Marine sediments were collected along Chonburi coastline from Ban Suan to Bang Lamung district (part of the upper Gulf of Thailand, a semi-enclosed gulf ) over about 50 km distance. Each sampling point was located approximately 1 km away from the shore in three seasons (rainy: September. 2010, winter: December, 2010,and summer: March. 2011). Coordinates were determined by the global positioning system (figure 1). The physical parameters consisting of temperature, electrical conductivity, salinity and dissolved oxygen were measured at each half depth below the sea level by using YSI-60 multimeter .The sediment samples were collected by Ekman dredge grab and some samples were taken by scuba diving. The depth of the sediment cores were between 0-10 cm.
After air drying, the dried sediment was ground and sieved through a 2 mm test sieve. The ground sediment was then filled into a plastic cylindrical container with the same geometry as IAEA Soil 6 reference material (7.5 x 7 cm²)