Induction of the P450 reporter gene system bioassay by polycyclic aromatic hydrocarbons in Ulsan Bay (South Korea) sediments

Polycyclic aromatic hydrocarbons (PAHs) and induction of the P450 reporter gene system (RGS) for 6- and 16-h exposure periods were determined in organic extracts of Ulsan Bay (South Korea) sediments to assess the utility of this bioassay as a screening tool for PAH contamination. The sum of the concentrations of 23 individual PAHs in 30 sediment samples (sigma PAH) based on GC-MS analysis ranged from 0.05 to 6.1 micrograms/g dry wt. P450 RGS fold induction ranged from 4.0 to 320 micrograms/g based on benzo[a]pyrene toxic equivalents (BaPEq). P450 RGS BaPEq and the 'chemical BaPEq', defined as the sum of the products of individual PAH concentrations and pre-determined toxic equivalency factors, exhibited very strong positive correlations with sigma PAH (r2 > 0.90; P < 0.001). Fold induction did not increase (and in some cases decreased) after the optimal incubation period (6 h) for PAHs, indicating that other compounds known to induce the P450 RGS (e.g. chlorinated organics) were not present at levels effecting significant induction. This was supported by GC-ECD analysis where non-ortho and mono-ortho polychlorinated biphenyls (PCBs) known to be strong P450 RGS inducers were found to be at very low or non-detectable levels in samples with the highest P450 RGS responses. The profound difference in PAH profiles for the two most contaminated sites suggested that this assay is especially sensitive for selected PAHs with greater than four rings. Combined with previous results, the P450 RGS shows promise as a useful screening tool for predicting deleterious biological effects resulting from CYP1A1-inducing, sediment-associated chemicals, particularly high molecular weight PAHs.     

Allocation of reproductive effort in Mus domesticus: responses of offspring sex ratio and quality to social density and food availability

Summary Female mammals in good condition can maximize their inclusive fitness by investing more in male offspring than in female offspring during periods of poor environmental quality. To test this hypothesis, we measured the effects of undernutrition and crowding before and during gestation on the sex ratio and weight of offspring at parturition and at weaning in Mus domesticus. Sex ratio was not significantly affected by density. Dams altered the sex ratio of their offspring in response to food availability, but only if variance in competitive success within the experimental subpopulation was evident. Thus ad lib fed females produced litters with an unbiased sex ratio, competitively successful females under moderate food availability produced a male-biased sex ratio, and severely food deprived females produced litters with a female-biased sex ratio. In groups that experienced competition for food, successful dams favoured male offspring during lactation. These results are consistent with the predictions of Trivers and Willard (1973). Analysis of within-cell variance and covariance suggests that the interaction of social structure and food availability provides specific cues for the dams' tactical reproductive choices.     

An empirical analysis of economic strategies for controlling air pollution

In evaluating current environmental protection policy, economists often note that current regulations are more costly than necessary to meet environmental quality standards. While the a priori case is strong that current regulatory approaches are resulting in higher-than-necessary costs to attain environmental standards, there is relatively little empirical evidence to support this claim. The purpose of this paper is to supply some of the missing evidence by presenting the results of one study that assesses some of the potential savings associated with implementing economic, rather than command-and-control, regulatory approaches to abate one type of air pollution in one region of the country. Specifically, the paper examines the costs of meeting a prospective short-term standard for nitrogen dioxide under a range of alternative emissions control strategies for stationary sources of nitrogen oxide emissions in the Chicago Air Quality Control Region. The alternative strategies that are considered range from those that might result under current regulatory policy to those that economic policy approaches (such as emissions charges or marketable permits) are designed to implement. The analysis shows that the most efficient program of emissions controls may be more than an order of magnitude less costly than current regulatory strategies, and that economic approaches have additional advantages over more conventional regulatory approaches.     

A STATISTICAL APPROACH TO ASSESS FACTORS AFFECTING WATER CHEMISTRY USING MONITORING DATA1

ABSTRACT: A method to partition the variation in concentrations of water chemistry parameters in a river is described. The approach consists of fitting a family of curves for each chemical parameter. Each curve indicates the response of the parameter to river flow for a particular time period or location. An analysis of covariance is then used to identify statistically significant differences between curves. Such differences result largely from two factors: (1) the discharge of effluents and (2) river flow-concentration relationships. The deviations from the fitted curves indicate month-to-month variations unrelated to river flow that are controlled by factors such as temperature-related seasonal patterns. Underlying statistical assumptions are discussed with respect to water chemistry data. The technique is applied to a data set consisting of monthly samples of 22 water chemistry parameters from the Sulphur River of Texas and Arkansas. Several patterns of response to river flow and to two effluent discharges were revealed.     

