University of Peradeniya

About: University of Peradeniya is a education organization based out in Kandy, Sri Lanka. It is known for research contribution in the topics: Population & Poison control. The organization has 5970 authors who have published 7388 publications receiving 197002 citations.

Medical geology in tropical countries with special reference to Sri Lanka.

Abstract: Sri Lanka provides an ideal opportunity for the study of the effect of geology on human health. The vast majority of the people of Sri Lanka still live in rural areas within areas termed geochemical provinces. Very broadly, one could say that a geochemical province has characteristic chemical composition in soil, water stream sediments and rocks, enabling their delineation from others. The chemical composition is presumed to be have an impact on the health of the inhabitants of the particular geochemical province, particularly because of the fact that their food and water are obtained mostly from the terrain itself. This leads to the concept of “diseases of geochemical origin”. Among these are dental fluorosis, iodine deficiency disorders (IDDs) and selenium-based diseases. The Dry Zone of Sri Lanka has several areas rich in groundwater fluoride, the ingestion of which leads to dental fluorosis. Iodine deficiency diseases are more common in the Wet Zone, though their aetiologies are more complicated. Interestingly, it has also been observed that significant proportions of the female population of Sri Lanka are selenium-deficient, which could well be related to the geological environment. Chronic renal failure (CRF) has been observed in some areas of the Dry Zone of Sri Lanka, where there is a relationship of CRF with the mineral content of drinking water. This subject matter falls under the auspices of Medical Geology, a scientific discipline still in its infancy, and much more concerted studies are needed to attract the attention of medical research.

Spatial and temporal variation of rainfall trends of Sri Lanka

Abstract: This study was based on daily rainfall data of 48 stations distributed over the entire island covering a 30-year period from 1981 to 2010. Data analysis was done to identify the spatial pattern of rainfall trends. The methods employed in data analysis are linear regression and interpolation by Universal Kriging and Radial Basis function. The slope of linear regression curves of 48 stations was used in interpolation. The regression coefficients show spatially and seasonally variable positive and negative trends of annual and seasonal rainfall. About half of the mean annual pentad series show negative trends, while the rest shows positive trends. By contrast, the rainfall trends of the Southwest Monsoon (SWM) season are predominantly negative throughout the country. The first phase of the Northeast Monsoon (NEM1) displays downward trends everywhere, with the exception of the Southeastern coastal area. The strongest negative trends were found in the Northeast and in the Central Highlands. The second phase (NEM2) is mostly positive, except in the Northeast. The Inter-Monsoon (IM) periods have predominantly upward trends almost everywhere, but still the trends in some parts of the Highlands and Northeast are negative. The long-term data at Watawala Nuwara Eliya and Sandringham show a consistent decline in the rainfall over the last 100 years, particularly during the SWM. There seems to be a faster decline in the rainfall in the last 3 decades. These trends are consistent with the observations in India. It is generally accepted that there has been changes in the circulation pattern. Weakening of the SWM circulation parameters caused by global warming appears to be the main causes of recent changes. Effect of the Asian Brown Cloud may also play a role in these changes.

Geochemical characteristics of groundwater in different climatic zones of Sri Lanka

Abstract: Sri Lanka is characterized by well-demarcated climatic zones based on the rainfall pattern known as wet zone, dry zone and intermediate zone. Groundwaters in these three zones are extracted mainly for drinking and irrigation from metamorphic hard rock aquifers and saprolite developed on metamorphic rocks. Detailed hydrogeochemical investigations were carried out covering these three climatic zones in order to characterize the groundwater. A total of 166 groundwater samples were collected representing three climatic zones and analyzed for their major and trace element geochemistry. The results indicate a clear difference in the geochemistry of groundwater between climatic regions, whereas semiarid dry zone groundwater is characterized with higher dissolved mineral contents compared that of the wet and intermediate zones. Low pH levels were noticed in the wet zone areas, while high calcium and fluoride contents were observed in the dry and intermediate terrains. Remarkably, high phosphate contents were observed in all three regions, indicating the influence of fertilizer application on groundwater. Particularly in the dry zone regions, the groundwater chemistry is mainly controlled by rock–water interactions and ion exchange processes in which high mineral contents are added from underlying metamorphic rocks to the drinking and irrigation water. The results indicate that groundwater in the dry zone area is under stress compared to other climate areas, but in the wet zone groundwater shows remarkable influence of anthropogenic activities.