Pollution History Research Articles

Application of tree cores to investigate the historical pollution trends of atmospheric polycyclic aromatic compounds: A case study in a typical coal-contaminated region of China

In this study, 76 polycyclic aromatic compounds (PACs) were detected in air, soil, and tree core samples from Huainan, a typical coal-contaminated region of China. Concentrations of ΣPACs in soil and air samples were 2400 ± 5100 ng/g and 150 ± 63 ng/m3, respectively. Priority PAHs were predominant in both air and soil samples, contributing over 50 % of ΣPACs. Source analysis indicated that PAC contamination in Huainan primarily originated from local coal-related activities. The benzo[a]pyrene (BaP)-toxic equivalent concentrations (TEQBaP) of PACs in the air samples (5.6 ± 5.3 ng/m3) exceeded the threshold of 1 ng/m3. Some PACs, such as benzo[e]pyrene (BeP) and Alk-BaPs, demonstrated significant toxicity and are recommended for consideration as priority pollutants. The historical pollution trends of atmospheric PACs were obtained based on the tree core samples. PAC concentrations in tree core segments showed a strong correlation with atmospheric PM10 levels in Huainan. As air quality has improved in recent years, the PACs concentrations in tree core segments have also decreased. Historical fluctuations of atmospheric PACs were largely attributed to the changes in the gas treatment systems of a nearby coal-fired power plant and adjustments in environmental policies. By integrating trends observed in tree core segments with air concentrations, the historical atmospheric PAC concentrations were extrapolated. The extrapolated results showed similar concentration levels and trends when compared with historical data from other studies in China. Thus, tree cores can not only reflect the historical trends of atmospheric PACs with high temporal precision but also are feasible for extrapolating historical concentrations of airborne PACs.

Metagenomic analyses of a consortium for the bioremediation of hydrocarbons polluted soils.

A bacterial consortium was isolated from a soil in Noblejas (Toledo, Spain) with a long history of mixed hydrocarbons pollution, by enrichment cultivation. Serial cultures of hydrocarbons polluted soil samples were grown in a minimal medium using diesel (1mL/L) as the sole carbon and energy source. The bacterial composition of the Noblejas Consortium (NC) was determined by sequencing 16S rRNA gene amplicon libraries. The consortium contained around 50 amplicon sequence variants (ASVs) and the major populations belonged to the genera Pseudomonas, Enterobacter, Delftia, Stenotrophomonas, Achromobacter, Acinetobacter, Novosphingobium, Allorhizobium-Neorhizobium-Rhizobium, Ochrobactrum and Luteibacter. All other genera were below 1%. Metagenomic analysis of NC has shown a high abundance of genes encoding enzymes implicated in aliphatic and (poly) aromatic hydrocarbons degradation, and almost all pathways for hydrocarbon degradation are represented. Metagenomic analysis has also allowed the construction of metagenome assembled genomes (MAGs) for the major players of NC. Metatranscriptomic analysis has shown that several of the ASVs are implicated in hydrocarbon degradation, being Pseudomonas, Acinetobacter and Delftia the most active populations.

Decade-long historical shifts in legacy and emerging per- and polyfluoroalkyl substances (PFAS) in surface sediments of China's marginal seas: Ongoing production and ecological risks

Since the addition of perfluorooctane sulfonate (PFOS) to the Stockholm Convention in 2009, it became imperative to reassess the distribution and ecological risk of per- and polyfluoroalkyl substances (PFAS) in coastal sediments over the past decade as sediment records the history of pollutants from human activities. To achieve this, sediments were collected in 2009 and 2021 from China's coastal regions. Despite the consistent geographical pattern where the highest concentrations of ∑PFAS were found in the Yellow Sea, temporal changes have emerged. During the studied period, ∑PFAS levels experienced an increase in the East China Sea while concurrently witnessing a decrease in the South China Sea. Of significance, emerging PFAS compounds displayed not only rising concentrations but also a broader array, pointing towards their intensified production and utilization within China. Alarmingly, PFOS levels in sediments taken from the East China Sea maintained a consistently high ecological risk status over the last ten years. Significant correlations were found between long-chain PFAS and organic carbon content. Comparisons between datasets from 2009 to 2021 uncovered a shifting ecological risk landscape, with heightened concerns for PFOA in the East China Sea, while PFOS-associated risks appeared to diminish in the South China Sea—potentially reflecting the transition to alternative PFAS chemicals. The research reinforces the importance of continuous monitoring and emphasizes the urgent necessity for deeper exploration into the environmental implications and hazards posed by emerging PFAS.

