Arsenic, Cadmium, Lead, and Mercury in surface soils, Pueblo, Colorado: implications for population health risk

Decades of intensive industrial and agricultural practices as well as rapid urbanization have left communities like Pueblo, Colorado facing potential health threats from pollution of its soils, air, water and food supply. To address such concerns about environmental contamination, we conducted an urban geochemical study of the city of Pueblo to offer insights into the potential chemical hazards in soil and inform priorities for future health studies and population interventions aimed at reducing exposures to inorganic substances. The current study characterizes the environmental landscape of Pueblo in terms of heavy metals, and relates this to population distributions. Soil was sampled within the city along transects and analyzed for arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb). We also profiled Pueblo’s communities in terms of their socioeconomic status and demographics. ArcGIS 9.0 was used to perform exploratory spatial data analysis and generate community profiles and prediction maps. The topsoil in Pueblo contains more As, Cd, Hg and Pb than national soil averages, although average Hg content in Pueblo was within reported baseline ranges. The highest levels of As concentrations ranged between 56.6 and 66.5 ppm. Lead concentrations exceeded 300 ppm in several of Pueblo’s residential communities. Elevated levels of lead are concentrated in low-income Hispanic and African-American communities. Areas of excessively high Cd concentration exist around Pueblo, including low income and minority communities, raising additional health and environmental justice concerns. Although the distribution patterns vary by element and may reflect both industrial and non-industrial sources, the study confirms that there is environmental contamination around Pueblo and underscores the need for a comprehensive public health approach to address environmental threats in urban communities.     

Exploring the assumed invariance of implied emission factors for forest biomass in greenhouse gas inventories

Reviews of each nation's annual greenhouse gas inventory submissions including forestland are part of the ongoing reporting process of the United Nations Framework Convention on Climate Change. Goals of these reviews include improving quality and consistency within and among reports. One method of facilitating comparisons is the use of a standard index such as an implied emission factor (IEF), which for forest biomass indicates net rate of carbon emission or sequestration per area. Guidance on the use of IEFs in reviews is limited, but there is an expectation that values should be relatively constant both over time and across spatial scales. To address this hypothesis, we examine IEFs over time, derived from U.S. forests at plot-, state-, and national-levels. Results show that at increasingly aggregated levels, relative heterogeneity decreases but can still be substantial. A net increase in U.S. whole-forest IEFs over time is consistent with results from temperate forests of nations in the European Community. IEFs are better viewed as a distribution of values rather than one constant value principally because of sensitivities to productivity, disturbance, and land use change, which can all vary considerably across a nation's forest land.     

Intertemporal and intergenerational pareto efficiency revisited

This paper demonstrates that Bishop's formulation deviates in a fundamental way from our model and, in so doing, Bishop has assumed the problem away. Bishop utilizes a utility function that is too general to discriminate the time pattern of consumption from that of production. Hence, the intertemporal nature of the goods that we analyzed cannot be captured by Bishop's representation. Furthermore, we show that current benefit cost methods that discount the benefit stream of a public asset are Pareto intertemporally inefficient.     

ESTIMATION OF COASTAL WATER CONTAMINATION LONG-TERM TREND USING SEASONAL LINEAR MODELS1

ABSTRACT: Bivalves are used as bioindicators to assess trends of the chemical quality of coastal and marine environments due to their ability to concentrate chemicals. These shellfish are subject to seasonal physiological changes influencing the chemical concentration. Using quarterly data, we model concentration via linear regression with a biologically based seasonal component. This was applied to cadmium concentration measured in the blue mussel (Mytilus edulis) at three sites in the Seine estuary (Normandy, France). In this case we have a high concentration season from January to June and a “low concentration” season from July to December. This season definition was checked a posteriori, using box-and-whisker plots and a statistical test of comparison of pair-wise adjusted least-squares mean differences, and it appears to be very reasonable. We averaged data by season and across sites. Our final model (R²= 0.846 with N= 27 observations) includes highly significant terms: a season effect, which accounts for 45% of the total variability, a linear and a quadratic time term. Outliers were identified by high Studentized residual values and attributed to bias in the temporal sampling schemes. The methodology developed will further be used with other shellfish and/or other trace elements and organic chemicals.     

222RN IN THE WATER DISTRIBUTION SYSTEM OF TUCSON,ARIZONA1

ABSTRACT: A study of ²²²Rn concentrations in the water distribution system of Tucson, Arizona, revealed levels of 60 to 1260 pCi/L in domestic waters. These measurements are comparable to levels of between 80 and 1400 pCi/l for ²²²Rn found in ground water samples in the North-Central Tucson basin (Kahn et al., 1994). Estimated loss of ²²²Rn due to radioactive decay during travel from the well head to the home ranges from 8 to 50 percent.     

Negotiating for assistance and cost control: Effectively interacting with environmental regulatory agencies

Regulatory agencies are involved in analysis of plans for, and results of, virtually every environmental site investigation and remediation project. Controlling the cost of such projects is largely dependent on arriving at a reasonable scope of work. Regulatory approval is heavily influenced by the approach, cooperation, level of expertise, communication skills, preparation, and diplomacy of those who interact directly with agency personnel. Agencies also can be sources of assistance in obtaining the cooperation of other responsible parties. This article discusses a practical approach to maximize assistance, cooperation, and collaboration from regulatory agencies.     

Human behavior incorporation into ecological computer simulations

The responses of ecological computer simulations are significantly changed by the inclusion of human behavior patterns. Two computer simulations illustrate this principle for internal and external decision making. The Northwest Educational Trawler Simulation (NETS) models the interaction between fish populations, fishing effort, markets, and a fishing community. This simulation includes an internal decision making submodel for changing fishing effort based on observed behaviors of fishermen. NOGERO, a simulation of a mythical coastal fishing culture, uses external decision making where simulation users act as stewards. The patterns of model response vary depending on the attitudes and goals of decision makers. This shows how human behavior interacts with ecosystem dynamics to produce a variety of results.