Capitalizing property rights insecurity in natural resource assets

Property rights are commonly touted as a solution to common pool resource problems. In practice, however, the security of property rights over natural resources varies substantially; this may affect returns to ownership and asset values. We use an analytical model to examine the effects of insecure property rights to natural resources on the market value of assets. We then use a unique dataset of fisheries from three countries to examine empirically how differences in property rights affect market outcomes. We find significant asset market capitalization of insecurity arising from (1) ownership disputes, (2) illegal extraction from resource stocks, and (3) the possibility of government revocation of rights.     

Applications of isotope differentiation for metabolic studies with di‐(2‐ethylhexyl) phthalate

Abstract

The pervasiveness of the plasticizer di‐(2‐ethylhexyl) phthalate (DEHP) in the environment and especially in the laboratory results in a background that may cause severe interference with analytical studies. Animal‐to‐animal variability in the distribution of DEHP metabolites in excreta normally makes it necessary to use large groups of animals when different treatments are compared. Finally, radioactive tracers are usually considered undesirable for metabolic studies involving human subjects. All of these problems can be overcome through the use of muliple isotopic labels, especially ¹²C/¹³C/¹⁴C. Examples are given involving rats and monkeys, and applicability to humans is discussed. The principles involved are not limited to any particular class of test compounds. In rats, the competing pathways for metabolism of phthalate esters produce a different distribution of metabolites from a small intravenous dose of DEHP than from a large oral dose.     

Review of submarine groundwater discharge (SGD) in coastal zones of the Southeast and Gulf Coast regions of the United States with management implications

Groundwater serves as the primary drinking water source for over half of the coastal populations of the Southeast and Gulf Coast regions, two of the fastest growing regions in the United States. Increased demand for this resource has exceeded sustainable yields in many areas and induced saltwater intrusion of coastal aquifers. A process associated with coastal groundwater, submarine groundwater discharge (SGD), has been documented as a source of subsurface fluids to coastal ocean environments throughout the Southeast and Gulf Coast regions and is potentially a significant contributor to nearshore water and geochemical budgets (i.e., nutrients, carbon, trace metals) in many coastal regions. The importance of groundwater as a drinking water source for coastal populations and the influences of submarine groundwater discharge to the coastal ocean warrant increased research and management of this resource. This paper highlights findings from recent SGD studies on three hydrogeologically different continental margins (Onslow Bay, NC, southern Florida, and the Louisiana margin), provides background on the common methods of assessing SGD, and suggests a regional management plan for coastal groundwater resources. Suggested strategies call for assessments of SGD in areas of potentially significant discharge, development of new monitoring networks, and the incorporation of a regional coastal groundwater resources council.     

Source areas contributing to the episodic acidification of a forested headwater stream

A study was initiated on the Leading Ridge Experimental Watersheds in central Pennsylvania to investigate the extent to which episodic depressions of streamwater pH result from direct channel interception of acidified rainwaters and from rapid subsurface stormflow. During a 4.78-cm rainfall event on June 6, 1986, stream pH declined from 5.93 to 5.46. Analysis of the storm hydrograph indicated that direct channel interception accounted for only 2.8% of the total stormflow volume but contributed 40% of the total increase in the concentration of H⁺. At peak flow, channel interception accounted for 5.7% of the stormflow volume and 72% of H⁺. Large increases in the height of the saturated soil zone and coinciding increases in H⁺ concentrations in soilwater were measured at a number of soilwater observation wells. These fluctuations occurred almost simultaneously with measured fluctuations in both streamflow and streamwater H⁺ concentrations, indicating direct interactions between saturated soilwater and the storm discharge. These results indicate that cathcments in which soil macropores permit rapid subsurface flow could be especially susceptible to stream acidification.