Historical Pollution Exposure Impacts on PM2.5 Dry Deposition and Physiological Responses in Urban Trees

Historical Pollution Exposure Impacts on PM2.5 Dry Deposition and Physiological Responses in Urban Trees

Trace metals in coastal marine sediments: Natural and anthropogenic sources, correlation matrices, and proxy potentials

Rapidly spreading industrialization since the 19th century has led to a drastic increase in trace metal deposition in coastal sediments. Provided that these trace metals have remained relatively immobile after deposition, their sedimentary enrichments can serve as records of local–regional pollution histories. Factors controlling this proxy potential include trace metal geochemistry (carrier-, and host phase affinity), and depositional environmental factors (redox variability, particulate shuttling, organic matter loading, bathymetry). Yet, the relative importance and interactions between these controls are still poorly understood, hampering the reliable use of trace metal-based environmental proxies. By summarizing nine site-specific correlation matrices of 16 metal (loid) s (Pb, Cd, Cu, Zn, Sb, Sn, Ni, As, Tl, V, Mo, U, Re, Fe, Mn, Al), total organic C, and S contents in short sediment cores into a single meta-matrix, we test a novel approach for quickly detecting common and contrasting trace metal enrichment patterns across different study locations. Our meta-matrix shows two trace metal groups, within which positive correlations of e.g., Pb, Cd, Zn, Cu, Sb suggest a primary “anthropogenically sourced” (group I) control, whereas known “redox-sensitive” (group II) trace metals (Mo, U, Re) are characterized by fewer positive correlations. However, some group I metals (Cd, Zn, Cu, Sb) also covary with group II metals, inferring that redox variability may obscure primary anthropogenic signals; Sb even shows advantages over Mo and U under oxic conditions. As a more robust pollution indicator we identified Pb; yet for reconstructing historical Pb atmospheric pollution signals (1970s Pb peak), it is crucial to consider the distance from shore. In near-shore environments, local (fluvial) pollution signals may overprint large-scale (atmospheric) signals. Our findings demonstrate that combining site-specific sedimentary correlation and distribution patterns with a meta-matrix considerably aids the understanding of trace metal sequestration in different coastal sedimentary environments, which thereby improves trace metal proxy reliability.

A column study: Impact of redox, substrate composition and exposure order on toluene and benzene biodegradation and microbial communities

Aromatic compounds persist as hazardous contaminants in both aquatic and terrestrial environments, needing rapid and effective remediation strategies. This study evaluated toluene and benzene biodegradation under sulfate and nitrate-reducing conditions in column experiments, utilizing aquifer sediments from a contaminated site. Over a period of 36 weeks, four glass columns were operated simultaneously in an alternating flow-batch regime. Each column received either nitrate or sulfate as an electron acceptor while being exposed to different substrate compositions in varied exposure orders. A redox dependent contaminant removal efficiency was observed, with toluene removal efficiency at 81% under sulfate and 55% under nitrate-reducing conditions, and benzene removal efficiency approximately at 44% and 59%, respectively, within 4–6 weeks. The rapid removal under anaerobic conditions was attributed to the alternating flow-batch regime, allowing biomass growth in batch mode, and applying selection pressure to non-specific biodegraders during flow regime. Toluene removal remained unaffected by benzene's presence but exhibited slight inhibition in the presence of an aromatic mixture composed of BTEX, indene, indane, and naphthalene. Benzene removal efficiency dropped to 8% in the presence of toluene but remained unaffected by the mixture. Pre-exposure to a single compound enhanced breakdown efficiency when further faced with a more complex mixture. Additionally, beta-diversity analysis conducted on the four columns revealed distinct microbial community clustering between sulfate and nitrate-reducing conditions, emphasizing the determining role of redox conditions. Findings of this study can be used to develop more effective pollution cleanup strategies, specifically targeting parameters like redox conditions, substrate interactions, and pollution history, thus improving our ability to mitigate contamination across diverse environments.