Private aquaculture and commercial fisheries: Bioeconomics of salmon ranching

This paper shows that common property problems associated with open access salmon ranching in the absence of a commercial fishery result in inefficiency characterized by overstocking. The presence of an open access fishery presents additional common property problems which will inhibit the development of fish ranching. At prices where salmon ranching does occur, the open access commercial fishery will tend to overexploit the natural fish stock to a greater extent than if there were no salmon ranching. It is shown that there exists a range of prices where both fish stocks can coexist with open access. However, there is a limit price above which the natural stock will be driven to extinction through overfishing stimulated by stock from salmon ranchers. The range of prices under which both species can coexist can be increased through either restrictions of fishery effort or reducing the catchability of aquacultured stock. Cooperative management of both aquaculture and commercial fishing results in profits from both activities and will not cause extinction of the natural fish stock.     

Raman spectroscopic documentation of Oligocene bladder stone

Discovery of a fossil (30–35 million-year-old) urolith from Early Oligocene deposits in northeastern Colorado provides the earliest evidence for the antiquity of bladder stones. These are spherical objects with a layered phosphatic structure and a hollow center. Each layer is composed of parallel crystals oriented perpendicular to the surface. Macroscopic and microscopic examination and X-ray diffraction analysis, along with comparison with 1,000 contemporary uroliths, were used as evidence in the confirmation of this diagnosis. Raman microspectroscopy verified the presence of organic material between layers, confirming its biologic origin.     

Reconstructing the history of 14C discharges from Sellafield: part 1--atmospheric discharges

14C specific activities, above ambient background levels, were determined in individual treerings (corresponding to the years 1950-1999) sectioned from an oak tree that was felled in autumn 1999, from a location 1.5 km east of the Sellafield nuclear fuel reprocessing plant in Cumbria. north-west England. The data were used to produce a new, improved, reconstruction of Sellafield's annual atmospheric 14C discharges between 1951 and 1999, using the most reliable discharge data set (1994-1999) as the primary basis for the determination of a new calibration factor that relates excess 14C activity in individual tree rings to the annual discharge during the corresponding year. The results indicate that the current British Nuclear Fuels plc (BNFL) estimate of total 14C discharges to the atmosphere prior to 1978 is significantly overestimated, while the current estimate of total 14C discharges after 1978 is very similar to that determined in this study. In this study, the total activity of 14C discharged to the atmosphere from Sellafield between 1951 and 1999 is estimated to be 259+/-63 TBq (at 2 std. dev.). The BNFL current estimate is 360TBq.     

Protection from fishing alters the species composition of fish assemblages in a temperate-tropical transition zone

Closure of areas to fishing is expected to result in an increase in the abundance of targeted species; however, changes to populations of species not targeted by fishermen will depend upon their role in the ecosystem and their relationship with targeted species. The effects of protection on targeted and non-targeted reef fish species at the Houtman Abrolhos Islands, Western Australia were studied using baited remote underwater stereo–video cameras. Video images were collected from shallow (8–12 m) and deep (22–26 m) reef sites inside a Marine Protected Area (MPA) at each of three island groups and from three replicate fished locations at each of these groups that span a temperate-tropical transition area. The MPAs were established in 1994 and vary in size from 13.72 km² at the Pelsaert group in the south to 22.29 km² at the Easter group to 27.44 km² at the Wallabi group in the north. The relative abundances of 137 fish species from 42 families were recorded. Large differences in fish assemblage structure existed between MPA and fished locations, and also between shallow and deep regions. Targeted fish species Plectropomus leopardus, Lethrinus miniatus, Lethrinus nebulosus, Pagrus auratus and Glaucosoma hebraicum were more abundant inside MPAs than in areas open to fishing. Their abundance inside MPAs was between 1.13 and 8 times greater than their abundance at fished locations. For non-targeted fish species many were more abundant in areas open to fishing, e.g. Coris auricularis, Thalassoma lutescens, Thalassoma lunare, Dascyllus trimaculatus, however others were conversely more abundant inside MPAs, e.g. Gymnothorax spp, Kyphosus sydneyanus, Scarus microhinos, Chromis westaustralis, Chaetodon spp. This study demonstrates that the removal of abundant targeted species from an ecosystem by fishing can indirectly impact non-fished species and alter the trophic structure of fish assemblages. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.