China, the Democratic Republic of the Congo, and artisanal cobalt mining from 2000 through 2020.

From 2000 through 2020, demand for cobalt to manufacture batteries grew 26-fold. Eighty-two percent of this growth occurred in China and China's cobalt refinery production increased 78-fold. Diminished industrial cobalt mine production in the early-to-mid 2000s led many Chinese companies to purchase ores from artisanal cobalt miners in the Democratic Republic of the Congo (DRC), many of whom have been found to be children. Despite extensive research on artisanal cobalt mining, fundamental questions about its production remain unanswered. This gap is addressed here by estimating artisanal cobalt production, processing, and trade. The results show that, while total DRC cobalt mine production grew from 11,000 metric tons (t) in 2000 to 98,000 t in 2020, artisanal production only grew from 1,000 to 2,000 t in 2000 to 9,000 to 11,000 t in 2020 (with a peak of 17,000 to 21,000 t in 2018). Artisanal production's share of world and DRC cobalt mine production peaked around 2008 at 18 to 23% and 40 to 53%, respectively, before trending down to 6 to 8% and 9 to 11% in 2020, respectively. Artisanal production was chiefly exported to China or processed within the DRC by Chinese firms. An average of 72 to 79% of artisanal production was processed at facilities within the DRC from 2016 through 2020. As such, these facilities may be potential monitoring points for artisanal production and its downstream consumers. This finding may help to support responsible sourcing initiatives and better address abuses related to artisanal cobalt mining by focusing local efforts at the artisanal processing facilities through which most artisanal cobalt production flows.

Identifying the origins of obsidian artifacts in the Deh Luran Plain (Southwestern Iran) highlights community connections in the Neolithic Zagros.

Exchange networks created by Neolithic pastoral transhumance have been central to explaining the distant transport of obsidian since chemical analysis was first used to attribute Near Eastern artifacts to their volcanic origins in the 1960s. Since then, critical reassessments of floral, faunal, and chronological data have upended long-held interpretations regarding the emergence of food production and have demonstrated that far-traveled, nomadic pastoralists were more myth than reality, at least during the Neolithic. Despite debates regarding their proposed conveyance mechanisms, obsidian artifacts' transport has received relatively little attention compared with zooarchaeological and archaeobotanical lines of investigation. The rise of nondestructive and portable instruments permits entire obsidian assemblages to be traced to their sources, renewing their significance in elucidating connections among early pastoral and agricultural communities. Here we share our findings about the obsidian artifacts excavated from the sites of Ali Kosh and Chagha Sefid in the southern Zagros. In the 1960s and 1970s, 28 obsidian artifacts from the sites were destructively tested, and the remainder were sorted by color. Our results emphasize a dynamic, accelerating connectivity among the Early and Late Neolithic communities. Here we propose and support an alternative model for obsidian distribution among more settled communities. In brief, diversity in the obsidian assemblage accelerated diachronically, an invisible trend in the earlier studies. Our model of increasing population densities is supported by archaeological data and computational simulations, offering insights regarding the Neolithic Demographic Transition in the Zagros, an equivalent of which is commonly thought to have occurred around the world.

The eco-evolutionary risks of not changing seed provenancing practices in changing environments.

Sourcing seed from local populations has been the long-standing default for native restoration plantings for numerous eco-evolutionary reasons. However, rapidly changing environments are revealing risks associated with both non-local and local provenancing. As alternative strategies gain interest, we argue to progress seed sourcing discussions towards developing risk-based decision-making that weighs the risks of changing and not changing in a changing environment, transcending historic default positions and local versus non-local debates.

Innovation at the Interface between Academia and Industry: The BioMed X Model.

In the evolving landscape of biomedical research, the convergence of molecular biology and translational medicine has ushered in a new era of pharmaceutical innovation. This paradigm shift, characterized by significant advances in targeted therapies and gene editing, emphasizes the critical role of integrating academic research - and academic researchers - within industry settings. Contemporary innovation models are moving beyond traditional, corporation-centered frameworks, adopting more open, collaborative approaches. Here, we discuss the challenges and solutions brought about by this new direction in pharma innovation and describe the BioMed X innovation model, a unique open innovation approach that has been growing continuously over the past ten years.

Web-based psychoacoustics: Hearing screening, infrastructure, and validation.

