Public Health Risk Assessment Research Articles

Salmonella Paratyphi A infection: implications for public health management of extra-intestinal presentations – case study of a neck abscess

This study explores the implications of unusual presentations of Salmonella enterica subsp. enterica ser. Paratyphi (S. Paratyphi) infection for public health management, through a literature review and case study. In 2016, a 36-year-old male presented with a five-day history of right sided painful neck swelling, coryza and a two-day history of fevers after arriving in Australia from India nine weeks earlier. S. Paratyphi A was isolated from a fine needle aspirate sample. A descriptive epidemiological review was performed of confirmed cases of S. Paratyphi notified in New South Wales between 2008 and 2017. S. Paratyphi was isolated in blood and/or faecal samples in 247 cases (98.4%). Only four specimens (1.6%) were from a focal site. A literature review of extraintestinal infections of S. Paratyphi A or B was performed. Of the 41 such cases reported, 16 (39%) had a clear history of a prior gastroenteritis and/or febrile illness, or information suggested this was highly likely. No preceding gastroenteritis or febrile illness occurred in 15 (37%) of the cases. Information was reviewed and presented with a public health lens, valuable for ‘evidence-informed’ public health risk assessment of contacts and exposures related to these types of S. Paratyphi infection. S. Paratyphi infection usually presents as an enteric fever illness. Our case illustrates the variable nature of infectious diseases and the importance of laboratory testing in obtaining a diagnosis. S. Paratyphi can have unusual presentations, which may require adjustment in the public health management of the case. Public health staff should keep an open mind when investigating possible sources and assessing risk. In Western Sydney, this disease is largely associated with residents travelling to high-incidence countries to visit family and friends, and receiving family visits from these countries. The increasing number of cases of S. Paratyphi (prior to COVID-19) in Western Sydney and the importance of awareness of the risk of enteric fever to travellers to endemic regions is highlighted.

Metagenomics combined with comprehensive validation as a public health risk assessment tool for urban and agricultural run-off

Early detection of emerging and life-threatening pathogens circulating in complex environments is urgently required to combat infectious diseases. This study proposed a public health risk assessment workflow with three stages, pathogen screening, pathogen genotyping, and risk assessment. In stage one, pathogens were screened with metagenomic sequencing, microfluidic chip, and qPCR. In stage two, pathogens were isolated and genotyped with multi-locus sequence typing (MLST) or conventional PCR. Finally, virulence genes from metagenomic data were assessed for pathogenicity. Two regions (Donggang and Zhanjiang) with potential public health concerns were selected for evaluation, each of which comprised of one urban and one farming wastewater sampling location. Overall, metagenomic sequencing reflected the variation in the relative abundance of medically important bacteria. Over 90 bacterial pathogens were monitored in the metagenomic dataset, of which 56 species harbored virulence genes. In Donggang, a pathogenic Acinetobacter sp. reached high abundances in 2018 and 2020, whereas all pathogenic Vibrio spp. peaked in October 2019. In Zhanjiang, A. baumanni, and other Enterobacteriaceae species were abundantly present in 2019 and 2020, whereas Aeromonas and Vibrio spp. peaked in November-2017. Forty species were subsequently isolated and subtyped by MLST, half of which were prevalent genotypes in clinical data. Additionally, we identified the African Swine Fever Virus (ASFV) in water samples collected in 2017, ahead of the first reported ASFV outbreak in 2018 in China. RNA viruses like Hepatitis A virus (HAV) and Enterovirus 71 (EV71) were also detected, with concentrations peaking in April 2020 and April 2018, respectively. The dynamics of HAV and EV71 were consistent with local epidemic trends. Finally, based on the virulence gene profiles, our study identified the risk level in wastewater of two cities. This workflow illustrates the potential for an early warning of local epidemics, which helps to prioritize the preparedness for specific pathogens locally.

COVID-19 Pandemic: Public Health Risk Assessment and Risk Mitigation Strategies.

