Evidence of differences in the biotransformation of organic contaminants in three species of freshwater invertebrates

Acute static bioassays were performed using three freshwater invertebrate species (the oligochaete Lumbriculus variegatus, the fingernail clam Sphaerium corneum and the larvae Chironomus riparius) exposed separately to a variety of 14C radiolabelled contaminants. The aim of this work was to investigate if the chemicals remained as parent compounds after the treatments. Chemicals used were 2,4-dichlorophenol; 2,4,5-trichlorophenol; pentachlorophenol; pyrene; Fenpropidin, and Trifluralin. Homogenates of the whole body tissue of each organism were prepared and total radioactivity was measured. Contaminants were then extracted into organic solvents and analysed by high-pressure liquid chromatography techniques. Chromatograms showed that most of the substances extracted were present as parent compounds in S. corneum and in L. variegatus. In contrast, for C. riparius a low proportion of the chemicals was recovered as parent compounds. These results suggest that different metabolic processes could take place in the different species.     

Why are bumble bees risk-sensitive foragers?

Summary In a controlled laboratory experiment, we re-examined the question of bumble bee risk-sensitivity. Harder and Real's (1987) analysis of previous work on bumble bee risk aversion suggests that risk-sensitivity in these organisms is a result of their maximizing the net rate of energy return (calculated as the average of expected per flower rates). Whether bees are risk-sensitive foragers with respect to minimizing the probability of energetic shortfall is therefore still an open question. We examined how the foraging preferences of bumble bees for nectar reward variation were affected by colony energy reserves, which we manipulated by draining or adding sucrose solution to colony honey pots. Nine workers from four confined colonies of Bombus occidentalis foraged for sucrose solution in two patches of artificial flowers. These patches yielded the same expected rate of net energy intake, but floral volumes were variable in one patch and constant in the other. Our results show that bumble bees can be both risk-averse (preferring constant flowers) and risk-prone (preferring variable flowers), depending on the status of their colony energy reserves. Diet choice in bumble bees appears to be sensitive to the target value a colony-level energetic requirement. Offprint requests to: R.V. Cartar     

Corporate environmental performance expectations in the 1990s: More than just compliance

What do General Motors and Ben and Jerry's Homemade Ice Cream have in common? Both companies have endorsed the CERES principles, a model corporate code of environmental conduct developed by the Coalition for Environmentally Responsible Economies (CERES). This model code generally goes well beyond what is now typically required of industry to maintain compliance with already stringent requirements established by regulatory agencies. And the CERES principles are not the only game in town. Many other environmental initiatives have surfaced both in the United States and abroad over the past few years. This article discusses six sets of current initiatives and provides managers with a vital tool for discussing these initiatives with top management and others throughout their organizations.     

Defining Forest Fragmentation by Corridor Width: The Influence of Narrow Forest-Dividing Corridors on Forest-Nesting Birds in Southern New Jersey

In studies of forest fragmentation, a fundamental inconsistency exists in the distance criterion used to define the discreteness of forest fragments. We examined three types of ubiquitous, narrow, forest-dividing corridors for effects that influence the relative abundance and community composition of forest-nesting birds. Fixed-radius (100-meter) point counts were conducted on 54 transects established along three width classes of corridors: unpaved roads (8 meters wide), paved roads (16 meters wide), and powerlines (23 meters wide). Transect locations were distributed equally among corridor edge, forest margin 100 meters from corridor edge, and forest interior 300 meters from corridor edge. Forest-interior species of Neotropical migrants had significantly reduced relative abundances on edge transects along 16- and 23-meter corridors, compared with 8-meter corridors and with forest interior points along all three corridor-width classes. At a landscape scale, the consequences of apparently small reductions in forest area by the presence of narrow forest-dividing corridors may be cumulatively significant for abundances of forest-interior species. Brown-headed Cowbirds were more abundant than 20 of 21 forest-interior Neotropical migrants. We found surprisingly high abundances of cowbirds associated with narrow forest-dividing corridors, especially those with mowed grass. Corridor widths as narrow as 8 meters produce forest fragmentation effects in part by attracting cowbirds and nest predators to corridors and adjacent forest interiors. The most serious implication of this study is that narrow forest-dividing corridors may function as ecological traps for forest-interior Neotropical migrants. We suggest that these widespread corridors may be inconspicuous but important contributors to declines of forest-interior nesting species in eastern North America.     

Prenatally diagnosed portocaval shunt and postnatal outcome: a case report

Congenital absence of the portal vein (CAPV) is a rare anomaly in the form of a portocaval shunt, whereby the intestinal and splenic venous drainage bypasses the liver and drains directly into the systemic circulation. We report a case of CAPV diagnosed prenatally after the recognition of a dilated umbilical vein draining directly into a large inferior vena cava (IVC). The IVC then drained into the right atrium of a dilated, hyperdynamic heart. The ductus venosus could not be identified. Repeated postnatal scans showed a gradual disappearance of venous lakes in the region of the porta hepatis and a clear drainage of the splenic vein to the left renal vein and the superior mesenteric vein to the IVC. From birth up to twelve months follow-up there was no evidence of liver dysfunction, encephalopathy or liver lesions. Copyright © 2004 John Wiley & Sons, Ltd.     

