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Jacob Gibs

Publications and source records attributed to Jacob Gibs.

14 recordsLinked to original sources
USGS2013

Occurrence and partitioning of antibiotic compounds found in the water column and bottom sediments from a stream receiving two wastewater treatment plant effluents in northern New Jersey, 2008.

An urban watershed in northern New Jersey was studied to determine the presence of four classes of antibiotic compounds (macrolides, fluoroquinolones, sulfonamides, and tetracyclines) and six degradates in the water column and bottom sediments upstream and downstream from the discharges of two wastewater treatment plants (WWTPs) and a drinking-water intake (DWI). Many antibiotic compounds in the four classes not removed by conventional WWTPs enter receiving waters and partition to stream sediments. Samples were collected at nine sampling locations on 2 days in September 2008. Two of the nine sampling locations were background sites upstream from two WWTP discharges on Hohokus Brook. Another background site was located upstream from a DWI on the Saddle River above the confluence with Hohokus Brook. Because there is a weir downstream of the confluence of Hohokus Brook and Saddle River, the DWI receives water from Hohokus Brook at low stream flows. Eight antibiotic compounds (azithromycin (maximum concentration 0.24 μg/L), ciprofloxacin (0.08 μg/L), enrofloxacin (0.015 μg/L), erythromycin (0.024 μg/L), ofloxacin (0.92 μg/L), sulfamethazine (0.018 μg/L), sulfamethoxazole (0.25 μg/L), and trimethoprim (0.14 μg/L)) and a degradate (erythromycin-H2O (0.84 μg/L)) were detected in the water samples from the sites downstream from the WWTP discharges. The concentrations of six of the eight detected compounds and the detected degradate compound decreased with increasing distance downstream from the WWTP discharges. Azithromycin, ciprofloxacin, ofloxacin, and trimethoprim were detected in stream-bottom sediments. The concentrations of three of the four compounds detected in sediments were highest at a sampling site located downstream from the WWTP discharges. Trimethoprim was detected in the sediments from a background site. Pseudo-partition coefficients normalized for streambed sediment organic carbon concentration were calculated for azithromycin, ciprofloxacin, and ofloxacin. Generally, there was good agreement between the decreasing order of the pseudo-partition coefficients in this study and the order reported in the literature.

New Jersey↗
USGS2012

Chapter A6. Section 6.8. Use of multiparameter instruments for routine field measurements

The miniaturization of sensors and other technological advances in electronics have resulted in water-quality instruments that house multiple sensors capable of simultaneous readings for various field measurements in environmental waters. With the use of these multiparameter instruments, field measurements can be determined with considerable reduction in the field work that generally is required when using multiple single-parameter instruments. This section addresses the short-term or discrete-measurement use of portable multiparameter instruments. Each chapter of the National Field Manual is published separately and revised periodically. Newly published and revised chapters will be announced on the USGS Home Page on the World Wide Web under 'New Publications of the U.S. Geological Survey.'

Techniques of Water-Resources Investigations↗
USGS2011

Demonstration/validation of the Snap sampler passive groundwater sampling device

Laboratory studies and a field demonstration were conducted to determine the ability of the Snap Sampler to recover representative concentrations of several types of inorganic analytes from ground water. Analytes included non-metals, transition metals, alkaline earth metals, alkali metals, and a metalloid. In the laboratory studies, concentrations of analytes in Snap Sampler samples were com-parable with concentrations of the analytes in samples collected from a standpipe (i.e., control samples). For the field demonstration, there were sampling events at the former Pease Air Force Base. Samples taken using a Snap Sampler were compared with samples collected using conventional low-flow purging and sampling and a regenerated cellulose passive diffusion sampler. Based upon statistical analyses, analyte concentrations were found to be equivalent to those in the low-flow samples with one exception – unfiltered iron, where concentrations were significantly higher in the Snap Sampler samples. Differences were most pronounced in samples collected from the two stainless steel wells and from wells with higher turbidity levels. Elevated turbidities may have resulted from installing additional sampling equipment (including the baffle, pump, samplers, and bottom weight) in the well before sampling. We will examine this issue further at our next test site.

