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.

Impact of harvesting on constructed wetlands performance - a comparison between Scirpus grossus and Typha angustifolia.

Abstract: Three units of free water surface (FWS) constructed wetlands treating domestic wastewater under tropical conditions were examined in terms of water quality and biomass characteristics. One unit (L2) was planted with Scirpus grossus, one with Typha angustifolia (L3), and the unplanted third (L1) served as control. Influent and effluent quality parameters: biological oxygen demand (BOD5), nitrate (NO3 −-N), ammonium (NH4 +-N), phosphorus (P), total suspended solids (TSS) and fecal coliforms were regularly measured. The average BOD5 reductions were 37.0%, 58.5%, and 53.8% for units L1, L2, and L3, respectively. The planted units removed pollutants more effectively although there was no significant difference between the Scirpus grossus and Typha angustifolia units. Plant growth was monitored in marked quadrats by measuring shoot height and other growth parameters. The above-ground organs in L2 and L3 was harvested whenever the shoots reached maximum shoot height and formed flowers. Scirpus grossus had sustai...

N-mineralization in polyphenol-rich plant residues and their effect on nitrification of applied ammonium sulphate

Abstract: Soil was incubated under greenhouse conditions with plant residues having varying phenolic and nitrogen contents. The total plant material added in staggered applications every 4 months was 15 g kg−1 soil and the total incubation period was 12 months. The N-mineralization in these plant residues as influenced by their phenol and N contents was examined. The nitrification of applied (NH4)2SO4 in these amended soils was also investigated under optimum conditions of pH. A high plant-N content resulted in increased N-mineralization of plant residue, but this effect was lowered by the presence of high concentrations of polyphenols in the decomposing residue, most probably due to increased participation of N with polyphenols in the formation of humus fractions. Soils amended with phenol-rich residues did not show any inhibition of nitrification of applied (NH4)2SO4. Possible reasons are discussed. In organic matter decomposition, the quality of the leaf polyphenols appears to determine the degree of inhibition to soil nitrification.

Pattern of pesticide storage before pesticide self-poisoning in rural Sri Lanka.

Abstract: Background: Deliberate self-poisoning with agricultural pesticides is the commonest means of suicide in rural Asia. It is mostly impulsive and facilitated by easy access to pesticides. The aim of this large observational study was to investigate the immediate source of pesticides used for selfharm to help inform suicide prevention strategies such as reducing domestic access to pesticides. Methods: The study was conducted in a district hospital serving an agricultural region of Sri Lanka. Patients who had self-poisoned with pesticides and were admitted to the adult medical wards were interviewed by study doctors following initial resuscitation to identify the source of pesticides they have ingested. Results: Of the 669 patients included in the analysis, 425 (63.5%) were male; the median age was 26 (IQR 20-36). In 511 (76%) cases, the pesticides had been stored either inside or immediately outside the house; among this group only eight patients obtained pesticides that were kept in a locked container. Ten percent (n = 67) of the patients used pesticides stored in the field while 14% (n = 91) purchased pesticides from shops within a few hours of the episode. The most common reasons for choosing the particular pesticide for self-harm were its easy accessibility (n = 311, 46%) or its popularity as a suicide agent in their village (n = 290, 43%). Conclusion: Three quarters of people who ingested pesticides in acts of self-harm used products that were available within the home or in close proximity; relatively few patients purchased the pesticide for the act. The study highlights the importance of reducing the accessibility of toxic pesticides in the domestic environment.