Dental data challenge the ubiquitous presence of Homo in the Cradle of Humankind.

The origins of Homo, as well as the diversity and biogeographic distribution of early Homo species, remain critical outstanding issues in paleoanthropology. Debates about the recognition of early Homo, first appearance dates, and taxonomic diversity within Homo are particularly important for determining the role that southern African taxa may have played in the origins of the genus. The correct identification of Homo remains also has implications for reconstructing phylogenetic relationships between species of Australopithecus and Paranthropus, and the links between early Homo species and Homo erectus. We use microcomputed tomography and landmark-free deformation-based three-dimensional geometric morphometrics to extract taxonomically informative data from the internal structure of postcanine teeth attributed to Early Pleistocene Homo in the southern African hominin-bearing sites of Sterkfontein, Swartkrans, Drimolen, and Kromdraai B. Our results indicate that, from our sample of 23 specimens, only 4 are unambiguously attributed to Homo, 3 of them coming from Swartkrans member 1 (SK 27, SK 847, and SKX 21204) and 1 from Sterkfontein (Sts 9). Three other specimens from Sterkfontein (StW 80 and 81, SE 1508, and StW 669) approximate the Homo condition in terms of overall enamel-dentine junction shape, but retain Australopithecus-like dental traits, and their generic status remains unclear. The other specimens, including SK 15, present a dominant australopith dental signature. In light of these results, previous dietary and ecological interpretations can be reevaluated, showing that the geochemical signal of one tooth from Kromdraai (KB 5223) and two from Swartkrans (SK 96 and SKX 268) is consistent with that of australopiths.

Fruit Flies: Challenges and Opportunities to Stem the Tide of Global Invasions.

Global trade in fresh fruit and vegetables, intensification of human mobility, and climate change facilitate fruit fly (Diptera: Tephritidae) invasions. Life-history traits, environmental stress response, dispersal stress, and novel genetic admixtures contribute to their establishment and spread. Tephritids are among the most frequently intercepted taxa at ports of entry. In some countries, supported by the rules-based trade framework, a remarkable amount of biosecurity effort is being arrayed against the range expansion of tephritids. Despite this effort, fruit flies continue to arrive in new jurisdictions, sometimes triggering expensive eradication responses. Surprisingly, scant attention has been paid to biosecurity in the recent discourse about new multilateral trade agreements. Much of the available literature on managing tephritid invasions is focused on a limited number of charismatic (historically high-profile) species, and the generality of many patterns remains speculative.

Sleep Composition of Patients With Colorectal Cancer and Their Sleep-Partner Caregivers: Physical Health Correlates of Sleep Diary and Actigraphy Measurements.

BACKGROUND: Disturbed sleep is frequently identified in adult patients with cancer and their caregivers, with detrimental impact on physical health. Less known is the extent to which self-reported and actigraph-measured sleep patterns are similar between patients and their sleep-partner caregivers, and how these different modes of sleep measurements are related to physical health. METHODS: Patients diagnosed with colorectal cancer and their sleep-partner caregivers (81 dyads) completed a questionnaire for physical functioning and collected saliva samples for seven consecutive days, from which cortisol slope was quantified. Additionally, participants completed a daily sleep diary and wore actigraph for 14 consecutive days, from which sleep duration, sleep onset latency (SOL), and duration of wake after sleep onset (WASO) were calculated. RESULTS: Participants reported sleep patterns that fell within or close to the optimal range, which were similar between patients and their caregivers. Self-reported and actigraph-measured sleep duration had moderate levels of agreement (ICC = 0.604), whereas SOL and WASO had poor agreement (ICC = 0.269). Among patients, longer self-reported WASO was associated with poorer physical health and flatter cortisol slope (p ≤ 0.013). Among caregivers, longer self-reported SOL was associated with poorer physical functioning, actigraph-measured WASO was associated with steeper cortisol slope, and longer self-reported sleep markers studied than actigraph-measured were associated with poorer physical functioning (p ≤ 0.042). CONCLUSION: Findings suggest that employing multiple assessment modes for sleep and physical health is vital for comprehensive understanding of sleep health. Furthermore, when addressing patients' sleep health, it may be beneficial to include their sleep-partner caregivers who may experience similar disturbed sleep.