DNA stable isotope probing reveals the impact of trophic interactions on bioaugmentation of soils with different pollution histories

BackgroundBioaugmentation is considered a sustainable and cost-effective methodology to recover contaminated environments, but its outcome is highly variable. Predation is a key top-down control mechanism affecting inoculum establishment, however, its effects on this process have received little attention. This study focused on the impact of trophic interactions on bioaugmentation success in two soils with different pollution exposure histories. We inoculated a 13C-labelled pollutant-degrading consortium in these soils and tracked the fate of the labelled biomass through stable isotope probing (SIP) of DNA. We identified active bacterial and eukaryotic inoculum-biomass consumers through amplicon sequencing of 16S rRNA and 18S rRNA genes coupled to a novel enrichment factor calculation.ResultsInoculation effectively increased PAH removal in the short-term, but not in the long-term polluted soil. A decrease in the relative abundance of the inoculated genera was observed already on day 15 in the long-term polluted soil, while growth of these genera was observed in the short-term polluted soil, indicating establishment of the inoculum. In both soils, eukaryotic genera dominated as early incorporators of 13C-labelled biomass, while bacteria incorporated the labelled biomass at the end of the incubation period, probably through cross-feeding. We also found different successional patterns between the two soils. In the short-term polluted soil, Cercozoa and Fungi genera predominated as early incorporators, whereas Ciliophora, Ochrophyta and Amoebozoa were the predominant genera in the long-term polluted soil.ConclusionOur results showed differences in the inoculum establishment and predator community responses, affecting bioaugmentation efficiency. This highlights the need to further study predation effects on inoculum survival to increase the applicability of inoculation-based technologies.9HmCi-USiFQRck8tFgyMqrVideo

Current state, sources, and potential risk of heavy metals in sediments of typical inner lakes in the Dongting Lake Area

The region has been increasingly experiencing environmental issues related to heavy metals (HMs) due to human activities. However, the contamination levels of HMs (Cr, Ni, Cu, Zn, As, Cd, and Pb) in various inner lakes in the Dongting Lake area remain unclear. In this study, surface sediment samples from 9 inner lakes and sediment core samples from 3 typical inner lakes were collected to evaluate the spatial distribution, contamination status, environmental and ecological risks, and possible sources of these HMs. The results showed that all HMs, except Zn, exceeded background values, with particularly high levels observed in aquaculture lakes compared to other lakes. Vertical profiles of HMs from 3 lakes show that the various types of lakes in the study area have different pollution histories. Additionally, results from Sediment quality guidelines (SQGs), Contamination factor (CF), Geo-accumulation index method (Igeo), and Hakanson potential ecological risk index (PERI) indicated that As, Cd, and Pb are the primary pollutants. The multivariate analysis concluded that Ni, Cu, Zn, As, Cd, and Pb had anthropogenic sources, primarily from agricultural, fisheries, industrial, and transportation activities, while Cr was influenced by natural factors. The results of this study enhance our understanding of sedimentary metal content in inner lakes and emphasize the importance of controlling HMs content in these lakes. This information is crucial for developing effective lake management and pollution control strategies.

From Man vs. Nature to Environment vs. Budget - The Shifting Battles in the History of Pollution and Toxicity in Hamilton Harbour

Hamilton Harbour is the principle port serving South Western Ontario and the Niagara Peninsula region with two of Canada’s largest steel manufacturers occupying the waterfront. As early as the 1860s fishery inspectors in Hamilton noted that fish tasted of coal, and that there were dead ducks and small animals that were coated in oil from refineries. In the 1950s the Hamilton Harbour was deemed unfit for recreational use and, even today, has yet to be delisted from the International Joint Commission’s Area of Concerns designations list. Giglia’s article seeks to add to the growing scholarship on the environmental history of Ontario. She analyzes historical sources of pollution and shows how they have affected Hamilton Harbor’s ecology. Furthermore, Giglia weighs the efforts and effectiveness of specific groups in their attempt to delist the Hamilton Harbour from the Area of Concerns designation list.

