Assessing the impact of petrol stations on their immediate surroundings

This paper describes a novel methodology for evaluating the extent to which petrol stations affect their surroundings. The method is based on the fact that the ratio of the concentrations of aliphatic and aromatic hydrocarbon pollutants in the air of the petrol stations and their surroundings (basically determined by vapor emissions from unburned gasoline) differs from the ratio found in urban air, which is mainly influenced by traffic emissions. Bearing this in mind, the spatial limit of influence of petrol stations in any direction would be the first point, moving away from the station, where the ratio becomes equal to the urban background ratio. Application of the methodology involves multipoint measuring campaigns of the air at the studied petrol station and built-up area in general and processing the data with software capable of providing isoconcentration contours. The procedure should help local authorities in terms of land management, so that a “belt” can be established around petrol stations where housing or vulnerable populations and activities such as those in schools, hospitals and community centers should be restricted.     

Radiological and multi-element analysis of sediments from the Proserpina reservoir (Spain) dating from Roman times

The Proserpina dam was built in Roman times to provide drinking water to Emerita Augusta (today's Mérida in SW Spain). During maintenance work, a sediment core was extracted, offering an excellent opportunity to analyze the historical environmental impacts of the dam and its reservoir over the 2000 years since Roman times. In order to establish an accurate chronology, ¹⁴C ages were determined by accelerator mass spectrometry (AMS). Core samples were assayed for their content in uranium and thorium series isotopes, ⁴⁰K, and the anthropogenic radionuclides ¹³⁷Cs, ⁹⁰Sr, and ^239+240Pu. Potassium-40 presented the highest activity level and was not constant with depth. The uranium and thorium series were generally in equilibrium, suggesting there had been no additional input of natural radionuclides. The presence of ¹³⁷Cs was only found in relation with the global fallout in the early 1960s. Multi-element assays were performed using the PIXE and PIGE techniques. Some variations in the multi-element concentrations were observed with depth, but the sediment core could be considered as clean, and no presumptive anthropogenic pollutants were found. Nevertheless, an unusually high Zn content was detected at depths corresponding to pre-Roman times, due to geological anomalies in the area.     

Assessing Public Preferences for Forest Biomass Based Energy in the Southern United States

This article investigated public preferences for forest biomass based liquid biofuels, particularly ethanol blends of 10% (E10) and 85% (E85). We conducted a choice experiment study in three southern states in the United States: Arkansas, Florida, and Virginia. Reducing atmospheric CO₂, decreasing risk of wildfires and pest outbreaks, and enhancing biodiversity were presented to respondents as attributes of using biofuels. Results indicated that individuals had a positive extra willingness to pay (WTP) for both ethanol blends. The extra WTP was greater for higher blends that offered larger environment benefits. The WTPs for E10 were $0.56 gallon^?1, $0.58 gallon^?1, and $0.48 gallon^?1, and for E85 they were $0.82 gallon^?1, $1.17 gallon^?1, and $1.06 gallon^?1 in Arkansas, Florida, and Virginia, respectively. Although differences in WTP for E10 were statistically insignificant among the three states, significant differences were found in the WTP for E85 between AR and FL and between AR and VA. Preferences for the environmental attributes appeared to be heterogeneous, as respondents’ were willing to pay a premium for E10 in all three states to facilitate the reduction of CO₂ and the improvement of biodiversity but were not willing to pay more for E85 in order to enhance biodiversity.     

Atmospheric PCB congeners across Chicago

We have measured PCBs in 184 air samples collected at 37 sites in the city of Chicago using an innovative system of high-volume air samplers mounted on two health clinic vans. Here we describe results of sampling conducted from November 2006 to November 2007. The samples were analyzed for all 209 PCB congeners using a gas chromatograph with tandem mass spectrometry (GC-MS/MS). The ΣPCBs (sum of 169 peaks) in Chicago ranged from 75 pg m(-3) to 5500 pg m(-3) and primarily varied as a function of temperature. The congener patterns are surprisingly similar throughout the city even though the temperature-corrected concentrations vary by more than an order of magnitude. The average profile resembles a mixture of Aroclor 1242 and Aroclor 1254, and includes many congeners that have been identified as being aryl hydrocarbon receptor (AhR) agonists (dioxin-like) and/or neurotoxins. The toxic equivalence (TEQ) and neurotoxic equivalence (NEQ) in air were calculated and investigated for their spatial distribution throughout the urban-industrial complex of Chicago. The NEQ concentrations are linearly correlated with ΣPCBs while the TEQ concentrations are not predictable. The findings of this study suggest that airborne PCBs in Chicago are widely present and elevated in residential communities; there are multiple sources rather than one or a few locations of very high emissions; the emission includes congeners associated with dioxin-like and neurotoxic effects and congeners associated with unidentified sources.     

Remediation of PCB contaminated soils using iron nano-particles

In this study, iron nano-particles were used to remediate PCB contaminated soil and an attempt was made to maximize PCB destruction in each treatment step. The results show that nano-particles do aid in the dechlorination process and high PCB destruction efficiencies can be achieved. The destruction efficiency during the preliminary treatment (mixing of soil and iron nano-particles in water) can be increased by increasing the water temperature. The maximum thermal destruction (pyrolysis/combustion of soil after preliminary treatment) of soil-bound PCBs occurs at 300 degrees C in air. A minimum total PCB destruction efficiency of 95% can be achieved by this process. The effect of changing treatment parameters such as type of mixing, time of mixing and mixing conditions and application of other catalysts like iron oxide and V(2)O(5)/TiO(2) was also investigated. It was found that at 300 degrees C in air, iron oxide and V(2)O(5)/TiO(2) are also good catalysts for remediating PCB contaminated soils.     

