproducts on the earthworm Eisenia fetida

The increasing production of nanomaterials will in turn increase the release of nanosized byproducts to the environment. The aim of this study was to evaluate the behaviour, uptake and ecotoxicity of TiO₂ byproducts in the earthworm Eisenia fetida. Worms were exposed to suspensions containing 0.1, 1 and 10 mg/L of byproducts for 24 h. Size of TiO₂ byproducts showed aggregation of particles up to 700 μm with laser diffraction. Only worms exposed at 10 mg/L showed bioaccumulation of titanium (ICP-AES), increasing expression of metallothionein and superoxide dismutase mRNA (Real-time PCR) and induction of apoptotic activity (Apostain and TUNEL). TiO₂ byproducts did not induce cytotoxicity on cœlomocytes, but a significant decrease of phagocytosis was observed starting from 0.1 mg/L. In conclusion, bioaccumulation of byproducts and their production of reactive oxygen species could be responsible for the alteration of the antioxidant system in worms.     

An integrated environmental approach to investigate biomarker fluctuations in the blue mussel Mytilus edulis L. in the Vilaine estuary, France

Estuarine areas represent complex and highly changing environments at the interface between freshwater and marine aquatic ecosystems. Therefore, the aquatic organisms living in estuaries have to face highly variable environmental conditions. The aim of this work was to study the influence of environmental changes from either natural or anthropogenic origins on the physiological responses of Mytilus edulis. Mussels were collected in the Vilaine estuary during early summer because this season represents a critical period of active reproduction in mussels and of increased anthropogenic inputs from agricultural and boating activities into the estuary. The physiological status of the mussel M. edulis was evaluated through measurements of a suite of biomarkers related to: oxidative stress (catalase, malondialdehyde), detoxication (benzopyrene hydroxylase, carboxylesterase), neurotoxicity (acetylcholinesterase), reproductive cycle (vitelline, condition index, maturation stages), immunotoxicity (hemocyte concentration, granulocyte percentage, phagocytosis, reactive oxygen species production, oxidative burst), and general physiological stress (lysosomal stability). A selection of relevant organic contaminant (pesticides, (polycyclic aromatic hydrocarbons, polychlorobiphenyls) was measured as well as environmental parameters (water temperature, salinity, total suspended solids, turbidity, chlorophyll a, pheopigments) and mussel phycotoxin contamination. Two locations differently exposed to the plume of the Vilaine River were compared. Both temporal and inter-site variations of these biomarkers were studied. Our results show that reproduction cycle and environmental parameters such as temperature, organic ontaminants, and algal blooms could strongly influence the biomarker responses. These observations highlight the necessity to conduct integrated environmental approaches in order to better understand the causes of biomarker variations.     

Environmental impact of sunscreen nanomaterials: ecotoxicity and genotoxicity of altered TiO2 nanocomposites on Vicia faba

Mineral sunscreen nanocomposites, based on a nano-TiO₂ core, coated with aluminium hydroxide and dimethicone films, were submitted to an artificial ageing process. The resulting Altered TiO₂ Nanocomposites (ATN) were then tested in the liquid phase on the plant model Vicia faba, which was exposed 48 h to three nominal concentrations: 5, 25 and 50 mg ATN/L. Plant growth, photosystem II maximum quantum yield, genotoxicity (micronucleus test) and phytochelatins levels showed no change compared to controls. Oxidative stress biomarkers remained unchanged in shoots while in roots, glutathione reductase activity decreased at 50 mg ATN/L and ascorbate peroxidase activity decreased for 5 and 25 mg ATN/L. Nevertheless, despite the weak response of biological endpoints, ICP-MS measurements revealed high Ti and Al concentrations in roots, and X-ray fluorescence micro-spectroscopy revealed titanium internalization in superficial root tissues. Eventual long-term effects on plants may occur.     

Detection of free and covalently bound microcystins in animal tissues by liquid chromatography-tandem mass spectrometry

Microcystins are cyanobacterial hepatotoxins capable of accumulation into animal tissues. The toxins act by inhibiting specific protein phosphatases and both non-covalent and covalent interactions occur. The 2-methyl-3-methoxy-4-phenylbutyric acid (MMPB) method determines the total, i.e. the sum of free and protein-bound microcystin in tissues. The aim of the method development in this paper was to tackle the problems with the MMPB methodology: the rather laborious workflow and the loss of material during different steps of the method. In the optimised workflow the oxidation recovery was of acceptable level (29-40%), the extraction efficiency good (62-97%), but the signal suppression effect from the matrix remained severe in our system (16-37% signal left). The extraction efficiency for the determination of the free, extractable microcystins, was found to be good, 52-100%, depending on the sample and the toxin variant and concentration.     