Creating elite encounters: The ‘campaign’ as approach for interviewing corporate elites

Qualitative research in economic geography recognizes the value of accessing business elite perspectives, yet identifying, approaching and interviewing elites present researchers with a set of challenges. Both practical and ethical, these challenges can be particularly acute for research involving ‘contentious’ firms and sectors – those facing increased societal scrutiny due to histories of labour exploitation, bribery and pollution and where there are often strong asymmetries in social power. This paper proposes a systematic approach for managing these challenges and successfully conducting interviews with business elites that we term an interview ‘campaign’. We propose the interview campaign as a strategic, organized and nimble approach designed to achieve a specific goal – an elite encounter. We show how instrumentalism and strategic ambiguity are central to the campaign, and how both can be harnessed to navigate an environment characterized by uncertainty, serendipity and structured relations of power. Our ‘campaign approach’ systematically breaks down a complex process into manageable parts without losing sight of the whole, via clear goals, strategic planning and critical reflection. The need for evidence-based research on corporate strategic action in relation to a wide range of contemporary economic phenomena suggests the campaign approach may have value across many areas of economic geography, business studies and beyond. The paper draws upon established social science literatures on elite interviewing and political campaigning, and on our own experience conducting interviews with senior executives in the oil and gas industry.

Aggravating Pollution of Emerging Aryl Organophosphate Esters in Urban Estuarine Sediments of South China.

Emerging aryl organophosphate esters (aryl-OPEs) have been employed as substitutes for organohalogen flame retardants in recent years; however, their environmental occurrence and associated impacts in urban estuarine sediments have not been adequately investigated, impeding regulatory decision-making. Herein, field-based investigations and modeling based on surface sediment and sediment core analysis were employed to uncover the historical pollution and current environmental impacts of aryl-OPEs in the Pearl River Estuary, South China. Our results revealed a substantial increase in aryl-OPE emission, particularly emerging aryl-OPEs, through sediment transport to the estuary since the 2000s. The emerging aryl-OPEs comprised 83% of the total annual input in the past decade, with an average annual input of 155,000 g. Additionally, the emerging-to-traditional aryl-OPE concentration ratios increased with decreasing distance from the shore, peaking in the highly urbanized riverine outlets. These findings indicate that inventories of emerging aryl-OPEs are likely increasing in estuarine sediments and their emissions are surpassing those of traditional aryl-OPEs. Our risk-based priority screening approach indicates that some emerging aryl-OPEs, particularly bisphenol A bis(diphenyl phosphate), can pose a higher environmental risk than traditional aryl-OPEs in estuarine sediments. Overall, our study highlights the importance of recognizing the environmental impacts of emerging aryl-OPEs.

Hazardous Hope

This special section seeks to reconsider our troubled times and their histories of irreversible toxic pollution through the lens of hopeful yet critical ways of engaging with this unprecedented condition of life. Thinking with “hazardous hope” as a tool of analysis, the five contributions—combining perspectives from ecocriticism, environmental philosophy, film studies, visual arts, and history—showcase alternative presents and futures of living responsibly with a permanently polluted planet. Writing from the perspective of hazardous hope, the section’s editors argue, includes a plethora of conceptual and methodological repositionings to embrace the ambiguity that comes with living responsibly on a permanently polluted planet. Among them is a shift in focus on the acts and modes of hazardous hope as a relational practice that is focused on reorganizing established processes in radically different ways rather than wishing to achieve a predefined outcome, while at the same time remaining mindful of the polluted status quo. Contributions in this special section are situated across the entire troubled planet, from Chernobyl’s exclusion zone to Brazilian oil fields and from Canada’s tar sands to British asbestos-loaded homes.