A newly emerged respiratory viral disease called severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is also known as pandemic coronavirus disease (COVID-19). This pandemic has resulted an unprecedented global health crisis and devastating impact on several sectors of human lives and economies. Fortunately, the average case fatality ratio for SARS-CoV-2 is below 2%, much lower than that estimated for MERS (34%) and SARS (11%). However, COVID-19 has a much higher transmissibility rate, as evident from the constant increase in the count of infections worldwide. This article explores the reasons behind how COVID-19 was able to cause a global pandemic crisis. The current outbreak scenario and causes of rapid global spread are examined using recent developments in the literature, epidemiological features relevant to public health awareness, and critical perspective of risk assessment and mitigation strategies. Effective pandemic risk mitigation measures have been established and amended against COVID-19 diseases, but there is still much scope for upgrading execution and coordination among authorities in terms of organizational leadership’s commitment and diverse range of safety measures, including administrative control measures, engineering control measures, and personal protective equipment (PPE). The significance of containment interventions against the COVID-19 pandemic is now well established; however, there is a need for its effective execution across the globe, and for the improvement of the performance of risk mitigation practices and suppression of future pandemic crises.

Mining of Cyanobacterial Genomes Indicates Natural Product Biosynthetic Gene Clusters Located in Conjugative Plasmids.

Microbial natural products are compounds with unique chemical structures and diverse biological activities. Cyanobacteria commonly possess a wide range of biosynthetic gene clusters (BGCs) to produce natural products. Although natural product BGCs have been found in almost all cyanobacterial genomes, little attention has been given in cyanobacterial research to the partitioning of these biosynthetic pathways in chromosomes and plasmids. Cyanobacterial plasmids are believed to disperse several natural product BGCs, such as toxins, by plasmids through horizontal gene transfer. Therefore, plasmids may confer the ability to produce toxins and may play a role in the evolution of diverse natural product BGCs from cyanobacteria. Here, we performed an analysis of the distribution of natural product BGCs in 185 genomes and mapped the presence of genes involved in the conjugation in plasmids. The 185 analyzed genomes revealed 1817 natural products BGCs. Individual genomes contained 1–42 biosynthetic pathways (mean 8), 95% of which were present in chromosomes and the remaining 5% in plasmids. Of the 424 analyzed cyanobacterial plasmids, 12% contained homologs of genes involved in conjugation and natural product biosynthetic pathways. Among the biosynthetic pathways in plasmids, manual curation identified those to produce aeruginosin, anabaenopeptin, ambiguine, cryptophycin, hassallidin, geosmin, and microcystin. These compounds are known toxins, protease inhibitors, odorous compounds, antimicrobials, and antitumorals. The present study provides in silico evidence using genome mining that plasmids may be involved in the distribution of natural product BGCs in cyanobacteria. Consequently, cyanobacterial plasmids have importance in the context of biotechnology, water management, and public health risk assessment. Future research should explore in vivo conjugation and the end products of natural product BGCs in plasmids via chemical analyses.

What is a "high" prevalence of obesity? Two rapid reviews and a proposed set of thresholds for classifying prevalence levels.

SummaryCategories such as “low” and “high” have been used for several decades to describe the prevalence of stunting and wasting in populations of children aged under 5 years. They provide support for public health risk assessment and policy‐making, including alerting health departments and aid agencies to national trends and local needs. In the light of the need for monitoring progress to meet globally agreed targets for overweight and obesity, the classification of their prevalence will be a valuable to aid in policy development, to target resources, and to promote public health interventions. This paper reviews the current use of categories to describe obesity prevalence in policy, advocacy, and research literature. Where prevalence categories have been formally proposed, this paper compares their application on large‐scale datasets. The paper then develops a set of recommended threshold values to classify prevalence levels for overweight and obesity among children under age 5 years, children aged 5–19 years, and adults.

The First Intra-Action Review of Indonesia's Response to the COVID-19 Pandemic, August 2020.