Pharmacodynamics, pharmacokinetics and CYP3A4 interaction potential of the selective P2X3 receptor antagonist filapixant: A randomized multiple ascending-dose study in healthy young men.

AIMS: We report on investigations exploring the P2X3-receptor antagonist filapixant's effect on taste perception and cough-reflex sensitivity and describe its pharmacokinetics, including its CYP3A4-interaction potential. METHODS: In a randomized, placebo-controlled, double-blind study, 3 × 12 healthy men (18-45 years) were assigned (3:1) to filapixant (20, 80 or 250 mg by mouth) or placebo twice daily over 2 weeks. A single dose of midazolam (1 mg), a CYP3A4 substrate, was administered with and without filapixant. Assessments included a taste-strips test, a taste questionnaire, cough challenge with adenosine triphosphate, adverse event reports and standard safety assessments. RESULTS: Taste disturbances were observed mainly in the 250-mg group: six of nine participants (67%) in this group reported hypo- or dysgeusia in the questionnaire; eight participants (89%) reported taste-related adverse events. Five participants (56%) had a decrease in overall taste-strips-test scores ≥2 points (point estimate -1.1 points, 90% confidence interval [-3.3; 1.1]). Cough counts increased with adenosine triphosphate concentration but without major differences between treatments. Filapixant exposure increased proportionally to dose. Co-administration of filapixant had no clinically relevant effect on midazolam pharmacokinetics. Area under the concentration-time curve ratios and 90% confidence intervals were within 80-125%. No serious or severe adverse events were reported. CONCLUSIONS: Overall, filapixant was safe and well tolerated, apart from mild, transient taste disturbances. Such disturbances occurred more frequently than expected based on (in vitro) receptor-selectivity data, suggesting that other factors than P2X3:P2X2/3 selectivity might also play an important role in this context. The cough-challenge test showed no clear treatment effect. Filapixant has no clinically relevant CYP3A4 interaction potential.

Longer Operative Time for Lower Extremity Bypass Surgery is Associated With Inferior Outcomes.

INTRODUCTION: This study aims to assess the association of operative time with the postoperative length of stay and unplanned return to the operating room in patients undergoing femoral to below knee popliteal bypasses, stratified by autologous vein graft or polytetrafluoroethylene (PTFE). MATERIALS AND METHODS: A retrospective analysis of vascular quality initiative database (2003-2021). The selected patients were grouped into the following: vein bypass (group I) and PTFE (group II) patients. Each group was further stratified by a median split of operative time (i.e., 210 min for autologous vein and 155 min for PTFE) to study the outcomes. The outcomes were assessed by univariate and multivariate approach. RESULTS: Of the 10,902 patients studied, 3570 (32.7%) were in the autologous vein group, while 7332 (67.3%) were in the PTFE group. Univariate analysis revealed autologous vein and PTFE graft recipients that had increased operative times were associated with a longer mean postoperative length of stay and a higher incidence of all-cause return to the operating room. In PTFE group, patients with prolonged operative times were also found to be associated with higher incidence of major amputation, surgical site infection, and cardiovascular events, along with loss of primary patency within a year. CONCLUSIONS: For patients undergoing femoral to below knee popliteal bypasses using an autologous vein or PTFE, longer operative times were associated with inferior outcomes. Mortality was not found to be associated with prolonged operative time.

The influence of everyday emotions on mucosal immunity: An intensive longitudinal modeling approach.

