Chemical and biological profiles of sediments as indicators of sources of contamination in Hamilton Harbour. Part II: bioassay-directed fractionation using the Ames Salmonella/microsome assay

Bottom sediment and suspended sediment samples from Hamilton Harbour (western Lake Ontario) and from a major tributary were profiled using a bioassay-directed fractionation approach. Sample extracts were fractionated using an alumina/Sephadex gel clean-up procedure to afford non-polar aromatic fractions which were characterized using chemical analyses and the Ames/microsome bacterial assay in Salmonella typhimurium strains YG1025 with the addition of oxidative metabolism (S9), and YG1024 without S9. Non-polar aromatic fractions of selected samples were separated by normal phase HPLC into 1-min fractions which were subjected to bioassay analyses. The bioassays using strain YG1025+S9, a TA100-type strain, were performed to assess genotoxicity arising from the presence of polycyclic aromatic hydrocarbons (PAH). Fractions which exhibited mutagenic activity contained PAH with molecular masses of 252, 276 and 278 amu; these fractions contained over 80% of the genotoxicity attributable to PAH. Individual compounds identified using Gas Chromatography-Mass Spectrometry analyses in these active fractions included benzo[a]pyrene, indeno[cd]pyrene and dibenz[a,h]anthracene. The YG1025+S9 mutagenic activity profiles were similar for all samples. Mutagenic activity profiles generated using strain YG1024-S9, a TA98-type strain sensitive to compounds characteristic of mobile source emissions, were very different. The mutagenic activities in strain YG1024-S9 were greatest for harbour-suspended sediment samples collected from sites impacted by a major tributary. Suspended sediments collected near areas known to contain high levels of coal tar-contamination in the bottom sediments contained higher levels of genotoxic PAH than suspended sediments collected from other areas of the harbour.     

A MORPHOLOGICAL AND ECONOMIC EXAMINATION OF PLUNGE POOLS AS ENERGY DISSIPATERS IN URBAN STREAM CHANNELS1

ABSTRACT: Naturally formed plunge pools (scour holes) are a common morphologic feature in many urban stream systems where the transition between a pipe and a natural channel occurs. Plunge pools serve as significant stream energy dissipaters, increasing flow resistance and enhancing stream channel stability. Such features may also improve habitat diversity and serve as refugia for stream biota during low flow periods. The morphologic characteristics of several naturally formed plunge pools associated with road crossing culvert outlets in the metropolitan Charlotte, North Carolina, area are presented. Plunge pool dimensions surveyed include maximum depth, length, and width, and longitudinal and side slopes as well as bed material. Culvert outlet dimensions and hydraulic characteristics of the scouring jet for each study site are also reported. Design equations developed from flume studies generally failed to predict the naturally formed plunge pool dimensions. Pool volume was significantly correlated with drainage area, with pool depth being the least sensitive dimension to changes in the magnitude of the scouring flow. The excavation costs for designed plunge pools compare favorably to initial construction costs of traditional culvert outlet riprap aprons.     

Application of function analysis to bathing areas in the Maltese Islands

On a small island such as Malta where many developers and policy makers place a large emphasis on social use and develoment values, which encourages recreational/industrial development, it is often hard to promote the monetary value of coastal conservation due to strong competition with the large tourism industry. An assessment of the ecological (conservation) and economic (use/development) values of four popular Maltese bathing areas (Mellieha, St. George’s, Ramla and Ghajn Tuffieha Bay) was carried out by evaluating their ability to provide a number of functions. This is dependent on the environments’ inherent characteristics within the context of locally applicable time and space functions. Function Analysis is an innovative technique able to provide a means for assessing changes in environmental quality of an area and evaluating the sustainability of applied management regimes. This paper is a first example of an application of the Functional Analysis approach in Malta. Local application of this technique indicates a need for additional refinement in application to coastal areas. Analysis showed that St. George’s, had the lowest conservation value, Ramla and Ghajn Tuffieha bay had the highest conservation values, Mellieha Bay had high conservation value and use/development potential. In this context, conservation value is understood to reflect values of biodiversity, information/knowledge and environmental quality.     