The COVID-19 pandemic has had an unprecedented impact on health, society, and the economy globally and in Indonesia. The World Health Organization (WHO) recommended the use of intra-action reviews (IARs) to identify best practices, gaps, and lessons learned to make real-time improvements to the COVID-19 response. The Emergency Committee of the International Health Regulations (2005) has recommended that countries share COVID-19 best practices and lessons learned with peer countries through IARs. Using WHO-established methodology, we conducted the first IAR of Indonesia's COVID-19 response from January through August 2020. The review covered 10 thematic areas (pillars): (1) command and coordination; (2) operational support and logistics; (3) surveillance, rapid response teams, risk assessment, and field investigation; (4) laboratories; (5) case management; (6) infection prevention and control; (7) risk communication and community empowerment; (8) points of entry, international travel, and transportation; (9) large-scale social restrictions; and (10) maintaining essential health services and systems. We held focus group discussions with a variety of stakeholders from a range of government departments, provincial health offices, and nongovernmental organizations. We used the results of the focus group discussions and other key findings from the IAR to formulate recommendations. The IAR identified key areas for improvement at national and subnational levels across all 10 pillars. Priority recommendations included improving multisectoral coordination and monitoring of COVID-19 response plan indicators; strengthening implementation of public health response measures, including case detection, isolation, infection prevention and control, contact tracing, and quarantine; and improving data collection, analysis, and reporting to inform public health risk assessment and response. The IAR is a useful tool for reviewing progress and identifying areas to improve the COVID-19 response in real time and provides a means to share information on areas of need with COVID-19 response partners and contributes to International Health Regulations (2005) core capacity development.

Intensity and frequency of extreme novel epidemics

Observational knowledge of the epidemic intensity, defined as the number of deaths divided by global population and epidemic duration, and of the rate of emergence of infectious disease outbreaks is necessary to test theory and models and to inform public health risk assessment by quantifying the probability of extreme pandemics such as COVID-19. Despite its significance, assembling and analyzing a comprehensive global historical record spanning a variety of diseases remains an unexplored task. A global dataset of historical epidemics from 1600 to present is here compiled and examined using novel statistical methods to estimate the yearly probability of occurrence of extreme epidemics. Historical observations covering four orders of magnitude of epidemic intensity follow a common probability distribution with a slowly decaying power-law tail (generalized Pareto distribution, asymptotic exponent = -0.71). The yearly number of epidemics varies ninefold and shows systematic trends. Yearly occurrence probabilities of extreme epidemics, Py, vary widely: Py of an event with the intensity of the "Spanish influenza" (1918 to 1920) varies between 0.27 and 1.9% from 1600 to present, while its mean recurrence time today is 400 y (95% CI: 332 to 489 y). The slow decay of probability with epidemic intensity implies that extreme epidemics are relatively likely, a property previously undetected due to short observational records and stationary analysis methods. Using recent estimates of the rate of increase in disease emergence from zoonotic reservoirs associated with environmental change, we estimate that the yearly probability of occurrence of extreme epidemics can increase up to threefold in the coming decades.

Experience in using statistical and mathematical technologies to assess the impact of atmospheric pollution on public health in a large industrial center

Introduction. The issue of air pollution is relevant in cities where the majority of the population lives and a large number of industrial enterprises are concentrated in relatively small areas. Currently, the federal project “Clean Air” is being implemented in 12 industrial centres of Russia within the framework of the national project “Ecology”. The purpose of the work was to justify using statistical and mathematical methods for assessing the impact of atmospheric pollution on the health of the population in the city of Novokuznetsk, Kemerovo region. Materials and methods. The following methods were used: assessment and management of public health risk, statistical analysis methods: factor analysis, multiple regression analysis, discriminant analysis. Results. Statistical indices and public health risk parameters can be used to assess the impact. Examples of the effect of complex pollution indices (the main components of pollution, the integral indicator P) and the concentrations of individual impurities in the air basin (suspended substances, ozone) were given. The carcinogenic risk to the population of Novokuznetsk, calculated from the calculated concentrations of atmospheric pollutants, was found to exceed the acceptable risk threshold. The specific weight of carcinogens in the formation of the risk to other oncological incidence was determined. An assessment of the risk from the emissions of a coal-processing plant located near residential areas of the city was carried out. The values of the hazard indices showed an excess of the acceptable non-carcinogenic risk only from the emissions of the coal processing plant, taking into account the background level of air pollution in the air basin. Conclusion. In Novokuznetsk, it is proposed to use the method of ranking atmospheric protection measures in terms of the unit cost of risk reduction in health risk management. To manage the risk, it is proposed to calculate the population indices of aerogenic hazard or the probabilistic parameters of the individual threat associated with air pollution. It is noted that a 20-22% reduction in pollutant emissions for Novokuznetsk may not be enough. The reasonable measures for the further study of the aerogenic impact on the population of the city are presented.