Chlorophenol tolerant and degradative bacteria isolated from a river receiving pulp mill discharges

A screening was carried out in a river receiving pulp mill discharges (BioBio river, central Chile) to study the bacterial population able to tolerate and degrade chlorophenols. In four selected stations and at different seasons, water samples were taken from the river. Total bacterial population and the number of chlorophenol tolerant bacteria were counted. Bacterial tolerance to 25, 50, 100, 200 and 400 μg/ml of 2,4‐dichlorophenol (DCP), 2,4,6‐trichlorophenol (TCP) and pentachlorophenol (PCP) was determined. Strains able to tolerate at least 400 μg/ml chlorophenols were found. Eighteen bacterial strains able to use chlorophenols as the sole carbon source were isolated: five of them were Pseudomonas fluorescens, two Alcaligenes sp., one Citrobacter freundii, one Aeromonas sp. and nine unidentified Gram negative bacilli. A good correlation (r ² = 0.758) between the logarithm of DCP tolerant bacteria and the content of adsorbable organic halogen (AOX) at low dilution in the river water was established. Four groups of tolerant bacteria were found: growing on PCP and DCP, growing on PCP and TCP, growing only on PCP and growing only on TCP.     

Sex differences in the consequences of maternal loss in a long-lived mammal, the red deer (Cervus elaphus)

In several primates, the presence of mothers affects the growth, survival and reproduction of their offspring, but similar effects have not yet been demonstrated in ungulates. Here, we investigate the effects of the mother’s presence in a population of red deer (Cervus elaphus) on the Isle of Rum, Scotland, which is the subject of a long-term, individual-based study. We compared measures of performance including antler growth in young males and age at first reproduction in females and survival of deer with mothers still alive against those that have lost their mothers (orphans). We show that orphaning both before and after weaning increases the risk of a natural death for both sexes. For males, no maternal benefit was detectable past 24 months of age while, for females, post-weaning benefits continued throughout life. Orphaning resulted in compromised male physical condition as measured by a reduced probability of growing antlers by 16 months of age while no evidence for compromised reproduction was found in females. These results support assertions that post-weaning maternal associations affect the development and survival of offspring.     

Social monogamy in the shrimp Pontonia margarita, a symbiont of Pinctada mazatlanica, off the Pacific coast of Panama

A previous study predicted the evolution of monogamy in symbiotic crustaceans inhabiting scarce, relatively small hosts in tropical environments where predation risk away from hosts is high. This prediction was tested in the shrimp Pontonia margarita, which inhabits the pearl oyster Pinctada mazatlanica. A total of 68 oysters were collected from the intertidal and shallow subtidal at two islands (Islas Secas [N 27° 55′, W 82° 03′] and Isla de La Coiba [N 27° 50′, W 97° 03′]) off the eastern tropical Pacific coast on 15 and 17 March 2007, respectively. The population structure, distribution, male-female association pattern, and relative growth of the major claw and pleura of the second abdominal segment of each shrimp retrieved were examined. Shrimps were found as heterosexual pairs in the mantle cavity of hosts more frequently than would be expected by chance alone. Males occurred with females in the same host, independent of the reproductive condition of the female or the stage of development of brooded embryos. This observation, and strong correlations between the host and shrimp body size in both males and females suggest a long-term association between males and females in each host. Sexual dimorphism in body size was minor, with males being just slightly smaller than females. In agreement with predictions for monogamous species, the major claw of males did not display positive allometry, which has been generally reported for polygamous shrimps. In turn, the pleura of the second abdomen presented negative allometry in males but positive allometry in females. All available information suggests that Pontonia margarita has a socially monogamous mating system with males and females forming exclusive pairs in their hosts.     

Factors influencing fire behaviour in shrublands of different stand ages and the implications for using prescribed burning to reduce wildfire risk

Fire behaviour under experimental conditions is described in nine Mediterranean gorse shrublands ranging from 3-12 years of age with different fuel loads. Significant differences in the fire-line intensity, fuel load and rate of fire spread have been found to be related to the stage of development of the communities. Fire spread is correlated with fuel moisture using multiple regression techniques. Differences in fuel moisture between mature and young communities under moderate weather conditions have been found. The lower moisture content identified in the mature shrubland is due both to the decreasing moisture content of senescent shrubland in some species, mainly in live fractions of Ulex parviflorus Pour. fuel, and to a substantial increase in dead fuel fractions with low percentages of moisture content. The result is that the older the shrubland is, the greater will be the decrease in the total moisture content of the vegetation. In these moderate weather conditions, the fire intensity of the mature community was as high as the maximum intensity recommended for prescribed fires. This fact seems to indicate that, even under moderate conditions, prescribed burning as an alternative management tool in the mature shrubland must always take into account fuel control; on the other hand, this technique could be applied more easily when the shrubland is at an intermediate growth stage (4-5 years of age). Therefore, more frequent low-intensity prescribed fires are indicated to abate the risk of catastrophic fire.