Conference paper
Impact of global challenges on acid sulfate soils in Muthurajawela: assessment of net acidity level
Annual Technical Sessions of Geological Society of Sri Lanka (GSSL), 36th (Solis Hotel, Sri Lanka, 28/02/2020)
28/02/2020
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Abstract
Muthurajawela marsh is an integrated, tidally influenced coastal wetland ecosystem underlying a peat deposit and potential acid sulfate soils (PASS). It is also surrounded by highly
urbanized and industrialized areas. At present, Muthurajawela is highly vulnerable to be affected by the impacts of global challenges such as climate change (e.g. prolonged droughts, bush fires, sea level rise) and population growth (e.g. land clearing, residential, industrial, infrastructural activities). Consequences of climatic changes and anthropogenic activities may lead to expose the underneath PASS resulting in their oxidation and subsequent acidity production thereby increasing the mobility of trace elements. Therefore, a systematic study to evaluate the acidity status in the marsh is essential to mitigate the impact of those global challenges. The objective of this study was to assess the acidity hazard by uantifying the “Net Acidity” level using Acid-Base Accounting (ABA) approach. Soil core samples of 1.5 m deep were collected from two sites covering the northern and middle sections of the marsh. Field pH (i.e. pHF >4), field oxidation pH (i.e. pHFOX <4) and chip incubation data (i.e. pHINC < 4.5 after 19 weeks of incubation) indicated the presence of hypersulfidic sediments. The study sites had substantial amounts of net acidity with appreciable amount of potential sulfidic acidity (PSA) as indicated by chromium reducible
sulfur (CRS) which exceeded the recommended threshold value of 0.01%. Furthermore, the study sites showed absence of inherent buffering capacity to neutralize the acidity. This reveals that there is an abundant amount of reduced inorganic sulfur (RIS) is present in the marsh and any disturbance to the soil materials can adversely affect soil, water and biota and have a detrimental impact on fishing, aquaculture, recreation and tourism and also human health and visual amenity. Thus, as a geologist, it is paramount to quantify the acidity to properly manage the development activities taking place in the marsh.
Details
- Title
- Impact of global challenges on acid sulfate soils in Muthurajawela: assessment of net acidity level
- Creators
- K M P A K Ulapane (Corresponding Author) - University of PeradeniyaC L Vithana - Southern Cross UniversityR L R Chandrajith - Southern Cross University
- Conference
- Annual Technical Sessions of Geological Society of Sri Lanka (GSSL), 36th (Solis Hotel, Sri Lanka, 28/02/2020)
- Grants
- NSF Postdoctoral Research Scientist Grant, NSF/PDRS/2018/01, National Science Foundation of Sri Lanka (Sri Lanka, Colombo) - NSF
- Identifiers
- 991012855899702368
- Academic Unit
- Southern Cross GeoScience
- Resource Type
- Conference paper