Acute toxicity of aromatic and non-aromatic fractions of naphthenic acids extracted from oil sands process-affected water to larval zebrafish

The toxicity of oil sands process-affected water (OSPW) has regularly been attributed to naphthenic acids, which exist in complex mixtures. If on remediation treatment (e.g., ozonation) or on entering the environment, the mixtures of these acids all behave in the same way, then they can be studied as a whole. If, however, some acids are resistant to change, whilst others are not, or are less resistant, it is important to establish which sub-classes of acids are the most toxic.     

Effect of steam hydration on performance of lime sorbent for CO2 capture

Lime is considered a feasible sorbent for the capture of CO₂ from large stationary sources. The positive attributes of a natural source material, low cost and lack of harmful by-products are offset by rapid deterioration in performance and high regeneration temperature. Performance can be improved by hydrating the lime using steam. We investigate a steam hydration process wherein lime is hydrated for 5 min at 300 °C and atmospheric pressure in a mixture of steam and CO₂. The experiments consisted of 10 capture cycles with 60% of the lime active at the end. Extrapolation using a decay model suggests a residual carbonation level of 48%, significantly higher than the 8% achieved by dry lime cycles. The cost of replacement sorbent under these conditions is less than $1/t of CO₂ captured. The hydrated lime process also reduces the thermal load, for heating and cooling, by half as well as the inventory, and therefore solids handling, by a factor 5 over dry lime. The introduction of the hydration reaction provides another exothermic reaction for heat management.     

Soil sensitivity to acidification in Asia: status and prospects

Exceedance of steady-state critical loads for soil acidification is consistently found in southern China and parts of SE Asia, but there is no evidence of impacts outside of China. This study describes a methodology for calculating the time to effects for soils sensitive to acidic deposition in Asia under potential future sulfur (S), nitrogen (N), and calcium (Ca) emission scenarios. The calculations are matched to data availability in Asia to produce regional-scale maps that provide estimates of the time (y) it will take for soil base saturation to reach a critical limit of 20% in response to acidic inputs. The results show that sensitive soil types in areas of South, Southeast, and East Asia, including parts of southern China, Burma, Hainan, Laos, Thailand, Vietnam, and the Western Ghats of India, may acidify to a significant degree on a 0-50 y timescale, depending on individual site management and abiotic and biotic characteristics. To make a clearer assessment of risk, site-specific data are required for soil chemistry and deposition (especially base cation deposition); S and N retention in soils and ecosystems; and biomass harvesting and weathering rates from sites across Asia representative of different soil and vegetation types and management regimes. National and regional assessments of soils using the simple methods described in this paper can provide an appreciation of the time dimension of soil acidification-related impacts and should be useful in planning further studies and, possibly, implementing measures to reduce risks of acidification.     

Heavy metal mobility in runoff water and absorption by eggplant fruits from sludge treated soil

Sewage sludge addition to agricultural lands requires judicious management to avoid environmental risks arising from heavy metal and nitrate contamination of surface water and accumulation in edible plants. A field study was conducted on a silty-loam soil of 10% slope at Kentucky State University Research Farm. Eighteen plots of 22 x 3.7 m each were separated using metal borders and the soil in six plots was mixed with sewage sludge and yard waste compost mix (SS-YW) at 15 t acre(-1), six plots were mixed with sewage sludge (SS) at 15 t acre(-1), and six unamended plots that never received sludge were used for comparison purposes. Plots were planted with eggplant, Solanum melongena L. as the test plant. The objectives of this investigation were to: 1) assess the effect of soil amendments on the transport of NO3, NH4, and heavy metals (Cd, Cr, Ni, Pb, Zn, Cu, and Mo) into surface water; 2) investigate the effect of soil amendments on heavy metal bioavailability in eggplant fruits at harvest; and 3) assess chemical and physical properties of soil following addition of soil amendments and their impact on the yield and quality of eggplant fruit. SS-YW treatments reduced runoff water by 63% while plots incorporated with sewage sludge alone reduced runoff water by 37% compared to control treatment. The SS-YW treatments transported more mineral nitrogen (NO3-N and NH4-N) in runoff water than SS treatments. Total marketable yield (lbs acre(-1)) and number of eggplant fruits were greatest in SS-YW treatments. This response may be due to improved soil porosity, water, and nutrient retention of the soil amended with SS-YW mixture. Concentrations of heavy metals in soil amended with sludge were below the U.S. Environmental Protection Agency (USEPA) limits. Chromium, Ni, Zn, and Cu were taken up by eggplant fruits but their concentrations were below the Codex Commission allowable levels.     

‘A powerful alternative to Williams’ test with application to toxicological dose-response relationships of normally distributed data

The comparison of increasing doses of a treatment to a negative control is frequently part of toxicological studies. For normally distributed data Williams (1971, 1972) introduced a maximum likelihood test under total order restriction. But until now there seems to have been no solution for the arbitrary unbalanced case. According to the idea proposed by Robertson et al. (1988) we will apply in this article the basic concept of Williams on the class of multiple contrast tests for the general unbalanced parametric set-up. Simulation results for size and power and two examples for estimating the minimal toxic dose (MTD) are given.     

