A MUNICIPAL WATER DEMAND MODEL FOR THE CONTERMINOUS UNITED STATES1

With the increasing Federal role in all aspects of water resource planning, the need for a planning model to enable calculations of projected Municipal Water requirements has become evident. This study represents an initial effort at developing an econometric model of Municipal Water requirements which (1) incorporates variables (or proxies) reflecting the various factors affecting water demand (i.e., demographic, social, industrial), and (2) requires only readily available, published data for its use. This model permits determinations of the water requirements of 488 cities grouped into 19 geographic regions or “Pseudo States.” Separate regression functions have been fitted to the cities within each of the 19 regions. Derivation of the exact functions for each region entailed a cross section stepwise regression analysis in which some 18 different variables were examined. KEY WORDS: planning model; econometric model; initial effort; municipal water     

Approaches and initial findings of a state-sponsored research programme on population exposure to toxic substances

Summary Population exposure to toxic chemicals in the environment has become one of the most important, if not the most important, environmental issue of the 1980's. In response to finding high cancer mortality rates, the State of New Jersey organized an extensive program of research to determine public exposure to toxic substances in the environment. Three parts of that research are described. One focusing on toxic substances in the water has detected very low concentrations of many substances. These substances tend to be found in three distinct chemical groups: pesticides, light chlorinated hydrocarbons, and heavy metals. Gross pesticide contamination tends to occur in agricultural and forest areas; gross light chlorinated hydrocarbon pollution is in urban areas. The second component of the research is toxic substances in the air. Like the water studies, low levels of contamination have been found. Limited sampling to date has found groupings of ubiquitous organic chemicals in urban areas, two groups of specialized organic chemicals near industrial sites, and high lead levels near major highways. The third project is developing a computerized information bank about the use and disposal of 155 chemicals and will look for associations between industrial disposal practices and contamination of the environment.     

Kelp as a Bioindicator: Does it Matter Which Part of 5 M Long Plant is Used for Metal Analysis?

Kelp may be useful as a bioindicator because they are primary producers that are eaten by higher trophic level organisms, including people and livestock. Often when kelp or other algae species are used as bioindicators, the whole organism is homogenized. However, some kelp can be over 25 m long from their holdfast to the tip of the blade, making it important to understand how contaminant levels vary throughout the plant. We compared the levels of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in five different parts of the kelp Alaria nana to examine the variability of metal distribution. To be useful as a bioindicator, it is critical to know whether levels are constant throughout the kelp, or which part is the highest accumulator. Kelp were collected on Adak Island in the Aleutian Chain of Alaska from the Adak Harbor and Clam Cove, which opens onto the Bering Sea. In addition to determining if the levels differ in different parts of the kelp, we wanted to determine whether there were locational or size-related differences. Regression models indicated that between 14% and 43% of the variation in the levels of arsenic, cadmium, chromium, manganese, mercury, and selenium was explained by total length, part of the plant, and location (but not for lead). The main contributors to variability were length (for arsenic and selenium), location (mercury), and part of the plant (for arsenic, cadmium, chromium and manganese). The higher levels of selenium occurred at Clam Cove, while mercury was higher at the harbor. Where there was a significant difference among parts, the holdfast had the highest levels, although the differences were not great. These data indicate that consistency should be applied in selecting the part of kelp (and the length) to be used as a bioindicator. While any part of Alaria could be collected for some metals, for arsenic, cadmium, chromium, and manganese a conversion should be made among parts. In the Aleutians the holdfast can be perennial while the blade, whipped to pieces by winter wave action, is regrown each year. Thus the holdfast may be used for longer-term exposure for arsenic, cadmium, chromium and manganese, while the blade can be used for short-term exposure for all metals. Cadmium, lead and selenium were at levels that suggest that predators, including people, may be at risk from consuming Alaria. More attention should be devoted to heavy metal levels in kelp and other algae from Adak, particularly where they may play a role in a subsistence diets.     

Stress,work and professional satisfaction and militancy among Canadian physicians

The introduction of a national health care system in Canada has resulted in regular and increasing conflict between the medical profession, government and other political actors. The present study utilizes a stressor–strain framework to understand physician militancy in Canada. Data were collected from 2087 men and women physicians using questionnaires completed anonymously. Four groups of predictor variables identified in previous research were considered: individual demographic characteristics, practice characteristics, work stressors, and work and professional satisfactions. Empirical support for the model was found. Each panel of predictor variables had significant and unique relationships with measures of physician militancy.     

