Article
Geography, Physical
Richard S. Vachula, Allison T. Karp, Elizabeth H. Denis, Nicholas L. Balascio, Elizabeth A. Canuel, Yongsong Huang
Summary: This study examined the relationship between PAH fluxes preserved in lake sediments in the Sierra Nevada, California, and the area burned, finding that certain PAHs may be influenced by anthropogenic pollution sources when recording area burned. However, other specific PAHs were found to be reliable proxies of burned areas within certain spatial scales.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Masanobu Yamamoto, Takafumi Kikuchi, Hiromichi Sakurai, Ryoma Hayashi, Osamu Seki, Takayuki Omori, Abdullah Sulaiman, Hasrizal Shaari, Mohd Zulhilmy Abdullah, Lulie Melling
Summary: The study indicates that over the past 6,000 years, peatlands in Borneo have experienced repeated dry conditions and wildfires due to higher solar activity reducing rainfall and increasing the frequency of dryness and wildfires. This challenges the hypothesis that high solar activity intensifies atmospheric convection in the Western Pacific Warm Pool region.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geography, Physical
Yi Song, Yuan Tian, Jianxin Yu, Thomas J. Algeo, Genming Luo, Daoliang Chu, Shucheng Xie
Summary: This study provides evidence for the link between wildfire frequency and climate change during the Permian-Triassic transition. By analyzing fossils and coal deposits, researchers found that climate warming and drying were the main factors contributing to increased wildfires.
GLOBAL AND PLANETARY CHANGE
(2022)
Article
Geosciences, Multidisciplinary
Allison T. Karp, Jake W. Andrae, Francesca A. McInerney, Pratigya J. Polissar, Katherine H. Freeman
Summary: The establishment of C-4 grasslands in Australia was delayed compared to other continents, possibly due to the presence of fire-adapted C-3 woody vegetation and changes in rainfall affecting soil carbon transport. This ecosystem shift altered carbon storage and hydroclimate, leading to unique responses to climate change in Australian ecosystems.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geography, Physical
Rebecca G. Topness, Richard S. Vachula, Nicholas L. Balascio, William J. D'Andrea, Genevieve Pugsley, Moussa Dia, Martina Tingley, Lorelei Curtin, Stephen Wickler, R. Scott Anderson
Summary: This study analyzes lake sediment records from the Lofoten Islands, Norway to investigate the fire history of the region. The results show an increase in fire activity starting from around 7500 years ago, with human impacts becoming evident around 5000 years ago. The establishment and expansion of agricultural settlements during the Late Bronze Age and Pre-Roman Iron Age contributed to a significant increase in fire activity around 3500 years ago. Decreased burning during the Late Iron Age and early medieval period is reflected in decreased PAH accumulation rates. From approximately 1000 years ago to the present, there is an intensification of human activity as indicated by a shift towards higher molecular weight PAHs and overall increase in PAHs.
Article
Environmental Sciences
Agnieszka Krzyszczak, Michal P. Dybowski, Magdalena Konczak, Bozena Czech
Summary: In recent years, there has been significant progress in the study of thermal transformation of waste into valuable materials such as biochar. High-temperature processes can lead to the formation of toxic polycyclic aromatic hydrocarbons (PAHs). However, the pyrolysis process can also result in the formation of derivatives containing oxygen, nitrogen, or sulfur, which may have higher toxicity than parent PAHs. The bioavailability of PAHs is an important parameter in the agricultural application of carbonaceous materials.
ENVIRONMENTAL RESEARCH
(2022)
Article
Chemistry, Analytical
Dandan Li, Yi'an Zhou, Haixia Ding, Lu Chang, Ning Fu, Xia Wang, Xuemei Tao
Summary: Low-cost materials prepared from corn straw and medicago (CB and MB) showed highly efficient adsorption capability in removing BaP from contaminated soil. The adsorption of BaP by CB and MB followed pseudo-secondary kinetics and could be well described by Freundlich and Langmuir equations. In the SPE experiment, CB and MB demonstrated a significant contribution to the removal of BaP.
ANALYTICAL METHODS
(2022)
Article
Environmental Sciences
Natasha Klasios, Hannah De Frond, Ezra Miller, Meg Sedlak, Chelsea M. Rochman
Summary: The study found microplastics and other anthropogenic microparticles in bivalves from San Francisco Bay, with significant variations in abundance between different sites, and no correlation between the number of microparticles and PAH concentrations. Bivalves may be suitable as bioindicators for microplastic levels in sediment, but not in surface water.