Anonymous web-based experiments are increasingly used in many domains of behavioral research. However, online studies of auditory perception, especially of psychoacoustic phenomena pertaining to low-level sensory processing, are challenging because of limited available control of the acoustics, and the inability to perform audiometry to confirm normal-hearing status of participants. Here, we outline our approach to mitigate these challenges and validate our procedures by comparing web-based measurements to lab-based data on a range of classic psychoacoustic tasks. Individual tasks were created using jsPsych, an open-source JavaScript front-end library. Dynamic sequences of psychoacoustic tasks were implemented using Django, an open-source library for web applications, and combined with consent pages, questionnaires, and debriefing pages. Subjects were recruited via Prolific, a subject recruitment platform for web-based studies. Guided by a meta-analysis of lab-based data, we developed and validated a screening procedure to select participants for (putative) normal-hearing status based on their responses in a suprathreshold task and a survey. Headphone use was standardized by supplementing procedures from prior literature with a binaural hearing task. Individuals meeting all criteria were re-invited to complete a range of classic psychoacoustic tasks. For the re-invited participants, absolute thresholds were in excellent agreement with lab-based data for fundamental frequency discrimination, gap detection, and sensitivity to interaural time delay and level difference. Furthermore, word identification scores, consonant confusion patterns, and co-modulation masking release effect also matched lab-based studies. Our results suggest that web-based psychoacoustics is a viable complement to lab-based research. Source code for our infrastructure is provided.

Combining crowd-sourcing, census data, and public review forums for real-time, high-resolution food desert estimation.

BACKGROUND: It has been hypothesized that low access to healthy and nutritious food increases health disparities. Low-accessibility areas, called food deserts, are particularly commonplace in lower-income neighborhoods. The metrics for measuring the food environment's health, called food desert indices, are primarily based on decadal census data, limiting their frequency and geographical resolution to that of the census. We aimed to create a food desert index with finer geographic resolution than census data and better responsiveness to environmental changes. MATERIALS AND METHODS: We augmented decadal census data with real-time data from platforms such as Yelp and Google Maps and crowd-sourced answers to questionnaires by the Amazon Mechanical Turks to create a real-time, context-aware, and geographically refined food desert index. Finally, we used this refined index in a concept application that suggests alternative routes with similar ETAs between a source and destination in the Atlanta metropolitan area as an intervention to expose a traveler to better food environments. RESULTS: We made 139,000 pull requests to Yelp, analyzing 15,000 unique food retailers in the metro Atlanta area. In addition, we performed 248,000 walking and driving route analyses on these retailers using Google Maps' API. As a result, we discovered that the metro Atlanta food environment creates a strong bias towards eating out rather than preparing a meal at home when access to vehicles is limited. Contrary to the food desert index that we started with, which changed values only at neighborhood boundaries, the food desert index that we built on top of it captured the changing exposure of a subject as they walked or drove through the city. This model was also sensitive to the changes in the environment that occurred after the census data was collected. CONCLUSIONS: Research on the environmental components of health disparities is flourishing. New machine learning models have the potential to augment various information sources and create fine-tuned models of the environment. This opens the way to better understanding the environment and its effects on health and suggesting better interventions.

Strategic nutrient sourcing for biomanufacturing intensification.

The successful design of economically viable bioprocesses can help to abate global dependence on petroleum, increase supply chain resilience, and add value to agriculture. Specifically, bioprocessing provides the opportunity to replace petrochemical production methods with biological methods and to develop novel bioproducts. Even though a vast range of chemicals can be biomanufactured, the constraints on economic viability, especially while competing with petrochemicals, are severe. There have been extensive gains in our ability to engineer microbes for improved production metrics and utilization of target carbon sources. The impact of growth medium composition on process cost and organism performance receives less attention in the literature than organism engineering efforts, with media optimization often being performed in proprietary settings. The widespread use of corn steep liquor as a nutrient source demonstrates the viability and importance of "waste" streams in biomanufacturing. There are other promising waste streams that can be used to increase the sustainability of biomanufacturing, such as the use of urea instead of fossil fuel-intensive ammonia and the use of struvite instead of contributing to the depletion of phosphate reserves. In this review, we discuss several process-specific optimizations of micronutrients that increased product titers by twofold or more. This practice of deliberate and thoughtful sourcing and adjustment of nutrients can substantially impact process metrics. Yet the mechanisms are rarely explored, making it difficult to generalize the results to other processes. In this review, we will discuss examples of nutrient sourcing and adjustment as a means of process improvement. ONE-SENTENCE SUMMARY: The potential impact of nutrient adjustments on bioprocess performance, economics, and waste valorization is undervalued and largely undercharacterized.