New Hampshire↗
USGS2010

Sediment oxygen demand in the Saddle River and Salem River watersheds, New Jersey, July-August 2008

Many factors, such as river depth and velocity, biochemical oxygen demand, and algal productivity, as well as sediment oxygen demand, can affect the concentration of dissolved oxygen in the water column. Measurements of sediment oxygen demand, in conjunction with those of other water-column water-quality constituents, are useful for quantifying the mechanisms that affect in-stream dissolved-oxygen concentrations. Sediment-oxygen-demand rates are also needed to develop and calibrate a water-quality model being developed for the Saddle River and Salem River Basins in New Jersey to predict dissolved-oxygen concentrations. This report documents the methods used to measure sediment oxygen demand in the Saddle River and Salem River watersheds along with the rates of sediment oxygen demand that were obtained during this investigation. In July and August 2008, sediment oxygen demand was measured in situ in the Saddle River and Salem River watersheds. In the Saddle River Basin, sediment oxygen demand was measured twice at two sites and once at a third location; in the Salem River Basin, sediment oxygen demand was measured three times at two sites and once at a third location. In situ measurements of sediment oxygen demand in the Saddle River and Salem River watersheds ranged from 0.8 to 1.4 g/m2d (grams per square meter per day) and from 0.6 to 7.1 g/m2d at 20 degrees Celsius, respectively. Except at one site in this study, rates of sediment oxygen demand generally were low. The highest rate of sediment oxygen demand measured during this investigation, 7.1 g/m2d, which occurred at Courses Landing in the Salem River Basin, may be attributable to the consumption of oxygen by a large amount of organic matter (54 grams per kilogram as organic carbon) in the streambed sediments or to potential error during data collection. In general, sediment oxygen demand increased with the concentration of organic carbon in the streambed sediments. Repeated measurements made 6 to 7 days apart at the same site locations resulted in similar values.

Scientific Investigations Report↗
USGS2007

Comparison of downhole and surface sampling for the determination of volatile organic compounds (VOCs) in ground water

The relative precision and accuracy of sampling and analysis methods for the determination of trace concentrations of volatile organic compounds (VOCs) in ground water were compared. Samples were collected from a well containing nanogram‐per‐liter (ng/L) to microgram‐per‐liter (μg/L) levels of VOCs. A Keck helical rotor submersible pump was used to collect samples at the surface for analysis by purge and trap (P&T) and for analysis by adsorption/thermal desorption (ATD). Downhole samples were collected by passing water through an ATD cartridge. Although slight spontaneous bubble outgassing occurred when the water was brought to the surface, the relative precisions and comparabilities of the surface and downhole methods were generally found to be equivalent from a statistical point of view. A main conclusion of this study is that bringing sample water to the surface for placement in VOC vials (and subsequent analysis by P&T) can be done reliably under many circumstances. However, care must still be taken to prevent adsorption losses and cross contamination. Samples subject to strong bubble outgassing will need to be handled in a special fashion (e.g., by downhole ATD) to minimize volatilization losses. Additionally, the higher sensitivity of the ATD method allows lower detection limits than are possible with P&T. For example, several compounds present at the ng/L level could be determined with confidence by ATD, but not by P&T.

New Jersey↗
USGS2007

Effects of sample isolation and handling on the recovery of purgeable organic compounds

This report compares the recovery of purgeable organic compounds (POCs) obtained by using a downhole isobaric sampler developed by the U.S. Geological Survey, a helical-rotor submersible pump, and a point source bailer to collect and isolate samples of ground water from three wells in Now York and New Jersey: the samples contained a total of 13 PCX's delectable at concentrations ranging from 0.5 μg/L to about 400 μg/L. This report also compares the effects of sample handling, specifically the differences in PCX concentration recovery when an isobaric sample container is filled at land surface vs. when it is filled downhole. and when samples art taken using a bailer with and without a bottom-emptying device. These case studies are used to quantify the possible effects of different sample-isolation find sample-handling techniques on POC recovery. The relative effectiveness of the three devices varied by site and by compound. Overall, the POC recoveries achieved by using the helical-rotor submersible pump and the downlink isobaric sampler were not significantly different at the 95 percent confidence, level. POC recovery obtained by using the point source bailer was 11 percent lower overall. The downhole isobaric sampler results exhibited smaller coefficients of variation than did the helical-rotor submersible pump or the point-source bailer results. However, the differences between the coefficients of variation of the downhole isobaric sampler and those of the helical-rotor submersible pump were not significant at the 95 percent confidence level. The nonsignificant smaller coefficient of variation of the downhole isobaric sampler apparently resulted from two fewer sample handling steps that exposed the sample water to ambient air. An independent experiment performed with a different downhole sampler at one of the wells used in this investigation produced a similar statistical result. Also, the POC recovery obtained by pouring sample water out the lop of a point source bailer into 40-mL vials was S percent lower than that obtained by filling vials from a bailer with a bottom-emptying device.

