The influence of sewage sludge (SS) and sewage sludge biochar (SSBC) upon biomass yield and the bioaccumulation of PAHs into lettuce plants grown in contaminated soil (∑16PAH 20.2 ± 0.9 mg kg−1) is presented. All SSBC amendments (2, 5 and 10%) and the 2% SS amendment significantly (P < 0.01) increased lettuce biomass. Both SS and SSBC amendments significantly reduced (P < 0.01) the bioaccumulation of PAHs at all application levels; with reduction in ∑16PAH concentration ranging between 41.8 and 60.3% in SS amended treatments and between 58.0 and 63.2% in SSBC amended treatments, with respect to the control. Benefits in terms of biomass production and PAHs bioaccumulation reduction were greatest where SSBC was used as a soil amendment. At high application rates (10%) SSBC reduced bioaccumulation of PAHs by between 56% and 67%, while SS reduced bioaccumulation of PAHs by less than 44%.

Two mesotrophic grassland species, Ranunculus acris and Dactylis glomerata were exposed to a range of ozone treatments (16.2–89.5 ppb 24 h mean) and two watering regimes under naturally fluctuating photosynthetically active radiation (PAR), vapour pressure deficit (VPD) and temperature. Stomatal conductance was measured throughout the experiments, and the combined data set (>1000 measurements) was analysed for effects of low and high ozone on responses to environmental stimuli. We show that when D. glomerata and R. acris were grown in 72.6–89.5 ppb ozone the stomata consistently lose the ability to respond, or have reduced response, to naturally fluctuating environmental conditions in comparison to their response in low ozone. The maximum stomatal conductance (gmax) was also significantly higher in the high ozone treatment for D. glomerata. We discuss the hypotheses for the reduced sensitivity of stomatal closure to a changing environment and the associated implications for ozone flux modelling.

This study evaluated the dietary uptake kinetics and sublethal toxicity of p,p′-dichlorodiphenyl dichloroethylene (p,p′-DDE) in Antarctic krill. The uptake rate constant (characterised by the seawater volume stripped of contaminant sorbed to algae) of 200 ± 0.32 mL g−1 wet weight h−1, average absorption efficiency of 86 ± 13% and very low elimination rate constant of 5 × 10−6 ± 0.0031 h−1 demonstrate the importance of feeding for p,p′-DDE bioaccumulation in Antarctic krill. Faecal egestion of unabsorbed p,p′-DDE of 8.1 ± 2.7% indicates that this pathway contributes considerably to p,p′-DDE sinking fluxes. A median internal effective concentration (IEC50) of 15 mmol/kg lipid weight for complete immobility indicates baseline toxicity and that Antarctic krill exhibit comparable toxicological sensitivity as temperate species under similar 10 d exposure conditions. These findings support the critical body residue approach and provide insight to the role of Antarctic krill in the biogeochemical cycling of p,p′-DDE in the Southern Ocean.

A simulated oxidation technique was used to examine the impacts of degradation on the surface properties of biochar and the potential implications of the changes in biochar properties were discussed. To simulate the short- and long-term environmental degradation, mild and harsh degradation were employed. Results showed that after mild degradation, the biochar samples showed significant reductions in surface area and pore volumes. After harsh degradation, the biochar samples revealed dramatic variations in their surface chemistry, surface area, pore volumes, morphology and adsorption properties. The results clearly indicate that changes of biochar surface properties were affected by biochar types and oxidative conditions. It is suggested that biochar surface properties are likely to be gradually altered during environmental exposure. This implies that these changes have potential effects for altering the physicochemical properties of biochar amended soils.

In this study, the aqueous uptake and dietary assimilation (trophic transfer) of two endocrine disrupting compounds (dioxin and phathalic acid) in the green mussel Perna viridis were quantified. During short-term exposure period, dioxin rapidly sorbed onto phytoplankton and its accumulation was much higher than that of phthalate. The uptake of these two compounds by the mussels increased with increasing temperature and salinity (for dioxin only). The dietary assimilation of the two contaminants was rather modest (10–64% for dioxin and 20–47% for phthalate), and was greatly dependent on the food species and concentration. Interestingly, dietary assimilation increased with increasing diatom food concentration. Gut passage time was partially responsible for the variable dietary assimilation. Given the high dissolved uptake rate and the modest dietary assimilation, aqueous exposure was predicted to be the dominant bioaccumulation source for both dioxin and phthalate in the green mussels under most conditions.