ENVIRONMENTAL POLLUTION
(2021)
Article
Chemistry, Applied
Gizem Goker, Sezer Kiralan, Aziz Tekin, Ferruh Erdogdu
Summary: The study found that the formation of PAHs in olive pomace during drying is influenced by temperature and time, with the total PAH formation rate increasing with temperature. The activation energy and frequency factor values also increase as temperature rises.
Article
Public, Environmental & Occupational Health
Andrew P. W. Banks, Phong Thai, Michelle Engelsman, Xianyu Wang, Andres F. Osorio, Jochen F. Mueller
Summary: Firefighters are exposed to a variety of chemicals, including PAHs, when attending fire scenes. Exposure to PAHs was higher in particleboard fires compared to diesel pan fires. Urinary OH-PAH metabolites can be used to observe PAH exposure in compartment burns with high concentrations of PAHs, such as in particleboard fires. Overall, urinary OH-PAH concentrations were relatively low considering the potential exposure in these burns, suggesting that protective equipment and decontamination measures are effective in controlling exposure.
INTERNATIONAL JOURNAL OF HYGIENE AND ENVIRONMENTAL HEALTH
(2021)
Article
Environmental Sciences
Ulrika Eriksson, Ivan A. Titaley, Magnus Engwall, Maria Larsson
Summary: Tire granulates recovered from end-of-life tires contain a complex mixture of toxic polyaromatic compounds (PACs), which are only partially monitored. This study used chemical analysis and bioassays to determine PAC concentrations and activities in tire granulates, revealing the presence of unknown bioactive compounds that contribute significantly to the effects observed. Further investigations are needed to identify and apportion these toxicants.
Article
Environmental Sciences
Bo Fang, Mercedes A. Bravo, Hong Wang, Lulu Sheng, Wenyi Wu, Yuanke Zhou, Xuan Xi, Truls ostbye, Qin Liu
Summary: This study found that PAH exposures may delay puberty timing in girls. Specific urinary PAH metabolite concentrations were significantly associated with delayed breast development, pubic hair development, and axillary hair development.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Multidisciplinary Sciences
Wei Jin, Yuan Li, Li Lu, Dong Zhang, Shanying He, Jiali Shentu, Qiwei Chai, Lei Huang
Summary: The comprehensive water quality index (CWQI) is a mathematical statistic that reflects the pollution status of rivers based on several water quality indicators. This study established a CWQI for a typical river in eastern China, using 1-year monitoring data from 20 sampling sets. The predicted CWQI for each monitoring section indicates that most sections are moderately polluted, with some sections being seriously polluted. The analysis shows that TN, n-ary sumation PAHs, and n-ary sumation n-Alks are the main factors influencing water quality, particularly due to the impact of petroleum hydrocarbons in the middle and lower reaches.
SCIENTIFIC REPORTS
(2022)
Article
Environmental Sciences
Jennifer L. A. Keir, William Papas, Adam Wawrzynczak, Rocio Aranda-Rodriguez, Jules M. Blais, Paul A. White
Summary: This study evaluated the use of silicone wristbands as passive samplers to assess firefighters' exposures to polycyclic aromatic hydrocarbons (PAHs) during firefighting. The results showed that silicone wristbands could accurately capture exposures to various PAHs, but their effectiveness may be influenced by short sampling time, high temperatures, and high turbulence.
ENVIRONMENTAL RESEARCH
(2023)
Article
Environmental Sciences
Tao Wang, Kai Xiang, Yuan Zeng, Haifeng Gu, Yufeng Guan, Shejun Chen
Summary: A study conducted in a subtropical rainforest in southern China found that forest canopies play a crucial role in scavenging airborne semi-volatile organic compounds. The study measured polycyclic aromatic hydrocarbons (PAHs) in the understory air, foliage, and litterfall, revealing spatial and temporal variations in PAH concentrations. The research provides important insights into the degradation and accumulation dynamics of PAHs in subtropical rainforests.
