자원·환경경제연구 ISSN:1229-9146(Print) Environmental and Resource Economics Review

Marine plastic litter poses multiple threats to coastal ecosystems and economic activities in developing countries, yet quantitative estimates of public willingness to pay (WTP) for its reduction remain scarce in South Asian contexts. This study estimates the WTP for a 50% reduction in marine plastic litter on Sri Lankan coastal beaches by employing the One-and-One-Half-Bound (OOHB) dichotomous choice Contingent Valuation Method (CVM). Contingent valuation (CV) data were collected from 600 households residing in the western and southern provinces of Sri Lanka during November 2021, following a pilot survey conducted in early October 2021. A face-to-face interview method was adopted, with interviewers administering two versions of the questionnaire, lower-bound and upper-bound bid variants to randomly assigned respondents. An annual environmental tax over a five-year period served as the payment vehicle. Given the presence of zero-WTP responses among 15.5% of the sample, a spike model was applied alongside a conventional linear logistic model. The truncated mean annual WTP estimated from the spike model was 2,510 LKR (USD 12.6) per household, statistically significant at the 1% level. Extrapolated to the national household population of 5.1 million and discounted over the five-year period at a 15% annual rate, the aggregated present value of benefits reached approximately 42,911 million LKR (USD 214.6 million). Household income, environmental awareness, beach visitation frequency, and age were statistically significant positive determinants of WTP. Attitudinal analysis highlighted respondents’ particularly strong recognition of the linkage between marine litter reduction and coastal tourism development. These findings provide quantitative evidence to support policy financing and priority-setting for marine plastic litter management programs in Sri Lanka and, more broadly, in small island developing states.