Roles of regional hydrodynamic and trophic contamination in cadmium bioaccumulation by Pacific oysters in the Marennes-Oléron Bay (France)

The Marennes-Oléron Bay, hosting the largest oyster production in France, is influenced by the historic polymetallic pollution of the Gironde Estuary. Despite management efforts and decreasing emissions in the Gironde watershed, cadmium levels in oysters from the bay are close to the consumption limit (5 μg g⁻¹ dw, EC). From mid April to mid July 2009, we investigated the role of tidal resuspension and regional hydrodynamics on Cd speciation (seawater, SPM, phytoplankton, sediment, microphytobenthos) and bioaccumulation in 18 month-old oysters (gills, digestive glands, rests of tissues) reared under natural conditions (i) at ∼60 cm above the sediment and (ii) on the sediment surface. Dissolved and particulate Cd concentrations in surface and bottom waters were similar and constant over tidal cycle suggesting the absence of Cd release during sediment resuspension. Temporal dissolved and particulate Cd concentrations were closely related to Gironde Estuary water discharges, showing increasing concentrations during flood situations and decreasing concentrations afterwards. Cd depletion in the water column was associated with increasing Cd in the [20-100 μm] plankton fraction, suggesting Cd bioaccumulation. After 3 months, enrichment factors of Cd in tissues of oysters exposed in the water column and directly on the sediment were respectively 3.0 and 2.2 in gills, 4.7 and 3.2 in digestive glands and 4.9 and 3.4 in remaining tissues. Increasing Cd bioaccumulation in gills, digestive glands and remaining tissues can be related to elevated dissolved Cd in the bay, suggesting gill contamination via the direct pathway and subsequent internal redistribution of Cd to other organs and tissues. Elevated Cd contents in oysters reared on tables could be attributed to different trophic Cd transfer (phytoplankton versus microphytobenthos) or to different oyster metabolisms between the rearing conditions as suggested by metallothionein concentrations.     

Congener-specific egg contribution of polychlorinated biphenyls to nestlings in two passerine species

Quantifying polychlorinated biphenyl (PCB) residues in nestlings of avian species is a common method for assessing trophic transfer and risk at PCB-contaminated sites. The proportion of nestling PCB mass due to maternal transfer is often accounted for by subtracting total PCB mass in eggs from nestlings. However, variation in physicochemical properties and metabolism among congeners may lead to differences between egg contribution based on total PCBs and dioxin-like congeners. We examined congener-specific variation in contribution of PCBs from eggs to nestlings in tree swallows and European starlings. Egg contribution of total PCB mass was 14.3 and 16.2%, respectively, whereas contribution based on dioxin-like congeners was 14.8 and 13.6%, respectively. These data suggest that using total PCB mass in eggs to adjust estimates of PCB accumulation in nestlings may not reflect patterns for dioxin-like congeners, potentially over or under-estimating the risk of toxicity of PCBs.     

An examination of the factorial,construct, and predictive validity and utility of the regulatory focus at work scale

Although interest in regulatory focus research continues to grow, there has been very little work to date on the assessment and usefulness of regulatory focus in the workplace. The present research effort reports the results of a series of studies designed to assess the validity and utility of the Regulatory Focus at Work Scale (RWS). The results indicate that the RWS is reliable, valid, and showed incremental validity beyond general and trait‐like measures of regulatory focus in predicting relevant work outcomes of task performance, citizenship performance, safety performance, and productivity performance. The overall results of these studies support our claims that the RWS shows utility in predicting workplace outcomes and should prove useful for future research on regulatory focus in the workplace. Copyright © 2008 John Wiley & Sons, Ltd.     

Modification of a full-scale sequencing batch reactor operational mode for biological nutrient removal.

Two biological nutrient removal modes, consisting of anaerobic, anoxic, and oxic sequences, were tested in a full-scale sequencing batch reactor. The modes, identified as BNR-S1 and BNR-S2, had average total nitrogen removals of 84 and 89%, respectively, for the months of August to October. Over the same period, total phosphorus removals for BNR-S1 and BNR-S2 were 88 and 87%, respectively. In contrast, total nitrogen and total phosphorus removals for the regular aerobic mode were 54.7 and 44.7%, respectively. When the wastewater temperature changed from approximately 20 to 15 degrees C in the winter months, total nitrogen and total phosphorus removals for BNR-S2 were reduced to 81 and 70%, respectively. Total nitrogen effluent concentrations were between 2.5 and 4 mg-N/L (at approximately 20 degrees C), while the effluent total phosphorus concentrations were between 1 and 2 mg/L. The BNR-S2 mode was found to require less energy per kilogram of soluble chemical oxygen demand removed than the regular and BNR-S1 modes.     

‘Are you prepared?’ Representations and management of floods in Lomanikoro,Rewa (Fiji)

The islands of Fiji, in the Western Pacific, are exposed to a wide range of natural hazards. Tropical storms and associated floods are recurring natural phenomena, but it has been regularly alleged that Fijians lack preparation, over‐rely on state assistance in post‐disaster situations or engage in risky behaviours that aggravate the negative impact of floods. Risk reduction strategies, which are now implemented by government authorities and international organisations, heavily promote the principle of ‘community preparedness’. Both community awareness programmes and capacity‐building programmes are conducted throughout the country in the most vulnerable communities. This paper analyses how the inhabitants of Lomanikoro village, in the low areas of the Rewa Delta, perceive and manage existing flood risks. It examines social and cultural factors that contribute to shape risk response locally—in particular, why villagers may be reluctant to adopt some recommended preparedness measures and resettle in higher, safer zones.