Overview of state approaches to vapor intrusion: 2018

Regulatory requirements for the evaluation of vapor intrusion vary significantly among states. For site owners and responsible parties that have sites in different regulatory jurisdictions, one challenge is to know and understand how the requirements or expectations for vapor intrusion differ from one jurisdiction to the next. Differences in requirements can make it difficult to manage sites in a consistent manner across jurisdictions. Eklund, Folkes, et al. (2007, February, Environmental Manager, 10–14) published an overview of state guidance for vapor intrusion in 2007 that provided a detailed summary of pathway screening values and other key vapor intrusion policies. An update by Eklund, Beckley, et al. (2012, Remediation, 22, 7–20) was published in 2012, which expanded the evaluation to additional states. Since that time, numerous states have substantially revised their guidance and some states that did not have vapor intrusion‐specific guidance have issued new guidance. This article provides an update to the 2012 study. For each state, the review includes tabulations of the types of screening values included (e.g., groundwater, soil, soil gas, indoor air) and the screening values for selected chemicals that commonly drive vapor intrusion investigations (i.e., trichloroethylene [TCE], tetrachloroethylene, and benzene) along with other compounds of potential interest. In addition, for each state, the article summarizes a number of key policy decisions that are important for the investigation of vapor intrusion including: distance screening criteria, default subsurface to indoor air attenuation factors, mitigation criteria, and policies for evaluation of short‐term TCE exposure.     

A test of fluctuating asymmetry in Bluegills (Lepomis macrochirus Rafinesque) as a measure of pH-related stress

Fluctuating asymmetry of bilateral anatomical characters, previously proposed as an indicator of stress induced by agents affecting the calcium metabolism of fishes, was measured in bluegills (Lepomis macrochirus) from eleven Wisconsin lakes. The fluctuating asymmetries of three meristic characters-numbers of pored lateral line scales, pectoral fin rays and gill rakers on the outer arch-were either unrelated or only marginally related to either lake pH or waterborne calcium concentration. The asymmetry variance of gill raker counts was negatively correlated with both lake pH and waterborne calcium concentration; however, the overall asymmetry mean of gill raker counts in bluegills from five low pH lakes only slightly exceeded that in bluegills from six lakes with circumneutral pH. Fluctuating asymmetry in adult fishes was judged to be insensitive as a potential measure of pH-related stress.     

Assessing impacts of power plants on fish populations: A general strategy

Environmental impact statements are often characterized by extraneous data collection, irrelevant statistical procedures, misapplied models and concomitant ambiguity in conclusions. Impact assessment is difficult but when explicit objectives are not stated and specific tasks are not linked to these objectives, assessment becomes impossible. We emphasize a flexible approach that can be adapted to site-specific requirements. The strategy consists of six steps: (1) Conceptualization of the ecosystem, (2) design and execution of pilot studies, (3) refinement of conceptualization, (4) design of a study plan, (5) execution of the study plan and (6) evaluation of impact. Development of a conceptual model leads to specification of testable hypotheses directly linked to the objectives of impact assessment. Deterministic and stochastic simulation modeling can be coupled effectively with traditional statistical methods to reduce the probability of decisions which impose unnecessary risks on the environment or costs to industry.