Investigation of microplastics in edible wild mussels from İzmir Bay (Aegean Sea, Western Turkey): A risk assessment for the consumers

The presence of microplastics (MPs) was determined in Mediterranean mussel (Mytilus galloprovincialis Lamarck, 1819) and grooved carpet shell (Ruditapes decussatus Linnaeus, 1758) together with water samples from in İzmir Bay (Aegean Sea, Western Turkey). A total of 895 MPs from Karşıyaka (Station 1), and 787 MPs from Gülbahçe (Station 2) were detected in 60 mussel samples, giving a total content of 1682 MPs. In water samples, a total of 545 MPs were detected in samples from Station 1 and 1287 MPs in samples from Station 2 (1832 MPs total). The amount of MPs in water samples was less in Station 1 than in Station 2. This difference is probably caused by Çiğli Wastewater Treatment Plant (WWTP) located near Station 1. Public health risk assessment on the consumption of the species M. galloprovincialis revealed that 70.82 items person−1 year−1 MPs through this species could enter consumers' digestive systems.

Chemical interactions and mixtures in public health risk assessment: An analysis of ATSDR's interaction profile database

The Agency for Toxic Substances and Disease Registry (ATSDR) develops interaction profiles using binary weight of evidence (BINWOE) methodology to determine interaction directions of common environmental mixtures. We collected direction of interactions, BINWOE score determination, and BINWOE score confidence rating from 13 interaction profiles along with toxicodynamic and toxicokinetic influences on interaction direction. By doing so, we quantified the 1) direction of interaction and indeterminate evaluations; 2) characterized confidence in the BINWOE determinations; and 3) quantified toxicokinetic/toxicodynamic, and other influences on projected BINWOE interaction directions. Thirty-nine percent (130/336) of the attempts to make a BINWOE were indeterminate due to no interaction data or inadequate or conflicting evidence. Out of remaining BINWOEs, 25% were additive, 9% were greater-than-additive, and 27% were less-than-additive interactions. Fifty-five percent of BINWOEs were explained by toxicokinetic interactions, 12% and 5% were explained by toxicodynamic and other explanations, respectively. High quality mixture toxicology in vivo studies along with mixture in vitro and in silico studies will lead to greater confidence in interaction directions and influences. Limitations for interpretation of the data were also included.

Impact of an accelerated melting of Greenland on malaria distribution over Africa

Studies about the impact of future climate change on diseases have mostly focused on standard Representative Concentration Pathway climate change scenarios. These scenarios do not account for the non-linear dynamics of the climate system. A rapid ice-sheet melting could occur, impacting climate and consequently societies. Here, we investigate the additional impact of a rapid ice-sheet melting of Greenland on climate and malaria transmission in Africa using several malaria models driven by Institute Pierre Simon Laplace climate simulations. Results reveal that our melting scenario could moderate the simulated increase in malaria risk over East Africa, due to cooling and drying effects, cause a largest decrease in malaria transmission risk over West Africa and drive malaria emergence in southern Africa associated with a significant southward shift of the African rain-belt. We argue that the effect of such ice-sheet melting should be investigated further in future public health and agriculture climate change risk assessments.

