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James Pontolillo

Publications and source records attributed to James Pontolillo.

10 recordsLinked to original sources
USGS2018

Reductive dechlorination rates of 4,4′-DDE (1-chloro-4-[2,2-dichloro-1-(4-chlorophenyl)ethenyl]benzene) in sediments of the Palos Verdes Shelf, CA

Wastes from the world's largest manufacturer of DDT (1-chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene) were released into the Los Angeles County municipal sewer system from 1947 to 1971. Following primary treatment, the effluent was discharged through a submarine outfall system whereupon a portion of the DDT and associated degradation products were deposited in sediments of the Palos Verdes Shelf (PVS). Parent DDT is present only in trace amounts in the sediments today, the vast majority having been transformed to DDE (1-chloro-4-[2,2-dichloro-1-(4-chlorophenyl)ethenyl]benzene) shortly following deposition. Previously believed to be inert, DDE is slowly being converted to DDMU (1-chloro-4-[2-chloro-1-(4-chlorophenyl)ethenyl]benzene) and DDMU to DDNU (1-chloro-4-[1-(4-chlorophenyl)ethenyl]benzene) via microbially-mediated reductive dechlorination (RDC). Kinetic and compositional data suggest that this process began sometime in the mid- to late 1970s. Rates of DDE RDC in shelf sediments are spatially variable and have proven difficult to determine accurately. This limits our ability to understand the factors controlling RDC rates and to predict the course of natural recovery. In the present study, concentrations of ten DDT compounds and twelve PCB (polychlorinated biphenyl) congeners were determined in cores collected at two locations on the PVS (stations 3C, 6C, ~7km and ~2km downcurrent from the outfalls, respectively). DDE inventories, normalized to those of non-degrading PCB congeners having similar physico-chemical properties, were modeled to yield first-order RDC rates for the period 1981–2010. Average rates at stations 3C and 6C were 0.044±0.004 and 0.008±0.002yr −1 , respectively, with depth-dependent RDC rates at station 3C (1992–2003) ranging from 0.0025 to 0.102yr −1 . Comparison of RDC and total loss (i.e., RDC+physical loss) rates suggests that the average per cent loss of DDE due to RDC is ~90% at station 3C (1981–2010) and ~57% at station 6C (1992–2010). Trajectories of adjusted molar inventories of DDE, DDMU, and DDNU were forecast using a first-order multi-step reaction series (M-SRS) model. The results for DDE are consistent with the normalization procedure; RDC rates at stations 3C and 6C were 0.036±0.002yr −1 and 0.010±0.001yr −1 , respectively. At station 6C, the DDE to DDMU transformation appears to be the rate limiting step in the reaction sequence, DDE k 1 → DDMU k 2 → DDNU k3 → unidentified compound(s), whereas at station 3C RDC rates for DDE and DDMU are roughly equivalent. At both locations the transformation rate of DDNU is 7–20 times that of the other steps. Estimated half-lives of DDE at stations 3C and 6C based on the M-SRS model results are ~19 and 72 years, respectively.

California↗
USGS2018

DDT and related compounds in pore water of shallow sediments on the Palos Verdes Shelf, California, USA

For nearly two and a half decades following World War II, production wastes from the world's largest manufacturer of technical DDT (1-chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene) were discharged into sewers of Los Angeles County. Following treatment, the wastes were released via a submarine outfall system to nearshore coastal waters where a portion accumulated in shallow sediments of the Palos Verdes Shelf (PVS). An investigation of the pore-water geochemistry of DDT-related compounds (DDX) was undertaken in an effort to understand factors controlling the rate of reductive dechlorination (RDC) of the major DDT degradate, 4,4′-DDE (1-chloro-4-[2,2-dichloro-1-(4-chlorophenyl)ethenyl]benzene). Equilibrium matrix-solid phase microextraction (matrix-SPMEeq) combined with automated thermal desorption-gas chromatography/mass spectrometry (TDGC/MS) was used to determine freely dissolved concentrations of ten DDX analytes in sediment cores collected from three locations on the PVS (stations 3C, 6C, 8C, which are 7 km, 2 km, and 0 km, respectively, downcurrent from the outfall system). Pore-water concentrations (pM) of the principal DDX compounds involved in RDC were: 3C-DDE: 6.0–24, DDMU (1-chloro-4-[2-chloro-1-(4-chlorophenyl)ethenyl]benzene): 11–160, DDNU (1-chloro-4-[1-(4-chlorophenyl)ethenyl]benzene): 1.8–68; 6C-DDE: 5.6–170, DDMU: 5.6–177, DDNU: 1.7–87; 8CDDE: 27–212, DDMU: 31–403, DDNU: 5.5–89. Variations in the spatial distribution of DDX analytes in pore water reflect several factors including proximity to the outfalls, RDC reaction rates, and natural variability in sedimentation and post-depositional transport processes. A comparison of pore-water data produced using matrix-SPME eq /TD-GC/MS and whole-core squeezing/solvent extraction/liquid injection-GC/MS indicates that the majority of the DDE in the upper sediment column (≤about 10 cm) is associated with dissolved/colloidal organic matter. Below that depth, freely-dissolved DDE predominates. The principal organic geochemical phase controlling sorption of DDE in PVS sediments are residual hydrocarbons, the vast majority of which originated from petroleum refinery wastes. Organic carbon-normalized sediment-water distribution coefficients (KOC) were calculated from solid-phase and pore-water concentrations of DDX and organic carbon. Log K OC values (L/kg) were relatively invariant across the shelf and with depth in the sediment column. Shelf-wide compound-specific coefficients (log K OC ) were: DDE: 7.5 ± 0.11, DDMU: 6.92 ± 0.13, DDNU: 6.37 ± 0.19. The spatial uniformity of K OC means that biological exposure and availability of the DDX compounds can, in principle, be estimated from solid-phase chemical measurements.

