Parker, DougCan aggressive pollution reduction in one sector compensate for continued pollution in another? Pollution credit markets are designed to make this trade-off work. But is the time ripe for water quality credit trading systems to serve as an effective means of reducing pollution from farmland? Dr. Doug Parker of the University of Maryland is skeptical.en-USwater pollutionwater qualitypollution credit tradingeconomicsfarmingChesapeake BayTechnical Report