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30 results on '"O'Driscoll, Nelson J."'

4. The long-term effects of water resource development on blood mercury levels and the trophic ecology of Namew (lake sturgeon, Acipenser fulvescens)

Author

Lescord, Gretchen L., Simard, Jennifer, Johnston, Thomas A., Seguin, Jacob, Farrell, Claire E., O'Driscoll, Nelson J., and O'Connor, Constance M.

Abstract

Water resource development can alter the movement and ecology of sturgeons. We studied total (THg) and methylmercury concentrations in whole blood sampled non-lethally from namew (Moose Cree L-dialect, lake sturgeon, Acipenser fulvescens), an endangered and culturally important subsistence fish. Namew were sampled from two tributaries within the Moose Cree Homeland: the Lower Mattagami River (an impacted system with four hydroelectric generating stations) and the North French River (a reference system that is free-flowing system with no development). Results indicated namew from the North French River had higher blood [THg] than those from the Mattagami River. Further modeling showed that trophic position was the primary driver of these differences, with North French namew having the highest nitrogen isotope ratios. Based on further isotope modeling, crayfish were major components of namew diet at all sites, while other prey items differed between sites. Specifically, namew with unobstructed access to the lower watershed had notably more enriched isotope values when compared to the freshwater benthic macroinvertebrates sampled, implying that other prey not captured herein may contribute to their diets and [THg]. Overall, we found differences in namew’s trophic ecology but no elevation in blood mercury levels at a site impacted by hydroelectric operations 60+ years post-impoundment.

Published
2024
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20. Unveiling the neurotoxicity of methylmercury in fish ( Diplodus sargus ) through a regional morphometric analysis of brain and swimming behavior assessment

Author

Puga, Sónia, primary, Pereira, Patrícia, additional, Pinto-Ribeiro, Filipa, additional, O’Driscoll, Nelson J., additional, Mann, Erin, additional, Barata, Marisa, additional, Pousão-Ferreira, Pedro, additional, Canário, João, additional, Almeida, Armando, additional, and Pacheco, Mário, additional

Published
2016
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29. Air Concentrations of Gaseous Elemental Mercury and Vegetation–Air Fluxes within Saltmarshes of the Tagus Estuary, Portugal.

Author

Cesário, Rute, O'Driscoll, Nelson J., Justino, Sara, Wilson, Claire E., Monteiro, Carlos E., Zilhão, Henrique, and Canário, João

Subjects
*MERCURY, *SALT marshes, *HAZARDOUS waste sites, *ESTUARIES, *LEAF area, *FLUX (Energy)
Abstract

In situ air concentrations of gaseous elemental mercury (Hg(0)) and vegetation–atmosphere fluxes were quantified in both high (Cala Norte, CN) and low-to-moderate (Alcochete, ALC) Hg-contaminated saltmarsh areas of the Tagus estuary colonized by plant species Halimione portulacoides (Hp) and Sarcocornia fruticosa (Sf). Atmospheric Hg(0) ranged between 1.08–18.15 ng m−3 in CN and 1.18–3.53 ng m−3 in ALC. In CN, most of the high Hg(0) levels occurred during nighttime, while the opposite was observed at ALC, suggesting that photoreduction was not driving the air Hg(0) concentrations at the contaminated site. Vegetation–air Hg(0) fluxes were low in ALC and ranged from −0.76 to 1.52 ng m−2 (leaf area) h−1 for Hp and from −0.40 to 1.28 ng m−2 (leaf area) h−1 for Sf. In CN, higher Hg fluxes were observed for both plants, ranging from −9.90 to 15.45 ng m−2 (leaf area) h−1 for Hp and from −8.93 to 12.58 ng m−2 (leaf area) h−1 for Sf. Mercury flux results at CN were considered less reliable due to large and fast variations in the ambient air concentrations of Hg(0), which may have been influenced by emissions from the nearby chlor-alkali plant, or historical contamination. Improved experimental setup, the influence of high local Hg concentrations and the seasonal activity of the plants must be considered when assessing vegetation–air Hg(0) fluxes in Hg-contaminated areas. [ABSTRACT FROM AUTHOR]

Published
2021
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30. Dissolved Gaseous Mercury Production at a Marine Aquaculture Site in the Mercury-Contaminated Marano and Grado Lagoon, Italy

Author

Sara J. Klapstein, Federico Floreani, Stefano Covelli, Elisa Petranich, Alessandro Acquavita, Nelson J. O'Driscoll, O’Driscoll, Nelson J., Covelli, Stefano, Petranich, Elisa, Floreani, Federico, Klapstein, Sara, and Acquavita, Alessandro

Subjects
Photoreduction, Ultraviolet Rays, Health, Toxicology and Mutagenesis, chemistry.chemical_element, Aquaculture, 010501 environmental sciences, Toxicology, 01 natural sciences, Contamination, Ecotoxicology, 14. Life underwater, Dissolved gaseous mercury, Lagoon, Ultraviolet radiation, 0105 earth and related environmental sciences, Gaseous mercury, Volatilisation, business.industry, Marine aquaculture, 04 agricultural and veterinary sciences, General Medicine, Mercury, Pollution, Mercury (element), chemistry, Italy, Solubility, Environmental chemistry, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, Gases, Volatilization, business, Water Pollutants, Chemical
Abstract

Dissolved gaseous mercury (DGM) production was examined in relation to ultraviolet radiation within a marine aquaculture site in the contaminated Marano and Grado Lagoon (Italy). The measured rates of DGM production relative to time elapsed (17.06 and 20.68 pg h−1, respectively) were substantially (6–20 times) higher than what has been observed in other marine Hg studies. We measured similar levels of DGM relative to dissolved total mercury (THgD) (0.84%–8.91%) at these sites in comparison to uncontaminated marine sites, however relative to other moderately-contaminated marine sites in Portugal the % DGM/THgD was high. These results suggest a substantial capacity for Hg volatilization from these highly contaminated lagoons to the atmosphere due to photoreduction mechanisms.

Published
2019

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