Distribution Of Acid Volatile Sulfide Research Articles

Anthropogenic impacts on water quality of the lagoonal coast of Fongafale Islet, Funafuti Atoll, Tuvalu

Water pollution, evident by negative values of redox potential in waters, occurs at the lagoonal coast located near the densely populated area of Fongafale Islet on Funafuti Atoll, Tuvalu, Central Pacific. Sediment microbial quinone analysis revealed that these coastal sediments exhibit 2.7–10.4 times more microbial biomass, significantly different microbial community structure and low microbial diversity, when compared to an undisturbed natural coastal sediment. Thus, the pollution is chronic. By considering the total land use/coverage on the islet, the situation of septic tank installations, temporal changes in water redox potential and Escherichia coli numbers in the coastal waters and the spatial distribution of acid volatile sulfide in the sediments, we conclude that domestic wastewater is the primary source of pollution. This pollution is proposed to occur via the following mechanism: during ebb tides, domestic wastewater leaking from bottomless septic tanks and pit toilets run off into the lagoonal coast. Tide changes control the pollution load of domestic wastewater.

象山港南沙岛不同养殖类型沉积物酸可挥发性硫化物的时空分布

Xiangshan Bay,located on the east coast of China,is a semi-enclosed bay with slow rate of water exchange.Nansha Bay,lies in the middle of Xiangshan Bay,is an important fish cage farming area.This paper presented the results of the seasonal and spatial distribution of acid volatile sulfide(AVS) in sediments from three different mariculture areas including seaweed culture area,shellfish culture area and fish cage culture area in Nansha Bay in 2007.The results revealed that AVS content in the whole investigation region ranged from 0.01 to 30.03 μmol/g,the average value was 3.75 μmol/g.The mean value of AVS in shellfish culture area,seaweed culture area,fish cage culture area and the control area were 1.03,0.64,5.06,and 0.70 μmol/g,respectively.Although there was no significant change of AVS in surface sediment,significant difference of AVS in columnar sample(0—15cm) was found among winter,summer,spring and autumn,with the average value 3.48,3.05,8.31 and 6.57 μmol/g in,respectively.The value of AVS increased with the sediment depth,and reached the maximum in 6 to 9 centimeter,especially in summer and autumn.Cluster analysis showed the AVS distribution in the sediment of Nansha Bay could be divided into 3 categories: central cage area(S10) and surrounding cage area(S12 and S13);cage culture area(S6,S7 and S14) far away from central cage area;shellfish culture area(S1),algae culture area(S2) and control area(S5).The average values of AVS in different categories were 7.34,2.62 and 0.75 μmol/g,respectively.Overall,the AVS content was highest in central cage area and gradually reduced with the distance along the central cage area.The impact of fish cage farming on AVS mainly concentrated in the area within 200 m from fish cages and influence slightly far away from 500m.

The distribution of acid-volatile sulfide and simultaneously extracted metals in sediments from a mangrove forest and adjacent mudflat in Zhangjiang Estuary, China

The distribution of acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) were studied in sediments collected from mangrove forest, forest fringe and adjacent mudflat in the Zhangjiang Estuary, China. The aim was to examine the spatial distribution of AVS and SEM in sediments of the Estuary and determine the influence of mangrove trees on AVS and SEM concentrations in the sediments. The results indicated that AVS concentrations in forest sediments were significantly lower than those in mudflat sediments. There was a significant positive correlation between AVS values and moisture contents in forest sediments, while LOI played an important role in AVS concentrations of mudflat sediments. In the forest sediment core, the peak value of AVS appeared deeper in the sediment profile compared to it appeared in the mudflat core. The distribution of SEM showed different trends from that of AVS, and potential toxicity existed in the upriver forest sediments.

On the Vertical Distribution and Influencing Factors of Acid-Volatile Sulfide in the Sediments of Donghu Lake (Wuhan)

Lake Donghu(Wuhan), a subtropical shallow lake near the Yangze River, is polluted heavily by some sewage inputs. Based on total phosphorus (TP) and chlorophyll-a, Station I is defined as a hypertrophic lake, and Station II is defined as a eutrophic lake, and Station III is defined as mesotrophic lake. The main purposes of this paper are to describe the vertical distribution of acid volatile sulfide (AVS) in the sediments of three stations with different trophic levels in Lake Donghu, and to discuss the possible mechanisms underlining these patterns with emphasis on the possible effects of organic matter. The results indicate that AVS peak appeared in anoxic sediments in all three stations. Two patterns of AVS distribution were found. The AVS profiles in cores of Station I and II showed a maximum concentration at about 5-cm depth, and then a drop down at a lower level. On the contrary, the AVS profile in the cores of Station III showed AVS peak between 10 cm to 20 cm depths. There was closer relationship between OM and AVS in the sediment with high concentration of OM than with low concentration of OM, and AVS/OM ratio was in the order of Station I II III. This indicates that organic matter exerted great effects on the distribution of AVS in the sediment. The content of AVS in sediments is mainly affected by decompose of organic matter, deposition, dissolution and oxidation of AVS. High organic matter flux shifted AVS peak into the surface sediment, and narrowed the depth interval over which the accumulation of AVS became maximized at the more eutrophic Stations I and II. The convection-diffusion model of AVS reported by Fang et al was tested. The vertical distribution of AVS accorded with the model better in eutrophic lake with high concentration of OM than with low concentration of OM.