Mucosal immunity is a multifaceted system of immunological responses that provides a barrier against pathogenic invasion and can be regulated by psychosocial and neuroendocrine factors. The present study aims to elucidate the association between everyday emotional states, emotion regulation skills, and mucosal immunity by utilizing an ambulatory assessment approach. 30 healthy subjects (61% male; M = 30.18 years old) completed an emotion questionnaire (PANAS) and collected saliva samples via passive drool to determine salivary immunoglobulin-A (S-IgA) excretion rate three times a day over a period of 1 week. In a multi-level model, the influence of emotions on S-IgA, both on a within-subject and between-subject level, was estimated. We found that most of the variation in S-IgA (74%) was accounted for by within-subject changes rather than stable between-subject differences. On a within-subject level, negative emotions had a significant positive effect on S-IgA levels (b = 1.87, p = .015), while positive emotions had no effect. This effect of negative emotions was moderated by the individual emotion regulation skills, with higher regulation skills corresponding to smaller effects (b = -2.67, p = .046). Furthermore, S-IgA levels decreased over the course of a day, indicating circadian rhythmicity (b = -0.13, p = .034). These results highlight the possibilities of intensive longitudinal data to investigate the covariance between psychological and immunological states over time.

Dental age assessment in the living: a comparison of two common stage classifications for assessing radiographic visibility of the root canals in mandibular third molars.

After dentition is complete, degenerative tooth characteristics can be used for dental age assessment. Radiological assessment of the visibility of the root canals of the mandibular third molars in dental panoramic radiographs (DPRs) is known to be one such suitable feature. Essentially, two different stage classifications are available for evaluating the visibility of the root canals of mandibular third molars in the DPR. The aim of this study was to determine if one method outperforms the other. Therefore, the 2010 method of Olze et al. was directly compared to the 2017 method of Lucas et al. in the 2020 modification of Al Qattan et al. To this end, 233 DPRs from 116 females and 117 males aged 20.0 to 40.9 years were evaluated by three independent experienced examiners. In addition, one examiner ran two independent evaluations. Correlation between age and stage was investigated, and the inter- and intra-rater reliability was estimated for both methods. Correlation between age and stage was higher with the Olze method (Spearman rho 0.388 [95% CI 0.309, 0.462], males and 0.283 [95% CI 0.216, 0.357], females) than the Lucas method (0.212 [95% CI 0.141, 0.284], males and 0.265 [95% CI 0.193, 0.340], females). The intra-rater repeatability of the Olze method (Krippendorff's α = 0.576 [95% CI 0.508, 0.644], males and α = 0.592 [95% CI 0.523, 0.661], females) was greater than that for the Lucas method (intra-rater α = 0.422 [95% CI 0.382, 0.502], males and α = 0.516 [95% CI 0.523, 0.661], females). Inter-rater reproducibility was also greater for the Olze method (α = 0.542 [95% CI 0.463, 0.620], males and α = 0.533 [95% CI 0.451, 0.615], females) compared to the Lucas method (α = 0.374 [95% CI 0.304, 0.443], males and α = 0.432 [95% CI 0.359, 0.505], females). The method of Olze et al. was found to present marginal advantages to the Lucas et al. method across all examinations and may be a more appropriate method for application in future studies.

Insights into dental age estimation: introducing multiple regression data from a Black South African population on modified gustafson's criteria.

Dental Age Estimation (DAE) is an effective instrument of the rule of law for verifying dubious age claims in living individuals. Once tooth development is complete, only degenerative dental characteristics can be used for this purpose. The influence of ethnicity on these degenerative dental characteristics has not been clarified.Degenerative changes were examined using modified Gustafson's criteria including secondary dentin formation, cementum apposition, periodontal recession and attrition using the Olze et al. (2012) staging scales. Orthopantomograms of 1882 black South Africans, consisting of 934 females and 948 males, from 12.00 to 40.96 years of chronological age were utilized. Two independent examiners performed the evaluations, with one of the two evaluating all radiographs twice.The relationship between individual characteristics and chronological age was analyzed using multiple regression analysis with chronological age as the dependent variable. The resulting R2 values ranged from 0.22 to 0.35, and the standard error of estimate were between 6.6 and 7.3 years. The correlation with age was consistently lower for females compared to males. The characteristic of cementum apposition emerged as critical in this population, due to a particularly low correlation with age and observer agreements partly in the "slight" range. The formula's values for the correlation with age were in general below the literature values for other populations. Overall, the limited precision of the age estimation by the formulae presented, especially for females, must be emphasized. The question of whether ethnicity per se exerts an influence on the characteristics in question, or whether the different socio-economic status, which encompasses factors such as nutrition and healthcare, is the determining factor, needs to be assessed in future studies.