California↗
USGS2017

Final data report for factors controlling DDE dechlorination rates on the Palos Verdes Shelf: A field and laboratory investigation

This data report provides a compilation of information developed over the last 6+ years by a multi-disciplinary, multi-institutional research team. The overall goal of this work has been to identify the biological, chemical, and physical factors that control rates of reductive dechlorination of DDE and DDMU in sediments of the Palos Verdes Shelf (PVS). More specific questions and objectives are delineated in the Scope of Work (section 12.1., Appendix 1). The study was composed of two parts: 1) field characterization studies, and 2) laboratory microcosm experiments. The goal of the field characterization studies was to define the conditions under which reductive dechlorination of DDE (and DDMU) is occurring in PVS sediments. This involved two separate cruises (2009, 2010) during which sediment cores, bottom water and other real-time field measurements (e.g., conductivity, temperature, depth of the water column) were acquired. The sediment cores were distributed among research team members for detailed chemical (R. Eganhouse, B. Orem, M. Reinhard), microbiological (A. Spormann), and physical (B. Edwards) analysis as well as for laboratory microcosm experiments (M. Reinhard). A team of collaborating USGS scientists generously contributed valuable information pertaining to geochronology (P. Swarzenski), the character of sedimentary geosorbent phases (P. Hackley), mineralogy (D. Webster), and grain-size characteristics (C. Sherwood) of PVS sediment samples. Together, this information will serve as framework for a conceptual model of natural degradation processes in the DDT-contaminated sediments on the PVS. These findings will enable the USEPA to gain a better understanding of the controls on reductive dechlorination and how dechlorination rates vary spatially and temporally. This, in turn, should facilitate decision making concerning the progress of natural attenuation and when monitoring at the site can be terminated. Toward that end, a brief Synthesis Report, summarizing and interpreting the acquired data, is being prepared and will be released in the coming year.

Palos Verdes Shelf↗
USGS2012

Determination of nonylphenol isomers in landfill leachate and municipal wastewater using steam distillation extraction coupled with comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry

4-Nonylphenols (4-NPs) are known endocrine disruptors and by-products of the microbial degradation of nonylphenol polyethoxylate surfactants. One of the challenges to understanding the toxic effects of nonylphenols is the large number of isomers that may exist in environmental samples. In order to attribute toxic effects to specific compounds, a method is needed for the separation and quantitation of individual nonylphenol isomers. The pre-concentration methods of solvent sublimation, solid-phase extraction or liquid–liquid extraction prior to chromatographic analysis can be problematic because of co-extraction of thousands of compounds typically found in complex matrices such as municipal wastewater or landfill leachate. In the present study, steam distillation extraction (SDE) was found to be an effective pre-concentration method for extraction of 4-NPs from leachate and wastewater, and comprehensive two-dimensional gas chromatography (GC × GC) coupled with fast mass spectral data acquisition by time-of-flight mass spectrometry (ToFMS) enhanced the resolution and identification of 4-NP isomers. Concentrations of eight 4-NP isomers were determined in leachate from landfill cells of different age and wastewater influent and effluent samples. 4-NP isomers were about 3 times more abundant in leachate from the younger cell than the older one, whereas concentrations in wastewater effluent were either below detection limits or <1% of influent concentrations. 4-NP isomer distribution patterns were found to have been altered following release to the environment. This is believed to reflect isomer-specific degradation and accumulation of 4-NPs in the aquatic environment.

