Tritium In Groundwater Research Articles

Assessment of the annual effective dose and lifetime cancer risks associated with tritium in groundwater within different age groups

Tritium is a radioactive isotope of hydrogen that emits low-energy radiation. When humans are exposed to tritium, the primary concern is internal exposure through inhalation, ingestion, or absorption through the skin. The severity of the adverse health effects depends on the duration, amount, and route of exposure. Therefore, estimating the tritium levels in groundwater and the corresponding health risks within different age groups is essential. The annual effective dose is determined by considering several factors, including the concentration of tritium, the volume of water consumed, and the duration of exposure. The calculated annual effective doses were then compared to the safety limit as directed by international organizations. The estimated tritium concentration in the searched groundwater samples was significantly low, ranging from 0.014 to 0.114 Bq/L. The annual effective dose of tritium exposure for infants, children, and adults varies from 0.028 to 0.605 μSv/y and is within the safe limit recommended by the World Health Organization (WHO) and other international organizations. The lifetime cancer risk (LTCR) for the consumer in the searched areas was estimated for males and females based on the average lifetime. Mortality and morbidity rates varied slightly between males and females across samples due to differences in activity concentrations and locations. However, the estimated LTCR values were below the radiological cancer risk limit. These findings will provide valuable insights to regulatory authorities, assisting them in developing strategies to ensure public safety against human exposure to tritium.

Enrichment of Low-Level Tritium in Groundwater via an Electrolysis Process for Liquid Scintillation Counting Applications

Tritium levels in the groundwater of arid regions are very low; in most cases, these low tritium levels cannot be detected using a conventional liquid scintillation counter (LSC). To measure the tritium activity concentration, low-level tritium in groundwater needs to be enriched by a known factor so that the scintillation counter can detect it. An electrolysis process with electrolytic cells was designed and fabricated in our laboratory following the International Atomic Energy Agency (IAEA) instructions. Nine spiked samples with a known quantity of tritium were enriched, and the tritium activity concentration was measured using the scintillation counter. The enriched water exhibits a comparable level of spiked samples, albeit with some degree of uncertainty. A correlation was drawn among the tritium activity, enrichment factor, and the required time for the electrolysis procedure. This study confirmed that an enrichment process of approximately ten- to fortyfold of the initial concentration of the tritium could be achieved using the electrolysis process with the fabricated electrolytic cells. The simple design and fabrication of the electrolysis process by controlling various parameters make it affordable to measure low-level tritium using a conventional LSC. Various statistical analyses confirmed the accuracy and precision of the data obtained by the electrolysis process. This enrichment technique would prove valuable in regions where tritium levels in groundwater are extremely low, making them challenging to detect using conventional liquid scintillation counter.

Modern groundwater reaches deeper depths in heavily pumped aquifer systems

Deep groundwater is an important source of drinking water, and can be preferable to shallower groundwaters where they are polluted by surface-borne contaminants. Surface-borne contaminants are disproportionately common in ‘modern’ groundwaters that are made up of precipitation that fell since the ~1950s. Some local-scale studies have suggested that groundwater pumping can draw modern groundwater downward and potentially pollute deep aquifers, but the prevalence of such pumping-induced downwelling at continental scale is not known. Here we analyse thousands of US groundwater tritium measurements to show that modern groundwater tends to reach deeper depths in heavily pumped aquifer systems. These findings imply that groundwater pumping can draw mobile surface-borne pollutants to deeper depths than they would reach in the absence of pumping. We conclude that intensive groundwater pumping can draw recently recharged groundwater deeper into aquifer systems, potentially endangering deep groundwater quality.

Reconstruction of the record of tritium in precipitation in the temperate zone of South America

AbstractTritium, a radioisotope of hydrogen, is an ideal tracer for groundwater and surface dating and tracking since it is part of the water molecule. The knowledge of the history of tritium in precipitation and recharge is the key link for the calculation of groundwater tritium age. However, records of tritium in precipitation are usually sparse and discontinuous, especially in regions like South America, and often need to be reconstructed. To solve this problem, different reconstruction methods of the tritium input function have been analysed and compared. Clustering of Global Network of Isotopes in Precipitation stations by regions and the correlation with the complete and continuous data recorded in Kaitoke (New Zealand) proved to be the most effective approach, having low relative errors and a much more extended coverage in time compared to other interpolation or reference curves methods. Thus, tritium time series for five different regions of the temperate zone of South America were obtained. These curves can be used as representative tritium input curves in future studies for these regions. The results obtained also allow a quick qualitative analysis of groundwater ages in these areas, based on their current or past tritium concentrations. In addition, they contributed to the understanding of the patterns and characteristics of tritium distribution in the atmosphere of the southern sector of South America.

