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Organic complexation of zinc in estuarine interstitial and surface water samples 1
Author(s) -
van den Berg Constant M. G.,
Dharmvanij Sirichai
Publication year - 1984
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1984.29.5.1025
Subject(s) - zinc , seawater , estuary , salinity , chemistry , environmental chemistry , surface water , fraction (chemistry) , flux (metallurgy) , environmental science , geology , environmental engineering , chromatography , oceanography , organic chemistry
The organic complexing capacity for zinc in natural water samples was determined by equilibration of added 65 Zn with MnO 2 . Stability constants for complexes with EDTA and NTA in seawater were determined in preliminary tests. Samples were collected from interstitial waters in surficial sediments from the upper Gulf of Thailand and the estuary of the River Mersey in England and from surface water from the estuaries of the Rivers Dee and Ribble in England. Complexing capacities for zinc of between 0.02 and 2 × 10 −6 M (averaging 0.66 × 10 −6 M) were detected in the interstitial water and between 0.006 and 0.04 × 10 −6 M (averaging 0.024 × 10 −6 M) in the surface water. Values for conditional stability constants, log K′ zn l , ranged from 7.4 to 9.3 and decreased with increasing salinity. At a salinity of 32‰ the observed values for log K′ were similar to that of EDTA. It was calculated that the organic fraction of zinc represents 93–98% of total zinc in most interstitial water samples, 13–26% in most surface water samples. The organic zinc fraction was smaller in cases where the complexing capacity had been saturated with zinc and other metal ions as a result of pollution.