Legal sourcing of ten cannabis products in the Canadian cannabis market, 2019-2021: a repeat cross-sectional study.

BACKGROUND: One of the objectives of cannabis legalization in Canada is to transition consumers from the illegal to the legal market. Little is known about how legal sourcing varies across different cannabis product types, provinces, and frequency of cannabis use. METHODS: Data were analyzed from Canadian respondents in the International Cannabis Policy Study, a repeat cross-sectional survey conducted annually from 2019 to 2021. Respondents were 15,311 past 12-month cannabis consumers of legal age to purchase cannabis. Weighted logistic regression models estimated the association between legal sourcing ("all"/ "some"/ "none") of ten cannabis product types, province, and frequency of cannabis use over time. RESULTS: The percentage of consumers who sourced "all" their cannabis products from legal sources in the past 12 months varied by product type, ranging from 49% of solid concentrate consumers to 82% of cannabis drink consumers in 2021. The percentage of consumers sourcing "all" their respective products legally was greater in 2021 than 2020 across all products. Legal sourcing varied by frequency of use: weekly or more frequent consumers were more likely to source "some" (versus "none") of their products legally versus less frequent consumers. Legal sourcing also varied by province, with a lower likelihood of legal sourcing in Québec of products whose legal sale was restricted (e.g., edibles). CONCLUSION: Legal sourcing increased over time, demonstrating progress in the transition to the legal market for all products in the first three years of legalization in Canada. Legal sourcing was highest for drinks and oils and lowest for solid concentrates and hash.

Responsible sourcing for energy transitions: Discussing academic narratives of responsible sourcing through the lens of natural resources justice.

The Paris Agreement and the United Nations' Sustainable Development Goals clearly demonstrate the need for global energy transitions. Evolving energy generation and the expansion of the renewable energy capacity and associated infrastructure contribute to changing and increasing demands for minerals and metals. The potential negative environmental, social and economic impacts of increased mineral resource production have been contested and are under increasing scrutiny by both academia and civil society. Responsible Sourcing (RS) has become a management approach for companies and policymakers to identify, monitor and address potential negative impacts along their raw materials' supply chains. Although RS might contribute to sustainability along the supply chain, this paper raises the question of whether it also contributes to Natural Resource Justice (NRJ) in energy transitions. Based on a bibliometric network analysis, this study investigated current narratives of RS literature and to what degree core aspects of NRJ (e.g., distribution of benefits and burdens, power asymmetries, property rights) are reflected in the RS debate following a deductive approach. The results obtained show that compared with other sectors (e.g., timber, food, biomass, textiles) debates on RS in renewable energy-related sectors are still scarce and fragmented. The analysis indicates that different foci are aligned with one or more of the traditional three sustainability dimensions (i.e., environmental, social, economic), while few addressed aspects of NRJ. The authors observed a distinct lack of holistic justice considerations in the current RS debate and only a few individual issues are discussed, such as the detection of burden shifting, accountability for supplier behavior, and sharing of financial benefits. This research contributes to the understanding of different RS approaches and extends the RS discussion to NRJ considerations in energy transitions. It also points out important paths for future research to contribute to just energy transitions.

Quantifying ecological and human health risks of heavy metals from different sources in farmland soils within a typical mining and smelting industrial area.

The quality of food crops and human health is threatened by heavy metals (HMs) accumulated in farmland soils for a long time. In this study, we selected 148 soil samples randomly from farmlands in a region featuring abandoned lead-zinc (Pb-Zn) mining activities with the aim to quantify the pollution risk and identify potential sources of heavy metals, based on a case in the southwestern of China. The median contents of metals, such as Pb, Zn, Cd, As, Cu and Cr, are above the background values for Chinese soils and prescribed pollution threshold guide values (GB15618-2018), except Hg and Ni. The farmland soils in sites surrounding areas with previous Pb-Zn mining and smelting activities were classified as seriously polluted. Pollution sources were evaluated using GIS-based geostatistical methods, multivariate statistical analyses and positive matrix factorization (PMF) modeling. Four sources were quantitatively apportioned, which were industrial sources such as mining and smelting (53.1%), agricultural practices (11.6%), natural source (21.6%) and other industrial sources such as electroplating (13.7%). The potential risks of contamination associated with the heavy metals were evaluated using several indices including the Nemerow, geoaccumulation (Igeo) and ecological risk (RI) indices. Based on the Igeo index, As and Pb were the most severe pollutants among all of those measured. With the combination of the potential ecological risk index (RI) and human health risk (HHR) assessment models, the ecological risk and HHR from different sources were analyzed quantitatively. Industrial activities such as mining and smelting were the greatest contributors to ecological risk, non-carcinogenic risk and carcinogenic risk, accounting for about 86.9%,73.9% and 81.9%, respectively. Additionally, the health risks of children were more serious relative to those of adults from the perspective of non-carcinogenic and carcinogenic risks.