Tritium as a tool to assess leachate contamination: An example from Conversano landfill (Southern Italy)

This paper describes the geochemical and isotopic data processing combined with statistical analysis aimed to fine-tune the tritium background threshold limits to identify groundwater contamination due to leachate dispersion at a very high level of sensitivity. The selected case study refers to a landfill located in area subjected to marine intrusion and intense anthropic pressure due to agricultural activities. The investigated aquifer pertains to a karst system with a geological structure that potentially allows an easy spread of contamination. Twenty wells, with depth ranging from 179 to 462 m, and 4 leachate samples, were collected and analysed for main dissolved ions, some minor and trace species (NH4+, NO2−, Br−) and isotope content (δ18O, δ2H and tritium). The adopted approach allowed defining the geochemical background of groundwater tritium content, and confirming that tritium content is an effective leachate tracer, both for the high contrast between groundwater and leachate, and for its conservative characteristics. These characteristics make tritium the leachate tracer par excellence, far preferable to any chemical or other isotopic parameters, whose variations may be influenced by chemical and physical processes other than leachate contamination.

Constraining the Spatial Distribution of Tritium in Groundwater Across South Africa

AbstractTritium (3H) has become synonymous with modern groundwater and is used in a myriad of applications, ranging from sustainability investigations to contaminant transport and groundwater vulnerability. This study uses measured 3H groundwater activities from 722 sample locations across South Africa to construct a 3H groundwater distribution surface. Environmental covariables are tested using geostatistical analysis to constrain external controls on 3H variability, namely: (a) depth to groundwater, (b) distance from the ocean, and (c) summer versus winter rainfall proportion. The inclusion of covariables in the “fit” of residual variograms improved prediction variance significantly yet does not mitigate issues with sample density. The distribution of 3H in groundwater agrees well to expected controls, with proximal (<100 km) coastal regions, winter rainfall zones, and greater depth to groundwater predicted to have lower 3H activities. Conversely, inland localities with shallower depth to groundwater and/or summer rainfall are predicted to have elevated 3H activities. Some 3H high and low anomalies cannot be explained by known phenomena and may simply be regions of variable recharge and/or longer isolated groundwater flow paths. Regions that receive modern groundwater recharge are more vulnerable to climate change as well as modern pollution. Less actively recharged groundwater may be more resilient to climate change yet represents a potentially nonrenewable resource for abstraction in South Africa. The application of 3H distributions in the assessment of hydrological resilience is pertinent to effective groundwater management studies.

Landside tritium leakage over through years from Fukushima Dai-ichi nuclear plant and relationship between countermeasures and contaminated water

There has been tritium groundwater leakage to the land side of Fukushima Dai-ichi nuclear power plants since 2013. Groundwater was continuously collected from the end of 2013 to 2019, with an average tritium concentration of approximately 20 Bq/L. Based on tritium data published by Tokyo Electric Power Company Holdings (TEPCO) (17,000 points), the postulated source of the leakage was (1) leaks from a contaminated water tank that occurred from 2013 to 2014, or (2) a leak of tritium that had spread widely over an impermeable layer under the site. Based on our results, sea side and land side tritium leakage monitoring systems should be strengthened.

Usefulness of historical measurements of tritium content in groundwater for recharge assessment in semi-arid regions: application to several aquifers in central Tunisia

Tritium is a well-known tracer, used to estimate the age of modern groundwater (<50 years) and consequently to capture information on the longer-term components of recharge in aquifers. However, its current low concentration in groundwater limits its usefulness for recharge assessment, which is more symptomatic of arid and semi-arid regions where the recharge is characterized by extreme spatial and temporal variability. Regions where groundwater tritium was studied at a time close to the peak of nuclear bomb testing (1963) would be worth studying again today to establish new information. This report describes the application of a radioactivity decay model to a long (up to 50 years) record of tritium in rainfall and the associated recharge to several aquifers in central Tunisia; these aquifers were sampled for tritium in 1967. The results show that the groundwater renewal rate has a large range: 0.06–2.2% of annual mean rainfall for Plio-Quaternary aquifers, 0.1–6.46% for Mio-Pliocene aquifers, and 0.1–1.5% for the upper Oligocene aquifers. A good agreement was found between the recharge estimated in this study and the recharge estimated in previous studies only for the upper Oligocene aquifers. This suggest that the methodology of recharge estimation, described in this report, is reliable only for aquifers of homogeneous lithology with a localized recharge area, but the method is less consistent for detrital aquifers, i.e. composed of lenticular sediments. The results also highlight the usefulness of historical (1950–1970) measurements of tritium in groundwater for the estimation of the groundwater recharge.

