Effect of Waste Discharges into a Silt-laden Estuary: A Case Study of Cook Inlet, Alaska

Cook Inlet is not well known. Although its thirty-foot tidal range is widely appreciated, its other characteristics, such as turbulence, horizontal velocities of flow, suspended sediment loads, natural biological productivity, the effects of fresh water inflows, temperature, and wind stresses, are seldom acknowledged. The fact that the Inlet has not been used for recreation nor for significant commercial activity explains why the average person is not more aware of these characteristics. Because of the gray cast created by the suspended sediments in the summer and the ice floes in the winter, the Inlet does not have the aura of a beautiful bay or fjord. The shoreline is inhospitable for parks and development, the currents too strong for recreational activities, and, because of the high silt concentration, there is little fishing. Yet, Cook Inlet, for all its negative attributes, can in no way be considered an unlimited dumping ground for the wastes of man. It may be better suited for this purpose than many bays in North America, but it does have a finite capacity for receiving wastes without unduly disturbing natural conditions. This report was written for the interested layman by engineers and scientists who tried to present some highly technical information in such a manner that it could be understood by environmentalists, concerned citizens, students, decision makers, and lawmakers alike. In attempting to address such a diverse audience, we risked failing to be completely understood by any one group. However, all too often research results are written solely for other researchers, a practice which leads to the advancement of knowledge but not necessarily to its immediate use by practicing engineers nor to its inclusion in social, economic, and political decision-making processes. We hope this report will shorten the usual time lag between the acquisition of new information and its use. Several additional reports will be available for a limited distribution. These will be directed to technicians who wish to know the mathematical derivations, assumptions, and other scientific details used in the study. Technical papers by the individual authors, published in national and international scientific and engineering journals, are also anticipated.The work upon which this report is based was supported in part by funds (Proj. B-015-ALAS) provided by the United States Department of the Interior, Office of Water Resources Research, as authorized under the Water Resources Act of 1964, as amended

GAMMA-IRRADIATION REDUCES SURVIVORSHIP, FEEDING BEHAVIOR, and OVIPOSITION of FEMALE AEDES AEGYPTI

Aedes aegypti is a prominent disease vector that is difficult to control through traditional integrated vector management due to its cryptic peridomestic immature-stage habitat and adult resting behavior, increasing resistance to pesticide formulations approved by the US Environmental Protection Agency, escalating deregistration of approved pesticides, and slow development of new effective chemical control measures. One novel method to control Ae. aegypti is the sterile insect technique (SIT) that leverages the mass release of irradiated (sterilized) males to overwhelm mate choice of natural populations of females. However, one potential liability of SIT is sex sorting errors prior to irradiation, resulting in accidental release of females. Our goal in this study was to test the extent to which irradiation affects female life-history parameters to assess the potential impacts of releasing irradiated females accidentally sorted with males. In this study, we determined that a radiation dose ≥30 Gy—a dose sufficient to sterilize males while preserving their mating competitiveness—may substantially impact longevity, bloodfeeding, oviposition, and egg hatch rate of female Ae. aegypti after being irradiated as pupae. These findings could reduce public concern for accidental release of females alongside irradiated males in an operational Ae. aegypti SIT control program

Prediction, Assessment of the Rift Valley Fever Activity in East and Southern Africa 2006–2008 and Possible Vector Control Strategies

Historical outbreaks of Rift Valley fever (RVF) since the early 1950s have been associated with cyclical patterns of the El Niño/Southern Oscillation (ENSO) phenomenon, which results in elevated and widespread rainfall over the RVF endemic areas of Africa. Using satellite measurements of global and regional elevated sea surface temperatures, elevated rainfall, and satellite derived-normalized difference vegetation index data, we predicted with lead times of 2–4 months areas where outbreaks of RVF in humans and animals were expected and occurred in the Horn of Africa, Sudan, and Southern Africa at different time periods from September 2006 to March 2008. Predictions were confirmed by entomological field investigations of virus activity and by reported cases of RVF in human and livestock populations. This represents the first series of prospective predictions of RVF outbreaks and provides a baseline for improved early warning, control, response planning, and mitigation into the future