Abstract
Chronic liver disease is recently becomes the most sever disease to residents of northern Ethiopia (Shire area) which was started 1980. Pervious health study reviles that this liver disease is not caused by virus and there is a fear that it can be caused by toxic chemical pollutants from the water they used to drink. Therefor the main objective of this study is to identify which geochemical elements cause this disease and its associations, to map their spatial distribution and lithological associations, to see how using compositional data analysis improves analyzing association within geochemical elements as compared to normal (classical) statistical method and to simulate how nitrate and carbon from the recent fertilizer practice can change the dissolution rate of trace elements by changing redox system of aquifers. During filed work 16 water 16 soil and 14 rock samples were collected. Chemical analysis of trace elements was done by Inductively Couple Plasma Mass Spectrometer (ICP-MS) for water and Optical Emission Spectrometry (ICP/OES) for soil and rock samples. Statistical analysis was done by different software s like excel, past, R, CoDaPack and PHREEQC for redox reaction simulation. The analysis reveals that the potable quality of water is poor and the possible cause of this disease could be Pb and Zn at the eastern and As at the western part of the study area and also it could be caused by the interaction of elements of additive or synergetic effects. The high value of; TDS, pH, sulfate, association of Cu, Fe, Mo and Mn with Pb and Zn in water samples and high sulfur and Polar organic compounds in the rock samples indicates that the incidence of liver disease at eastern part of the study area is related to graphite schist type of rock which could be related to the organic sulfide minerals. There is lack of pattern in association of trace elements within water, soil and rock samples which could be because of the dispersion process and the high transmissivty of highly fractured aquifers found in the study area. Compositional data analysis does not improve the relationship analysis between geochemical pollutants. This could be because of in compositional data analysis data are transformed in logratio which is a logarithmic function. This logarithmic and ratio function removes the influence of anomalous values which are the crucial values that cause different biotoxic effect to human health. The reason for the recent occurrence of this liver disease could be related to the recent fertilizer practice. The simulation indicates that nitrate and carbon could change the dissolution of trace elements from sulfide minerals in the anoxic zone of aquifer system by change the redox system of a given aquifer. Trace element pollution study is a complex science it needs a lot of investigation.
Chronic liver disease is recently becomes the most sever disease to residents of northern Ethiopia (Shire area) which was started 1980. Pervious health study reviles that this liver disease is not caused by virus and there is a fear that it can be caused by toxic chemical pollutants from the water they used to drink. Therefor the main objective of this study is to identify which geochemical elements cause this disease and its associations, to map their spatial distribution and lithological associations, to see how using compositional data analysis improves analyzing association within geochemical elements as compared to normal (classical) statistical method and to simulate how nitrate and carbon from the recent fertilizer practice can change the dissolution rate of trace elements by changing redox system of aquifers. During filed work 16 water 16 soil and 14 rock samples were collected. Chemical analysis of trace elements was done by Inductively Couple Plasma Mass Spectrometer (ICP-MS) for water and Optical Emission Spectrometry (ICP/OES) for soil and rock samples. Statistical analysis was done by different software s like excel, past, R, CoDaPack and PHREEQC for redox reaction simulation. The analysis reveals that the potable quality of water is poor and the possible cause of this disease could be Pb and Zn at the eastern and As at the western part of the study area and also it could be caused by the interaction of elements of additive or synergetic effects. The high value of; TDS, pH, sulfate, association of Cu, Fe, Mo and Mn with Pb and Zn in water samples and high sulfur and Polar organic compounds in the rock samples indicates that the incidence of liver disease at eastern part of the study area is related to graphite schist type of rock which could be related to the organic sulfide minerals. There is lack of pattern in association of trace elements within water, soil and rock samples which could be because of the dispersion process and the high transmissivty of highly fractured aquifers found in the study area. Compositional data analysis does not improve the relationship analysis between geochemical pollutants. This could be because of in compositional data analysis data are transformed in logratio which is a logarithmic function. This logarithmic and ratio function removes the influence of anomalous values which are the crucial values that cause different biotoxic effect to human health. The reason for the recent occurrence of this liver disease could be related to the recent fertilizer practice. The simulation indicates that nitrate and carbon could change the dissolution of trace elements from sulfide minerals in the anoxic zone of aquifer system by change the redox system of a given aquifer. Trace element pollution study is a complex science it needs a lot of investigation.