Year-long sampling campaign of quasi-ultrafine particles (PM0.25) was conducted at 10 distinct locations across the Los Angeles south coast air basin and concentrations of trace elements and metals were quantified at each site using high-resolution inductively coupled plasma sector field mass spectrometry. In order to characterize sources of trace elements and metals, principal component analysis (PCA) was applied to the dataset. The major sources were identified as road dust (influenced by vehicular emissions as well as re-suspended soil), vehicular abrasion, residual oil combustion, cadmium sources and metal plating. These sources altogether accounted for approximately 85% of the total variance of quasi-ultrafine elemental content. The concentrations of elements originating from source and urban locations generally displayed a decline as we proceeded from the coast to the inland. Occasional concentration peaks in the rural receptor sites were also observed, driven by the dominant westerly/southwesterly wind transporting the particles to the receptor areas.

We investigated the impacts of effluent discharge from small flow-through fish farms on stream water characteristics, the benthic invertebrate community, whole-system nitrate uptake, and ecosystem metabolism of three tropical headwater streams in southeastern Brazil. Effluents were moderately, i.e. up to 20-fold enriched in particulate organic matter (POM) and inorganic nutrients in comparison to stream water at reference sites. Due to high dilution with stream water, effluent discharge resulted in up to 2.0-fold increases in stream water POM and up to 1.8-fold increases in inorganic nutrients only. Moderate impacts on the benthic invertebrate community were detected at one stream only. There was no consistent pattern of effluent impact on whole-stream nitrate uptake. Ecosystem metabolism, however, was clearly affected by effluent discharge. Stream reaches impacted by effluents exhibited significantly increased community respiration and primary productivity, stressing the importance of ecologically sound best management practices for small fish farms in the tropics.

The present study was conducted to assess morphological, biochemical and yield responses of palak (Beta vulgaris L. cv Allgreen) to ambient and elevated levels of CO2 and O3, alone and in combination. As compared to the plants grown in charcoal filtered air (ACO2), growth and yield of the plants increased under elevated CO2 (ECO2) and decreased under combination of ECO2 with elevated O3 (ECO2 + EO3), ambient O3 (ACO2 + AO3) and elevated O3 (EO3). Lipid peroxidation, ascorbic acid, catalase and glutathione reductase activities enhanced under all treatments and were highest in EO3. Foliar starch and organic carbon contents increased under ECO2 and ECO2 + EO3 and reduced under EO3 and ACO2 + AO3. Foliar N content declined in all treatments compared to ACO2 resulting in alteration of C/N ratio. This study concludes that ambient level of CO2 is not enough to counteract O3 impact, but elevated CO2 has potential to counteract the negative effects of future O3 level.

Hexabromocyclododecanes (HBCDs) has just been listed into Stockholm Convention as a persistent organic pollutant recently. This paper studied the HBCDs in 79 wild fish from high mountain lakes and rivers of the Tibetan Plateau. The ∑HBCDs in fish muscles ranged from non detectable levels to 13.7 ng/g lipid weight (lw) (mean value of 2.12 ng/g lw) with a high detection frequency of 65.8%. α-HBCD dominated among the isomers and accounted for 78.2% of the total burden. Concentrations of ∑HBCDs in the fish were significantly correlated with the lipid content. A decreasing trend was observed between α-HBCD and trophic level. Positive correlation was also noted between the HBCD levels in fish from lakes and the annual precipitation, and this implied the long-range atmospheric transport of HBCDs to the Tibet Plateau. This was the first work to widely explore HBCDs contamination in the aquatic ecosystems of the Tibetan Plateau.

Covalent coupling to natural humic constituents comprises an important transformation pathway for anilinic pollutants in the environment. We systematically investigated the reactions of chlorine substituted anilines with catechol and syringic acid in horseradish peroxidase (HRP) catalyzed systems. It was demonstrated that although nucleophilic addition was the mechanism of covalent bonding to both catechol and syringic acid, chloroanilines coupled to the 2 humic constituents via slightly different pathways. 1,4-addition and 1,2-addition are involved to catechol and syringic acid, respectively. 1,4-addition showed empirical 2nd order kinetics and this pathway seemed to be more permanent than 1,2-addition. Stability experiments demonstrated that cross-coupling products with syringic acid could be easily released in acidic conditions. However, cross-coupling with catechol was relatively stable at similar conditions. Thus, the environmental behavior and bioavailability of the coupling products should be carefully assessed.