Dental age assessment and dental scoring systems: combined different statistical methods.

INTRODUCTION: Age Estimation has been considered as a human basic right, carried out through the use of tables for dental age assessment based on the chronology of tooth eruption. As such, the final aim of this investigation is to create tables with applicability to the Portuguese population, for the different scoring systems used and combined different statistical approaches. MATERIALS AND METHODS: For this purpose, dental age assessment was achieved in all four third molars, using different scoring systems, in a total sample of 626 orthopantomograms (324 females, 302 males), aged between 12 and 25 years old, from the database population of Lisbon North University Hospital Center, approved by the Ethic Committee. RESULTS: The values of validation showed excellent results both on precision and on reproducibility. Mostly all methods showed statistically significant differences between the estimated age and the chronological age and, therefore, the presence of estimation errors. Kullman's and Mincer's methods are the ones with best applicability in the Portuguese population, in the lower third molars. The reliability measures (sensitivity, specificity and accuracy) values decrease as age increases. CONCLUSION: A combination of the scoring systems as a protocol for dental age assessment in Portuguese nationality was established. Tables, for all the scoring systems used, were made with applicability in the Portuguese population.

New equation for estimation of dental age by tooth cementum thickness in adolescents and adults: forensic aspects.

OBJECTIVE: Our research was aimed to establish the equation and to determine its precision for dental age estimation in adolescents, adults and the elderly based on the thickness of deposited dental cement. DESIGN: The study sample consisted of 206 donor teeth of both sexes (10 to 82 years of age). The roots were transversely cut (6 cuts) on an ISOMET 1000 cutter at apical, middle, and cervical parts (slice thickness 0.3 to 0.5 µm). Measurements of cement thickness on incisions were made with a light microscope and an Olympus EP50 camera with previous microscope calibration for each measurement episode. Measurements were carried out clockwise at 4 measuring points on each incision. Statistical analyses were conducted using statistical software packages STATISTICA version 12.0 StatSoft, Inc. 2013, and MedCalc® version 22.0. RESULTS: Mean cement thickness (MCT) significantly declined from apical to cervical cuts (P < 0.001, ANOVA) and was thicker in teeth with a destroyed tooth crown (P < 0.001, ANOVA) and in molars compared to incisors (P < 0.001, ANOVA). MCT was greater in men and in teeth with more than one root but without reaching statistical significance. MCT showed a significant increase from the second decade of chronological age with a peek at sixth decade and declined to the ninth decade (P < 0.001, ANOVA). Piecewise linear regression defined a breakpoint age of 53 years, so two different equations were calculated (≤ 53 years and > 53 years). CONCLUSIONS: The resulting equation is recommended for estimating dental age in forensic analyses.

Root canal widths of mandibular molars in predicting the legal age threshold 18 years in a sample of juveniles and sub-adults of south-indian origin: an orthopantomographic study.

Pursuing a proficient age estimation methodology introducing novel radiographic methods remains an ongoing and demanding aspect of forensic and medicolegal research. In 2017, Roberts GJ et al. (J Forensic Sci 62(2):351-4, 2017) described a new radiographic method, i.e., root canal width (RCW) patterns to assign a subject to above 18-year-age threshold. Since then, few researchers have investigated the validity of this radiographic method in other populations. The present study aimed to test the usefulness of these RCW patterns in predicting 18 years in a sample of South Indian juveniles and sub-adults aged between 16 and 23. Descriptive analysis revealed that pattern-A was initially observed at a minimum age of 16.08 and 16.22 years in males and females. Pattern-B at 16.31 years in males and 16.22 years in females, while pattern-C was initially recorded at 18.73 years in males and 19.01 years in females, respectively. In summary, if an individual, regardless of sex, exhibits a fully-formed (apex closed) mandibular first, second, and third molars and concurrently displays RCW-C, there is a strong likelihood that the person has exceeded the legally relevant age of 18 years. However, due to higher rate of technically unacceptable errors (adults wrongly identified as individuals below 18 years), reliance on this method alone should be restricted, and it is advisable to combine it with other methods.

