Form and feeding mechanism of a living Planctosphaera pelagica (phylum Hemichordata)

We describe aspects of the anatomy and suspension-feeding mechanism of a single Planctosphaera pelagica captured from the plankton in June 1992 off Bermuda in the western Atlantic. We also describe several unusual features of the larva, including its occurrence in surface waters, unusually large size, and limited swimming ability. Our account of the form and feeding behavior of P. pelagica is the first based on observations of a specimen captured and observed alive. Our limited observations suggest that the planctosphaera may use a suspension-feeding mechanism much like that of the other feeding deuterostome larvae (the pluteus and bipinnaria larvae of echinoderms and the tornaria larva of enteropneust hemichordates) known to capture food particles using a single ciliated band. Although we could not observe cilia directly, the movement of dye streams and food particles and the structure of the ciliated band suggest that some particles may be captured at the ciliated band by the reversal of ciliary beat. The planctosphaera possesses many prominent mucous glands near the food grooves. This suggests an important role of mucus in the biology of the larva, but we were not able to observe directly any role of mucus in particle capture.     

Preparation of high molecular weight DNA from hermatypic corals and its use for DNA hybridization and cloning

Previous attempts to extract high molecular weight DNA from hermatypic corals have failed because the starting material was mature tissue. The following paper describes the isolation of DNA from coral sperm which is of high molecular weight, and is suitable for DNA hybridization, digestion with restriction endonucleases and cloning. Gross DNA hybridization and hybridization with cloned repetitive DNA was used to investigate relatedness amongst members of the scleractinian coral family Acroporidae. Acropora formosa and A. pulchra were found to share a common (highly homologous) DNA sequence repeat; a related but less homologous sequence was present in A. latistella, and no homologous sequence was detected in Montipora digitata. These results imply a close taxonomic relationship between A. formosa and A. pulchra, and suggest that molecular criteria of this sort will be extremely useful in coral taxonomy.     

Successful Deployment of an Innovative Environmental Technology: The Terra-Kleen Experience

The National Research Council's report, Innovations in Ground Water and Soil Cleanup: From Concept to Commercialization, reviewed the implementation of innovative remediation technologies and portrayed a bleak outlook for them. Conversely, Terra-Kleen has invented, patented, permitted, and profited through the use of an innovative technology in the current market. Terra-Kleen has implemented a solvent extraction technology for the removal of PCBs, PAHs, and chlorinated pesticides from soil, sediment, and debris. To date, Terra-Kleen has successfully processed over 23 million pounds of PCB-contaminated soil in Alaska, California, Florida, Ohio, and Oklahoma. The company has been profitable each year since its inception, and has averaged a revenue growth rate of 94 percent per year for the last four years. Corporate growth has been financed entirely through profits and conventional bank loans at favorable interest rates. This article reviews the factors that have led to Terra-Kleen's success, overviews the solvent extraction technology, and details specific projects that have implemented the technology.     

Filling the Gaps in the Risks vs. Benefits of Mammalian Adult-Cell Cloning: Taking Bernard Rollin's Philosophy Its Next Step

A critique is made of Bernard Rollin's examination of the ethics of cloning adult mammalian cells. The primary concern is less to propound an anticloning or procloning position than to call for full exploration of the ethical complexities before a rush to judgment is made. Indeed, the ethical examination in question rushes toward an ethical position in such a way that does not appear consistent with Rollin's usual methodology. By extending this methodology – which entails full weighing of benefits and costs – it becomes apparent that there are real potential risks to this type of cloning in both animals and humans, besides the possible benefits, and that the scientific, political, philosophical, and broader academic communities should explore these risks and benefits extensively. Rollin's usual methodological call for hesitation before risks would translate into hesitation before the ethical risks of adult mammalian cell cloning instead of his paper's curiously laissez-faire stance.     

Trace elements in soil and biota in confined disposal facilities for dredged material

We studied the relation of trace element concentrations in soil to those in house mice (Mus musculus), common reed (Phragmites australis) and ladybugs (Coccinella septempunctata at five disposal facilities for dredged material. The sites had a wide range of soil trace element concentrations, acid soils and a depauperate fauna. They were very poor wildlife habitat because they were dominated by the common reed. Bioassay earthworms exposed to surface soils from three of the five sites died, whereas those exposed to four of five soils collected a meter deep survived, presumably because the deeper, unoxidized soil, was not as acid. Concentrations of Ni and Cr in the biota from each of the sites did not seem to be related to the concentrations of the same elements in soil. Although Pb, Zn and Cu concentrations in biota were correlated with those in soil, the range of concentrations in the biota was quite small compared to that in soil. The concentrations of Pb detected in mice were about as high as the concentrations previously reported in control mice from other studies. Mice from the most contaminated site (530 ppm Pb in soil) contained only slightly more Pb (8 ppm dry wt) than did mice (2-6 ppm dry wt) from sites containing much less Pb (22-92 ppm in soil). Despite the acid soil conditions, very little Cd was incorporated into food chains. Rather, Cd was leaching from the surface soil. We concluded that even the relatively high concentrations of trace elements in the acid dredged material studied did not cause high concentrations of trace elements in the biota.     