Tracing natural groundwater recharge to the Thiaroye aquifer of Dakar, Senegal

Urban groundwater in Sub-Saharan Africa provides vital freshwater to rapidly growing cities. In the Thiaroye aquifer of Dakar (Senegal), groundwater within Quaternary unconsolidated sands provided nearly half of the city’s water supply into the 1980s. Rising nitrate concentrations traced to faecal contamination sharply curtailed groundwater withdrawals, which now contribute just 5% to Dakar’s water supply. To understand the attenuation capacity of this urban aquifer under a monsoonal semi-arid climate, stable-isotope ratios of O and H and radioactive tritium (3H), compiled over several studies, are used together with piezometric data to trace the origin of groundwater recharge and groundwater flowpaths. Shallow groundwaters derive predominantly from modern rainfall (tritium >2 TU in 85% of sampled wells). δ18O and δ2H values in groundwater vary by >4 and 20‰, respectively, reflecting substantial variability in evaporative enrichment prior to recharge. These signatures in groundwater regress to a value on the local meteoric water line that is depleted in heavy isotopes relative to the weighted-mean average composition of local rainfall, a bias that suggests recharge derives preferentially from isotopically depleted rainfall observed during the latter part of the monsoon (September). The distribution of tritium in groundwater is consistent with groundwater flowpaths to seasonal lakes and wetlands, defined by piezometric records. Piezometric data further confirm the diffuse nature and seasonality of rain-fed recharge. The conceptual understanding of groundwater recharge and flow provides a context to evaluate attenuation of anthropogenic recharge that is effectively diffuse and constant from the vast network of sanitation facilities that drain to this aquifer.

Research on Establishing Tritium Concentration Model of Precipitation in Northeast of Tarim Basin Based on Factor Analysis

In the study of groundwater quantitative dating with tritium isotope, the establishment of tritium concentration model in precipitation is the key link, which provides the input function value for the calculation of groundwater tritium age. The Global Network of Isotopes in Precipitation (GNIP) jointly established by the international atomic energy agency (IAEA) and the world meteorological organization (WMO) provides a lot of data for the study of tritium isotopes in precipitation. Factor analysis is able to reduce variables with complex relations into a few comprehensive factors based on the internal dependence of variables. Therefore, factor analysis has obvious advantages in establishing tritium concentration model of precipitation based on a large number of tritium data in precipitation. In this paper, a tritium concentration model of precipitation in northeast Tarim basin had been established using factor analysis method, and calibrated with real data. The calculated results of model were in a good agreement with real data, showing that the model is reasonable. Meanwhile, considering the influence of nuclear test in the 20th century on the tritium concentration in the atmosphere of the study area, some previous research results were adopted, and the tritium concentration data in precipitation from 1960 to 2009 were finally recovered. In order to further verify the reasonability of the model, the recovered tritium concentration data in precipitation in northwest of Tarim basin were put to piston flow model and mixed flow model to date four groundwater samples in Kuketag, and the results showed that the tritium age of groundwater was consistent with the hydrogeological condition of study area. Therefore, it was considered that the tritium concentration model of precipitation in northeastern tarim basin was reasonable and reliable.

Characterization of recharge mechanisms in a Precambrian basement aquifer in semi-arid south-west Niger

