Responsible Care© Programs for Hazardous Chemicals

This article describes the development, use, and learnings of a comprehensive Responsible Care^® program as applied to the management of hazardous substances at various stages during the life cycle of the product. The article offers specific examples for stewardship programs in the biocide industry, and discusses the role of the medical community. © 2001 John Wiley & Sons, Inc.     

Computer estimation of the Atmospheric gas-phase reaction rate of organic compounds with hydroxyl radicals and ozone

The Atmospheric Oxidation Program (AOP) is a computer program that estimates the rate constant for the atmospheric, gas-phase reaction between photochemically produced hydroxyl radicals (OH) and organic chemicals. It also estimates the rate constant for the gas-phase reaction between ozone and olefinic/acetylenic compounds. AOP, which uses estimation methods developed by Atkinson and co-workers, estimates more accurate rate constants than the PCFAP (Fate of Atmospheric Pollutants) program that was part of the U.S. EPA's Graphical Exposure Modeling System (GEMS). Due to its superior predictive ability, the EPA is currently using AOP to evaluate the atmospheric fate of compounds defined under Sections 4, 5 and 6 of the Toxic Substances Control Act (TSCA).     

The evolution of polyandry by queens in social Hymenoptera: the significance of the timing of removal of diploid males

Summary Multiple mating by queens in social Hymenoptera with single locus sex determination may be an adaptation to reduce the effect of genetic load caused by the production of diploid males, if there is a concave relationship between queen fitness and the proportion of diploid male offspring in the colony. In this situation queens should be selected to reduce the variance in the production of diploid male offspring by multiple mating. It has been suggested that this concave relationship occurs in species such as the honey bee, Apis mellifera, in which reproduction occurs near the peak of colony population. This paper suggests that the timing of diploid male removal may influence mating frequency, with early removal of diploid males favoring multiple mating and late removal of diploid males favoring single mating. This idea is explored in two ways. A mathematical model shows that cell use in the brood area of species that rear young in cells will be more efficient with multiple mating. This would favor multiple mating in species, such as the honey bee, in which brood rearing is constrained by the usable area of the brood chamber. Secondly, comparison of polyandrous honey bees (early removal of diploid males as young larvae) with monandrous fire ants, Solenopsis invicta, and Melipona bees (non-removal of immature diploid males) suggests that in the species without diploid male removal, variance reduction may reduce queen fitness. Suggestions are made for testing this hypothesis.     

Toxicity of organophosphorus esters to laying hens after oral and dermal administration

Fourteen organophosphorus esters (OPs) were evaluated for their potential to cause organophosphorus ester induced delayed neurotoxicity (OPIDN) when administered dermally and/or orally to white leghorn hens. The compounds were chlorpyrifos, DEF, dichlorvos, dimethoate, EPN, ethoprop, fenthion, isofenphos, leptophos, merphos, ronnel, tetrachlorvinphos, terbufos, and trichlorfon. DEF induced ataxia if given dermally or orally at over 21 mg/kg/day for up to 90 days. Hens treated with EPN developed irreversible ataxia after repeated exposure to as little as 1.3 mg/kg dermally or 5 mg/kg/day orally, while leptophos was neurotoxic at doses of 6-7 mg/kg/day dermally and 10 mg/kg/day orally. Multiple treatments of chlorpyrifos, terbufos, dichlorvos and dimethoate caused death after varying periods of increasing debility; although birds had difficulty walking, they did not display typical symptoms of OPIDN. Fenthion and isofenphos induced drastic weight loss in hens at low levels of treatment; Isofenphos treated hens developed OPIDN, but died soon afterwards. Dichlorvos given at greater than 6 mg/kg/day po or dermally at 1 mg/kg/day produced cholinergic symptoms and most hens died before the end of the treatment period. At lower levels, dichlorvos did not induce overt ataxia. None of the other compounds in this series induced consistent ataxia whether administered orally or dermally. Ethoprop, with an acute oral LD50 near 5 mg/kg and an acute dermal LD50 of approximately 3 mg/kg, was the most toxic compound tested and could not be fully evaluated for its potential to cause OPIDN.     

HYDROLOGICAL EFFECTS OF AN UNCONTROLLED FLOWING WELL,RED RIVER VALLEY,NORTH DAKOTA,USA1

ABSTRACT: In areas of the Red River Valley that overlie permeable Paleozoic sediments, wetlands and salinization have developed where unregulated flowing wells discharge brackish water. Field data were collected to assess the fate of water and salt from a well 25 km northwest of Grand Forks. Drilled during the drought of the 1930s, discharge was used to replenish water in a small oxbow pond used by livestock. The unregulated well discharges about 56 m³/day, measured since 1993. This discharge exceeds ground water flow from the site, thereby forming a ground water mound with a maximum height of 1 m and a diameter of about 300 m. Most soil and underlying sediments near the well have a hydraulic conductivity of 0.3 m³/day. Flow net analysis suggests that less than 25 percent infiltrates, with the remaining water lost to surface flow and evapotranspiration (ET). Evapotranspiration and slow infiltration has led to increased salinization, with shallow soils exhibiting EC to 500 milliSiemens/m. The most pronounced soil salinization occurs along the margins of the oxbow pond and meander scars. Wetland vegetation with low diversity comprises three zones, with species associations similar to those of closed basin prairie potholes to the west.     

MODELING NORTH CASCADES ANNUAL RUNOFF DISTRIBUTION USING DRAINAGE BASIN ELEVATION DISTRIBUTION1

ABSTRACT: The annual distribution of flow in a drainage basin within a given region is a function of many factors. These may include annual distribution of rainfall, basin orientation, ground cover, or presence of glaciers. Since the North Cascades region of northern Washington State has little variation in precipitation distribution by month, and the region has significant snowpack, one would predict that in an unregulated basin, basin elevation would be one of the most important factors impacting an annual hydrograph distribution. Such a prediction can be made since the higher a drainage basin is, the larger the portion of runoff that would occur as late spring snowmelt. Given that there is a relationship between elevation distribution and annual hydrograph, the problem becomes one of how to use this relationship to model an ungaged basin's hydrograph. This study concludes that, within the North Cascades region and perhaps within other regions, an effective method of determining annual flow distribution is to model ungaged flows in the same manner as flows from a gaged basin with an elevation distribution similar to that of the subject basin.     

Glucosephosphate isomerase genotype frequencies,homozygous excess and size relationships in the sand flounder Rhombosolea plebeia

Genetic variation was studied at two polymorphic loci for 3 yr (November 1978–February 1982) in juvenile sand flounder (Rhombosolea plebeia) in Wellington Harbour, New Zealand. The Gpi-1 locus showed a heterogeneity in genotype frequencies, but this was not clearly related to season or to fish length. At the Gpi-2 locus, genotype frequencies were dependent upon length and showed a significant excess of homozygotes in juveniles but not in adults. This latter phenomenon has been reported previously in several species of marine molluscs, and so may be common to marine organisms producing large numbers of pelagic larvae. Reasons for the excess of homozygotes are discussed, and it is suggested that assortative mating is the most likely explanation and that this is an area of marine population genetic research which has been over-looked.