ENVIRONMENTAL POLLUTION
(2023)
Article
Geochemistry & Geophysics
Yuan Yao, Jiaju Zhao, Richard S. Vachula, Sian Liao, Gaoyuan Li, Emma J. Pearson, Yongsong Huang
Summary: This study analyzed the distribution of LCAs and LCEs in surface sediments and suspended particulate matter from 37 saline lakes in northern China, revealing the existence of three Group 2 subclades in different ecological niches. Based on existing data, two possible alternative proxies for paleotemperature reconstructions in saline lakes were proposed.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geography, Physical
Haiyan Dong, Xiaobei Wei, Rencheng Li, Richard S. Vachula, Shuhui Tan, Lintong Zhou, Tianxi Gan
Summary: Developing and refining fire proxies is crucial for reconstructing and inferring fire in the Earth system. This study focuses on the burned phytoliths and their relationship with fire activity. The results show that the carbon content of burned phytoliths is higher than unburned phytoliths, indicating adsorption of black carbon during exposure to open flames. This suggests that phytolith-related carbon could be a potential indicator of paleofire using soils and sediments.
Article
Geography, Physical
Richard S. Vachula, Allison T. Karp, Elizabeth H. Denis, Nicholas L. Balascio, Elizabeth A. Canuel, Yongsong Huang
Summary: This study examined the relationship between PAH fluxes preserved in lake sediments in the Sierra Nevada, California, and the area burned, finding that certain PAHs may be influenced by anthropogenic pollution sources when recording area burned. However, other specific PAHs were found to be reliable proxies of burned areas within certain spatial scales.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Geography, Physical
Richard S. Vachula, Jie Liang, Jarunetr Sae-Lim, Haichao Xie
Summary: Recent fire events in Alaskan tundra ecosystems have highlighted the impact of climate change on fire activity in this region. This study investigates the climatic controls of tundra fire by comparing paleofire records with climate, vegetation, and environmental datasets. The results show that atmospheric CO2, summer temperature, and precipitation are the most important factors influencing tundra fire occurrence. The findings raise concerns considering the rising atmospheric CO2 levels and climate projections.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Geography, Physical
Ted Goebel, John F. Hoffecker, Kelly E. Graf, Richard S. Vachula
Summary: Biomarker data suggests the presence of humans in arctic Alaska as early as 34,000 years ago. However, a recent archaeological reconnaissance of Lake E5 in the Kuparuk River Valley yielded negative results, with no prehistoric archaeological materials found. This may be due to false signals in the biomarker data or low archaeological visibility in the small lake and basin environment.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Environmental Sciences
Lee Frank-DePue, Richard S. Vachula, Nicholas L. Balascio, Kayla Cahoon, James M. Kaste
Summary: This study analyzes the morphology and morphometry of sedimentary charcoal in a mill pond in southeastern Virginia, USA, and finds that the morphology and morphometry of charcoal particles changed in response to historical land use and population shifts. Different charcoal morphologies are associated with different fuel types, but the variability of morphometric characteristics makes it unlikely that other morphologies are sourced from sole fuel types. The study proposes three additional morphotypes and highlights the need for calibrating paleofire methodologies in the southeastern USA.
JOURNAL OF PALEOLIMNOLOGY
(2023)
Article
Geography, Physical
Richard S. Vachula, Emma Rehn
Summary: This study used a charcoal dispersal model to examine the differences in dispersal patterns between wood and grass charcoal particles. The findings indicate that there are substantial differences in particle dispersal and source area between the two types of charcoal. The study highlights the importance of considering the nuances and limitations of charcoal as a fire proxy when interpreting paleofire data.
Article
Geosciences, Multidisciplinary
Xinyue Luo, Sylvia Dee, Trinity Lavenhouse, Samuel Munoz, Nathan Steiger
Summary: The Mississippi River basin floods have significant socioeconomic impacts over the central United States. Understanding the dynamical controls on the hydroclimate of the Mississippi basin is crucial for improving flood predictability. However, the short instrumental records make it challenging to determine the connections between flooding and climate variability.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Review
Biology
John F. Hoffecker, Scott A. Elias, G. Richard Scott, Dennis H. O'Rourke, Leslea J. Hlusko, Olga Potapova, Vladimir Pitulko, Elena Pavlova, Lauriane Bourgeon, Richard S. Vachula
Summary: Were Beringian environments a barrier or was access to the Americas controlled by ice sheets? East Siberian Arctic Shelf had a dry steppe-tundra biome while southern Bering-Chukchi Platform had a mesic tundra. Ancestors of First Peoples from the NW Pacific coast probably dispersed to America when the corridor reopened 14,000 years ago. Non-arctic First Peoples show a genetic 'arctic signal', indicating their ancestral population lived in the East Siberian Arctic Shelf during the Last Glacial Maximum.