Perspectives of a large scale environmental survey for chlorinated dioiins: water analyses

During 1983 and 1984, The Dow Chemical Company conducted a study to determine the extent of dioxin contamination at its Midland, Michigan plant and the surrounding area. The primary objectives of this study were to identify, rank order, and when possible quantify potential sources of dioxins to the environment and also to determine the extent of contamination in areas affected by the Dow facility. Early in the study, it was estimated that approximately 0.6g/year of 2378-TCDD was being emitted in 2.5 × 10¹⁰L of wastewater effluent. Data will describe observed sources of TCDD (both current and historical), environmental levels, existing water treatment methods, control measures taken, and future improvements on the water system to reduce TCDD in the effluent.     

Prediction of the vertical profile of ozone based on ground-level ozone observations and cloud cover

A number of statistical techniques have been used to develop models to predict high-elevation ozone (O3) concentrations for each discrete hour of day as a function of elevation based on ground-level O3 observations. The analyses evaluated the effect of exclusion/inclusion of cloud cover as a variable. It was found that a simple model, using the current maximum ground-level O3 concentration and no effect of cloud cover provided a reasonable prediction of the vertical profile of O3, based on data analyzed from O3 sites located in North Carolina and Tennessee. The simple model provided an approach that estimates the concentration of O3 as a function of elevation (up to 1800 m) based on the statistical results with a +/- 13.5 ppb prediction error, an R2 of 0.56, and an index of agreement, d1, of 0.66. The inclusion of cloud cover resulted in a slight improvement in the model over the simple regression model. The developed models, which consist of two matrices of 24 equations (one for each hour of day for clear to partly cloudy conditions and one for cloudy conditions), can be used to estimate the vertical O3 profile based on the inputs of the current day's 1-hr maximum ground-level O3 concentration and the level of cloud cover.     

Equilibrium nonaqueous phase liquid pool geometry in coarse soils with discrete textural interfaces

This paper presents a model for the geometry of nonaqueous phase liquid (NAPL) pools and mounds in homogeneous soils and soils with discrete textural interfaces. It is shown that the concepts of capillary pressure-saturation curve hysteresis and entry pressures are integral to the complete conceptualization of pool and mound geometry. Unless hysteresis is included in the analysis, light NAPL (LNAPL) in homogeneous soils cannot exist in pools at all, and dense NAPL (DNAPL) will not mound on horizontal textural interfaces unless lateral confining boundaries are present. The proposed model also implies that remobilization of DNAPL pools will occur at lower hydraulic gradients than those predicted with previous models. Comparing predicted and experimental DNAPL and LNAPL pool thicknesses and the location of an LNAPL lens with respect to the top of the capillary fringe validate the model.     

Irrigation runoff insecticide pollution of rivers in the Imperial Valley, California (USA)

The Alamo and New Rivers located in the Imperial Valley, California receive large volumes of irrigation runoff and discharge into the ecologically sensitive Salton Sea. Between 1993 and 2002 we conducted a series of studies to assess water quality using three aquatic species: a cladoceran (Ceriodaphnia dubia), a mysid (Neomysis mercedis), and a larval fish (Pimephales promelas). Although no mortality was observed with the P. promelas, high-level toxicity to the invertebrate species was documented in samples from both rivers during many months of each year. Toxicity identifications and chemical analyses identified the organophosphorus insecticides (OP), chlorpyrifos and diazinon, as the cause of C. dubia toxicity. The extent of the C. dubia mortality was highly correlated with quantities of these OPs applied in the river watersheds. C. dubia mortality occurred during more months of our 2001/2002 study than in the 1990s investigations. During 2001/2002, the extensive C. dubia mortality observed in New River samples was caused by OP insecticide pollution that originated from Mexico. Mortality to N. mercedis in New River samples was likely caused by contaminants other than OP insecticides. Our studies document OP insecticide-caused pollution of the Alamo River over a 10-year period and provide the necessary information for remediation efforts.     

Use of hydrophilic and hydrophobic microfiltration membranes to remove microorganisms and organic pollutants from primary effluents.

Primary-effluent wastewater from the Allegheny County Sanitary Authority (Pennsylvania) was used as a surrogate for combined-sewer-overflow waters contained in the sewershed. Pathogens contained in combined-primary-effluent wastewaters or combined-sewer overflows (CSOs) may pose a human-health threat to those coming in contact with such receiving waters. Polymeric ultra- and nano-membranes can be used to capture these microorganisms from CSOs. This research investigates the ability of polymeric hydrophobic and hydrophilic membranes, ranging in pore size from 0.2 to 0.8 microm, to remove pathogen-indicator organisms (Escherichia coli, enterococcus, and fecal coliforms). Membranes, with pore size 0.45 microm and smaller, were able to reduce the bacteria levels to nondetectable levels, with the sole exception of one membrane with pore size 0.3 microm.