In the central part of the semi-arid Dargol Basin of southwestern Niger, most of the groundwater resource is contained in the fractured aquifers of the Precambrian basement. The groundwater resource is poorly characterized and this study is the first attempt to better describe the recharge mechanisms and hydrogeochemical behaviour of the aquifers. Hydrogeochemical and piezometric methods were combined to determine changes in recharge rate and origin of groundwaters for the shallow weathered aquifer and the deep fissured/fractured aquifer. At the basin scale, the groundwater fluxes towards the Niger River are influenced mainly by topography, with no visual long-term trend in groundwater levels (1980–2009). The hydro-geochemical signature is dominated by the calcic-bicarbonate to magnesian (70%) type. It shows evolution from an open environment with CO2 and low mineralized water (granitoids, alterites) towards a more confined environment with more mineralized waters (schists). Stable water isotopes (δ18O, δ2H) analysis suggests two main groundwater recharge mechanisms: (1) direct recharge with nearly no post-rainfall fractionation signature and (2) indirect recharge from evaporated surface waters and/or stream-channel beds. Groundwater tritium content indicates that recharge is mostly recent, with an age less than 50 years (3H > 3 TU), with only 10% indicating low or even no recharge for the past decades. A median value of the groundwater renewal rate estimated from individual values of tritium is equivalent to 1.3% year−1, close to the one determined for groundwater samples dating to the early 1980s, thus indicating no measurable long-term change.

Assessing aquifer vulnerability from lumped parameter modeling of modern water proportions in groundwater mixtures: Application to California's South Coast Range

Groundwater in agriculture-dominated regions of California has historically experienced nitrate pollution due to the application of excess nitrogen fertilizers. This study examines the nitrate pollution vulnerability of groundwater in sedimentary aquifers of California's South Coast Range using stepwise logistic regression (LR) modeling. Our results indicate an overall excellent model fit, but an acceptable statistical significance, according to a Wald statistic (p-Wald) cutoff of 0.1, for only two explanatory variables: (1) the dissolved oxygen (DO) concentration, and (2) the modern (i.e., less than ~60year old) water proportion (MWP) in the groundwater mixture. The latter parameter was estimated via Lumped Parameter Modeling (LPM) of groundwater tritium, helium and radiocarbon data that have been corrected for isotopic dilution and exchange using a modified Fontes and Garnier (F&G) approach. The observation that other explanatory variables on land cover (i.e., percentage of agricultural land use, abundance of septic tanks and leaking underground fuel tanks, etc.) were statistically insignificant points out the limitations of low-resolution land cover data in groundwater vulnerability assessments. Our results highlight the utility of quantitative groundwater age and mixing data to evaluate pollution probability in the saturated zone. The herein presented approach can thus provide valuable results in comparable settings where the availability of fertilizer application, crop nitrogen uptake, and soil texture data is limited.

Tritium in groundwater in the Black Hills of South Dakota

Tritium from 1950s and 1960s atmospheric hydrogen-bomb tests was dispersed into the stratosphere and around the globe. The fallout of tritium in precipitation was especially high in the northern hemisphere, peaking during a flurry of atmospheric nuclear testing in 1963. Rainout from hydrogen-bomb tests recharged aquifers, and this maximum of tritiated water inadvertently has provided hydrogeologists with a way to establish the time of recharge because prior to hydrogen-bomb explosions, practically no tritium existed in groundwater. In 1967, the US Geological Survey took numerous Inyan Kara Group groundwater samples in the Dewey/Burdock area of the southwestern Black Hills. They found tritium concentrations exceeding 200 tritium units and determined a groundwater velocity of 4.6 m per day in the Inyan Kara aquifer, assuming the tritium originated from rainout on nearby outcrops in 1963. In 2011, the US Geological Survey took groundwater samples in the same general area as the 1967 study. These samples from the Inyan Kara Group had tritium concentrations ranging from ≤ 0 to 15.3 tritium units, much lower than the 1967 study and almost back to values expected from natural production of tritium. Because the half-life of tritium is ~ 12.3 years, only 7% of the tritium generated from tests in 1963 would still be present 48 years later in 2011. The maximum tritium values found in the 2011 study are approximately the values expected from radioactive decay only; this could be interpreted that in some locations very slow groundwater movement has occurred between 1967 and 2011, while in other locations lower tritium values show there has been much faster movement. However, the great range of tritium concentrations indicates considerable variability in groundwater dispersion has occurred. This variability is caused by the complex stratigraphic units of irregular geometry and permeability in the Inyan Kara Group.

