RISK ASSESSMENT OF PESTICIDE CONTAMINATION POTENTIALS IN EMBILlPITlYA AREA

Embilipitiya is a highly agricultural area, which has consumed a remarkable amount ofagrochemicals in last two decades. Hence pesticide movement level studies are necessaryto prevent the contamination of soil and water by these pesticides.Pesticides Impact Ranking Index (pIRI) is a simple computation model, which can beused for ranking pesticides according to their leaching ability and toxicity levels. Itrequires soil and climatic parameters. chemical and application information of pesticides,etc. The risk levels are indicated as very low, low, medium, high, very high andextremely high according to their leaching and toxicity conditionsThe modeling using PIRI was carried out to rank the most widely used three pesticides,3,4 DPA, Carbfuran and MCPA, for 14 different soil series present in Embilipitiya area.The risk level frequencies were calculated for each pesticide. For 8 soil series high riskleaching potential was obtained. Carbofuran and Walawa series has extremely highleaching potential than others. In comparison, MCPA has a medium risk potential for 10soil series. 3,4 DPA has a very low leaching potential for all soils.Toxicity levels obtained for most of the soil series are low except for Thimbolketiya andWalawa soil series. They have high and medium toxicity levels respectively forcarbofuran. Hence the risk level of carbofuran is very high, MCPA is medium and 3,4DPA is low in different soils present in Embilipitiya area and therefore the usage ofCarbofuran needs to be controlled. In pesticide usage and selection, extra care andawareness procedures are necessary to prevent ground water contamination in future

Assessment of the impact of diuron to water bodies in the Walawa area

Use of pesticides has significantly increased global food production and it is indispensable in modernagriculture to control weeds, insects, other pests and diseases. As the population increases the use ofpesticides also increases. The impact of these pesticides to the environment is not well understood forSri Lankan conditions Hence the sorption pattern of a non ionic pesticide, diuron {3-(3,4-dichlorophenyl)-l, l-dimethylurea; C9H IICI,KO} which is used as a herbicide to control weeds andmosses mainly in sugarcane, was studIed for-14 soil series in the right bank of the Walawa basin in SriLanka.Information was collected from fanners in Walawa areas on crops, historical cropping patterns, typeof pesticides used, pesticides handling knowledge etc. The survey revealed that pesticides use ismalpracticed by fanners. The distribution of crop types in the area during last three years shows thatPaddy, which is scattered through out the area, is the most prominent crop. The average area underpaddy cultivation is approximately 9800 ha. Banana was the second highest grown crop that is inabout 4200 ha. Sugarcane, which covers about 2500 ha, is the prominent monoculture in the Walawabasin.Adsorption of di uron to the collected surface (0-1 Ocrn) soi Is of the 14 soi I series in the Wa lawa basinwere measured using High Performance Liquid Chromatographic method. The Moraketiya seriesshowed the highest sorption among them. It also gives the highest Kd value of the selected soils andSiyambala series exhibited the lowest adsorption and Kd. The organic carbon content was highest inKachigalara series and it was lowest in the Walawa series. The measured Kd values were used topredict the risk of this pesticide to ground and surface water in the Walawa area using a simplemanagement model called Pesticide Impact Rating Index, PIRI which resulted a moderate risk forthe contamination of water bodies in the area.

Scientific Opinion addressing the state of the science on risk assessment of plant protection products for in-soil organisms

Following a request from EFSA, the Panel on Plant Protection Products and their Residues developed an opinion on the science behind the risk assessment of plant protection products for in-soil organisms. The current risk assessment scheme is reviewed, taking into account new regulatory frameworks and scientific developments. Proposals are made for specific protection goals for in-soil organisms being key drivers for relevant ecosystem services in agricultural landscapes such as nutrient cycling, soil structure, pest control and biodiversity. Considering the time-scales and biological processes related to the dispersal of the majority of in-soil organisms compared to terrestrial non-target arthropods living above soil, the Panel proposes that in-soil environmental risk assessments are made at in- and off-field scale considering field boundary levels. A new testing strategy which takes into account the relevant exposure routes for in-soil organisms and the potential direct and indirect effects is proposed. In order to address species recovery and long-term impacts of PPPs, the use of population models is also proposed

Flood Disaster, Wetland Loss and Ecosystem Services: Community Perceptions-A Case Study from Muthurajawela Wetland Complex, Sri Lanka

Urban expansion and population growth are increasingly apparent in many parts of Sri Lanka with significant impacts on the environment. Urban areas often have little room for nature. Yet, remaining ecosystems or habitats extend valuable ecosystem services to the communities. Ecosystems, therefore present avenues to serve humanity and enhance community resilience tomany stressors including natural disasters. This study focusses on Muthurajawela Marsh which is the largest coastal wetland in Sri Lanka. Even though this large wetland (3,068 ha in extent) provides provisional, regulatory, cultural and supportive services, how the residents value those services are largely not known. The present study examined how wetland loss has attributed to increased flood impacts as well as impairment of ecosystem services provided by the wetland to increase the resilience of the community. Loss of extent of the wetland was studied using Arc GIS software by providing thematic maps for the last eleven years (2008-2019). Here, we demarcated the study area considering the boundary of an administrative unit named Wattala. By 2019,Muthurajawela marsh has lost 35% of its wetland habitats in 2008. The area with the lowest loss of wetland habitats (35.5 ha loss) was Mahapamunugama with the least number of flood events (2) as well as a lower number of people affected (725). Conversely, the highest number of people affected (46,951) and the highest number of flood events (19) were reported in Kerawalapitiya where the wetland experienced the most severe loss of wetland habitats (86.7 ha loss). A rapid assessment of the social values of Ecosystem Services (ES) was carried out in both areas through a questionnaire survey. This assessment aimed at investigating how much ecosystem services help to strengthen the wellbeing of the local community in reality. Nineteen ecosystem services were apparent including the value of being a cultural heritage, aesthetic value, noise and visual buffering, providing habitatsfor biota and regulating the local climate in Mahapamunugama where the wetland is comparatively healthy and the communities were of high resilience. In contrast, where the wetland is highly disturbed (Kerawalapitiya), the number of ecosystem services provided was only eleven with lower mean social values. The results of the present study highlight the importance of the health ofwetlands in flood attenuation and increased community resilience as a result of ecosystem services they provide to the residents. Keywords: Ecosystem based disaster risk reduction (Eco-DRR), Ecosystem Services, Flood mitigating role of wetland

Estimation of nitrogen and phosporus fluxes to Embilikala and Malala Lagoons in Southern Sri Lanka

In Ratnasiri, J. (Ed.). Assessment of material fluxes to the coastal zone in South Asia and their impacts: Proceedings of the APN/START/LOICZ South Asia Regional Workshop, Negombo, Sri Lanka, 8-11 December 2002. Colombo, Sri Lanka: Sri Lanka National Committee of IGB