Ground Water Monitoring and Remediation↗
USGS2007

Efficiency of conventional drinking-water-treatment processes in removal of pharmaceuticals and other organic compounds

Samples of water and sediment from a conventional drinking-water-treatment (DWT) plant were analyzed for 113 organic compounds (OCs) that included pharmaceuticals, detergent degradates, flame retardants and plasticizers, polycyclic aromatic hydrocarbons (PAHs), fragrances and flavorants, pesticides and an insect repellent, and plant and animal steroids. 45 of these compounds were detected in samples of source water and 34 were detected in samples of settled sludge and (or) filter-backwash sediments. The average percent removal of these compounds was calculated from their average concentration in time-composited water samples collected after clarification, disinfection (chlorination), and granular-activated-carbon (GAC) filtration. In general, GAC filtration accounted for 53% of the removal of these compounds from the aqueous phase; disinfection accounted for 32%, and clarification accounted for 15%. The effectiveness of these treatments varied widely within and among classes of compounds; some hydrophobic compounds were strongly oxidized by free chlorine, and some hydrophilic compounds were partly removed through adsorption processes. The detection of 21 of the compounds in 1 or more samples of finished water, and of 3 to 13 compounds in every finished-water sample, indicates substantial but incomplete degradation or removal of OCs through the conventional DWT process used at this plant.

Science of the Total Environment↗
USGS2005

Effects of physical and chemical heterogeneity on water-quality samples obtained from wells

Factors that affect the mass of chemical constituents entering a well include the distributions of flow rate and chemical concentrations along and near the screened or open section of the well. Assuming a layered porous medium (with each layer being characterized by a uniform hydraulic conductivity and chemical concentration), a knowledge of the flow from each layer along the screened zone and of the chemical concentrations in each layer enables the total mass entering the well to be determined. Analyses of hypothetical systems and a site at Galloway, NJ, provide insight into the temporal variation of water-quality data observed when withdrawing water from screened wells in heterogeneous ground-water systems. The analyses of hypothetical systems quantitatively indicate the cause-and-effect relations that cause temporal variability in water samples obtained from wells. Chemical constituents that have relatively uniform concentrations with depth may not show variations in concentrations in the water discharged from a well after the well is purged (evacuation of standing water in the well casing). However, chemical constituents that do not have uniform concentrations near the screened interval of the well may show variations in concentrations in the well discharge water after purging because of the physics of ground-water flow in the vicinity of the screen. Water-quality samples were obtained through time over a 30 minute period from a site at Galloway, NJ. The water samples were analyzed for aromatic hydrocarbons, and the data for benzene, toluene, and meta+para xylene were evaluated for temporal variations. Samples were taken from seven discrete zones, and the flow-weighted concentrations of benzene, toluene, and meta+para xylene all indicate an increase in concentration over time during pumping. These observed trends in time were reproduced numerically based on the estimated concentration distribution in the aquifer and the flow rates from each zone. The results of the hypothetical numerical experiments and the analysis of the field data both corroborate the impact of physical and chemical heterogeneity in the aquifer on water-quality samples obtained from wells. If temporal variations in concentrations of chemical constituents are observed, they may indicate variability in the ground-water system being sampled, which may give insight into the chemical distributions within the aquifer and provide guidance in the positioning of new sampling devices or wells.

Groundwater↗
USGS2003

Methods for quality-assurance review of water-quality data in New Jersey

This report is an instructional and reference manual that describes methods developed and used by the U.S. Geological Survey (USGS), New Jersey District, to assure the accuracy and precision of the results of analyses of surface- and ground-water samples received from analyzing laboratories and, ultimately, to ensure the integrity of water-quality data in USGS databases and published reports. A statistical-analysis computer program, COMP.PPL, is used to determine whether the values reported by the laboratories are internally consistent, whether they are reasonable when compared with values for samples previously collected at the same site, and whether they exceed applicable drinking-water regulations. The program output consists of three files -- QWREVIEW, QWOUTLIERS, and QWCALC. QWREVIEW presents the results of tests of chemical logic and shows values that exceed drinking-water regulations. QWOUTLIERS identifies values that fall outside the historical range of values for the site sampled. QWCALC shows values and calculations used for reference purposes. Because values that are identified by the program as questionable may or may not be in error, the reviewer looks at both qualitative and quantitative relations between analytes during the period of record and then uses technical judgement to decide whether to accept a questionable value or investigate further. Guidelines for, and the use of regression analysis in, making this decision are described. Instructions are given for requesting that the analyzing laboratory reanalyze a constituent or otherwise verify the reported value. If, upon reanalysis or verification, a value is still questionable, consideration must be given to deleting the value or marking the value in the USGS National Water Information System database as having been reviewed and rejected.