A Protocol to Determine Circadian Phase by At-Home Salivary Dim Light Melatonin Onset Assessment.

Internal circadian phase assessment is increasingly acknowledged as a critical clinical tool for the diagnosis, monitoring, and treatment of circadian rhythm sleep-wake disorders and for investigating circadian timing in other medical disorders. The widespread use of in-laboratory circadian phase assessments in routine practice has been limited, most likely because circadian phase assessment is not required by formal diagnostic nosologies, and is not generally covered by insurance. At-home assessment of salivary dim light melatonin onset (DLMO, a validated circadian phase marker) is an increasingly accepted approach to assess circadian phase. This approach may help meet the increased demand for assessments and has the advantages of lower cost and greater patient convenience. We reviewed the literature describing at-home salivary DLMO assessment methods and identified factors deemed to be important to successful implementation. Here, we provide specific protocol recommendations for conducting at-home salivary DLMO assessments to facilitate a standardized approach for clinical and research purposes. Key factors include control of lighting, sampling rate, and timing, and measures of patient compliance. We include findings from implementation of an optimization algorithm to determine the most efficient number and timing of samples in patients with Delayed Sleep-Wake Phase Disorder. We also provide recommendations for assay methods and interpretation. Providing definitive criteria for each factor, along with detailed instructions for protocol implementation, will enable more widespread adoption of at-home circadian phase assessments as a standardized clinical diagnostic, monitoring, and treatment tool.

A Noninvasive Quantitative Method for Evaluating Intestinal Exposure to Microplastics Based on the Excretion and Metabolism Patterns of Microplastics and Their Additives.

Microplastics (MPs) pose potential health risks to the intestinal tract and gut microbiota, a topic that has garnered significant attention. However, the absence of quantitative assessment methods for human gut MP exposure impedes related health risk assessments. Here, we performed long-term continuous exposure experiments on mice using MPs that mimic actual human exposure characteristics. The daily excretion of fecal MPs and the concentrations of phthalates (PAEs) and their metabolites (mPAEs) in serum and urine were detected. The cumulative excretion rate of fecal MPs remains stable at about 93%. A significant linear correlation was observed between MP exposure and concentration of mPAEs in urine for both low MP (LMP; 150 µg of MPs/d) (R2 = 0.90) and high MP (HMP; 360 µg of MPs/d) groups (R2 = 0.97). Moreover, a strong correlation was found between daily PAEs exposure and total MP-associated PAEs exposure in both LMP (R2 = 0.77) and HMP (R2 = 0.88) groups. Based on these findings, we established a noninvasive model and evaluated multiple MP exposure parameters in the human gut across 6 continents, 30 countries, and 133 individuals. This study offers novel insights for the quantitative assessment of in vivo MP exposure and provides technical support for assessing the health risks of MPs.

The "Microplastome" - A Holistic Perspective to Capture the Real-World Ecology of Microplastics.

Microplastic pollution, an emerging pollution issue, has become a significant environmental concern globally due to its ubiquitous, persistent, complex, toxic, and ever-increasing nature. As a multifaceted and diverse suite of small plastic particles with different physicochemical properties and associated matters such as absorbed chemicals and microbes, future research on microplastics will need to comprehensively consider their multidimensional attributes. Here, we introduce a novel, conceptual framework of the "microplastome", defined as the entirety of various plastic particles (<5 mm), and their associated matters such as chemicals and microbes, found within a sample and its overall environmental and toxicological impacts. As a novel concept, this paper aims to emphasize and call for a collective quantification and characterization of microplastics and for a more holistic understanding regarding the differences, connections, and effects of microplastics in different biotic and abiotic ecosystem compartments. Deriving from this lens, we present our insights and prospective trajectories for characterization, risk assessment, and source apportionment of microplastics. We hope this new paradigm can guide and propel microplastic research toward a more holistic era and contribute to an informed strategy for combating this globally important environmental pollution issue.

