A metabolomics based approach to assessing the toxicity of the polyaromatic hydrocarbon pyrene to the earthworm Lumbricus rubellus

The biochemical response of the earthworm Lumbricus rubellus to pyrene exposure was assessed using 1H nuclear magnetic resonance (NMR) spectroscopy, gas chromatography mass spectrometry (GC-MS) and pattern recognition techniques. Both analytical methods enabled the establishment of reproducible metabolic profiles. NMR analysis identified a total of 32 metabolites while GC-MS identified 51. The results demonstrate that not only is pyrene toxic to L. rubellus, but that alterations in its normal metabolic profile could be observed even when individuals were exposed to concentrations of 40mg kg(-1): a pollution level that is both below the concentration previously found to significantly reduce reproduction and within the range of polycyclic aromatic hydrocarbons (PAHs) found on some contaminated sites. Pyrene was found to cause a dose dependant decrease in lactate and the concentrations of the saturated fatty acids tetradecanoic, hexadecanoic and octadecanoic acid and an increase in production of the amino acids alanine, leucine, valine, isoleucine, lysine, tyrosine and methionine. It is proposed that this indicates impaired glucose metabolism, with an associated increase in fatty acid metabolism and changes in TCA cycle intermediates. This study demonstrates the versatility of metabolomics as a tool to monitor toxicity in the environment as opposed to utilising model species studied in a laboratory setting. Since it is a non-carcinogenic PAH, we propose that the metabolic changes observed in worms may reflect the non-specific toxic effects of pyrene as a typical, non-polar organic compound.     

Polychlorinated biphenyls, organochlorine pesticides and polycyclic aromatic hydrocarbons in a one-off global survey of bivalves

During the Danish Galathea 3 expedition, bivalve samples were collected at the Faroe Islands, Greenland, Ghana, South Africa, Australia, Solomon Islands, New Zealand, Chile, US Virgin Islands, Boston, Newfoundland and Shetland Islands and analysed for organochlorines and PAHs. Concentration differences of up to three orders of magnitude were observed, with the highest concentrations at Boston harbour (SPCB 338 ng g(-1) dw, ΣSPAH 5966 ng g(-1) dw) and the Sydney estuary (ΣSPCB 282 ng g(-1) dw, SPAH 1453 ng g(-1) dw). Local impacts were also found for the Greenland capital Nuuk in terms of PCB and PAH levels, while other Greenland samples came closest to representing PAH background levels. Several locations had undetectable organochlorine levels, including Hobart and Chile, which had the lowest SPAH concentrations (<200 ng g(-1) dw). It was possible to group the stations according to their pyrogenic/petrogenic influence using Principal Component Analyses, and indications of petroleum sources were found at Nuuk.     

A project-based system for including farmers in the EU ETS

Farmers in the EU do not trade greenhouse gases under the Kyoto agreement. This is an empirical puzzle because agriculture is a significant contributor of greenhouse gases (GHG) in the EU and may harvest private net gains from trade. Furthermore, the US has strongly advocated land-use practices as 'the missing link' in past climate negotiations. We argue that farmers have relatively low marginal reduction costs and that consequences in terms of the effect on permit price and technology are overall positive in the EU Emission Trading System (ETS). Thus, we propose a project-based system for including the farming practices in the EU ETS that reduces the uncertainty from measuring emission reduction in this sector. The system encourages GHG reduction either by introducing a new and less polluting practice or by reducing the polluting activity. When doing so, farmers will receive GHG permits corresponding to the amount of reduction which can be stored for later use or sold in the EU ETS.     

Critical Limits for Hg(II) in soils, derived from chronic toxicity data

Published chronic toxicity data for Hg(II) added to soils were assembled and evaluated to produce a data set comprising 52 chronic end-points, five each for plants and invertebrates and 42 for microbes. With end-points expressed in terms of added soil Hg(II) contents, Critical Limits were derived from the 5th percentiles of species sensitivity distributions, values of 0.13 μg (g soil)⁻¹ and 3.3 μg (g soil organic matter)⁻¹ being obtained. The latter value exceeds the currently recommended Critical Limit, used to determine Hg(II) Critical Loads in Europe, of 0.5 μg (g soil organic matter)⁻¹. We also applied the WHAM/Model VI chemical speciation model to estimate concentrations of Hg²⁺ in soil solution, and derived an approximate Critical Limit Function (CLF) that includes pH; log [Hg²⁺]_crit = −2.15 pH −17.10. Because they take soil properties into account, the soil organic matter-based limit and the CLF provide the best assessment of toxic threat for different soils. For differing representative soils, each predicts a range of up to 100-fold in the dry weight-based content of mercury that corresponds to the Critical Limit.     

Maintaining a neutral water balance in a 450 MWe NGCC-CCS power system with post-combustion carbon dioxide capture aimed at offshore operation

A post-combustion CO₂ capture process intended for offshore operations has been designed and optimised for integration with a natural gas-fired power plant on board a floating structure developed by the Norway-based company Sevan Marine ASA—designated Sevan GTW (gas-to-wire). The concept is constrained by the structure of the floater carrying a SIEMENS modular power system rated at 450 MW_e, with a capture rate of 90% and CO₂ compression (1.47 Mtpa) for pipeline pressure at 12 MPa. A net efficiency of 45% (based on a lower heating value) is estimated for the system with CO₂ capture, thus suggesting that the post-combustion CO₂ capture system is accountable for a fuel penalty of nine percentage points.The rationale behind the technology selection is the urgency of replacing the dispersed aero-derivative gas turbines which power the offshore oil and gas production units in Norwegian waters with near-zero emission power.As (inherently) fresh water usually constitutes a limiting factor in sea operations, efforts are made to obtain a neutral water balance to obtain an optimal design. This is primarily achieved by controlling the cleaned flue gas temperature at the top of the absorber column.     

