Current and historical rates of input of mercury to the Penobscot River, Maine, from a chlor-alkali plant.
Sci Total Environ
; 637-638: 1175-1186, 2018 Oct 01.
Article
en En
| MEDLINE
| ID: mdl-29801211
ABSTRACT
Mercury inputs by surface and ground water sources to Penobscot River from a defunct Hg-cell chlor-alkali plant were measured in 2009-10 and estimated for the entire period of operation of this facility. Over the measured interval (422â¯days) approximately 2.3â¯kg (5.4â¯gâ¯day-1) of mercury was discharged to the Penobscot River by the two surface streams that drain the site, with most of the combined loading (1.8â¯kgâ¯Hg, 78%) associated with a single storm with rainfall in excess of 100â¯mm. Groundwater seepage rates from the site, as estimated from both a radon tracer and seepage meter methods were in the range of 3 to 4â¯cmâ¯day-1 and, when combined with a best estimate of the area of groundwater discharge (11,000â¯m2) and average seepage/porewater mercury concentration (242â¯ngâ¯L-1, UCL95), yielded a loading of 0.11â¯gâ¯day-1 for site groundwater. None of the municipal or other industrial point sources of mercury to the river between Veazie and Bucksport, Maine exceeded 1â¯gâ¯day-1 individually, nor was the aggregate loading of all such sources >3â¯gâ¯day-1 (based on State of Maine data). Mercury loadings for the three largest tributaries downstream of Veazie Dam were estimated to contribute 4.2, 3.7 and 2.5â¯gâ¯day-1, respectively, to the Penobscot River. Based on sampling (total Hgâ¯~â¯2 to 4â¯ngâ¯L-1) and historical mean discharge data (340-460â¯m3â¯s-1), the Penobscot River upstream of the plant site contributes as much as 160â¯gâ¯day-1 to the downstream reach depending on river discharge. Estimates of historical (1967-2012) mercury loading using both generic emission factors and measured releases ranged from 2.6 to 27â¯MT while the mass of mercury found in downstream sediments amounted to 9â¯MT.
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Texto completo:
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Bases de datos:
MEDLINE
Asunto principal:
Contaminantes Químicos del Agua
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Contaminación Química del Agua
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Monitoreo del Ambiente
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Mercurio
País/Región como asunto:
America do norte
Idioma:
En
Revista:
Sci Total Environ
Año:
2018
Tipo del documento:
Article