Rapid determination of arsenic species in freshwater organisms from the arsenic-rich Hayakawa River in Japan using HPLC-ICP-MS

摘要

Speciation analyses of water-soluble arsenicals from freshwater and biological samples collected from the Hayakawa River (Kanagawa, Japan), which contains a high concentration of arsenic, were performed using high performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC-ICP-MS). River water contained only arsenate, which is a pentavalent inorganic arsenical. The water bug Stenopsyche marmorata contained inorganic arsenicals accounting for 77% of the water-soluble arsenicals, followed by oxo-arsenosugar-glycerol, which is a type of dimethylarsinoylriboside (arsenosugar). The freshwater green macroalga Cladophora glomerata contained oxo-arsenosugar-glycerol and oxo-arsenosugar-phosphate as 64% of the water-soluble arsenicals. Production of the same types of arsenosu-gars was confirmed in the freshwater green microalga Chlamydomonas reinhardtii CC125 experimentally exposed to arsenate. The muscle tissues of all freshwater fish and crustaceans analyzed contained arsen-obetaine, oxo-arsenosugar-glycerol, and/or oxo-arsenosugar-phosphate in various concentrations. Seven freshwater fish (Cobitis biwae, Leuciscus hakonensis, Phoxinus lagowski steindachneri, Plecoglossus altivelis, Rhinogobius sp. CB, Rhinogobius sp. CO, Sicyopterus japonicus) and the crustacean Macrobracbium nippone-nese contained arsenobetaine in their muscle tissues as the predominant form, contributing up to 80% of the water-soluble arsenicals, while the freshwater fish Anguilla japonica muscle tissues primarily contained dimethylarsinic acid as 77% of the water-soluble arsenicals, followed by arsenobetaine. The freshwater fish Zacco platypus muscle tissues predominantly contained oxo-arsenosugar-phosphate, accounting for 51% of the water-soluble arsenicals, followed by dimethylarsinic acid and arsenobetaine. These biological samples possessed non-extractable arsenical(s) accounting for more than 50% of the total arsenic concentration.