Mercury cycling in contaminated coastal environments: modeling the benthic-pelagic coupling and microbial resistance in the Venice Lagoon

Anthropogenic activities have been releasing mercury for centuries, and despite global efforts to control emissions, concentrations in environmental media remain high. Coastal sediments can be a long-term repository for mercury, but also a secondary source, and competing processes in marine ecosystems can lead to the conversion of mercury into the toxic and bioaccumulative species methylmercury, which threatens ecosystem and human health. We investigate the fate and transport of three mercury species in a coastal lagoon affected by historical pollution using a novel high-resolution finite element model that integrates mercury biogeochemistry, sediment dynamics and hydrodynamics. The model resolves mercury dynamics in the seawater and the seabed taking into account partitioning, transport driven by water and sediment, and photochemical and microbial transformations. We simulated three years (early 2000s, 2019, and 2020) to assess the spatio-temporal distribution of mercury species concentrations and performed a sensitivity analysis to account for uncertainties. The modeled mercury species concentrations show high temporal and spatial variability, with water concentrations in some areas of the lagoon exceeding those of the open Mediterranean Sea by two orders of magnitude, consistent with available observations from the early 2000s. The results support conclusions about the importance of different processes in shaping the environmental gradients of mercury species. Due to the past accumulation of mercury in the lagoon sediments, inorganic mercury in the water is closely related to the resuspension of contaminated sediments, which is significantly reduced by the presence of benthic vegetation. The gradients of methylmercury depend on the combination of several factors, of which sediment resuspension and mercury methylation are the most relevant. The results add insights into mercury dynamics at coastal sites characterized by a combination of past pollution (i.e. sediment enrichment) and erosive processes, and suggest possible nature-based mitigation strategies such as the preservation of the integrity of benthic vegetation and morphology.

Centennial Records of Microplastics in Lake Cores in Huguangyan Maar Lake, China.

Microplastic records from lake cores can reconstruct the plastic pollution history. However, the associations between anthropogenic activities and microplastic accumulation are not well understood. Huguangyan Maar Lake (HML) is a deep-enclosed lake without inlets and outlets, where the sedimentary environment is ideal for preserving a stable and historical microplastic record. Microplastic (size: 10-500 μm) characteristics in the HML core were identified using the Laser Direct Infrared Imaging system. The earliest detectable microplastics appeared unit in 1955 (1.1 items g-1). The microplastic abundance ranged from n.d. to 615.2 items g-1 in 1955-2019 with an average of 134.9 items g-1. The abundance declined slightly during the 1970s and then increased rapidly after China's Reform and Opening Up in 1978. Sixteen polymer types were detectable, with polyethylene and polypropylene dominating, accounting for 23.5 and 23.3% of the total abundance, and the size at 10-100 μm accounted for 80%. Socioeconomic factors dominated the microplastic accumulation based on the random forest modeling, and the contributions of GDP per capita, plastic-related industry yield, and total crop yield were, respectively, 13.9, 35.1, and 9.3% between 1955-2019. The total crop yield contribution further increased by 1.7% after 1978. Coarse sediment particles increased with soil erosion exacerbated microplastics discharging into the sediment.

Past anthropogenic impacts revealed by trace elements in cave guano

Natural and human-induced toxic elements can accumulate in the environment, posing significant risks to human health and ecosystems. This study explores cave bat guano, an unconventional and relatively under-researched environmental repository, to reveal historical pollution trends and sources. Through trace elements analysis of a 1.5-m-thick guano deposit from Zidită Cave (Romania), we track changes in mining and metallurgy from 1000 CE–2012. We identified substantial pollution primarily from porphyry copper and Au–Ag–Te mines, but also impacts from usage of leaded gasoline and agricultural practices. Our record shows disruptions caused by the Bubonic plague around 1250 CE and a major surge ∼ 1500 CE. After the decline triggered by the European silver market collapse in 1525 CE, our study reveals a brief mining revival. This resurgence was followed by a continuous decline lasting until the early 1800s, driven by socio-economic upheavals and recurrent outbreaks of the bubonic plagues. The Industrial Revolution sparked prolonged growth that lasted until 1989 CE, only briefly interrupted by the Great Depression and World War II. Consequently, cave bat guano proves to be a critical resource for understanding spatial pollution patterns, both locally and regionally, and for identifying specific pollution sources.