Ökotoxikologische und humantoxikologische Risikobewertung PAK-belasteter Böden vor und nach biologischer Behandlung

The goal of the present work is to assess the adverse effects of soil bound polycyclic aromatic hydrocarbons (PAH) which remain in soils after biological remediation. We focus on risk assessment for mammalian species with respect to the oral uptake of contaminated soil particles and compare the results of a biomarker test with those of an ecotoxicological assay, the bioluminescence inhibition test withVibrio fischeri. As a biomarker effect in mammals, we determined the liver microsomal cytochrome P450 enzyme CYP1A1 which is induced by PAH in exposed rats. After biological soil treatment, different amounts of PAH remain in the soil depending on the soil properties and initial pollutant composition. Particularly, higher condensated PAH resists biological treatment due to its hydrophobicity. In addition, high amounts of organic carbon in the soils affect remediation efficiency. In the bioluminescence inhibition test, eluates of all biologically treated soils studied do not reveal any or only low inhibitory effects. In contrast, the oral uptake of biologically treated contaminated soils leads to induction levels for CYP1A1 similar to those in the untreated samples. A good correlation is obtained between CYP1A1 levels and the amount of 5 and 6-ring PAH in the soil samples. The main result is that the remediation efficiency determined by the luminescence test is not reflected by the biomarker test, a finding which indicates the high bioavailability of residual PAH in soils. Consequently, new criteria for human risk assessment can be delineated.     

The role of daytime cues in the development of magnetic orientation in a night-migrating bird

To assess the role of celestial rotation during daytime in the development of the magnetic compass course, pied flycatchers (Ficedula hypoleuca Pallas, Muscicapidae) were handraised in Latvia under various celestial and magnetic conditions. Tests were performed during autumn migration in the local geomagnetic field (50 000 nT, 73° inclination) in the absence of celestial cues. A group of birds that had never seen the sky showed a bimodal preference for the migratory southwest-northeast axis, whereas a second group that had been exposed to the natural sky from sunrise to sunset in the local geomagnetic field showed a unimodal preference for the seasonally appropriate southwesterly direction. A third group that had also been exposed to the daytime sky, but in the absence of magnetic compass information, also oriented bimodally along a southwest-northeast axis. These findings demonstrate that observing celestial rotation during daytime enables birds to choose the right end of the migratory axis for autumn migration at the Latvian test location. This transformation of axial behavior into appropriate migratory orientation, however, requires the birds to have simultaneous access to information on both celestial rotation and the geomagnetic field. Received: 19 September 1997 / Accepted after revision: 22 November 1997     

Cost‐effectiveness of conservation payment schemes for species with different range sizes

Payments to compensate landowners for carrying out costly land‐use measures that benefit endangered biodiversity have become an important policy instrument. When designing such payments, it is important to take into account that spatially connected habitats are more valuable for many species than isolated ones. One way to incentivize provision of connected habitats is to offer landowners an agglomeration bonus, that is, a bonus on top of payments they are receiving to conserve land if the land is spatially connected. Researchers have compared the cost‐effectiveness of the agglomeration bonus with 2 alternatives: an all‐or‐nothing, agglomeration payment, where landowners receive a payment only if the conserved land parcels have a certain level of spatial connectivity, and a spatially homogeneous payment, where landowners receive a payment for conserved land parcels irrespective of their location. Their results show the agglomeration bonus is rarely the most cost‐effective option, and when it is, it is only slightly better than one of the alternatives. This suggests that the agglomeration bonus should not be given priority as a policy design option. However, this finding is based on consideration of only 1 species. We examined whether the same applied to 2 species, one for which the homogeneous payment is best and the other for which the agglomeration payment is most cost‐effective. We modified a published conceptual model so that we were able to assess the cost‐effectiveness of payment schemes for 2 species and applied it to a grassland bird and a grassland butterfly in Germany that require the same habitat but have different spatial‐connectivity needs. When conserving both species, the agglomeration bonus was more cost‐effective than the agglomeration and the homogeneous payment; thus, we showed that as a policy the agglomeration bonus is a useful conservation‐payment option.     

Life cycle comparison of hydrothermal liquefaction and lipid extraction pathways to renewable diesel from algae

Algae biomass is an attractive biofuel feedstock when grown with high productivity on marginal land. Hydrothermal liquefaction (HTL) produces more oil from algae than lipid extraction (LE) does because protein and carbohydrates are converted, in part, to oil. Since nitrogen in the algae biomass is incorporated into the HTL oil, and since lipid extracted algae for generating heat and electricity are not co-produced by HTL, there are questions regarding implications for emissions and energy use. We studied the HTL and LE pathways for renewable diesel (RD) production by modeling all essential operations from nutrient manufacturing through fuel use. Our objective was to identify the key relationships affecting HTL energy consumption and emissions. LE, with identical upstream growth model and consistent hydroprocessing model, served as reference. HTL used 1.8 fold less algae than did LE but required 5.2 times more ammonia when nitrogen incorporated in the HTL oil was treated as lost. HTL RD had life cycle emissions of 31,000 gCO₂ equivalent (gCO₂e) compared to 21,500 gCO₂e for LE based RD per million BTU of RD produced. Greenhouse gas (GHG) emissions increased when yields exceeded 0.4 g HTL oil/g algae because insufficient carbon was left for biogas generation. Key variables in the analysis were the HTL oil yield, the hydrogen demand during upgrading, and the nitrogen content of the HTL oil. Future work requires better data for upgrading renewable oils to RD and requires consideration of nitrogen recycling during upgrading.     

Further evidence of nuclear reactions in the Pd/D lattice: emission of charged particles

Almost two decades ago, Fleischmann and Pons reported excess enthalpy generation in the negatively polarized Pd/D-D₂O system, which they attributed to nuclear reactions. In the months and years that followed, other manifestations of nuclear activities in this system were observed, viz. tritium and helium production and transmutation of elements. In this report, we present additional evidence, namely, the emission of highly energetic charged particles emitted from the Pd/D electrode when this system is placed in either an external electrostatic or magnetostatic field. The density of tracks registered by a CR-39 detector was found to be of a magnitude that provides undisputable evidence of their nuclear origin. The experiments were reproducible. A model based upon electron capture is proposed to explain the reaction products observed in the Pd/D-D₂O system.