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.

Pollution of River Mahaweli and farmlands under irrigation by cadmium from agricultural inputs leading to a chronic renal failure epidemic among farmers in NCP, Sri Lanka

Abstract: Chronic renal failure (CRF) associated with elevated dietary cadmium (Cd) among farming communities in the irrigated agricultural area under the River Mahaweli diversion scheme has reached a significantly higher level of 9,000 patients. Cadmium, derived from contaminated phosphate fertilizer, in irrigation water finds its way into reservoirs, and finally to food, causing chronic renal failure among consumers. Water samples of River Mahaweli and its tributaries in the upper catchment were analyzed to assess the total cadmium contamination of river water and the possible source of cadmium. Except a single tributary (Ulapane Stream, 3.9 μg Cd/l), all other tested tributaries carried more than 5 μg Cd/l, the maximum concentration level accepted to be safe in drinking water. Seven medium-sized streams carrying surface runoff from tea estates had 5.1–10 μg Cd/l. Twenty larger tributaries (Oya), where the catchment is under vegetable and home garden cultivation, carried 10.1–15 μg Cd/l. Nine other major tributaries had extremely high levels of Cd, reaching 20 μg Cd/l. Using geographic information system (GIS), the area in the catchment of each tributary was studied. The specific cropping system in each watershed was determined. The total cadmium loading from each crop area was estimated using the rates and types of phosphate fertilizer used by the respective farmers and the amount of cadmium contained in each type of fertilizer used. Eppawala rock phosphate (ERP), which is mostly used in tea estates, caused least pollution. The amount of cadmium in tributaries had a significant positive correlation with the cadmium loading of the cropping system. Dimbula Tea Estate Stream had the lowest Cd loading (495.9 g/ha/year), compared with vegetable-growing areas in Uma Oya catchment with 50,852.5 g Cd/ha/year. Kendall’s τ rank correlation value of total Cd loading from the catchment by phosphate fertilizer used in all crops in the catchment to the Cd content in the tributaries was +0.48. This indicated a major contribution by the cropping system in the upper catchment area of River Mahaweli to the eventual Cd pollution of river water. Low soil pH (4.5–5.2), higher organic matter content (2–3%), and 18–20 cmol/kg cation exchange capacity (CEC) in upcountry soil have a cumulative effect in the easy release of Cd from soil with the heavy surface runoff in the upcountry wet zone. In view of the existing water conveyance system from upcountry to reservoirs in North Central Province (NCP) through diversion of River Mahaweli, in addition to their own nonpoint pollution by triple superphosphate fertilizer (TSP), this demands a change in overall upper catchment management to minimize Cd pollution through agriculture inputs to prevent CRF due to elevated dietary cadmium among NCP farmers.

Dissolution of aluminium from sub-standard utensils under high fluoride stress: a possible risk factor for chronic renal failure in the North-Central Province

Abstract: Chronic renal failure of an endemic nature and unknown aetiology affects people in the North-Central Province of Sri Lanka. People affected, consume fluoride rich water and almost exclusively use sub-standard aluminium pots for cooking and storing water. Leaching of aluminium under different fluoride stress and under the acidic conditions used in cooking was studied. Aluminium was determined using a graphite furnace Atomic Absorption Spectrophotometer. In the absence of acidic spices, the amount of aluminium leached was quite small with a maximum of 1.20 ppm reached after 10 min of boiling in 6 ppm fluoride solution. However, under acidic conditions obtained during the use of tamarind at a pH of 3.02, the aluminium leached was around 18 ppm even in the absence of fluoride with a regular enhancement of leaching at higher fluoride levels. The aluminium leached at 6 ppm fluoride reached 29 ppm after 10 min of boiling. Similarly, at a pH of 2.12 in the presence of 0.1 M tartaric acid, the maximum aluminium concentration leached reached ca. 50 ppm. Aluminofluoride complexes may play a significant role in causing chronic renal failure.

Biocontrol activity and induced resistance as a possible mode of action for Aureobasidium pullulans against grey mould of strawberry fruit

Abstract: Efficacy and mode of action were investigated fox Aureobasidium pullulans, a potential biocontrol agent for grey mould on strawberry fruit. Wound inoculation of detached green strawberry cv. Elsanta fruit with Aureobasidium pullulans prevented grey mould rot on fruit inoculated 2 days later with Botrytis cinerea. Treatment of white, pink and red-ripe fruit did not, however, control grey mould. Treatment of wound sites on green fruit with both live and heat-killed A. pullulans cells reduced B. cinerea infection compared to controls. Dip-inoculation of unwounded green strawberry fruit with A pullulans when still attached to the plant delayed the development of grey mould after harvest at the fully ripe stage. The (i) efficacy of A. pullulans on green but not on ripening fruit, (ii) partial inhibitory effect of both live and heat-killed A. pullulans cells and (iii) absence of evidence for antibiotic production from in vitro competition tests suggest that control of grey mould on green fruit is at least partly due to a mechanism other than antagonism and / or competition. Bioassays showed that skin tissue from green fruit treated with A. pullulans had greater antifungal activity than control tissue. Thus, enhanced natural disease resistance in green strawberry fruit contributed to grey mould rot suppression by A. pullulans.