Parental care sex differences in the brown bullhead,Ictalurus nebulosus (Pisces,Ictaluridae)

Summary Males were the principal care-givers in the brown bullhead, Ictalurus nebulosus. Direct observations on individually tagged adults in nature revealed that males attended broods at closer distances than females and were the most frequent lone care-givers. However, females often participated in parental care and in some cases assumed the typical male role in the absence of the male. In the presence of her mate, females generally performed different care-giving functions than males. Females attended broods at a distance and chased other fishes more frequently than males. Males remained directly over the brood guarding. A series of mated pairs in each of three reproductive conditions were captured and examined. Different pairs were compared between reproductive conditions for body weight, body condition, gonadal-somatic index, and a gut-contents index. The inital costs of reproduction, as measured by weight loss, condition change, and gonadal-somatic index change, were more severe in females than males. During breeding and subsequent care-giving, males did little or no feeding whereas females increased their feeding during the same time period. However, males appeared to sustain only minor weight and condition losses due to care-giving. I suggest that males were the principal care-givers because the net benefits of remaining at the nest were greater than the net benefits of leaving. Males had little opportunity to mate with more than one female each season, and offspring had little chance of survival in the absence of a care-giving adult. Considerable variation in female behavior occurred which suggests that the net benefits of care-giving were nearly balanced with the net benefits of leaving the brood. The relative importance of feeding versus care-giving by females may vary with slight differences between females and the behavior of their mates as care-givers.Present address: Department of Zoology, Ohio State University, 1735 Neil Avenue, Columbus, Ohio 43210, USA     

NEW ENGLAND DROUGHT AND RELATIONS WITH LARGE SCALE ATMOSPHERIC CIRCULATION PATTERNS1

ABSTRACT: To provide a basis for regional hydroclimatic forecasting, New England (NE) precipitation and streamflow are compared with indices for the El Niño/Southern Oscillation, the Pacific North American (PNA) pattern, and the North Atlantic Oscillation (NAO). Significant positive correlations are found between the NAO index and monthly streamflow at western inland locations, with the strongest seasonal correlations occurring in winter. Smoothed records for the winter NAO and winter streamflow are highly correlated at some sites, suggesting that interrelationships are most significant in the low frequency spectrum. However, correlations between the NAO and precipitation are not significant, so further examination of other factors is needed to explain the relationship between the NAO and streamflow. NAO related regional air temperature, sea surface temperature (SST), storm tracking, and snowfall variability are possible mechanisms for the observed teleconnection. Exceptionally cool regional air temperatures, and SSTs, and unique regional storm track patterns characterized NE's climate during the famous 1960s drought, suggesting that concurrent (persistent) negative NAO conditions may have contributed to the severity of that event. Monthly and winter averaged regional streamflow variability are also significantly correlated with the PNA index. This, along with results from previous studies, suggests that tropospheric wave character and associated North Pacific SST anomalies are also related to NE regional drought conditions.     

Radiological risks and cleanup costs: A remediation case study

Potential health risks and cleanup costs are primary factors for measuring the effectiveness of a remediation project concerning a site contaminated with residual radioactive materials. Demanding cleanup of a contaminated site to its original condition, while eliminating any health risks after cleanup, can require prohibitive costs. However, by setting practical remediation objectives and by performing realistic but conservative risk assessments, health risks can be acceptable and cleanup costs can be reasonable. This article uses the South-Middle and Southeast Vaults Decontamination and Demolition Project at Argonne National Laboratory to demonstrate how negligible health risks can result after cleanup with minimal cleanup costs. Substantial cost savings of approximately $2 million was realized by implementing in-place decontamination and demolition (D&D) on the basis of acceptable risk, instead of requiring cleanup of the site to its original condition. By using the RESRAD computer program as a modeling tool, we show the maximum projected radiation dose (0.1 mrem per year) and the potential lifetime cancer risk (on the order of 10⁶) to an individual from exposure to the residual radioactivities are negligibly small. In addition to aiding in the selection of a preferred remediation alternative, results of the RESRAD modeling were also used to guide the implementation of the selected alternative to reduce exposures from the dominant pathway and to ensure that exposures from all pathways would be as low as reasonably achievable.     

The potential effect of ISO 14000 standards on environmental audit training in the United States

Training has been an important component of the environmental audit profession since its outset some 15–20 years ago. Training and education have taken on a variety of forms—from audit texts and articles, to formal courses, to videotapes, to on-the-job training programs. These efforts have helped to advance the sophistication of environmental auditing over the past few years. Now, with the advent of the international ISO 14012 Environmental Auditor Qualification Guidelines,¹ the auditing profession in the United States and around the world likely will be transformed in the near future. In fact, many organizations are now reengineering their programs in anticipation of the emerging Guidelines. The expected transformation holds for training and education programs as well. This article suggests some of the ways in which environmental audit training is likely to be reshaped as a result of ISO 14012. Offerors of training courses and seminars would be wise to anticipate the changes and modify their programs accordingly. A quick response could provide a competitive advantage. Moreover, corporate audit program managers should conduct critical evaluations of commercial offerings to assure that the programs' contents are consistent with ISO 14012 “auditor certification” expectations.