Symposium Objectives

The Control Systems Laboratory (CSL) of the Environmental Protection Agency has been developing improved technology for the control of participate emissions from stationary sources for nearly ten years. Starting about three years ago, emphasis has been gradually shifted to the study of fine particulate which we define as solid or liquid particles less than about 3µ in diameter. Rationale for this shift in emphasis is covered in Mr. Harrington’s Keynote Paper.     

Waste Analysis Plan Review Advisor: An Intelligent Database to Assist RCRA Permit Reviewers

The Waste Analysis Plan Review Advisor (WAPRA) system assists in the review of the Waste Analysis Plan Section of RCRA Part B facility permit applications. Specifically, this program automates two functions of the waste analysis plan review. First, the system checks all wastes which will be processed in the same treatment or disposal unit to identify possible chemical interactions which might pose a health threat to unit operators or degrade the performance of the waste processing unit. Second, sampling methods are analyzed and judged for appropriateness based on guidelines in EPA Reference SW-846. WAPRA is best classified as an intelligent database. It contains the expertise of a chemist in a menu-driven user-friendly interface.     

Estimating Contributions of Nitrate and Herbicides From Groundwater to Headwater Streams,Northern Atlantic Coastal Plain,United States1

Abstract: Groundwater transport often complicates understanding of surface‐water contamination. We estimated the regional flux of nitrate and selected herbicides from groundwater to nontidal headwater streams of the Atlantic Coastal Plain (New Jersey through North Carolina) based on late‐winter or spring base‐flow samples from 174 streams. Sampled streams were selected randomly, and flux estimates are based on resulting population estimates rather than on empirical models, which have been used previously for similar estimates. Base‐flow flux in the estimated 8,834 headwater streams of the study area are an estimated 21,200 kg/day of nitrate (as N) and 5.83, 0.565, and 20.7 kg/day of alachlor, atrazine, and metolachlor (and selected degradates), respectively. Base‐flow flux of alachlor and metolachlor is <3% of the total base‐flow flux of those compounds plus degradates. Base‐flow flux of nitrate and herbicides as a percentage of applications is typically highest in well‐drained areas and lowest in areas with abundant poor drainage and anoxic conditions. In Coastal Plain watersheds of Albemarle and Pamlico Sounds, <2% of applied nitrogen reaches headwater streams as base flow. On the Delmarva Peninsula part of the Chesapeake Bay watershed, however, more than 10% of such applications are transported through groundwater to streams, and base‐flow nitrate flux represents 70% of total nitrogen flux in headwater streams.     

Inorganic arsenic in Chinese food and its cancer risk

Even moderate arsenic exposure may lead to health problems, and thus quantifying inorganic arsenic (iAs) exposure from food for different population groups in China is essential. By analyzing the data from the China National Nutrition and Health Survey (CNNHS) and collecting reported values of iAs in major food groups, we developed a framework of calculating average iAs daily intake for different regions of China. Based on this framework, cancer risks from iAs in food was deterministically and probabilistically quantified. The article presents estimates for health risk due to the ingestion of food products contaminated with arsenic. Both per individual and for total population estimates were obtained. For the total population, daily iAs intake is around 42 μg day(-1), and rice is the largest contributor of total iAs intake accounting for about 60%. Incremental lifetime cancer risk from food iAs intake is 106 per 100,000 for adult individuals and the median population cancer risk is 177 per 100,000 varying between regions. Population in the Southern region has a higher cancer risk than that in the Northern region and the total population. Sensitive analysis indicated that cancer slope factor, ingestion rates of rice, aquatic products and iAs concentration in rice were the most relevant variables in the model, as indicated by their higher contribution to variance of the incremental lifetime cancer risk. We conclude that rice may be the largest contributor of iAs through food route for the Chinese people. The population from the South has greater cancer risk than that from the North and the whole population.     

