Stationary Combustion NOX Control A Summary of the 1989 Symposium

This paper summarizes information and results presented at the 1989 Symposium on Stationary Combustion NOX Control, held March 6-9, 1989 in San Francisco. Cosponsored by the Electric Power Research Institute (EPRI) and the U.S. Environmental Protection Agency, (EPA) the symposium was the fifth in a biennial series.     

Sorption of chlorpyrifos and fonofos on four soils and turfgrass thatch using membrane filters

Abstract

Chemical transport in soil is a major factor influencing soil and water contamination. Four soils and turfgrass thatch, representing a wide range of organic carbon OC content were studied to determine sorption K_d and K_f parameters for the insecticides chlorpyrifos and fonofos. The batch equilibrium method was used. The concentration of insecticide was measured in the solution as well as in the solid phase to determine the most accurate sorption data. Four soils and thatch were equilibrated for 24 h at 22 ± 1^OC with aqueous insecticide solutions. Four concentrations of the insecticides, each <50% of their respective water solubilities, were selected for the experiments. After extraction with an organic solvent, the concentration of insecticides in the aqueous solution was determined by gas liquid chromatography using electron capture detection for chlorpyrifos, and nitrogen/phosphorus detection for fonofos. Data obtained were fitted to the log and simple linear form of the Freundlich equation. Mass balance Freundlich isotherm exponents n ranged between 0.82 and 0.93 for chlorpyrifos. 0.82 and 1.21 for fonofos, with r² ≥ 0.97. K_oc (percent of organic carbon %OC normalized Sorption coefficient) values were calculated by using experimentally developed K_d and K_f coefficients in relation to OC levels from 0.29 to 34.85%. K_d and K_f coefficients of both insecticides were positively correlated with OC (r² ≥ 0.96). organic matter OM (r² ≥ 0.96), and cation exchange capacity CEC (r² ≥ 0.90).     

Sex-specific temperature dependence of foraging and growth of intertidal snails

Predicting the biological impacts of climate change requires an understanding of how temperature alters organismal physiology and behavior. Given differences in reproductive physiology between sexes, increases in global temperature may be experienced differently by the males and females of a species. This study tested for sex-specific effects of increased air temperature on foraging, growth, and survival of an intertidal snail, Nucella ostrina (San Juan Island, Washington, 48–30′44″N, 123–08′43″W). Snails exhibited periodic peaks in foraging. Subjecting snails to elevated low tide air temperatures did not alter the timing or magnitude of this pattern. Despite similar temporal patterns in foraging, females foraged more than males, even when the risk of thermal stress was high. While males and females appear to have a similar body temperature threshold for optimal growth, females were more likely to cross that threshold resulting in a loss of body mass when exposed to daily increases in air temperature. These results suggest that the consequences of a warming climate in the short term may be different for males and females of N. ostrina, but also imply longer-term costs of reduced reproductive output, abundance, and distribution of this ubiquitous intertidal predator. Generally, this study points to the possible significance of sex-specific responses in an increasingly warm world.     

Mesoscale, finescale and microscale distribution of micro- and nanoplankton in the Irish Sea, with emphasis on ciliates and their prey

We examined the degree of mesoscale (km), finescale (m), and microscale (cm) patchiness of ciliates and their prey in waters of varying hydrographic conditions. Samples were taken throughout the water column, along a transect across the Irish Sea (54°N), at scales ranging from 0.15 to 10⁵ m. We examined physical, chemical, and biological characteristics. The eastern and western Irish Sea were stratified, with a pycnocline at ∼20 to 30 m. The central waters were mixed and had adjacent frontal regions. Euphotic depth was ∼20 to 35 m. Generally, the upper waters were nitrogen-limited, with elevated levels associated with frontal regions and deeper waters. Microphytoplankton exhibited fine-mesoscale patchiness: diatom numbers were low in stratified waters, with higher levels in mixed and frontal regions; dinoflagellates were abundant in subsurface waters near the fronts. Nanoflagellate numbers and biomass decreased with depth below the pycnocline, and exhibited microscale distribution in upper waters; these micropatches may provide increased food levels for ciliates. Microscale distribution of ciliates was rare and only occurred at mixed/frontal sites; finescale ciliate patches were a more prominent feature of the water column. These finescale patches can be composed of a variety of taxa but can also be virtually monospecific. Finescale patches may produce localised regions of high productivity that is available to fishes and copepods, but may also be a sink, as patches can be short-lived and thus unavailable to predators. Received: 28 September 1998 / Accepted: 26 January 1999     

Sediment ecological risk assessment: In situ and laboratory toxicity testing of Lake Orta sediments

Specifically designed benthic chambers have been used to test whether the exposure for 48 hrs to polluted Lake Orta sediments could affect survival and reproduction behaviour of Daphnia obtusa and Echinogammarus stammeri. In situ results have been coupled to lab testing with Microtox, seed germination and root elongation (Lactuca sativa, Cucunris sativus, Lepidium sativum), and invertebrates (Daphnia obtusa, D. magna, E,. stammeri) acute toxicity tests.The technique and results here reported indicate the utility of in situ testing and suggest that under certain conditions this kind of test may be more realistic (avoiding sample manipulation in the lab) than traditional laboratory toxicity tests.