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2023)
Article
Astronomy & Astrophysics
Richard S. Vachula, Anson H. Cheung
Summary: This study critically examines the reliability of the statistical tool REDFIT in identifying solar signals and finds that the significance thresholds used by researchers vary significantly. It also reveals that the thresholds used in the literature are generally less stringent than the critical false-alarm level outlined by REDFIT's creators. Moreover, the study highlights the lack of consideration of age model uncertainty in REDFIT's reliability in identifying solar periodicities, suggesting that the relationship between solar irradiance and climate identified by REDFIT analyses may not be as strong as previously suggested.
EARTH AND SPACE SCIENCE
(2023)
Article
Geosciences, Multidisciplinary
Yuan Yao, Lu Wang, Yongsong Huang, Jie Liang, Richard S. S. Vachula, Yanjun Cai, Hai Cheng
Summary: Contrary to global warming projections, northern mid-latitude continents have experienced increased frequency of unusually cold winters. However, the lack of long-term records hampers our understanding of these temperature fluctuations. Here, we present a high-resolution record of cold-season temperatures since 1700 CE from Lake Luming in northeastern China, using Group 1 alkenones as proxies. We find that pre-industrial warmth from 1750 to 1850 CE was largely driven by the Arctic Oscillation, with little contribution from anthropogenic greenhouse-gas forcing.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Xuewen Zhou, Zhengchuang Hui, Richard S. Vachula, Xiao Wei, Peng Chen, Jun Zhang, Xiuxi Wang, Tingjiang Peng
Summary: This study provides a high-resolution charcoal record of mid-Miocene fire history and investigates the controls and possible drivers of long-term regional fire regime and fire activity on orbital timescales. The findings suggest that the increase in fire activity during the period of 16-13.86 Ma may be due to increased fuel ignitability and drying climate, while the significant decrease after 13.86 Ma is likely attributed to decreased fuel load caused by global cooling. Additionally, the study reveals the influence of Earth's orbital cycles on mid-Miocene fire activity variability.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2023)
Article
Environmental Sciences
Richard S. Vachula, Ann Sullivan Ojeda, Emma D. Henderson, Jun Inoue
Summary: Spheroidal carbonaceous particles (SCPs) are potential markers for the onset of the Anthropocene, but their atmospheric dispersal modeling is limited. We developed the DiSCPersal model, which is corroborated by empirical data from Osaka, Japan. The model reveals the primary controls of dispersal distance and explains the differences in dispersal distances reported in the literature, highlighting the need to incorporate localized dispersal patterns when interpreting SCP preservation.
Article
Geography, Physical
Rebecca G. Topness, Richard S. Vachula, Nicholas L. Balascio, William J. D'Andrea, Genevieve Pugsley, Moussa Dia, Martina Tingley, Lorelei Curtin, Stephen Wickler, R. Scott Anderson
Summary: This study analyzes lake sediment records from the Lofoten Islands, Norway to investigate the fire history of the region. The results show an increase in fire activity starting from around 7500 years ago, with human impacts becoming evident around 5000 years ago. The establishment and expansion of agricultural settlements during the Late Bronze Age and Pre-Roman Iron Age contributed to a significant increase in fire activity around 3500 years ago. Decreased burning during the Late Iron Age and early medieval period is reflected in decreased PAH accumulation rates. From approximately 1000 years ago to the present, there is an intensification of human activity as indicated by a shift towards higher molecular weight PAHs and overall increase in PAHs.
Article
Multidisciplinary Sciences
Richard S. Vachula, Jake R. Nelson, Anthony G. Hall
Summary: Although climate change plays a role in increasing wildfire activity in the US, humans also significantly contribute to wildfires, particularly on Independence Day due to the use of fireworks. The location and timing of fireworks-caused ignitions vary, with concentrations in the western and north central US on tribal lands. This study suggests that human behavior, cultural factors, and fireworks regulations affect the spatial and temporal distribution patterns of fireworks-caused ignitions. The findings have important management and policy implications, considering the predictability of these ignitions and the rising costs of wildfire mitigation.