Replacing Plastics with Alternatives Is Worse for Greenhouse Gas Emissions in Most Cases.

Plastics are controversial due to their production from fossil fuels, emissions during production and disposal, potential toxicity, and leakage to the environment. In light of these concerns, calls to use less plastic products and move toward nonplastic alternatives are common. However, these calls often overlook the environmental impacts of alternative materials. This article examines the greenhouse gas (GHG) emission impact of plastic products versus their alternatives. We assess 16 applications where plastics are used across five key sectors: packaging, building and construction, automotive, textiles, and consumer durables. These sectors account for about 90% of the global plastic volume. Our results show that in 15 of the 16 applications a plastic product incurs fewer GHG emissions than their alternatives. In these applications, plastic products release 10% to 90% fewer emissions across the product life cycle. Furthermore, in some applications, such as food packaging, no suitable alternatives to plastics exist. These results demonstrate that care must be taken when formulating policies or interventions to reduce plastic use so that we do not inadvertently drive a shift to nonplastic alternatives with higher GHG emissions. For most plastic products, increasing the efficiency of plastic use, extending the lifetime, boosting recycling rates, and improving waste collection would be more effective for reducing emissions.

Meta-ecosystem Frameworks Can Enhance Control of the Biotic Transport of Microplastics.

The lack of systematic approaches and analyses to identify, quantify, and manage the biotic transport of microplastics (MPs) along cross-ecosystem landscapes prevents the current goals of sustainable environmental development from being met. This Perspective proposes a meta-ecosystem framework, which considers organismal and resource flows among ecosystems to shed light on the research and management challenges related to both abiotic and biotic MP transport at landscape levels. We discuss MP transport pathways through species movements and trophic transfers among ecosystems and sub-ecosystems, and highlight these pathways in the mitigation of MP pollution. The integration of biotic pathways across landscapes prioritizes management actions for MP transport using diverse approaches such as wastewater treatment and plastic removal policies to mitigate contamination. In addition, our framework emphasizes the potential sink enhancement of MPs through habitat conservation and enhancement of riparian vegetation. By considering the mechanisms of meta-ecosystem dynamics through the processes of biotic dispersal, accumulation, and the ultimate fate of MPs, advances in the environmental impact assessment and management of MP production can proceed more effectively.

Unveiling Small-Sized Plastic Particles Hidden behind Large-Sized Ones in Human Excretion and Their Potential Sources.

Health risks of microplastic exposure have drawn growing global concerns due to the widespread distribution of microplastics in the environment. However, more evidence is needed to understand the exposure characteristics of microplastics owing to the limitation of current spectrum technologies, especially the missing information on small-sized particles. In the present study, laser direct infrared spectroscopy and thermal desorption-gas chromatography-mass spectrometry combined pyrolysis using a tubular furnace (TD-GC/MS) were employed to comprehensively detect the presence of plastic particles down to 0.22 µm in human excreted samples. The results showed that polyethylene (PE), polyvinyl chloride, PE terephthalate (PET), and polypropylene dominated large-sized (>20 µm) and small-sized plastic plastics (0.22-20 µm) in feces and urine. Moreover, fragments accounted for 60.71 and 60.37% in feces and urine, respectively, representing the most pervasive shape in excretion. Surprisingly, the concentration of small-sized particles was significantly higher than that of large-sized microplastics, accounting for 56.54 and 50.07% in feces (345.58 µg/g) and urine (6.49 µg/mL). Significant positive correlations were observed between the level of plastic particles in feces and the use of plastic containers and the consumption of aquatic products (Spearman correlation analysis, p < 0.01), suggesting the potential sources for plastic particles in humans. Furthermore, it is estimated that feces was the primary excretory pathway, consisting of 94.0% of total excreted microplastics daily. This study provides novel evidence regarding small-sized plastic particles, which are predominant fractions in human excretion, increasing the knowledge of the potential hazards of omnipresent microplastics to human exposure.

