Contaminants in Muscle of Plaice and Halibut Collected From the St. Lawrence Estuary and Northwest Atlantic

Levels of aromatic hydrocarbons in muscle or plaice and halibut were determined by fluorescence, using the chrysene standard, as recommended by the International Oceanographic Commision, for the analysis of PAH in environmental extracts. Concentrations were highest in muscle of halibut collected at the most contaminated, nearshore site, in the Saguenay Fjord of the St. Lawrence Estuary, compared to other locations further from shore. Although concentrations of fluorescing compounds were not statistically different in plaice, the saturated hydrocarbons displayed unquestionably more biodegradation, with a decrease of n-alkanes and increase of branched aliphatics, at the less contaminated site. Synchronous fluorescence indicated the presence of benzenoid and biphenyl hydrocarbons in the extracted mixtures, while GC-MS-TIC analysis tentatively identified the presence of a series of benzenoid (alkyl benzenes), chlorinated (PCB and DDE), N (trialkylamines) and O (phenols) hydrocarbons. These anthropogenic compounds could derive from petroleum products, surfactants and common products used in industry and households. This study emphasizes the importance of a multispectroscopic approach when investigating complex environmental mixtures.     

In vivo studies on the effect of some insecticides on the hepatic activities of L-tryptophan 2,3-dioxygenase and pyridoxal phosphokinase of male mice

The effect of Dimethoate, Carbaryl and Permethrin on the activities of liver L-tryptophan 2,3-dioxygenase (total-, holo-, and apo-forms) and pyridoxal phosphokinase of male mice was investigated. Dimethoate inhibited both enzyme systems after single and repeated dose treatment; except the dioxygenase holo-enzyme after repeated doses. Single dose of Carbaryl treatment inhibited the pyridoxal phosphokinase, total and holo-enzyme of L-tryptophan dioxygenase. However, the repeated dose treatment do not affect both enzyme systems. Permethrin inhibited only total-, holo- and apo-enzymes of L-tryptophan dioxygenase whereas repeated administration has no significant effect on both enzymes. The data indicate that these insecticides may induce abnormal tryptophan metabolism through which some endogenous bladder carcinogens are formed.     

Reestablishment of the Perdido Key Beach Mouse (Peromyscus polionotus trissyllepsis) on Gulf Islands National Seashore

Abstract: In April 1986, the endangered Perdido Key beach mouse (Peromyscus polionotus trissyllepsis) existed only as a small population of less than 30 animals on the western end of Perdido Key at Gulf State Park, Alabama This population was vulnerable to extinction from a variety of causes. Fifteen pairs of mice from Alabama were moved approximately 20 km on the same island to Gulf Islands National Seashore Florida between November 1986 and April 1988. The Alabama population was surveyed by live-trapping before each removal and showed a large increase during this study. Eleven pairs of mice were released into enclosures to stimulate burrowing and reduce dispersal at the release site. The last four pairs w e released unrestricted into the dune habitat Trapping in July 1988 revealed that virtually all available dune habitat (11,000 linear m; approximately 160 ha) had been occupied by the mice. Fifty-five individuals were captured including four of the released mice. Exchanges between the populations are recommended to prevent loss of genetic diversity. Future research should investigate demographics, dispersal pattern, and the application of DNA fingerprinting techniques to determine rates of gene flow in the population. The Perdido Key beach mouse provides an excellent model for studying the effects of a population bottleneck on genetic diversity and testing the predictions of population viability analysis.     

Concurrent Chemical and Histological Analyses: Are They Compatible?

Bivalves are often used as sentinel organisms in monitoring programmes for trace organic contaminants. the animal's physiological state may be important in interpreting trends in contaminant body burden. Simultaneous evaluation of physiological state and organic contaminant concentration in bivalves typically involves removal of a lipid-rich cross-section of the body mass for histopathological and/or gonadal analysis.

In this study, the bias introduced by this technique in the final trace organic concentrations, e.g. of polynuclear aromatic hydrocarbons, chlorinated pesticides and polychlorinated biphenyls, are evaluated on five different size groups of oysters. As a test case, we evaluated the use of this method in the NOAA's Status & Trends Mussel Watch (NS&T) Programme. the average biases introduced by this technique in the final trace organic concentrations in Gulf of Mexico oysters have been increasing since 1986 as a consequence of a continuous decrease in the size of the individuals sampled.     

Third party roles played by Turkish managers in subordinates' conflicts

This study investigated the third party roles of Turkish managers and how these roles were related to the conflict management styles used by their subordinates. Questionnaire data were collected from 295 Turkish managers in seven firms. Mediation and facilitation were found to be the third party roles reported more frequently than autocratic intervention and laissez-faire. Subordinates reported increased use of collaboration and compromise toward the other party when their managers, in a third party role, were seen as using more mediation and facilitation. Competitive behavior increased when the third party was seen as autocratic. The paper discussed the relationship of these findings to cultural characteristics such as uncertainty avoidance and collectivism.