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A paucity of literature has compared geotextile dewatering methods to more conventional dewatering methods (i.e., centrifuge, sedimentation) in the context of how geotextile dewatering performs at reducing particulate matter in dewatering effluent. Particulate matter is the primary source of inorganic and organic contaminants (i.e., dioxins and furans) in an unconsolidated sediment (estimated 577 000 [m.sup.3]) that has accumulated in a wastewater stabilization basin in Nova Scotia, Canada. Physical and chemical properties of contaminated sediment were initially characterized, and subsequent laboratory experiments were carried out for three common dewatering methods: sedimentation, centrifugation, and geotextile filtration. Filtrate quality of suspended solids (number, particle size distribution of particles) was examined for differences based on three dewatering techniques assessed. All three methods provided effective removal of particulate matter during dewatering, but geotextile dewatering could be a more cost-effective and practical solution for dewatering of these sediments. Key words: contaminated sediment, dewatering, geotextile, centrifuge, sedimentation, total suspended solid. Peu de documentation a compare les methodes de deshydratation par geotextile a des methodes de deshydratation plus classiques (c.-a-d. centrifugation, sedimentation) en vue de savoir comment la deshydratation geotextile contribue a reduire les particules solides dans les effluents de deshydratation. Les particules solides sont la principale source de contaminants inorganiques et organiques (c.-a-d. dioxines et furanes) dans un sediment non consolide (environ 577 000 [m.sup.3]) qui s'est accumule dans un bassin de stabilisation des eaux usees en Nouvelle-Ecosse, au Canada. Les proprietes physiques et chimiques des sediments contamines ont d'abord ete caracterisees, puis des experiences en laboratoire ont ete effectuees pour trois methodes courantes de deshydratation : la sedimentation, la centrifugation et la filtration geotextile. La qualite du filtrat des solides en suspension (nombre, distribution granulometrique des particules) a ete examinee en fonction des trois techniques de deshydratation evaluees. Les trois methodes ont permis d'eliminer efficacement les particules solides pendant la deshydratation, mais la deshydratation par geotextile pourrait etre une solution plus economique et plus pratique pour la deshydratation de ces sediments. [Traduit par la Redaction] Mots-cles: sediments contamines, deshydratation, geotextile, centrifugeuse, sedimentation, total des solides en suspension., Introduction The Boat Harbour Treatment Facility (BHTF) in Pictou County, Nova Scotia, Canada was constructed in the 1960s by damming a 140-hectare former tidal estuary to receive industrial wastewater from [...]

During Holocene advances of the Bear River Glacier, in northwestern British Columbia, ice pushed against a bedrock slope on the north side of Bear River Pass as it was being diverted eastward and westward along the pass. The result is a series of till sheets plastered against the rock slope and separated by wood mats. This sequence of tills provides an unusually detailed record of early-Neoglacial history and shows that Neoglacial expansion in the northern Coast Mountains began earlier than previously known. Moraines show the extent of ‘Little Ice Age’ expansion, and documents related to the long mining history of the area provide records of post-LIA recession. The oldest deposits in the area are a small lateral moraine outside of a prominent LIA moraine, and a till in the pass older than c. 3500 14C yr BP. The small moraine is undated; it may be equivalent to the latest-Pleistocene Crowfoot Advance which produced similar moraines in the southern Coast Mountains and eastern Cordillera. Wood mats in the pass show that Neoglacial advances occurred at c. 3700, 3500, 3300, and 1000 14C yr BP; each advance was slightly more extensive than the previous one. Documentary evidence indicates that the pass was still filled with ice in 1913, and diverging both eastward and westward, but glacier retreat has been rapid since then. Retreat from the pass in the mid-20th century resulted in the creation of Strohn Lake, through which meltwater from the glacier passes; a complicated lake history includes switching of discharge from eastward to westward and a series of jokuhlaups that damaged highway infrastructure to the west. A comparison of the history recorded at Bear River Pass with that recorded at the Todd Icefield 15 km to the north shows that different components of glacial history are preserved in different places, and many sites need to be examined to obtain a relatively complete regional history. [ABSTRACT FROM AUTHOR]

Seabirds are important biovectors of contaminants, like mercury, moving them from marine to terrestrial environments around breeding colonies. This transfer of materials can have marked impacts on receiving environments and biota. Less is known about biotransport of contaminants by generalist seabirds that exploit anthropogenic wastes compared to other seabird species. In this study, we measured total mercury (THg) in O-horizon soils at four herring gull (Larus smithsoniansus) breeding colonies in southern Nova Scotia, Canada. At colonies with dry substrate, THg was significantly higher in soils collected from gull colonies compared to nearby reference soils with no nesting gulls. Further, THg was distinct in soils among study colonies and was likely influenced by biotransport from other nesting seabird species, most notably Leach's storm-petrels (Hydrobates leucorhous). Our research suggests gulls that scavenge on anthropogenic wastes at local industrial sites are biovectors moving THg acquired at these sites to their colonies and may increase the spatial footprint of contaminants from these industries., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Rapid and accurate delineation of contaminated sediments in marine environments is critical for the effective assessment of site risks and the development of appropriate remedial action plans. In this study, a new application of the ultraviolet optical screening tool (UVOST) equipped with electrical conductivity measurement (UVOST-EC) is proposed to delineate a water-covered sediment contaminated with dioxins and furans in a decommissioned pulp and paper wastewater stabilization basin. Bench scale experiments are presented that were used to develop a UVOST-EC interpretation method for delineating between two different sediment types present in the basin: an anthropogenically derived organic rich contaminated sediment ("black sediment") and a naturally occurring grey organic silt sediment with marine provenance ("grey sediment"). The method involves comparative analysis of fluorescence and electrical conductivity signatures between the two sediments. Results indicate that each sediment type presents unique "signatures" related to fluorescence and electrical signals which corresponds to variability in their physio-chemical structure. Almost 100 UVOST-EC tests performed at the study site were paired with ex situ physical gravity core measurements of the black sediment to test the accuracy of the UVOST-EC-based method. A statistical analysis at seven sample "cluster" sites (i.e. multiple sub-samples within a defined area) indicated that the mean of sediment thickness obtained by the UVOST-EC measurement technique at a given site were not significantly different (p = 0.05) from measurements derived from sediment gravity core measurements. The UVOST-EC-based sediment thickness delineation method reliably determined the thickness of the dioxin and furan contaminated sediments as compared to gravity core determination for the sediment in this study. Application of this approach to other studies should be assessed in a similar manner. The UVOST-EC method offers health and safety, cost, logistics, and data interpretation benefits., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Author Sweet is an employee of the company that owns the UVOST equipment and whose company was given funding to perform apportion of the work by Nova Scotia Lands. However, Davidson, Lake and Spooner, as university researchers, were involved in the project specifically to be impartial in assessing the proposed method at the request of Nova Scotia Lands., (Copyright © 2021 Elsevier B.V. All rights reserved.)