Determination of mercury in thirty-three international stream sediment and soil reference samples by direct mercury analyser

Mercury was determined in thirty-three international stream sediment and soil reference samples (eleven Chinese soils, GSS-1 to GSS-11; twelve Chinese stream sediments, GSD-1A to GSD-12; four Canadian stream sediments STSD-1 to STSD-4; South African stream sediments, SARM-42, SARM-46 and SARM-47; Japanese stream sediments, JSd-1 to JSd-3) by direct mercury analyser. Samples were taken in 500 mu l quartz boats, placed in an auto sampler and processed (drying time 60 s at 300 degrees C; decomposition time 120 s at 850 degrees C; waiting time 45 s). The instrument was calibrated in the low (0-50 ng) and high ranges (50-500 ng) with two reference materials GSS-5 and GXR-2 (USGS). Using the calibration line, reference samples were analysed for Hg. The results of the determinations agreed with the recommended values of RMs in all cases except JSd-1. The RSD calculated for the RMs was found to be within 20%. The detection limit was 1 ng g(-1).