External costs of water pollution in the drinking water supply sector
研究量化了地下水硝酸盐污染对德国供水企业成本的影响，发现污染显著增加了处理和总成本，为估算农业非点源污染的外部成本提供了证据。
Abstract Nitrate pollution from agricultural production is a major threat to water resources worldwide. This study quantifies the consequences of groundwater nitrate pollution for the drinking water supply sector by estimating the effect of groundwater nitrate pollution on the costs of water utilities. In doing so, we contribute to the estimation of the external costs of agricultural nonpoint pollution associated with drinking water supply. Empirical evidence is based on fixed effects regressions using large panel data sets on water supply companies and groundwater sampling sites in Germany. Local nitrate pollution at the abstraction plant is approximated using spatial interpolation. Our findings reveal that water suppliers incur substantial costs through groundwater nitrate pollution in terms of increased treatment and total costs. The estimated cost elasticities range from 0.048 to 0.052 for treatment costs and up to 0.019 for total costs. For an average firm, these estimates imply annual increases in treatment and total costs of €39,000 and €116,000, respectively, for a 10 milligrams per liter increase in groundwater nitrate concentrations.