Journal of Chromatography A↗
USGS2008

Susceptibility of synthetic long-chain alkylbenzenes to degradation in reducing marine sediments

Long-chain alkylbenzenes (LCABs) synthesized for production of alkylbenzene sulfonate surfactants have been used as molecular markers of anthropogenic waste for 25 years. Synthetic LCABs comprise two classes, the tetrapropylene-based alkylbenzenes (TABs) and the linear alkylbenzenes (LABs). LABs supplanted TABs in the mid-1960s because of improved biodegradability of their sulfonated analogs. Use of LCABs for molecular stratigraphy depends on their preservation in sediments over decadal time scales. Most laboratory and field studies suggest that LABs degrade rapidly under aerobic conditions but are resistant to degradation when oxygen is absent. However, recent work indicates that LABs may not be as persistent under reducing conditions as previously thought. To assess the potential for degradation of LCABs in reducing sediments, box cores collected in 1992 and 2003 near a submarine wastewater outfall system were analyzed using gas chromatography/mass spectrometry. The TABs were effectively preserved; differences between whole-core inventories were within analytical error. By contrast, whole-core inventories of the LABs decreased by about 50−60% during the same time interval. Based on direct comparison of chemical inventories in coeval core sections, LAB transformation rates are estimated at 0.07 ± 0.01 yr −1 . These results indicate that caution should be exercised when using synthetic LCABs for reconstruction of depositional records.

Environmental Science & Technology↗
USGS2008

Assessment of 1-chloro-4-[2,2-dichloro-1-(4-chlorophenyl)ethenyl]benzene (DDE) transformation rates on the Palos Verdes Shelf, CA

In 1953, the world's largest producer of DDT, Montrose Chemical Corporation, began to discharge process wastes into sewers of the Los Angeles County Sanitation Districts (LACSD), California. By 1971, when the sewer connection was terminated, approximately 1,500-2,000 metric tons of DDT had been introduced to the LACSD treatment plant in Carson, CA. After treatment, effluent from this plant was released to the ocean through a submarine outfall system on the Palos Verdes Shelf (PVS) near Los Angeles, resulting in the accumulation of highly contaminated marine sediments. Numerous investigations of the PVS have been undertaken since the late 1960s, but few have focused on the biogeochemical fate of DDT and its transformation products. In the early 1990s, it was shown that DDE, the major DDT compound in the sediments, was being reductively dechlorinated by microorganisms resident in sediments on the PVS. The U.S. Geological Survey undertook a study in cooperation with the U.S. Environmental Protection Agency to provide a better understanding of the range of reductive dechlorination rates on the PVS and the environmental factors that control them. Existing data show that rates of reductive dechlorination are variable spatially. A comparison of data from two cores collected approximately 7 kilometers downcurrent from the outfall systems in 1992 and 2003 yielded an average first-order transformation rate of approximately 0.05 yr-1. A multistep reaction model suggests that inventories of DDE in PVS sediments at the study site will continue to decline, whereas the inventory of the metabolite DDNU will reach a maximum around 2014.

California↗
USGS2001

The search for reliable aqueous solubility (Sw) and octanol-water partition coefficient (Kow) data for hydrophobic organic compounds; DDT and DDE as a case study

The accurate determination of an organic contaminant’s physico-chemical properties is essential for predicting its environmental impact and fate. Approximately 700 publications (1944–2001) were reviewed and all known aqueous solubilities (S w ) and octanol-water partition coefficients (K ow ) for the organochlorine pesticide, DDT, and its persistent metabolite, DDE were compiled and examined. Two problems are evident with the available database: 1) egregious errors in reporting data and references, and 2) poor data quality and/or inadequate documentation of procedures. The published literature (particularly the collative literature such as compilation articles and handbooks) is characterized by a preponderance of unnecessary data duplication. Numerous data and citation errors are also present in the literature. The percentage of original S w and K ow data in compilations has decreased with time, and in the most recent publications (1994–97) it composes only 6–26 percent of the reported data. The variability of original DDT/DDE S w and K ow data spans 2–4 orders of magnitude, and there is little indication that the uncertainty in these properties has declined over the last 5 decades. A criteria-based evaluation of DDT/DDE S w and K ow data sources shows that 95–100 percent of the database literature is of poor or unevaluatable quality. The accuracy and reliability of the vast majority of the data are unknown due to inadequate documentation of the methods of determination used by the authors. [For example, estimates of precision have been reported for only 20 percent of experimental S w data and 10 percent of experimental K ow data.] Computational methods for estimating these parameters have been increasingly substituted for direct or indirect experimental determination despite the fact that the data used for model development and validation may be of unknown reliability. Because of the prevalence of errors, the lack of methodological documentation, and unsatisfactory data quality, the reliability of the DDT/ DDE S w and K ow database is questionable. The nature and extent of the errors documented in this study are probably indicative of a more general problem in the literature of hydrophobic organic compounds. Under these circumstances, estimation of critical environmental parameters on the basis of S w and K ow (for example, bioconcentration factors, equilibrium partition coefficients) is inadvisable because it will likely lead to incorrect environmental risk assessments. The current state of the database indicates that much greater efforts are needed to: 1) halt the proliferation of erroneous data and references, 2) initiate a coordinated program to develop improved methods of property determination, 3) establish and maintain consistent reporting requirements for physico-chemical property data, and 4) create a mechanism for archiving reliable data for widespread use in the scientific/regulatory community.

