Determination Of Dissolved Inorganic Antimony Species (sb(v) And Sb(Ⅲ)) In Natural Water And Their Distributions In The Yellow River Estuary And The Yellow Sea

Antimony is a global pollutant with several industrial applications and an annual world production of 12～15 tonnes. The widely industrial applications make the environmental pollution more and more serious. Compared to other metals (such as As and Hg), the biogeochemical cycles and environmental effects of antimony are poorly understood. The distributions and biogeochemical cycles of different antimony species in the ocean and river systems have been poorly documented in our country. Understanding its extent of global pollution, biogeochemical cycles and toxicity are most urgently needed. The distributions and concentrations of antimony in the Yellow River Estuary and the Yellow Sea are primarily studied in this dissertation.1. An improved method for the determinations of Sb(Ⅲ+Ⅴ) and Sb (Ⅲ) by atomic fluorescence spectrometry (HG-AFS) in natural water is established in this thesis. The optimum conditions are:the electricity for 60 mA, the voltage for-260 V, the temperature for 190℃and the Ar flux for 600 mL/min. The method is based on the different behavior of total antimony (Sb(Ⅲ+Ⅴ)) and antimony (Ⅲ) at different acid conditions. Total antimony is determined at 1 mol/L HCl and antimony (Ⅲ) is determined at pH=4.0～4.5. Under optimized conditions, the detection limit (3s) for Sb(Ⅲ+Ⅴ) and Sb(Ⅲ) are 0.024μg/L and 0.0013μg/L, respectively. For total antimony, the precisions for the samples with the concentrations of 0.3μg/L and 0.03μg/L are 1.95% and 1.92%, respectively (n=9). The linearity is 0±14μg/L. For Sb (Ⅲ), the precisions for the samples with the concentrations of 0.04μg/L and 0.01μg/L are 3.8% and 5.5%, respectively (n=9). The recoveries of the determinations for Sb(Ⅲ+Ⅴ) and Sb(Ⅲ) are 93.7%～105% and 91.1%～104%, respectively. The concentrations of Sb (Ⅴ+Ⅲ) and Sb (Ⅲ) in natural water can be determined by the presented method directly.2. As part of a study of estuarine antimony cycling, we measurd the concentrations in the Yellow River Estuary. The studies about Monthly observations showed obvious seasonal variations. Mean concentration is higest in summer and lowest in winter. Average concentration of Sb(Ⅴ) in daily observation were 8.06±1.00 nmol/L, with range of 7.12-11.07 nmol/L. Average concentrations of SPM were 2.35±1.62 g/L, with range of 0.09～5.11 g/L. Aerage concentrations of Sb(Ⅴ) at Kenli Station in the Yellow River during the daily observations is higher than the Yellow River Estuary. Before the flow and sand adjusting at Xiao Langdi, average concentrations of Sb(Ⅲ), Sb(Ⅴ+Ⅲ) and average ratio of Sb(Ⅲ)/Sb(Ⅴ) in the coastal area adjacent to the Yellow River Estuary were 0.54±0.14 nmol/L,3.45±1.00 nmol/L and 0.17±0.07, respectively. During the process of Xiao Langdi adjusting flow and sand transfer, average concentrations of Sb(Ⅲ), Sb(Ⅴ+Ⅲ) and average ratio of Sb(Ⅲ)/Sb(Ⅴ) were 0.44±0.25 nmol/L,4.55±1.28 nmol/L and 0.10±0.07, respectively. After Xiao Langdi adjusting flow and sand transfer, average concentrations of Sb(Ⅲ), Sb(Ⅴ+Ⅲ) and average ratio of Sb(Ⅲ)/Sb(Ⅴ) were 0.08±0.06 nmol/L,3.35±1.01 nmol/L and 0.03±0.02, respectively. The concentrations of Sb(Ⅴ) were decreased with the increasing distance off the Yellow River Estuary, which indicate that the Yellow River discharge is the dominant source for Sb(Ⅴ) in the study area. The concentrations of Sb(Ⅲ) were increased with the increasing distance off the Yellow River Estuary, The influencing factors for the distributions and seasonal variations of Sb(Ⅲ) in the Yellow River Estuary is not well understood yet.3. In the winter, the average concentrations of Sb(Ⅴ) and Sb(Ⅲ) in the Yellow Sea were 1.95±0.51 nmol/L and 0.31±0.11 nmol/L in the surface, while 1.95±0.56 nmol/L and 0.30±0.14 nmol/L in the bottom. In the early spring, average concentrations of Sb(Ⅴ) and Sb(Ⅲ) in the Yellow Sea were 1.91±0.34 nmol/L and 0.30±0.09 nmol/L in the surface, while 1.87±0.38 nmol/L and 0.29±0.07 nmol/L in the bottom. The distributions of Sb(Ⅲ+Ⅴ) and Sb(Ⅲ)/Sb(Ⅲ+Ⅴ) ratio did not show obvious seasonal variations. The vertical profiles of Sb(Ⅴ) and Sb(Ⅲ) in Yellow Sea are identical, with the surface maximum。The nfluencing factors for the distributions and seasonal variations of Sb species in the Yellow Sea is the mixing of different water masses.