Reconstruction of the pollution history of the Urft reservoir: an organic-geochemical investigation

BackgroundThe reconstruction of the pollution history using aquatic sedimentary archives is of major relevance not only for the present and past, but also for future actions. The extent and influence of past anthropogenic emissions can be correlated with site-specific (e.g., industrial) developments as well as political actions, regulations, and initiatives. Finally, the need for further restrictions, specific monitoring or other countermeasures can be defined. Accordingly, within the scope of this study, a drilling core of subaquatic sediment was comprehensively analyzed to reconstruct the pollution history of the Urft reservoir and to understand the linkage between introduction, fate, and behavior of different organic pollutants.ResultsThe Urft reservoir is well suitable for pollution reconstruction as the investigated interval covered a period of nearly 60 years of undisturbed sedimentation of fine-grained material. Additionally, specific input factors and their development (e.g., in industrial production) could be easily correlated with the emission profile detected for the reservoir. Overall, quantitative data of more than 60 lipophilic organic compounds were obtained and traced back to urban and industrial emissions. Concentrations were mainly in the range of ng/gTOC–µg/gTOC showing a decreasing tendency toward the surface and, thus, the effectiveness of political regulations. In addition, a clear maximum was detected for almost all substances at the end of the 1970s/beginning of the 1980s, probably related to an exceptional event such as a flood or a malfunction affecting wastewater-related compounds of both urban and industrial origin.ConclusionsBased on the organic-geochemical investigation and the associated dating, it was possible to reconstruct the pollution history of the Urft catchment in the northern Eifel mountains. Overall, organic indicators have proven to be very useful to obtain information on distribution patterns and the influence of industrial as well as governmental actions. For instance, catchment-specific developments such as the closure of ironworks were recognizable in the identified emission patterns. Generally, in the last 50 years, the pollution of the reservoir sediment has decreased clearly showing the efficiency of increasing environmental awareness and corresponding regulations.

Zinc isotope fractionation during the sorption of Zn to minerals and organic matter in sediment cores affected by anthropogenic pollution

Zinc stable isotopes (δ66Zn) serve as a widely fingerprinting tool for detecting anthropogenic Zn contamination. However, there is a limited understanding of δ66Zn behavior during the sorption of Zn to minerals and organic matter. In this study, we have determined the δ66Zn values in specific fractions to investigate their effectiveness in tracing anthropogenic Zn. The revised Community Bureau of Reference (BCR) extraction procedure was applied to a coastal marine core from Osaka Bay and from a lacustrine core from Lake Biwa, both with a history of anthropogenic metal pollution. The δ66Zn values varied from −0.14 ‰ to +1.00 ‰ across the four to five chemical fractions with up to 0.9 ‰ variation within a single horizon. The highest δ66Zn values in the acid-soluble fraction (up to +1.00 ‰) could be explained by the preferential sorption of 66Zn to carbonates and/or the preferential incorporation of 66Zn into calcite. The complex isotopic fractionation during the sorption of Zn to and co-precipitation with Fe–Mn oxyhydroxides likely resulted in an unclear pattern of the δ66Zn values of the reducible fraction. Low δ66Zn values in the oxidizable fraction (Osaka Bay) agree with the 64Zn enrichment in phytoplankton. Higher δ66Zn values of the reducible and oxidizable fractions of the Lake Biwa core indicate that environmental conditions (e.g. ionic strength) and for instance different phytoplankton species or dissolved and suspended particulate matter input drive the Zn isotope fractionation depending on the system (marine vs. lacustrine). The δ66Zn values of the acid-soluble fraction (Osaka Bay and Lake Biwa), of the reducible fraction (only Lake Biwa) and of oxidizable fraction (only Osaka Bay) better reflected the temporal changes in the Zn concentration than the bulk sediment, indicating that these fractions could be a sensitive fingerprinting tool for anthropogenic Zn contamination.