New Jersey↗
USGS2001

Water quality of the Delaware and Raritan Canal, New Jersey, 1998-99

Since 1934, the Delaware and Raritan Canal has been used to transfer water from the Delaware River Basin to the Raritan River Basin. The water transported by the Delaware and Raritan Canal in New Jersey is used primarily for public supply after it has been treated at drinking-water treatment plants located in the Raritan River Basin. Recently (1999), the raw water taken from the canal during storms has required increased amounts of chemical treatments for removal of suspended solids, and the costs of removing the additional sludge or residuals generated during water treatment have increased. At present, action to control algae is unnecessary. The water quality of the Delaware and Raritan Canal was studied for approximately 16.5 months from mid-January 1998 through May 1999 to determine whether changes in water quality along the length of the canal are associated with storms. Nine water-quality constituents, and field measured specific conductance and turbidity were statistically tested. Instantaneous or grab samples of water were collected from the Delaware and Raritan Canal after five storms and during four nonstorm events. Median values of water-quality constituents in samples collected immediately after storms and during nonstorm conditions when statistically compared by sampling location were not significantly different. Therefore, the data were combined or aggregated to eliminate one of the two explanatory variables, either individual sampling sites or the two types of sampling events, in order to generate a sample population large enough to show statistically significant differences. After combining sampling events, only the median concentration of suspended organic carbon, and field measured specific conductance and turbidity, were significantly different among sampling sites. Median concentrations of total and filtered ammonia plus organic nitrogen, total phosphorous, turbidity, ultraviolet absorbance at 254 nanometers, and dissolved organic carbon in samples collected after storms were significantly greater than in samples collected during nonstorm conditions, when the sampling locations were aggregated in the statistical analysis. Methyl tert-butyl ether, the most frequently detected volatile organic compound (VOC), was detected in 55 of 80 samples. The highest concentration of methyl tert-butyl ether, 3.2 micrograms per liter, was measured in a sample collected during nonstorm conditions. The median of the continuously monitored specific conductance during nonstorm conditions at Port Mercer, N.J., increased by approximately 3 to 4 ?S/cm (microsiemens per centimeter) (1.5 to 2 percent of the median specific conductance) relative to that at the nearest upstream site, at Lower Ferry Road. The land use in the influent basins for this reach of the Delaware and Raritan Canal is primarily urban. One possible source of water with high specific conductance is either domestic or industrial wastewater that continuously discharges into pipes, then empties into the canal. Another possible source is ground water from an area within this reach where the elevation of the water table is higher than that of the water surface of the Delaware and Raritan Canal. The median continuously monitored specific conductance measured during nonstorm conditions at the Route 18 Spillway site increased relative to that of the nearest upstream site, Ten Mile Lock, by approximately 3 to 4 ?S/cm. The mean net change in continuously monitored specific conductance for this reach during storms also increased. Land use in the two largest influent basins within this reach, the Borough of South Bound Brook and Als Brook, is predominantly urban. The mean and median of continuously monitored turbidity varied along the length of the canal. In the reach between Raven Rock and Lower Ferry Road, the mean and median for continuously monitored turbidity during the study period increased by 7.2 and 6.2 NTU (nephelometric turbidity units), respectively. The mean of continuously monitored turbidity decreased downstream from Lower Ferry Road to Ten Mile Lock. Turbidity could increase locally downstream from influent streams or outfalls, but because the average velocity of water in the canal is low, particles that cause turbidity are not transported appreciable distances. In the reach between Ten Mile Lock and the Route 18 Spillway, the mean and median of the continuously monitored turbidity changed less than 0.5 NTU during the period of record. The small change in turbidity in this reach is not consistent with an average velocity for the reach; the average velocity in this reach was the lowest in all of the reaches studied. The expected decrease in turbidity due to settling of suspended solids is likely offset by turbid water entering the canal from influent streams or discharges from storm drains. Field observation of a sand bar immediately downstream from the confluence of Als Brook and the canal confirmed that the Als Brook drainage basin has contributed stormwatergenerated sediment to the canal that could reach the monitor located at the Route 18 Spillway and the raw water intakes for two drinking-water treatment plants.

New Jersey↗