Water-Resources Investigations Report↗
USGS1996

Petrography and geochemistry of the San Miguel lignite, Jackson Group (Eocene), south Texas

The San Miguel lignite deposit (late Eocene, lower Jackson Group) of south Texas consists of four or more thin (generally < 1 m thick) lignite benches that are separated by claystone and mudstone partings. The partings are composed of altered volcanic air-fall ash that has been reworked by tidal or channel processes associated with a back-barrier depositional environment. The purpose of this study is to examine the relationship between the ash yield and the petrographic and geochemical characteristics of the San Miguel lignite as mined. Particular attention is given to 12 of the environmentally sensitive trace elements (As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Sb, Se, and U) that have been identified as possible hazardous air pollutants (HAPs) by the United States Clean Air Act Amendments of 1990. A total of 29 rock and lignite samples were collected and characterized by geochemical and petrographic methods. The major conclusions of the study are as follows: (1) The distribution of Mn is inversely related to the ash yield of the lignite samples. This indicates an organic affinity, or an association with finely disseminated minerals in the lignite that contain this element. (2) On a whole-coal basis, the concentration of the HAPs' element Pb is positively related to ash yield in lignite samples. This indicates an inorganic affinity for Pb. (3) Average whole-coal concentrations of As, Be, Sb, and U in the San Miguel samples are greater than published averages for these elements in other U.S. lignites. (4) The upper and lower lignite benches of the San Miguel deposit are both ash- and algal-rich, indicating that these intervals were probably deposited in wetter conditions than those in which the middle intervals formed. (5) The dominance of the eugelinite maceral subgroup over the huminite subgroup indicates that the San Miguel lignites were subjected to peat-forming conditions (either biogenic or chemical) that enabled degradation of wood cellular material into matrix gels, or that the plants that formed these lignite benches were less woody and more prone to formation of matrix gels. (6) An inertinite-rich layer (top of the B bed) might have formed from widespread oxidation of the San Miguel peat as a result of a volcanic ash fall which was subsequently reworked.

Organic Geochemistry↗
USGS1994

Tonsteins and clay-rich layers in coal-bearing intervals of the Eocene Manning formation, east-central Texas

Six samples from clay-rich intervals in the coal-bearing upper part of the Eocene Manning Formation were analyzed by scanning-electron microscopy and energy-dispersive X-ray fluorescence to determine the origin of minerals in the samples. Two samples were from surface-mine exposures of the 3500 coal bed near Bryan, Texas, and the remaining samples were from an exposure of a correlative interval at the Lake Somerville spillway about 60 km (37 mi) southwest of Bryan. Preliminary data suggest that both a 2-cm-thick (0.75-in) claystone from the upper part of the 3500 bed and the upper part of an 11-cm-thick (4.25-in) mudstone from the floor of the lower coal bed at the spillway were derived from volcanic ash falls. Both clay layers identified as possible tonsteins are composed of kaolinite and accessory quartz, euhedral to subhedral zircon, feldspars, and Ca-Al phosphates (crandallite?). Both alkali and plagioclase feldspars are observed in the two samples, but K-feldspar predominates in the upper clay layer of the 3500 bed, and plagioclase, with accessory Ti-bearing biotite, predominates in the sample from the floor of the spillway. These compositional differences suggest two separate volcanic ash falls. The other sampled clay layers contain rounded to subrounded zircons and feldspars in a mixed-layer clay groundmass, which suggests detrital rather than ash-fall origins.

Texas↗