Different behavior of two strains of the arbuscular mycorrhizal fungus Rhizophagus intraradices on Senecio bonariensis Hook. & Arn. against heavy metal soil pollution: a pilot-scale test

Arbuscular mycorrhizal fungi (AMF) have different biological mechanisms to alleviate stressful conditions in heavy metals (HMs) polluted soil. These mechanisms were widely assessed under controlled/greenhouse conditions, but scarcely studied at pilot or territory scale. The aim of this study was to evaluate the response of two Rhizophagus intraradices strains isolated from soils with different histories of pollution, in association with Senecio bonariensis plants, growing in an engineering vegetal depuration module filled with artificially HMs polluted substrate. Plants inoculated with GC3 strain uptook low amounts of HMs and translocated them to shoot biomass. Heavy metals (Mg, Zn, Mn, Cr, Cu and Ni) and macronutrients (Ca, K, S and P) were accumulated in roots of S. bonariensis when inoculated with GB8 strain, limiting their translocation to the shoot. Uninoculated plants showed high translocation of all studied elements to shoot tissues. Concluding, tested R. intraradices strains have exhibited different phytoprotection mechanisms under extremely toxic concentrations of HMs. Moreover, the development of the assay at such a high Technological Readiness Level represents a novel contribution in this field of study.

Shanghai and the Smoke Fiend: Obstacles to the Control of Urban Smoke, 1869–1943

As Shanghai industrialised, its Chinese and European residents suffered the scourge of coal-powered cities: smoke. Air pollution became a multi-sensory reality. Residents could see, smell, feel and taste the smoke that shrouded the city. Inspired by anthropologists and historians of the senses, we mined Chinese- and English-language sources to document the emergence of experiences of air pollution in Shanghai. Concerns began earlier than other historians have appreciated. The vigorous complaints from all parts of Shanghai society illuminate how the city’s governments attempted to respond to the crisis and mitigate the toxic consequences of industrialisation. We found many obstacles to the success of the governments’ approaches. While other scholars have emphasised Shanghai’s fractured governance, we also found evidence of financial conflicts of interest, industry obfuscation and anti-Chinese racism. Our work expands the understanding of the history of air pollution in China and offers a model that can be used to extend global histories of air pollution beyond their traditional focus on Europe and North America.

Do trees respond to pollution? A network study of the impact of pollution on spruce growth from Europe

Tree rings have been reliably used as an environmental proxy over the past decades for environmental reconstructions, simulations and forecasting. In our study, we investigated whether tree-ring chronologies are impacted by pollution. We chose sites in the Krušné hory and the Krkonoše Mountains in the Czech Republic which have a known history of pollution. We sampled Norway spruce (Picea abies [L.] Karst) in both ranges and compared their chronologies. We found no significant difference in the overall radial growth in the chronologies from both regions. However, we observed an increased heterogeneity in the growth of trees from the 1970s till the 1990s. Coherently, a severe reduction in tree growth from the late 1970s and a recovery towards the early 1990s was evident. We collected and analysed soil samples for pH and exchangeable element concentrations. All seven sampling sites' soils were strongly acidic (pHCaCl2 = 3.3 ± 0.4). The average soil base saturation at Krušné hory was higher than at Krkonoše (39% versus 12%), likely due to more intensive liming.Further, we compared these chronologies to other sites in Europe. Analysing 89 sites, we found that most (9 out of 14) of the sites with significantly reduced radial tree growth were located within the former ‘Black Triangle’, an area which was subjected to heavy industrialisation and pollution from the 1960s to the 1990s. Atmospheric sulphur deposition was found to negatively affect radial tree-growth, while limited quantities of oxidised nitrogen appeared to have a positive effect. Our results are consistent with previous research, indicating that atmospheric SO2 pollution and subsequent acid fog and rime have led to a reduction in annual radial tree growth across the Black Triangle.