Assessment of the ecological and social potential of the organization of ecological zones to ensure sustainable transport development of territories

The article presents the results of an assessment of the impact on the environment and public health of measures to prohibit entry into a certain territory of the city of cars belonging to low environmental classes (“ecological zone” or “ecozone”). When justifying the choice of the city on the example of which the research was conducted (Novosibirsk), both environmental and socio-economic aspects were taken into account. The assessment of the environmental impact of the ecozone organization consisted in modeling traffic flows on the road network before and after the organization of the ecozone, estimating the emissions of pollutants from the totality of traffic flows, calculating the maximum and average annual surface concentrations of the considered pollutants on the territory of the ecozone. Based on the calculated average annual concentrations of pollutants, characteristics of the population density living in the ecozone, and scenarios of its interaction with pollutants, public health risk assessments were carried out before and after the organization of the ecozone. Studies have shown that the change in gross emissions of major pollutants during the organization of the ecozone in Novosibirsk will be 40…60%. Ground-level concentrations of these pollutants will decrease by about the same amount. Carcinogenic and non-carcinogenic risks to the population will be reduced by about half.

Concentration of heavy metals in two fish species (Cynoscion regalis and Pomatomus saltatrix) from an oil drilling area in Western Coast of Ghana and public health risk assessment

This study assessed heavy metals (Lead (Pb), Nickel (Ni), Iron (Fe), Chromium (Cr), and Cadmium (Cd)) concentration in water (from borehole, hand-dug well and the sea) and fish (Cynoscion regalis and Pomatomus saltatrix species) and possible health risk exposure by the consumption of these fishes. A total of 18 samples of water and samples of two species of fish (C. regalis and P. saltatrix) were collected from Jomoro, Ellembelle and Ahanta West District and analyzed for the concentration of Pb, Ni, Fe, Cr, and Cd using Atomic Absorption Spectrometer (AAS). Results revealed appreciable concentrations of Pb, Ni, and Fe in the fish muscle and Ni, Cr, and Fe in water. Cadmium and Cr were not detected in the fish samples. Heavy metals in fish increased in the order Pb < Ni < Fe. The Estimated Daily Intake of fish value for adult ranged 1.88 x 10-3 to 2.03 x 10-1 (mg/kg bw/day), however, those for children were 4.40 x 10-3 to 4.74 x 10-1(mg/kg bw/day). For health risk assessment, the Total Targeted Hazard Quotient for adults was < 1; however, those for children were >1 for C. regalis but less than 1 (< 1) for P. saltatrix meaning children who consume C. regalis are exposed to health risk in their life time. The results confirmed that contaminated environments could result in bioaccumulation of metal pollutants in fish's muscle, which poses a health risk to humans when consumed. Awareness and education of the general public on the threshold of heavy metals in fish and water are crucial to safeguard against health risks.

Vector Surveillance, Host Species Richness, and Demographic Factors as West Nile Disease Risk Indicators.

West Nile virus (WNV) is the most common arthropod-borne virus (arbovirus) in the United States (US) and is the leading cause of viral encephalitis in the country. The virus has affected tens of thousands of US persons total since its 1999 North America introduction, with thousands of new infections reported annually. Approximately 1% of humans infected with WNV acquire neuroinvasive West Nile Disease (WND) with severe encephalitis and risk of death. Research describing WNV ecology is needed to improve public health surveillance, monitoring, and risk assessment. We applied Bayesian joint-spatiotemporal modeling to assess the association of vector surveillance data, host species richness, and a variety of other environmental and socioeconomic disease risk factors with neuroinvasive WND throughout the conterminous US. Our research revealed that an aging human population was the strongest disease indicator, but climatic and vector-host biotic interactions were also significant in determining risk of neuroinvasive WND. Our analysis also identified a geographic region of disproportionately high neuroinvasive WND disease risk that parallels the Continental Divide, and extends southward from the US–Canada border in the states of Montana, North Dakota, and Wisconsin to the US–Mexico border in western Texas. Our results aid in unraveling complex WNV ecology and can be applied to prioritize disease surveillance locations and risk assessment.

Probabilistic health risk assessment of toxic metals in chickens from the largest production areas of Dhaka, Bangladesh.