Evaluation of groundwater tritium content and mixing behavior of Tatapani geothermal systems, Chhattisgarh, India

Isotopic investigations were carried out on hot springs, groundwater and surface water to evaluate the mixing processes within the geothermal system. Physico-chemical parameter (EC, pH, Temp.) and tritium content of groundwater, hot springs and surface water were measured. The temperature of the hot springs were varied from 60 to 98.8 °C and EC from 674 to 728 μS/cm. The tritium content of groundwater varies from 1.5 to 5 TU whereas, geothermal water have slightly less tritium and their values ranges from 1.4 to 4.4 TU. Low tritium, higher EC and high temperature of a few hot springs indicate insignificant mixing whereas high tritium, lower EC and low temperature indicates significant mixing of thermal and non-thermal water. The degree of mixing for geothermal springs is estimated. It is found that the groundwater components present in the diluted thermal waters are about 25–80%. It is also observed that mixing process is prominent along the fault and in the area where groundwater exploitation is more. Extensive pumping of groundwater causes an increase in the rate of mixing of thermal and non-thermal water. The tritium content of groundwater, surface water and hot springs are indicating, it is of modern recharge.

Changes in HTO and OBT activity concentrations in the Perch Lake aquatic ecosystem

Perch Lake, a small shallow shield lake located on the Chalk River Laboratories (CRL) site, contains elevated levels of tritium due to inputs from a nearby nuclear waste management area. The releases have been going on for many years but tritium levels in Perch Lake have been gradually decreasing since about year 2000. Lake water, sediments, aquatic plants, clams and fish were collected during the summer and fall of 2003 and 2013 at three locations in the lake. HTO activity concentrations were measured in all samples and OBT activity concentrations were measured in sediments, plants, clams and fish. In 2003, 2013, HTO activity concentrations in lake water were roughly uniform in time and space, except close to the shoreline where concentrations were fluctuating according to stream water and groundwater tritium levels in streams entering the lake. HTO activity concentrations of biota were similar to concentrations in lake water at the site where they were collected. OBT activity concentrations in biota were not always correlating with the lake water HTO levels. OBT to HTO ratios were found to be less than 1 for aquatic plants, around 1 for clams and fish and above 1 for birds reared on the shore of the lake.

GROUNDWATER EXCHANGE IN THE BALTIC SHIELD MARGINAL AREAS AND ADJACENT ARTESIAN BASINS BASED ON ISOTOPE AND HYDROCHEMISTRY DATA. SCIENTIFIC PROBLEMS AND PRACTICAL APPLICATIONS. KARELIAN ISTHMUS

Water chemical and isotopic composition (deuterium content and oxygen-18), as well as the activity of tritium in groundwater of Riphean aquifer and Vendian complex in the Karelian Isthmus were studied. Estimation of recharge rate for groundwater of the Vendian complex by tritium yielded groundwater ages up to 100 years for this area, which is located not far from Central Karelian watershed. For the area where the Vendian complex is overlapped by the Kotlin aquiclude, water age varied from several hundreds to several thousands years as determined by the radium/radon method. Isotopic data (δ 2 H and δ 18 O) indicate that the Vendian complex has no recharge there, and the complex is therefore protected from contamination from the surface, and at the same time its resources are mainly supplied by lateral inflow. The Ladoga graben is apparently dominated by slow water exchange regime, given that at a depth of 250 m relict waters of the Baltic Ice Lake were identified by isotope and hydrochemical criteria.

Assessing Connectivity Between an Overlying Aquifer and a Coal Seam Gas Resource Using Methane Isotopes, Dissolved Organic Carbon and Tritium.

Coal seam gas (CSG) production can have an impact on groundwater quality and quantity in adjacent or overlying aquifers. To assess this impact we need to determine the background groundwater chemistry and to map geological pathways of hydraulic connectivity between aquifers. In south-east Queensland (Qld), Australia, a globally important CSG exploration and production province, we mapped hydraulic connectivity between the Walloon Coal Measures (WCM, the target formation for gas production) and the overlying Condamine River Alluvial Aquifer (CRAA), using groundwater methane (CH4) concentration and isotopic composition (δ13C-CH4), groundwater tritium (3H) and dissolved organic carbon (DOC) concentration. A continuous mobile CH4 survey adjacent to CSG developments was used to determine the source signature of CH4 derived from the WCM. Trends in groundwater δ13C-CH4 versus CH4 concentration, in association with DOC concentration and 3H analysis, identify locations where CH4 in the groundwater of the CRAA most likely originates from the WCM. The methodology is widely applicable in unconventional gas development regions worldwide for providing an early indicator of geological pathways of hydraulic connectivity.

