Occurrence of organotin compounds in seafood from Hong Kong market

Overview

Chung and colleagues measured four organotin compounds in edible portions of Hong Kong market seafood: DBT, TBT, TPhT, and DOT. The survey covered 341 fish, crustacean, and mollusc samples collected in 2017-2018 and analyzed by GC-ICP/MS. These are organotin tin species reported as μg Sn kg−1 wet weight, not total inorganic tin.

Key numbers

The abstract reports that TPhT was detected in 53% of samples and accounted for most of the detected organotins. Mean total OTC levels were 24 μg Sn kg−1 in fish, 14 μg Sn kg−1 in crustaceans, and 15 μg Sn kg−1 in molluscs. The highest detected TPhT, TBT, DBT, and DOT values were 480, 24, 4.5, and 0.89 μg Sn kg−1, respectively.

Table 1 reports mean fish contamination as μg Sn kg−1 wet weight; 0 was used in source calculations when samples were not detected:

Table 2 reports mean crustacean and mollusc contamination as μg Sn kg−1 wet weight:

Among all 341 samples, 205 samples (60%) had at least one OTC detected at quantified levels. TPhT was found in 180 samples (53%), followed by TBT in 73 samples (21%), DBT in 45 samples (13%), and DOT in 8 samples (2%). The sum of four OTCs ranged from ND to 490 μg Sn kg−1.

Methods (brief)

Samples were collected from Hong Kong wet markets and supermarkets between October 2017 and June 2018. Seafood was steamed for 20 min before edible portions were removed for analysis. The method used 2 g homogenized sample, freeze-drying, methanol/tropolone/hydrochloric-acid extraction, Florisil SPE cleanup, NaBEt4 derivatization, and GC-ICP/MS on an Agilent 7890 GC coupled to a 7700 series ICP-MS. Table 3 reports LOD 0.25 μg Sn kg−1 and LOQ 1.0 μg Sn kg−1 for DBT, TBT, TPhT, and DOT in seafood, with recovery ranges 82-105%, 83-105%, 88-110%, and 93-113%, respectively.

Implications

This source contributes broad Hong Kong market seafood occurrence evidence for organotin tin species in fish, crustaceans, and molluscs. The product routing should retain fish and shellfish separately, and the fish rows require later row-fit adjudication because the table includes marine predatory, marine non-predatory, and freshwater species. The values are wet-weight organotin species and should not be normalized or collapsed into total tin (Sn) by hand.

Update history

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