Chicken is one of the major protein sources and more affordable for the population of Bangladesh. Its quality monitoring is of high priority for food safety and public health risk assessment. This study determined metals (Fe, Cu, Zn, As, Ni, Cr, Sr, Hg, and Pb) in chickens from different farms of a high production area of Dhaka, Bangladesh, using an energy-dispersive X-ray fluorescence spectrometer to calculate the health risk through chickens consumption. In most cases, the toxic metals (As, Ni, Cr, Hg, and Pb) showed very high concentrations in different parts of chickens, especially livers that contained several times higher concentrations than the maximum allowable concentration (MAC). Analytical results showed some feed and water contain high concentrations of As and Cr that might be bioaccumulated in chicken. The estimated daily intake (EDI) for all metals was below the provisional tolerable daily intake (PTDI) values except As and Fe in few farms. Target hazard quotients (THQs) for most metals were less than 1 but THQs of As and Cr of few farms were higher than 1, indicating that the consumer would possess As- and Cr-based health hazards. Total target hazard quotient (TTHQ) of 42% for composite and 36% for body parts samples were > 1, suggesting potential health risk. The probabilistic risk and individual samples cancer risk (TR) were exceeded the acceptable level (10-4) for As and 75% of composite and 58% of body parts of chicken showed acceptable limit (10-6 to 10-4) for Pb, indicating that the peoples might be exposed to lifetime cancer risk in the long run.

Longitudinal Study on Seasonal Variation of Marine Biotoxins and Related Harmful Algae in Bivalve Mollusks Bred in Sardinia (Italy, W Mediterranean Sea) from 2015 to 2020 and Assessment of Potential Public Health Risks

Annual and interannual dynamics of shellfish toxins and associated harmful algal species (HAS) were analyzed from 2015 to 2020 in Tortolì Lagoon (Sardinia, west Mediterranean Sea). Analysis of seasonal occurrence of different harmful algae, such as Dinophysis spp., Prorocentrum spp., Pseudo-nitzschia spp. and Alexandrium minutum, was performed. The species Dinophysis acuminata and Dinophysis sacculus were responsible for the accumulation of lipophilic toxins belonging to the okadaic acid group (OAs) and pectenotoxins2 (PTX2) in bivalve mollusks. The highest HAS detection was recorded in the winter months; in particular, Dinophysis spp. was mostly present in January–February. Out of 1090 analyzed mollusk samples, 39 were non-compliant, exceeding the legal limits (160 μg OA eq/kg e.p.) reported in Regulation 853/2004 of the European Commission. A statistical analysis related to the presence of OA and PTX2 in mollusks with various environmental parameters (pH, water temperature, dissolved oxygen, algal density) was implemented, proving a clear winter seasonality. The present study highlights the necessity to better understand the different factors able to influence the production and accumulation of toxins in bivalve mollusks bred in an important Sardinian production area. The contribution of this research is important not only from an environmental and productive point of view but also from the view of implementing management in order to mitigate any harm to human health.

Assessment of Heavy Metal Concentrations and Public Health Risk in Fish Species of Sakarya River, Turkey

In this study, heavy metal concentrations including cadmium, lead, zinc, copper and arsenic concentrations were determined in five fish species (Capoeta sieboldii, Capoeta tinca, Scardinius erythrophthalmus, Squalius pursakensis and Barbus escherichii) obtained from the Sakarya River. The metal concentrations of fish supplied in four different seasons (winter, spring, summer and autumn) were determined by using atomic absorption spectrophotometry. Although the metal concentrations showed seasonal variations in some fish species and also varied with respect to particular fish species, the concentrations of these metals were found to be within the permissible limits. In addition, it was concluded that the concentration of metal contamination in the evaluated fish species would not pose a risk for human consuming fish species obtained from Sakarya River by considering estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and target cancer risk (TCR) values.

