The　concentrations,　spatial　distribution,　diastereoisomer-specific　profiles　of　hexabromocyclododecanes　(HBCDs)　in　surface　sediments　from　three　major　rivers　in　Shanghai　as　well　as　the　seasonal　variation　of　HBCDs　were　investigated.　The　concentrations　of　total　HBCD　diastereoisomers　ranged　from　0.05　to　6.87　ng　g(-1),　dw.　Significant　spatial　distribution　of　total　HBCDs　concentrations　were　observed.　The　mean　concentration　of　total　HBCDs　followed　the　order　of　Suzhou　Creek　(2.00　ng　g(-1))　＞　Huangpu　River　(1.59　ng　g(-1))　＞　Yunzao　Creek　(0.77　ng　g(-1)).　The　concentration　was　a　relatively　low　HBCDs　level　compared　to　levels　measured　in　domestic　and　other　parts　of　the　world.　The　proportions　of　alpha-HBCD　in　sediment　samples　were　generally　higher　than　that　of　commercial　formulations.　This　might　be　due　to　thermal　isomerization　from　gamma-HBCD　to　alpha-HBCD　and　slower　degradation　rate　of　alpha-HBCD　compared　to　gamma-HBCD　in　anaerobic　conditions.　The　concentrations　of　Sigma　HBCD　in　the　summer　were　significantly　higher　than　those　in　the　winter　(paired　t　test,　p　＜　0.01).　This　seasonal　variation　could　probably　be　attributed　to　a　combined　effect　of　temperature　and　wet　deposition.　Moreover,　a　poor　and　no　significant　correlation　between　Sigma　HBCD　levels　and　TOC　content　in　sediments　was　observed,　suggesting　that　the　spatial　distributions　of　HBCDs　were　not　constrained　by　the　TOC　in　sediments　of　Shanghai.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.