Spatial variation of groundwater arsenic distribution in the Chianan Plain, SW Taiwan: Role of local hydrogeological factors and geothermal sources

We present here major ion, trace element, stable and radioisotope data based on forty-six groundwater samples collected from various locations along few selected profiles across the Chianan Plain, southwestern Taiwan including the area affected by well known Blackfoot disease manifested by peripheral vascular gangrene. The objective of the study was to understand the role of local hydrogeology in terms of spatial variation of arsenic concentration in groundwater wells of the entire Chianan Plain and the foothill belt of the Central Mountain Range. An attempt has also been made to assess the contribution of nearby geothermal sources to the arsenic budget in groundwater of the Chianan Plain. Our study shows a gradual increase in all major and trace ion concentrations including total arsenic from foothill belt (arsenic: median = 4 μg/L, range = 0–667.6 μg/L, sample number n = 16) to coastal zones (arsenic: median = 42.74 μg/L, range = 0.14–348.6 μg/L, n = 15) of the plain. Inverse geochemical modeling shows that Ca may be exchanged on clays, and that the degree of the exchange increases from the foothill to the coastal zones. Inverse geochemical modeling further suggests that the oxidation of organic matter (CH2O) required in various east-west profiles across the plain to balance the total bicarbonate concentration and CO2 input from organic matters significantly increases from the foothill to the coastal zones with transfer coefficients ranging from 1.55 × 10−2 to 1.69 × 10−5 mol/L. High concentrations of tritium (mean = 1.33 ± 0.11 TU; n = 4) in foothill groundwater and low concentration of tritium in groundwater of central zone suggest gradually increasing water–rock interaction from the foothill to the coastal part. Few elevated arsenic (median = 171.8 μg/L, maximum = 667.60 μg/L, minimum = 24 μg/L; n = 6) hotspots are identified in the foothill belt. Available lithologs and aquifer test data suggest that the presence of impermeable clay around those pockets possibly inhibits vertical and lateral flushing of the aquifer and aids strong water–rock interactions subsequently leading to release of arsenic into groundwater. Using oxygen isotope and chloride mass balance method, we estimated that geothermal sources can recharge a maximum of 4% of groundwater in proximal aquifers and contribute <2% of average As concentration in the groundwater of Chianan Plain. Our preliminary observations thus show some arsenic enrichment in foothill aquifers, providing a necessity of detailed study of the aquifer systems in these understudied regions. Moreover, our research indicates that the contribution of arsenic from geothermal sources is insignificant, which stands in contrast to earlier studies suggesting that mud volcanoes and thermal springs in the Western Foothill Belt of the Central Mountain Range were potential sources of groundwater arsenic in the Chianan Plain aquifers.

Procedure for Radio Dating of Water Using Nuclear Hydrological Isotopes Techniques

The regular rates of decay for unstable radioactive elements were found to constitute a virtual clocks within a material they are found to be component. Some water molecules are found to be radioactive due to the increase of tritium in the atmosphere. Tritium concentration in groundwater reflect atmospheric tritium levels when the water was last in contact with the atmosphere, therefore, any measurable tritium concentrations in groundwater system provides clear evidence of recharge occurring into the system during the last four decades. Since 1970s, the atmospheric tritium concentration has decreased. Thus, the presence of excess tritium in groundwater indicates recharge on a time scale of approximately 60 years. Samples are collected along with geographical coordinate of the sampling point. The samples are collected from precipitation, surface water and groundwater which undergo three stages of tritium analysis viz: Screening, Tritium enrichment (Electrolysis) and Scintillation counting. Tritium activity AB in (Bq/Kg) and tritium concentration AT in (TU) are related as:

The design, construction, and initial characterization of an ultra-low-background gas-proportional counting system

Over the past several years, the Pacific Northwest National Laboratory (PNNL) has developed an ultra-low-background proportional counter (ULBPC) technology. The resulting detector is the product of an effort to produce a low-background, physically robust gas proportional counter for applications like radon emanation measurements, groundwater tritium, and 37Ar. In order to fully take advantage of the inherent low-background properties designed into the ULBPC, a comparably low-background dedicated counting system is required. An ultra-low-background counting system (ULBCS) was recently built in the new shallow underground laboratory at PNNL. With a design depth of 30 m water-equivalent, the shallow underground laboratory provides approximately 100× fewer fast neutrons and 6× fewer muons than a surface location. The ULBCS itself provides additional shielding in the form of active anti-cosmic veto (via 2-in-thick plastic scintillator paddles) and passive borated poly (1 in.), lead (6 in.), and copper (~3 in.) shielding. This work will provide details on PNNL’s new shallow underground laboratory, examine the motivation for the design of the counting system, and provide results from the characterization of the ULBCS, including initial detector background.