Comparison of gravimetric and gas chromatographic methods for assessing performance of textile materials against liquid pesticide penetration.

Penetration of liquid pesticides through textile materials is a criterion for determining the performance of protective clothing used by pesticide handlers. The pipette method is frequently used to apply liquid pesticides onto textile materials to measure penetration. Typically, analytical techniques such as Gas Chromatography (GC) are used to measure percentage penetration. These techniques are labor intensive and costly. A simpler gravimetric method was developed, and tests were conducted to compare the gravimetric and GC methods of analysis. Three types of pesticide formulations and 4 fabrics were used for the study. Diluted pesticide formulations were pipetted onto the test specimens and percentage penetration was measured using the 2 methods. For homogeneous formulation, the results of the two methods were fairly comparable. However, due to the filtering action of the textile materials, there were differences in the percentage penetration between the 2 methods for formulations that were not homogeneous.     

Measuring individuals’ valuation distributions using a stochastic payment card approach: application to solid waste management in Nigeria

The objectives of this study are twofold. First it aims to establish empirical grounds for pricing the services of a new environmental management initiative in Enugu state, Nigeria. A joint initiative of the UK Department for International Development (DfID), Enugu State Environmental Protection Agency (ENSEPA) and the State and Local Government Programme (SLGP). The second is to test the empirical performance of a new approach to the contingent valuation method (CVM) i.e., the Stochastic Payment Card (SPC) design proposed by Wang (Contingent valuation of environmental resources: A stochastic perspective, 1997a, Journal of Environmental Economics & Management, 32:219–232, 1997b). The SPC design unlike many of the conventional CVM elicitation formats, takes into account the stochastic nature of individuals’ valuation decisions. The data for the analysis were obtained from a random sample survey of a district in Enugu metropolis. The results show that, on average, households in this city are willing to pay (WTP) 215 Naira ($1.6) monthly as against 200 Naira ($1.5) currently charged for the service by ENSEPA. Analysis of individual’s valuation distribution function indicates that this amount is positively and significantly related to the gender of the respondent, household income and the respondent’s perception of environmental quality.