Mobilization of aluminium and deposition on fish gills during sea salt episodes--catchment liming as countermeasure.
Episodic events may be critical with respect to aluminium (Al) toxicity in moderately acidified salmon rivers. The present work demonstrates that sea salt episodes enhance the toxicity of Al in acidic rivers. The documented sea salt episode (300 [micro sign]M Cl) mobilized positively charged Al species (0.4 to 1.1 [micro sign]M Al(i)), enhanced the Al accumulation on fish gills (0.9 to 10 [micro sign]mol g(-1) dw) and caused increased stress responses (6 to15 mM blood glucose) in fish. Accumulated Al on gills remained high several days after the episode. The presented results are based on a six-week field study in two tributary rivers on the west coast of Norway. Changes in the river water qualities and Al speciation were followed using in situ fractionation techniques. Al accumulation on gills and stress responses were followed for Atlantic salmon (Salmo salar) kept in tanks continually exposed to the changing water quality. The potential mobilization of Al from the two catchments was studied by extracting soils with diluted seawater (salinity of 3). To counteract Al toxicity, one of the tributary catchments has been limed. The potential mobility of Al by sea salt was lower in limed soils compared to acid soils, and the Al deposition on fish gills (<3.5 [micro sign]mol g(-1) dw) and associated stress responses stayed low during the sea salt episode in the river draining the limed catchment. Thus, for acid river systems in coastal areas, catchment liming should be considered as a useful countermeasure for Al toxicity.
Agricultural University of Norway, Isotope Laboratory, Department of Soil and Water Sciences, PO Box 5028, N-1432 As, Norway. hans-christian.teien@ijvf.nlh.no
Hans-Christian
HC
Teien
William J F
WJ
Standring
Brit
B
Salbu
Marilyn
M
Marskar
Frode
F
Kroglund
Atle
A
Hindar
D000535:Aluminum / Q000493:pharmacokinetics / Q000633:toxicity*; D000818:Animals; D017610:Calcium Compounds / Q000737:chemistry; D005880:Gills; D006863:Hydrogen-Ion Concentration; D010087:Oxides / Q000737:chemistry; D020317:Salmo salar; D012965:Sodium Chloride / Q000494:pharmacology*; D014873:Water Pollutants / Q000493:pharmacokinetics / Q000633:toxicity*
D017610:Calcium Compounds; D010087:Oxides; D014873:Water Pollutants; D012965:Sodium Chloride; C016538:lime; D000535:Aluminum