Distribution of arsenic and other metals in crayfish tissues (Procambarus clarkii) under different production practices.

Louisiana is one of the world's largest producer of crayfish. Arsenic (As) and other metals (Cd, Cu, Pb and Zn) concentrations were determined in crayfish tissues, plant and soil samples collected from Louisiana paddy rice fields, where crayfish/rice rotation farming is a common practice. The samples were collected from November 2013 to April 2014 from three different crayfish farming systems. Concentration of As in rice grain, rice straw, and native vegetation ranged between 0.33 and 0.41, 3.14-4.93, and 3.26-5.89mgkg-1, respectively. The highest As levels in the crayfish external and internal body parts were found in gill (4.04±1.70mgkg-1), followed by hepatopancreas (3.42±1.57mgkg-1), exoskeleton (1.52±0.85mgkg-1), and muscle (1.50±0.69mgkg-1). Positive correlations between As levels in the crayfish muscle and the plant tissue on which they feed were found in all farming systems (r=0.405-0.438). The biomagnification factor (BMF) of As in different tissues varied between 0.29 and 1.08, having gill and hepatopancreas were the highest As accumulation while the lowest biomagnification was observed in crayfish muscle tissues which is a food source for human. The As levels along with other metals in crayfish muscle tissue were in acceptable levels for human consumption under all crayfish/rice rotation practices. Further studies are needed in determining the percentage of organic and inorganic arsenic in crayfish tissue. Published by Elsevier B.V.