The development and testing of technologies for the remediation of mercury contaminated soils task 7 52 topical report december 1992 december 1993

The release of elemental mercury into the environment from manometers that are used in the measurement of natural gas flow through pipelines has created a potentially serious problem for the gas industry. Regulations, particularly the Land Disposal Restrictions (LDR), have had a major impact on gas companies dealing with mercury-contaminated soils. After the May 8, 1993, LDR deadline extension, gas companies were required to treat mercury-contaminated soils by designated methods to specified levels prior to disposal in landfills. In addition, gas companies must comply with various state regulations that are often more stringent than the LDR. The gas industry is concerned that the LDRs do not allow enough viable options for dealing with their mercury-related problems. The US Environmental Protection Agency has specified the Best Demonstrated Available Technology (BDAT) as thermal roasting or retorting. However, the Agency recognizes that treatment of certain wastes to the LDR standards may not always be achievable and that the BDAT used to set the standard may be inappropriate. Therefore, a Treatability Variance Process for remedial actions was established (40 Code of Federal Regulations 268.44) for the evaluation of alternative remedial technologies. This report presents evaluations of demonstrations for three different remedial technologies: a pilot-scalemore » portable thermal treatment process, a pilot-scale physical separation process in conjunction with chemical leaching, and a bench-scale chemical leaching process.« le Document type: Repor

Monolingual and Bilingual Reading Processes in Russian: An Exploratory Scanpath Analysis

In the present study, we used a scanpath approach to investigate reading processes and factors that can shape them in monolingual Russian-speaking adults, 8-year-old children, and bilingual Russian-speaking readers. We found that monolingual adults’ eye movement patterns exhibited a fluent scanpath reading process, representing effortless processing of the written material: They read straight from left to right at a fast pace, skipped words, and regressed rarely. Both high-proficiency heritage-language speakers’ and second graders’ eye movement patterns exhibited an intermediate scanpath reading process, characterized by a slower pace, longer fixations, an absence of word skipping, and short regressive saccades. Second-language learners and low-proficiency heritage-language speakers exhibited a beginner reading process that involved the slowest pace, even longer fixations, no word skipping, and frequent rereading of the whole sentence and of particular words. We suggest that unlike intermediate readers who use the respective process to resolve local processing difficulties (e.g., word recognition failure), beginner readers, in addition, experience global-level challenges in semantic and morphosyntactic information integration. Proficiency in Russian for heritage-language speakers and comprehension scores for second-language learners were the only individual difference factors predictive of the scanpath reading process adopted by bilingual speakers. Overall, the scanpath analysis revealed qualitative differences in scanpath reading processes among various groups of readers and thus adds a qualitative dimension to the conventional quantitative evaluation of word-level eye-tracking measures