依法发展再生资源产业——对《再生资源回收管理办法》的解读与思考

依法发展再生资源产业是推行循环经济的必然要求。解读《再生资源回收管理办法,》认为实现再生资源产业的全面发展,还需建立健全再生资源法律体系。     

Intergenerational Impartiality: Replacing Discounting by Probability Weighting

Intergenerational impartiality requires putting the welfare of future generations at par with that of our own. However, rational choice requires weighting all welfare values by the respective probabilities of realization. As the risk of non-survival of mankind is strictly positive for all time periods and as the probability of non-survival is cumulative, the probability weights operate like discount factors, though justified on a morally justifiable and completely different ground. Impartial intertemporal welfare maximization is acceptable, though the welfare of people in the very far future has lower effects as the probabilities of their existence are also lower. However, the effective discount rate on future welfare values (distinct from monetary values) justified on this ground is likely to be less than 0.1 per annum. Such discounting does not compromise environmental protection and sustainability unduly. The finiteness of our universe implies that the sum of our expected welfare to infinity remains finite, solving the paradox of having to compare different infinite values in optimal growth/conservation theories.     

Experimental investigation of the effect of sediment transport patterns on the adsorption of cadmium ions onto sediment particles

The mechanism of flow turbulence, sediment supply conditions, and sediment transport patterns that affect the adsorption of cadmium ions onto sediment particles in natural waters are experimentally simulated and studied in this study both in batch reactors and in a turbulence simulation tank. By changing the agitation conditions, the sediment transport in batch reactors can be categorized into bottom sediment-dominated sediment and suspended sediment-dominated sediment. It is found that the adsorption rate of bottom sediment is much less than that of suspended sediment, but the sediment transport pattern does not affect the final (equilibrium) concentration of dissolved cadmium. This result indicates that the parameters of an adsorption isotherm are the same regardless of the sediment transport pattern. In the turbulence simulation tank, the turbulence is generated by harmonic grid-stirred motions, and the turbulence intensity is quantified in terms of eddy diffusivity, which is equal to 9.84F(F is the harmonic vibration frequency) and is comparable to natural surface water conditions.When the turbulence intensity of flow is low and sediment particles stay as bottom sediment, the adsorption rate is significantly low, and the adsorption quantity compared with that of suspended sediment is negligible in the 6 h duration of the experiment. This result greatly favors the simplification of the numerical modeling of heavy metal pollutant transformation in natural rivers. When the turbulence intensity is high but bottom sediment persists, the rate and extent of descent of the dissolved cadmium concentration in the tank noticeably increase, and the time that is required to reach adsorption equilibrium also increases considerably due to the continuous exchange that occurs between the suspended sediment and the bottom sediment.A comparison of the results of the experiments in the batch reactor and those in the turbulence simulation tank reveals that the adsorption ability of the sediment, and in particular the adsorption rate, is greatly over-estimated in the batch reactor.     

Modelling the joint effects of a metal and a pesticide on reproduction and toxicokinetics in Lumbricid earthworms

It is important to understand the aetiology of interactive mixtures effects (i.e. synergism and antagonism) if results from known cases are to be extrapolated to untested combinations. The key role of toxicokinetics in determining internal concentrations at target sites means that understanding chemical uptake in mixtures is an essential requirement for mechanistic understanding of interactions. In this paper, a combined approach using mixture toxicity testing, toxicokinetic studies and modelling has been used to address the link between joint toxicity and internal concentration. The study is conducted in Lumbricid earthworms with a binary mixture of a metal (nickel) and an organophosphate insecticide (chlorpyrifos) not a priori expected to show interactive toxicity. As expected from their dissimilar modes of action and detoxification, exposure to combinations of nickel and chlorpyrifos resulted in additive toxicity. Measurement of internal concentrations indicated that both chemicals were rapidly accumulated (within 3 days) to equilibrium. When exposed as a mixture, Ni uptake followed the same pattern as found for the single chemical. This was not the case for chlorpyrifos which showed a faster rate of uptake and elimination and a slightly higher equilibrium concentration in a mixture. That the difference in chlorpyrifos kinetics in the mixture did not result in interactive toxicity highlights the need to assess chemical toxicodynamics as well as toxicokinetics. Measurement of chlorpyrifos-oxon identified the presence of this toxic form but implementation of more complex approaches encompassing toxicogenomics and epigenetics are ultimately needed to resolve the toxicokinetic to toxicodynamic link for these chemicals.     

Outdoor and indoor cadmium distributions near an abandoned smelting works and their relations to human exposure

The relationship of measured or modelled Cd concentrations in soil, house dust and available to plants with human urinary Cd concentrations were assessed in a population living around a Cd/Pb/Zn smelter in the UK. Modelled air concentrations explained 35% of soil Cd variation indicating the smelter contributed to soil Cd loads. Multi-variate analysis confirmed a significant role of biological and life-style factors in determining urinary Cd levels. Significant correlations of urinary Cd with soil, house dust and modelled plant available Cd concentrations were not, however, found. Potential reasons for the absence of clear relationships include limited environmental contact in urban populations; the role of undefined factors in determining exposure; and the limited spatial scope of the survey which did not sample from the full pollution gradient. Further, the absence of any significant relationship indicates that environmental measures provide limited advantage over atmospheric model outputs for first stage human exposure assessment.