Graduated Driver Licensing Research, 2007-Present: A Review and Commentary

The evolution of graduated licensing systems in the past 25 years has resulted in dramatic growth in research on this topic. The most recent summary reports have covered the period up to 2007. In the present article more recent and ongoing research is categorized, summarized, and discussed.     

Remotely engaged? Towards a framework for monitoring the success of stakeholder engagement in remote regions

The importance of stakeholder engagement for the success of natural resources management processes is widely acknowledged, yet evaluation frameworks employed by administrators of environmental programmes continue to provide limited recognition of or insistence upon engagement processes. This paper presents a framework for monitoring and evaluation of engagement that aims to better incorporate community engagement into mainstream environmental programmes, in particular in remote regions such as arid and desert regions of the world. It is argued that successful monitoring of engagement should not only comprise a generic set of indicators but rather, in addition to the principles of good monitoring practice, should take into account a variety of the stakeholder interests as well as key regional drivers, addressing them at right geographic, institutional and time scale.     

Formaldehyde,Melhanol and Hydrocarbon Emissions from Methanol-fueled Cars

Exhaust and evaporative emissions tests were conducted on several methanol- and gasoline-fueled vehicles. Separate samples for chromatographlc analysis of formaldehyde, methanol, and Individual hydrocarbons were collected in each of the three phases of the driving cycle and in each of the two portions of the evaporative emissions test. One vehicle, equipped with an experimental variable-fuel engine, was tested using methanol/gasoline fuel mixtures of 100, 85, 50,15, and 0 percent methanol. Combustion-generated hydrocarbons were lowest using methanol fuel, and increased several-fold as the gasoline fraction was increased. Gasoline components In the exhaust Increased from zero as the gasoline fraction of the fuel was Increased. On the other hand, formaldehyde emissions were several times higher using methanol fuel than they were using gasoline. A dedicated methanol car and the variable-fuel car gave similar emissions patterns when they both were tested using methanol fuel. The organic-carbon composition of the exhaust was 85-90 percent methanol, 5-7 percent formaldehyde, and 3-9 percent hydrocarbons. Several cars that were tested using gasoline emitted similar distributions of hydrocarbons, even through the vehicles represented a broad range of current and developmental engine families and emissions control systems. These vehicles continue the trend of the past twenty years toward less photochemically reactive exhaust, with higher percentages of methane and total alkanes, and correspondingly lower percentages of oleflns and aromatlcs.     

Hydroxyl radical (OH) yields from the ozonolysis of both double bonds for five monoterpenes

A new method has been applied to determine OH-radical yields from the ozonolysis of both double bonds from five selected, atmospherically relevant monoterpenes, namely terpinolene, α-phellandrene, limonene, α-terpinene and γ-terpinene. While OH-yields for the faster reacting double bond agreed with previous literature values, the yields from the second double bond were determined for the first time and are as follows: limonene 7–10%, terpinolene 39–48%, α-phellandrene 8–11% and α-terpinene 12–14%. Only for γ-terpinene the rate coefficient for the reaction of ozone with the two double bonds was too similar in order to distinguish the OH-yield with this method. In all cases the yield from the second double bond was significantly lower than the first. The reasons for this difference are discussed in terms of the Criegee-intermediate reactions, in particular the number of abstractable H-atoms and the number of possible hydroperoxide products.     

Towards a renewed research agenda in ecotoxicology

New concerns about biodiversity, ecosystem services and human health triggered several new regulations increasing the need for sound ecotoxicological risk assessment. The PEER network aims to share its view on the research issues that this challenges. PEER scientists call for an improved biologically relevant exposure assessment. They promote comprehensive effect assessment at several biological levels. Biological traits should be used for Environmental risk assessment (ERA) as promising tools to better understand relationships between structure and functioning of ecosystems. The use of modern high throughput methods could also enhance the amount of data for a better risk assessment. Improved models coping with multiple stressors or biological levels are necessary to answer for a more scientifically based risk assessment. Those methods must be embedded within life cycle analysis or economical models for efficient regulations. Joint research programmes involving humanities with ecological sciences should be developed for a sound risk management.