Insights on common dolphin (<Emphasis Type="Italic">Delphinus delphis</Emphasis>) social organization from genetic analysis of a mass-stranded pod

Compared to terrestrial mammals, little is known of cetacean social systems as they are generally less accessible to behavioral investigations due to their aquatic environment. The present study investigates group structure of the pelagic common dolphin, Delphinus delphis, using genetic markers. Tissue samples from 52 individuals representing a recent live mass-stranding event were compared to 42 single strandings taken from presumably different groups. The mass-stranding event occurred in 2002 on the French coast of the English Channel, whereas the single strandings were collected between 1993 and 2003 along the western coast of France (Bay of Biscay and English Channel). Analysis of mitochondrial DNA control region sequences indicated that genetic variability within the mass-stranded pod was similar to variability observed in single strandings. The mass-stranded group was composed of 41 different mitochondrial haplotypes or matrilines while the single strandings revealed 29 different haplotypes. Analysis of 11 microsatellite loci revealed that average relatedness of the mass-stranded pod was not different from average relatedness among all single strandings suggesting that individuals within the group had no closer kin relationships than animals taken from presumably different groups. These results do not support a matriarchal system and suggest that common dolphins constituting a pod are not necessarily genetically related.     

CHANGING NEAR‐STREAM LAND USE AND RWER CHANNEL MORPHOLOGY IN THE VENEZUELAN ANDES1

ABSTRACT: The shape of a river channel is linked to surrounding land use through interacting hydrologic and geologic processes. This study analyzes the relationship between the change in near‐stream land use and the shape of the adjacent river channel over time. Three watersheds in the foothills of the Venezuelan Andes that have experienced differing degrees of development were studied to determine river channel width, sinuosity, and position relative to surrounding land use. Change in land use over time was obtained from multiple‐date aerial photographs (1946 and 1980) referenced to 1996 Landsat Thematic Mapper (TM) satellite imagery, and verified by field inspection. Measurements of land‐use type and amount and river channel morphology from the two dates were made using geographic information system (GIS) methods. The three watersheds differed in the extent of deforestation, the location of remaining forested land, and how much land‐use change had already occurred by 1946. Change in river channel morphology was greatest at the most deforested sites. Valley shape and channel constraint also had a discernible effect on change in channel morphology. This study introduces a method for analyzing change in coupled terrestrial‐aquatic systems based on multiple‐date, remotely sensed data and GIS analysis of spatial properties. The results document human impacts on river channels through a comparison of multiple watersheds over a 35‐year time interval.     

Characteristics of vehicle-animal crashes in which vehicle occupants are killed

During the past 10 years almost 1,500 people have been killed in motor vehicle collisions with animals. Police reports on 147 fatal vehicle-animal crashes during 2000-2002 were obtained from nine states. The goal was to determine common crash types, types of animals involved, and steps that could be taken to reduce the crashes and injuries. Seventy-seven percent of the struck animals were deer, but six other types of animals were involved including small ones such as dogs. Eighty percent of the crashes were single-vehicle events. In most of these cases a motorcycle struck an animal and the rider came off the vehicle, or a passenger vehicle struck an animal and then ran off the road; in a few cases the animal went through the windshield. Multiple-vehicle crashes included vehicles striking deer that went through the windshields of oncoming vehicles, vehicles striking animals and then colliding with other vehicles, and vehicles striking animals that subsequently were struck by other vehicles. Crashes occurred primarily in rural areas, on roads with 55 mph or higher speed limits, during evening or nighttime hours, and in darkness. Greater application of deer-vehicle collision countermeasures known to be effective is needed, but it is noteworthy that a majority of fatalities occurred from subsequent collisions with other vehicles or objects, not from animal contacts. Sixty-five percent of motorcyclists killed were not wearing helmets, and 60% of vehicle occupants killed were unbelted; many of these fatalities would not have occurred with proper protection.