Decay of infectious SARS-CoV-2 and surrogates in aquatic environments

The introduction of SARS-CoV-2 containing human stool and sewage into water bodies may raise public health concerns. However, assessment of public health risks by faecally contaminated water is limited by a lack of knowledge regarding the persistence of infectious SARS-CoV-2 in water. In the present study the decay rates of viable infectious SARS-CoV-2 and SARS-CoV-2 RNA were determined in river and seawater at 4 and 20°C. These decay rates were compared to S. typhimurium bacteriophage MS2 and pepper mild mottle virus (PMMoV). Persistence of viable SARS-CoV-2 was temperature dependent, remaining infectious for significantly longer periods of time in both freshwater and seawater at 4°C than at 20°C. T90 for infectious SARS-CoV-2 in river water was 2.3 days and 3.8 days at 20°C and 4°C, respectively. The T90 values were 1.1 days and 2.2 days in seawater at 20°C and 4°C, respectively. In contrast to the rapid inactivation of infectious SARS-CoV-2 in river and sea water, viral RNA was relatively stable. The RNA decay rates were increased in non-sterilised river and seawater, presumably due to the presence of microbiota. The decay rates of infectious MS2, MS2 RNA and PMMoV RNA differed significantly from the decay rate of SARS-CoV-2 RNA, suggesting that their use as surrogate markers for the persistence of SARS-CoV-2 in the environment is limited.

Proposal of new distribution coefficients (Kd) of potentially toxic elements in soils for improving environmental risk assessment in the State of São Paulo, southeastern Brazil

Soil solid-solution distribution coefficients (Kd) are used in predictive environmental models to assess public health risks. This study was undertaken to determine Kd for potentially toxic elements (PTE) Cd, Co, Cr, Cu, Ni, Pb, and Zn in topsoil samples (0–20 cm) from 30 soils in the State of São Paulo, southeastern Brazil. Batch sorption experiments were carried out, and PTE concentrations in the equilibrium solution were determined by High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICPMS). Sorption data was fitted to the Freundlich model. The Kd values were either obtained directly from the slope coefficients of C-type isotherms or derived from the slope of the straight line tangent to the non-linear L-type and H-type isotherms. Stepwise multiple regression models were used to estimate the Kd values through the combined effect of a number of soil attributes [pHH2O, effective cation exchange capacity (ECEC) and contents of clay, organic carbon, and Fe (oxy)hydroxides]. The smallest variation in Kd values was recorded for Cu (105-4598 L kg-1), Pb (121-7020 L kg-1), Ni (6-998 L kg-1), as variation across four orders of magnitude was observed for Cd (7–14,339 L kg−1), Co (2–34,473 L kg−1), and Cr (1–21,267 L kg−1). The Kd values for Zn were between 5 and 123,849 L kg−1. According to median values of Kd, PTE were sorbed in the following preferential order: Pb > Cu > Cd > Ni > Zn > Cr > Co. The Kd values were best predicted using metal-specific and highly significant (p < 0.001) linear regressions that included pHH2O, ECEC, and clay contents. The Kd values reported in this study are a novel result that can help minimize erroneous estimates and improve both environmental and public health risk assessments under humid tropical edaphoclimatic conditions.

Air quality and public health risk assessment: A case study in a typical polluted city, North China

To evaluate air quality changes along with public health in Jinan, a typical polluted city of North China, spatial and temporal features of six criteria pollutants and relative health risk were conducted from 2013 to 2017. In general, the concentrations of criteria air pollutants except ozone had obviously decreased. For spatial pattern, the air qualities in north Jinan were influenced by dust, vehicle and industry emission. Health risk evaluation showed people mainly suffered health risk from PM10 and PM2.5. However, O3 had become another noticeable pollutant in recent years. Compared with other cities in China, the citizens in Jinan were more likely to suffer from much higher health risk categories than the current Air Quality Index (AQI) approach, particularly in winter. During severe polluted episodes, secondary formation via heterogeneous reaction would increase public health risk from air pollution. Back trajectories and potential source contribution function (PSCF) analysis identified anthropogenic sources from near provinces particularly to the east and south may aggravate air pollution by air mass transport. In general, the emission controls on VOCs, NO2 and regional joint pollution prevention would be essential to reduce urban air pollution in the next phases.