A study of the partitioning behavior of Irgarol-1051 and its transformation products

Partitioning behavior of the antifouling booster biocide, Irgarol-1051 (2-methythio-4-tert-butylamino-6-cyclopropylamino-s-triazine), its production by-product, M3, and its environmental transformation products, M1 and M2, were studied. Octanol-water partition coefficients, log K(OW), and organic matter-water partition coefficients, log K(OC), of these s-triazines were measured by reversed-phase HPLC and a triphasic SPME equilibrium model, respectively. The average log K(OW) (+/-SD) of the four s-triazine species were: 4.39+/-0.07 (M3); 3.38+/-0.12 (Irgarol-1051); 2.92+/-0.12 (M2) and 2.54+/-0.11 (M1), while mean log K(OC) (+/-SD) of these species were: 2.47+/-0.03 (M3); 2.16+/-0.03 (Irgarol-1051); 1.97+/-0.03 (M2) and 1.79+/-0.04 (M1). These results were compared to reported physicochemical parameters of Irgarol-1051 in the literature. Partitioning behavior of these s-triazine species in the coastal environment revealed by their K(OW) and K(OC) were also discussed.     

Practical Incinerator Implications

This paper discusses a number of results obtained from a hazardous waste flat flame combustion study with implications to full scale incinerators. The results demonstrate that it is possible to obtain DREs of up to 99.95 percent firing mixtures of CH₂Cl₂/CH₄ and air in such a facility. These results are significant since residence times are at the millisecond level. The paper presents DRE results obtained with this CH₂Cl₂ flat flame system when systematically varying the chlorine loading and equivalence ratio within the flames. Additionally, a PIC DRE is defined as an alternative approach to measure total stack emissions. PIC DRE results are presented for systematic variation of chlorine loading and equivalence ratio. Based upon the data of the paper, a suggested two-stage incineration process is presented which may be both economically advantageous and result in less total PIC emissions as compared with conventional incinerators for certain wastes. The data of this work further indicate that it is kinetically possible to obtain high DREs with corresponding high CO levels for select wastes. Finally, an interpretation of the data suggests that, for a class of liquid wastes, it may be beneficial to vaporize the waste and premix it with gaseous fuel and oxidizer streams, thereby avoiding the need to atomize the waste.     

Synthesis of Environmental Evidence: Nitrogen Dioxide Epidemiology Studies

The use of meta-analysis Is becoming more common In the medical literature, but It Is not common in the environmental literature. Although meta-analysis cannot combine a group of poorly executed, conflicting studies to get an unequivocal answer, there are certain situations where it can be helpful. The Inability of studies to produce similar results may be a function of the power of the studies rather than a reflection of their quality. The literature on the effects of nitrogen dioxide on the odds of respiratory Illness in children is such an example. Three quantitative methods for the synthesis of this evidence are presented. Although the methods produce slightly different results, the conclusion from all three methods Is that the increase in the odds of respiratory Illness in children exposed to a long-term increase of 30 μg/m³ (comparable to the increase resulting from exposure to a gas stove) is about 20 percent. This estimated increase is not sensitive to the method of analysis.     

Assessment of Human Exposure to Ambient Particulate Matter

ABSTRACT

Recent epidemiological studies have consistently shown that the acute mortality effects of high concentrations of ambient particulate matter (PM), documented in historic air pollution episodes, may also be occurring at the low to moderate concentrations of ambient PM found in modern urban areas. In London in December 1952, the unexpected deaths due to PM exposure could be identified and counted as integers by the coroners. In modern times, the PM-related deaths cannot be as readily identified, and they can only be inferred as fractional average daily increases in mortality rates using sophisticated statistical filtering and analyses of the air quality and mortality data. The causality of the relationship between exposure to ambient PM and acute mortality at these lower modern PM concentrations has been questioned because of a perception that there is little significant correlation in time between the ambient PM concentrations and measured personal exposure to PM from all sources (ambient PM plus indoor-generated PM).

This article shows that the critical factor supporting the plausibility of a linear PM mortality relationship is the expected high correlation in time of people's exposure to PM of ambient origin with measured ambient PM concentrations, as used in the epidemiological time series studies. The presence of indoor and personal sources of PM masks this underlying relationship, leading to confusion in the scientific literature about the strong underlying temporal relationship between personal exposure to PM of ambient origin and ambient PM concentration. The authors show that the sources of PM of non-ambient origin operate independently of the ambient PM concentrations, so that the mortality effect of non-ambient PM, if any, must be independent of the effects of the ambient PM exposures.