Small-Intensity Rainfall Triggers Greater Contamination of Rubber-Derived Chemicals in Road Stormwater Runoff from Various Functional Areas in Megalopolis Cities.

Rubber-derived chemicals (RDCs) originating from tire and road wear particles are transported into road stormwater runoff, potentially threatening organisms in receiving watersheds. However, there is a lack of knowledge on time variation of novel RDCs in runoff, limiting initial rainwater treatment and subsequent rainwater resource utilization. In this study, we investigated the levels and time-concentration profiles of 35 target RDCs in road stormwater runoff from eight functional areas in the Greater Bay Area, South China. The results showed that the total concentrations of RDCs were the highest on the expressway compared with other seven functional areas. N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), 6PPD-quinone, benzothiazole, and 1,3-diphenylguanidine were the top four highlighted RDCs (ND-228840 ng/L). Seasonal and spatial differences revealed higher RDC concentrations in the dry season as well as in less-developed regions. A lag effect of reaching RDC peak concentrations in road stormwater runoff was revealed, with a lag time of 10-90 min on expressways. Small-intensity rainfall triggers greater contamination of rubber-derived chemicals in road stormwater runoff. Environmental risk assessment indicated that 35% of the RDCs posed a high risk, especially PPD-quinones (risk quotient up to 2663). Our findings contribute to a better understanding of managing road stormwater runoff for RDC pollution.

Region-Specific Sourcing of Lignocellulose Residues as Renewable Feedstocks for a Net-Zero Chemical Industry.

Biobased chemicals, crucial for the net-zero chemical industry, rely on lignocellulose residues as a major feedstock. However, its availability and environmental impacts vary greatly across regions. By 2050, we estimate that 3.0-5.2 Gt of these residues will be available from the global forest and agricultural sectors, with key contributions from Brazil, China, India, and the United States. This supply satisfies the growing global feedstock demands for plastics when used efficiently. Forest residues have 84% lower climate change impacts than agricultural residues on average globally but double the land-use-related biodiversity loss. Biobased plastics may reduce climate change impacts relative to fossil-based alternatives but are insufficient to fulfill net-zero targets. In addition, they pose greater challenges in terms of biodiversity loss and water stress. Avoiding feedstock sourcing from biodiversity-rich areas could halve lignocellulose residues-related biodiversity loss without significantly compromising availability. Improvements in region-specific feedstock sourcing, agricultural management and biomass utilization technologies are warranted for transitioning toward a sustainable chemical industry.

Traded Plastic, Traded Impacts? Designing Counterfactual Scenarios to Assess Environmental Impacts of Global Plastic Waste Trade.

The global trade of plastic waste has raised environmental concerns, especially regarding pollution in waste-importing countries. However, the overall environmental contribution remains unclear due to uncertain treatment shares between handling plastic waste abroad and domestically. Here, we conduct a life cycle assessment of global plastic waste trade in 2022 across 18 countries and six plastic waste types, alongside three "nontrade" counterfactual scenarios. By considering the required cycling rate, which balances importers' costs and recycling revenues, we find that the trade resulted in lower environmental impacts than treating domestically with the average treatment mix. The trade scenario alone reduced climate change impact by 2.85 million tonnes of CO2 equivalent and mitigated damages to ecosystem quality, human health, and resource availability by 12 species-years, 6200 disability-adjusted life years (DALYs), and 1.4 billion United States dollars (USD in 2013), respectively. These results underscore the significance of recognizing plastic waste trade as a pivotal factor in regulating global secondary plastic production when formulating a global plastics treaty.