Search

Data from entrainment survival sampling programs conducted in 1979, 1980, and 1988 at the Indian Point generating stations and in 1977, 1978, and 1980 at the Roseton generating station, both located on the tidal Hudson River estuary, were reanalyzed using a series of failure time models to estimate the survival of entrained striped bass Morone saxatilis based on sampling stress, mechanical entrainment stress, and thermal stress. The model with the lowest Akaike information criterion value was the most complex model examined, with year- and station-specific parameters for both sampling and entrainment. However, the lowest Bayesian information criterion was achieved with a model that had year- and station-specific sampling parameters but only station-specific entrainment parameters. The models indicated that survival was positively related to fish length and salinity and negatively related to discharge temperatures above 30°C. Parameter uncertainty was addressed via a bootstrap resampling procedure...

Equivalent loss models encompass a variety of life table-based approaches that can be used to convert age- and life stage-specific estimates of entrainment and impingement loss to a common, easily understood currency. This common currency can be expressed in terms of numbers of individuals, yield to the fishery, or biomass to the ecosystem. These models have at least two key uses in the Section 316(b) assessment process: screening for adverse environmental impact (AEI) and determination of environmental benefits associated with intake alternatives. This paper reviews the various forms of equivalent loss models, their data input requirements, and their assumptions and limitations. In addition, it describes how these models can be used as a second-level screening tool as part of the assessment of the potential for AEI. Given their relative simplicity and ease of use, equivalent loss models should prove to be an important tool in the arsenal of impact assessment methods for Section 316(b).

Since its inception, the 316(b) assessment process has undergone considerable evolution and refinement. In this paper, the authors review and discuss this evolutionary process focusing on several key scientific findings. Among these are that the potential for adverse environmental impact is relatively low for many ecosystem components (e.g., phytoplankton, microzooplankton); that the survival of entrained organisms is often quite high; that the prediction of adverse environmental impact is hampered by the present inability to effectively quantify compensatory processes; and that subsequent monitoring has revealed that the dire population consequences originally predicted for several aquatic populations have not been borne out. While this evolution has resulted in less divergence in the estimates of cooling water-related losses between the regulatory and regulated communities, accurate determination of the population level consequences of such losses remains elusive. This uncertainty makes final resolution of 316(b)-related issues difficult. To address these difficult issues, we propose an assessment approach based on an ecological risk framework coupled with adaptive resource management. This approach begins with a screening process which helps to focus the assessment on the key resources at risk, followed by a “weight-of-evidence” evaluation of all relevant predictive and retrospective information, and concludes with an evaluation of the relative cost and benefits of intake alternatives and the need for additional monitoring. Such an approach has been successfully employed at several large-scale 316(b) assessments completed in recent years and provides a mechanism for dealing with uncertainties in the assessment process, while at the same time ensuring reasonable protection of the environment.

Atlantic tomcod (Microgadus tomcod) collected from the Hudson River estuary during the winter spawning season revealed neoplastic and preneoplastic lesions in livers from 44% of the age 1 individuals and 93% of the age 2 individuals collected. These lesions appear as a continuum ranging from basophilic foci with little cellular alterations to hepatocellular carcinoma frequently involving the entire liver. Lesions were more prevalent in larger individuals within the same age group, suggesting a relationship between growth rate and tumor expression. Atlantic tomcod from a relatively unpolluted estuary in Connecticut did not reveal a comparable prevalence of hepatic lesions. Juvenile tomcod collected from the Hudson during the summer, only 4–5 mo prior to the winter spawning season had no hepatic lesions, suggesting that these lesions form rapidly, coincident with gonadal maturation. Chemical analysis of liver tissue revealed high levels of PCBs (2.5–38.2 mg/kg) and the presence of several pesticides including DDT (and metabolites), chlordane, and dieldrin (

The impact of the Bowline, Roseton, and Indian Point power plants has been studied by estimating entrainment and impingement mortality rates on striped bass at these plants and relating these mortality rates to reduction in equilibrium stock size under various hypothetical stock-recruitment relationships. The conditional rates of mortality due to entrainment by these three plants were 0.0811 in 1974 and 0.1188 in 1975. The conditional rates of mortality due to impingement were calculated to be 0.0426 in 1974 and 0.0229 in 1975. Based on a range of potential Ricker stock-recruitment curves, reduction in equilibrium stock size due to the estimated levels of power-plant-induced mortality were discussed.