Australian local government action on climate change adaptation: some critical reflections to assist decision-making

The primary objective of this paper is to discuss the limitations of risk management as a strategy for Australian local government climate change adaptation and explore the advantages of complementary approaches, including a social-ecological resilience framework, adaptive and transition management, and vulnerability assessment. Some federal and local government initiatives addressing the limitations of risk-based approaches are introduced. We argue that conventional risk-based approaches to adaptation, largely focused on hazard identification and quantitative modelling, will be inadequate on their own for dealing with the challenges of climate change. We suggest that responses to climate change adaptation should move beyond conventional risk-based strategies to more realistically account for complex and dynamically evolving social-ecological systems.     

Approaches to integrated water resource development and management

In southern Africa institutional capacity in the water sector is severely limited by diminishing regular budget and external assistance allocations. The result has been an overall decline in operational water resource management. This is ironic given the international community's current concern with 'integrated' or 'comprehensive' water resources management. Often, so-called integrated attempts at river basin planning and development have been conceived within the framework of a river basin authority or regional master plans. Such large-scale attempts have not necessarily been compatible either with the national capacity in water resources management or the existing institutional and legislative frameworks. In many cases the actual integration of a basin's physical resources and social, economic and environmental demands is poorly executed. To examine a way forward in resolving what is clearly an unsustainable state of affairs, a diagnostic study of the Kafue Basin, Zambia, was carried out in order to identify a set of water resource management options for a basin currently under stress. A physical framework for the Kafue Basin was established and principal subcatchments and hydro-geological subsystems identified. Current water resource issues in the basin are discussed and a multiobjective approach is proposed to allow intersectoral competition for the basin's limited water resources to be reconciled.     

Toward an improved ecosystem based management approach: incorporating catchment characteristics into better management and planning of the Great Barrier Reef marine ecosystem

Discharge from the Great Barrier Reef Catchment (GBRC) is considered the second most serious threat to the Great Barrier Reef, Australia. Utilising principal component analysis (PCA) and cluster analysis (CA), this research aimed to assess the variability and co-variation of 28 water basins (WBs) within the GBRC, in order to improve the institutional arrangements and regulation of water quality and increase collaboration horizontally between management organisations, and vertically between government tiers. Water basin variability was measured by nine variables: size (ha), population, agricultural land use (ha), number of major water storages, major rivers and major towns, total nitrogen exported (T/yr), total phosphorus exported (T/yr) and herbicide use (ha). The Fitzroy WB, with PC scores of 7.0081, 2.2897 and ?1.6504, was identified as the most dissimilar and therefore needing to be managed differently. Many WBs within the same regions were very dissimilar to each other, indicating that current management practices, based largely on geographic location, are unlikely to be the most efficient and effective. Instead, managing groups of WBs with similar geo-political properties (determined by the CA) could be more effective and efficient. Coordination and collaboration are key to successful ecosystem based management, therefore managing similar WBs together through inter-NRM (natural resource management) agreements, irrespective of their geographical location, facilitates management bodies building strong, cooperative working relationships.     

Use of a continuous nephelometer to measure personal exposure to particles during the U.S. Environmental Protection Agency Baltimore and Fresno Panel studies

In population exposure studies, personal exposure to PM is typically measured as a 12- to 24-hr integrated mass concentration. To better understand short-term variation in personal PM exposure, continuous (1-min averaging time) nephelometers were worn by 15 participants as part of two U.S. Environmental Protection Agency (EPA) longitudinal PM exposure studies conducted in Baltimore County, MD, and Fresno, CA. Participants also wore inertial impactor samplers (24-hr integrated filter samples) and recorded their daily activities in 15-min intervals. In Baltimore, the nephelometers correlated well (R2 = 0.66) with the PM2.5 impactors. Time-series plots of personal nephelometer data showed each participant's PM exposure to consist of a series of peaks of relatively short duration. Activities corresponding to a significant instrument response included cooking, outdoor activities, transportation, laundry, cleaning, shopping, gardening, moving between microenvironments, and removing/putting on the instrument. On average, 63-66% of the daily PM exposure occurred indoors at home (about 2/3 of which occurred during waking hours), primarily due to the large amount of time spent in that location (an average of 72-77%). Although not a reference method for measuring mass concentration, the nephelometer did help identify PM sources and the relative contribution of those sources to an individual's personal exposure.