Sourcing decisions with loss aversion under yield and demand randomness.

Yield and demand randomness are common in the industry, and loss aversion has been regarded as an inherent behavior for decision-makers. We combine these two factors and investigate a retailer's ordering decisions under both yield and demand randomness with loss aversion. Before the selling season, the demand is unknown and the loss-averse retailer places an order from an unreliable supplier with an uncertain yield rate. After the demand and supply from the unreliable supplier are known, the retailer can carry out emergency replenishment from a spot market during the selling season. We characterize the retailer's optimal ordering decisions in three scenarios: (1) the retailer is risk-neutral; (2) the retailer is loss-averse and has a zero reference profit; (3) the retailer is loss-averse and has a nonzero fixed reference profit (FRP). We compare the retailer's order quantities in the three scenarios and find that the order quantity of the loss-averse retailer with a zero reference profit is always lower than that of the risk-neutral retailer. However, the order quantity of the loss-averse retailer with a nonzero fixed reference profit is higher than that of the risk-neutral retailer when the salvage value is sufficiently large. Interestingly, we find that the loss-averse retailer's optimal order quantity decreases with the reference profit and increases with the loss-averse degree and the maximum fulfillment rate from the unreliable supplier under some conditions. We investigate these conditions under a uniform demand distribution. We further study the ordering quantity of the retailer with a prospect-dependent reference point (PRP) and compare the results under FRP and PRP.

Dual sourcing inventory management with nonconsecutive lead times from a supply chain perspective: a numerical study.

We study a stochastic multi-period two-echelon dual sourcing inventory system where the buyer can source a product from two different suppliers: a regular and an expedited supplier. The regular supplier is a low-cost offshore supplier, whereas the expedited supplier is a responsive nearshore supplier. Such dual sourcing inventory systems have been well studied in the literature, mostly being solely evaluated from the buyer's perspective. Since the buyer's decisions have an impact on the supply chain profit, we adopt the perspective of the entire supply chain, i.e., by taking the suppliers explicitly into consideration. In addition, we study this system for general (nonconsecutive) lead times for which the optimal policy is unknown or very complex. We numerically compare the performance of two different policies in a two-echelon setting: the Dual-Index Policy (DIP) and the Tailored Base-Surge Policy (TBS). From earlier studies we know that when the lead time difference is one period, DIP is optimal from the buyer's perspective, but not necessarily from the supply chain perspective. On the other hand, when the lead time difference grows to infinity, TBS becomes optimal for the buyer. In this paper, we evaluate the policies numerically (under various conditions) and we show that from a supply chain perspective, TBS typically outperforms DIP at a limited lead time difference of a few time periods. Based on data collected from 51 manufacturing firms, the results of our paper imply for many supply chains with a dual sourcing setting that TBS quickly becomes a beneficial policy alternative, especially given its simple and appealing structure.

Broad-scale eDNA sampling for describing aquatic species distributions in running waters: Pacific lamprey Entosphenus tridentatus in the upper Snake River, USA.

