The Silver Valley Lead Study:The Relationship between Childhood Blood Lead Levels and Environmental Exposure

This paper is directed to those persons concerned with the relationship between blood lead levels and environmental exposures to lead. Information presented in this paper represents one of the largest collections of epidemiologica! data relating blood lead levels to environmental exposures. The observed annual average ambient air lead concentration ranged from approximately 0.5 ng Pb/m³ to 23 ng Pb/m³, while lead in soil ranged from 50-24,600 ppm. Blood lead levels of children (ages 1-9 years) are related to a host of environmental variables via regression techniques. Blood lead levels were found to be most influenced by five variables. These variables are: ambient air lead, soil lead, age of the child, dustiness of the home, and occupational status of the parents. It is concluded, based upon the results of this study, that any environmental control strategy should address both the air and the soil. Soil levels in excess of 1000 ppm lead as well as air lead levels greater than 2 jug Pb/m³, 30 day average, were found to be unacceptable.     

Overpressure development during the combustion of a hydrogen–air mixture partial filling a confined space

The paper describes the results from experimental studies and theoretical predictions of the final overpressures developed on combustion of a partial volume inside a larger closed vessel. The partial volume is assumed flammable whilst the remainder of the volume is initially filled with air alone. Particular attention is given to partial volumes of hydrogen–air mixtures. The accuracy of two theoretical models for predicting the final equilibrium pressure throughout the entire closed volume are also assessed.     

Pyrrolizidine alkaloids and pentacyclic triterpene saponins in the defensive secretions of Platyphora leaf beetles

Summary. Field collected exocrine defensive secretions of nine neotropical Platyphora species were analyzed for the presence of plant acquired pyrrolizidine alkaloids (PAs) and pentacyclic triterpene saponins. All species secrete saponins. In addition, five species feeding on Tournefortia (Boraginaceae), Koanophyllon (Asteraceae, tribe Eupatorieae) and Prestonia (Apocynaceae) were shown to sequester PAs of the lycopsamine type, which are characteristic for species of the three plant families. The PA sequestering species commonly store intermedine, lycopsamine and their O^3′-acetyl or propionyl esters as well as O⁷- and O⁹-hydroxyisovaleryl esters of retronecine. The latter as well as the O^3′-acyl esters were not found in the beetles’ host plants, suggesting the ability of the beetles to esterify plant derived retronecine and intermedine or its stereoisomers. Despite the conformity of the beetles’ PA patterns, considerable inconsistencies exist regarding the PA patterns of the respective host plants. One host plant was devoid of PAs, while another contained only simple necines. Since the previous history of the field collected beetles was unknown this discrepancy remains obscure. In contrast to the Palearctic chrysomeline leaf beetles, e.g. some Oreina species which ingest and store PAs as their non-toxic N-oxides, Platyphora leaf beetles absorb and store PAs as the toxic free base (tertiary PA), but apparently avoid to accumulate PAs in the haemolymph. This suggests that Chrysolina and Platyphora leaf beetles developed different lines of adaptations in their parallel evolution of PA mediated chemical defense. Received 30 November 2000; accepted 5 February 2001     

Development of drinking water standards for perchlorate in the United States

Perchlorate, an anion that originates as a contaminant in ground and surface waters, is both naturally occurring and manmade. Because of its toxicity, there has been increased interest in setting drinking water safety standards and in health effects when perchlorate is present at low (parts per billion (ppb)) levels. In January 2009, the EPA issued a heath advisory to assist state and local officials in addressing local contamination of perchlorate in drinking water. The interim health advisory level of 15 micrograms per liter (μg/L), or ppb, is based on the reference dose recommended by the National Research Council (NRC) of the National Academy of Sciences (NAS). This paper describes scope and extent of contaminant issues and a legal process of setting standards for perchlorate concentration in drinking water in the United States of America.     

Issues in developing a capacity for integrated analysis of mitigation and adaptation

As policymakers and stakeholders increasingly consider relative merits and complementarities of climate change mitigation and adaptation strategies, it is important to improve analytical capacities to support this process. Because a single analytical approach is unlikely to fit all needs, this paper explores potentials for an integrated analytical framework that incorporates both top–down and bottom–up approaches.     

Injuries from ingesting wire bristles dislodged from grill-cleaning brushes — Providence,Rhode Island, 2009–2012

Foreign object ingestion is a common reason for visiting an emergency department; however, wire grill-cleaning brush bristles are an uncommon foreign object. This report describes a series of twelve cases identified in a single hospital system from July 2009 through June 2012. Patients included six males and six females; ages ranged from 11 to 75 (mean: 47 years). The patients all reported recent outdoor residential food grilling and use of commercially available wire grill-cleaning brushes. The severity of injury ranged from puncture of the soft tissues of the neck, causing severe pain on swallowing, to perforation of the gastrointestinal tract requiring emergent surgery. Before cooking, persons should examine the grill surface carefully for the presence of wire bristles that might have dislodged from the grill brush and could embed in cooked food. Alternative residential grill-cleaning methods or products might be considered.