Highly persistent butyltins in northern marine sediments: A long‐term threat for the Saguenay Fjord (Canada)

Abstract

An exhaustive study of the distribution of butyltin species was conducted in the sediment of the Saguenay Fjord (Canada), a semi-enclosed marine system with sediment permanently submitted to sub-Arctic cold conditions. Concentrations of total butyltins (tributyltin [TBT], dibutyltin, and monobutyltin) ranged from 6 to 288 ng Sn/g dry weight and were typical of those reported for contaminated coastal areas despite limited seasonal traffic of commercial vessels in the fjord. The distribution profiles of butyltin species in four sediment cores clearly indicated the high persistence of TBT that was dominating other species. The particular oceanographic conditions of the Saguenay Fjord (low seawater temperature, anoxic sediments, and low exchange rate of deep waters) combined with a high sediment/pore-water partition coefficient (Kdobs = 1.0 x 10(4) to 1.2 x 10(4) L/kg) and a low sediment/ water diffusive flux of TBT (J1 = 13 x 10(-8) mol/m2/year) are responsible for the burial and preservation of TBT in this marine ecosystem. The half-life of TBT in deep sediment was estimated to be approximately 87+/-17 years (+/-SEM), which implies a much slower degradation rate than any previously reported. Finally, a flood event that occurred five years before the sampling enabled us to calculate a very slow diffusive flux from the preflood to the postflood layer (J2 = 2 x 10(-8) mol/m2/year), indicating an almost permanent sequestration of TBT in the buried layers.

Tributyltin Originates from Pleasure Boats in Sweden in Spite of Firm Restrictions

“…De Mora (1989) [38] reported a TBT half-life of 1.85 years in Auckland, which is similar to an estimated 2.1 year half-life, determined over a 14-year period, in marina sediments in the UK [42]. A half-life of up to 87 ± 17 years was determined in sediments collected in western Canada [43]. Cornelissen and co-workers [19] reported values of >10 to 20 years in Oslo harbor.…”

Chemometric Analysis for Pollution Source Assessment of Harbour Sediments in Arctic Locations

“…It is worth noting that although POPs and TBT have been observed in sediments of pristine areas in the Arctic, the concentrations are much lower than those registered in this study (Evenset et al, 2007;Evenset et al, 2004;Harris et al, 2011;Jiao et al, 2009;Strand et al, 2006;Viglino et al, 2004). The concentrations of As, Cd, Cr and Ni in the sediments from the two harbours are equivalent to those found in remote areas (Evenset et al, 2007;Lu et al, 2013).…”

Valuation of ecotoxicological impacts from tributyltin based on a quantitative environmental assessment framework

“…The impact of organic contaminants is associated with the degradation rate (i.e., the time it takes for TBT to decompose), a factor that is usually temperature dependent, and estimates of TBT half-life vary between regions (e.g., Sarradin et al 1995;Viglino et al 2004). For Oslo harbor, Cornelissen et al (2008) reports a half-life of more than 10 up to 20 years.…”