One of the most fundamental yet challenging tasks for aquatic ecologists is to precisely delineate the range of species, particularly those that are broadly distributed, require specialized sampling methods, and may be simultaneously declining and increasing in different portions of their range. An exemplar is the Pacific lamprey Entosphenus tridentatus, a jawless anadromous fish of conservation concern that is actively managed in many coastal basins in western North America. To efficiently determine its distribution across the accessible 56,168 km of the upper Snake River basin in the north-western United States, we first delimited potential habitat by using predictions from a species distribution model based on conventionally collected historical data and from the distribution of a potential surrogate, Chinook salmon Oncorhynchus tshawytscha, which yielded a potential habitat network of 10,615 km. Within this area, we conducted a two-stage environmental DNA survey involving 394 new samples and 187 archived samples collected by professional biologists and citizen scientists using a single, standardized method from 2015 to 2021. We estimated that Pacific lamprey occupied 1875 km of lotic habitat in this basin, of which 1444 km may have been influenced by recent translocation efforts. Pacific lamprey DNA was consistently present throughout most river main stems, although detections became weaker or less frequent in the largest and warmest downstream channels and near their headwater extent. Pacific lamprey were detected in nearly all stocked tributaries, but there was no evidence of indigenous populations in such habitats. There was evidence of post-stocking movement because detections were 1.8-36.0 km upstream from release sites. By crafting a model-driven spatial sampling template and executing an eDNA-based sampling campaign led by professionals and volunteers, supplemented by previously collected samples, we established a benchmark for understanding the current range of Pacific lamprey across a large portion of its range in the interior Columbia River basin. This approach could be tailored to refine range estimates for other wide-ranging aquatic species of conservation concern.

[Social media-Chances and risks for rheumatology]. / Social Media ­ Chancen und Risiken für die Rheumatologie.

The use of social media and social networks has increased significantly in recent years. They are becoming progressively more important as information channels in private and professional contexts. Also, in medicine, social media are already being used in a variety of ways. For example, professional societies and patient interest groups are being increasingly represented in social networks. The broad use and wide audience of these networks offer new opportunities for the field of rheumatology. This review article provides an overview of the characteristics of some major social media platforms and systematically analyses the existing publications in the context of rheumatology. Furthermore, advantages, but also potential risks that may arise due to social media use are being addressed.

How has the COVID-19 pandemic affected the use of ride-sourcing services? An empirical evidence-based investigation for the Greater Toronto Area.

The ongoing COVID-19 pandemic has fundamentally changed the nature of day-to-day life in cities worldwide. In the transportation sector, COVID-19 appears to have impacted modal preferences. In particular, people seem to be less willing to use modes where they may encounter strangers (such as public transit) and modes that involve coming into contact with shared surfaces (such as ride-sourcing). Given the transformative impact that ride-sourcing services had on urban mobility before the pandemic, it is crucial to understand the effects of COVID-19 on the use of ride-sourcing moving forward. Using data from a web-based survey, this study combines descriptive analysis with the application of a two-stage ordered logit model framework to investigate the impacts of COVID-19 on the utilization of ride-sourcing services in the Greater Toronto Area, including how often ride-sourcing is used and the earliest stage of the pandemic that a person would consider using ride-sourcing. Generally speaking, the use of ride-sourcing has decreased since the start of the pandemic, however, there are also people who are using ride-sourcing more often than they did before the pandemic. The results indicate that the perception of risk, the tendency to take precautions when leaving home, and socio-economic factors influence the earliest stage of the pandemic where a person would consider using ride-sourcing. Overall, it appears that ride-sourcing usage will gradually increase as restrictions are lifted; however, it is unlikely to return to pre-pandemic levels until COVID-19 is no longer considered a public health threat.

Intentions to use ride-sourcing services in Vietnam: What happens after three months without COVID-19 infections?

The COVID-19 pandemic has brought new risks and stress for paid transport users worldwide. COVID-19 has changed mobility dynamics worldwide, including low- and middle-income countries (e.g., Vietnam). The present study aims to provide an in-depth understanding of ride-sourcing passengers' behavioural intentions when COVID-19 pandemic management successfully prevented community transmission by extending the TPB with two constructs: perceived virus infection risk and problem-focused coping. Using self-administered questionnaires, data were collected from ride-sourcing customers in Ho Chi Minh City (Vietnam). A total of 540 responses were used for validating the proposed theorethical model. The structural equation model results indicate that problem-focused coping is a multi-faceted construct with two dimensions: problem-solving and self-protection. Also, problem-focused coping has the highest total effect on the intention to use ride-sourcing services following a period of COVID-19 suppression (3 months without identified cases). The findings also reveal that attitude partially mediates the link between problem-focused coping and behavioural intention. The results of this study could be used to develop strategies to promote ride-sourcing services in the aftermath of the COVID-19 pandemic.

Exploring impacts of COVID-19 on city-wide taxi and ride-sourcing markets: Evidence from Ningbo, China.

The outbreak of the COVID-19 epidemic has brought enormous impacts and changes to human mobility. To better understand and quantify the impacts of COVID-19 on city-wide ride-sourcing and taxi markets, we present exploratory evidence on the factors such as coronavirus cases related attributes, policy-related attributes, operational status of transportation, socio-economic status related variables, demographics related variables, and other factors. Based on 5-month real-world ride-sourcing and taxi datasets in Ningbo, China, including 37-million trips, we study the temporal variations of drivers' working characteristics and productivity of ride-sourcing and taxi fleets. The spatial heterogeneity of the impacts of COVID-19 on taxi and ride-sourcing trips is demonstrated in terms of traffic analysis zones (TAZs). Regression models are established to examine the impacts of a variety of explanatory variables, including COVID-19 related variables, on the district-level productivity of taxi and ride-sourcing services. The results show that the accumulated cured coronavirus cases, policy of closed management, operational status of mass transit, and average fee spent on transportation per capita significantly impact the productivity of the taxi and ride-sourcing fleets. This paper empirically reveals the influence of the epidemic on ride-sourcing and taxi markets and the temporal and spatial variations. The findings can support decision-making to restore the ride-sourcing and taxi markets and benefit other COVID-19 related research efforts.

Adolescents' credibility justifications when evaluating online texts.

Research has shown that students differ in their abilities to evaluate the credibility of online texts, and, in general, many perform poorly on online evaluation tasks. This study extended current knowledge by examining students' abilities to justify the credibility of online texts from different perspectives, thus providing a more nuanced understanding of students' credibility evaluation ability. We examined how upper secondary school students (N = 73; aged 16 to 17) evaluated author expertise, author intention, the publication venue, and the quality of evidence when reading four texts about the effects of sugar consumption in a web-based environment. Additionally, we examined how students' prior topic knowledge, Internet-specific justification beliefs, and time on task were associated with their credibility justifications. Students evaluated author expertise, author intention, the venue, and the quality of evidence for each text on a six-point scale and provided written justifications for their evaluations. While students' credibility evaluations were quite accurate, their credibility justifications lacked sophistication. Inter-individual differences were considerable, however. Regression analysis revealed that time on task was a statistically significant unique predictor of students' credibility justifications. Instructional implications are discussed.

Using a new video rating tool to crowd-source analysis of behavioural reaction to stimuli.

Quantifying the intensity of animals' reaction to stimuli is notoriously difficult as classic unidimensional measures of responses such as latency or duration of looking can fail to capture the overall strength of behavioural responses. More holistic rating can be useful but have the inherent risks of subjective bias and lack of repeatability. Here, we explored whether crowdsourcing could be used to efficiently and reliably overcome these potential flaws. A total of 396 participants watched online videos of dogs reacting to auditory stimuli and provided 23,248 ratings of the strength of the dogs' responses from zero (default) to 100 using an online survey form. We found that raters achieved very high inter-rater reliability across multiple datasets (although their responses were affected by their sex, age, and attitude towards animals) and that as few as 10 raters could be used to achieve a reliable result. A linear mixed model applied to PCA components of behaviours discovered that the dogs' facial expressions and head orientation influenced the strength of behaviour ratings the most. Further linear mixed models showed that that strength of behaviour ratings was moderately correlated to the duration of dogs' reactions but not to dogs' reaction latency (from the stimulus onset). This suggests that observers' ratings captured consistent dimensions of animals' responses that are not fully represented by more classic unidimensional metrics. Finally, we report that overall participants strongly enjoyed the experience. Thus, we suggest that using crowdsourcing can offer a useful, repeatable tool to assess behavioural intensity in experimental or observational studies where unidimensional coding may miss nuance, or where coding multiple dimensions may be too time-consuming.

Improvements in identification and quantitation of alkylated PAHs and forensic ratio sourcing.

Parent and alkylated polycyclic aromatic hydrocarbons (PAHs) are present in a number of different sources in varying proportions depending on the source material and weathering. This range of PAH sources can make it difficult to determine the origin of exposure(s). Ratios of alkylated and parent PAHs have been applied as a forensic tool to distinguish between different sources. However, few studies have examined PAH ratios comprehensively as indicators for sourcing beyond a single study area or matrix type. In this paper, we introduce an expanded analytical method based on ASTM D7363-13a which we adapted for a gas chromatography triple quadrupole mass spectrometry instrument. The modifications increase selectivity and sensitivity compared to the ASTM method. We added five alkylated series to the method. This method has then been applied to 22 independent forensic ratios. We evaluated the method and the forensic ratios with certified reference materials and known environmental samples. This analytical method and thirteen PAH ratios were found to accurately predict sources of PAHs.