Development of a novel DGT passive sampler for measuring polycyclic aromatic hydrocarbons in aquatic systems

Polycyclic aromatic hydrocarbons (PAHs) are priority pollutants and need to be measured reliably in waters and other media, to understand their sources, fate, behaviour and to meet regulatory monitoring requirements. Conventional water sampling requires large water volumes, time-consuming pre-concentration and clean-up and is prone to analyte loss or contamination. Here, for the first time, we developed and validated a novel diffusive gradients in thin-films (DGT) passive sampler for PAHs. Based on the well-known DGT principles, the sampler pre-concentrates PAHs with typical deployment times of days/weeks, with minimal sample handling. For the first time, DGT holding devices made of metal and suitable for sampling hydrophobic organic compounds were designed and tested. They minimize sorption and sampling lag times. Following tests on different binding layer resins, a MIP-DGT was preferred - the first time applying MIP for PAHs. It samples PAHs independent of pH (3.9 -8.1), ionic strength (0.01 -0.5 M) and dissolved organic matter < 20 mg L-1, making it suitable for applications across a wide range of environments. Field trials in river water and wastewater demonstrated that DGT is a convenient and reliable tool for monitoring labile PAHs, readily achieving quantitative detection of environmental levels (sub-ng and ng/L range) when coupled with conventional GC-MS or HPLC. ENVIRONMENTAL IMPLICATIONS: PAHs are carcinogenic and genotoxic compounds. They are environmentally ubiquitous and must be monitored in waters and other media. This study successfully developed a new DGT passive sampler for reliable in situ time-integrated measurements of PAHs in waters at the ng/L level. This is the first time to use passive samplers for accurate measurements of hydrophobic organic contaminants in aquatic systems without calibration, a big step forward in monitoring PAHs. The application of this new sampler will enhance our understanding of the sources, fate, behavior and ecotoxicology of PAHs, enabling improved environmental risk assessment and management of these compounds.

Soil's Hidden Power: The Stable Soil Organic Carbon Pool Controls the Burden of Persistent Organic Pollutants in Background Soils

Persistent organic pollutants (POPs) tend to accumulate in cold regions by cold condensation and global distillation. Soil organic matter is the main storage compartment for POPs in terrestrial ecosystems due to deposition and repeated air-surface exchange processes. Here, physicochemical properties and environmental factors were investigated for their role in influencing POPs accumulation in soils of the Tibetan Plateau and Antarctic and Arctic regions. The results showed that the soil burden of most POPs was closely coupled to stable mineral-associated organic carbon (MAOC). Combining the proportion of MAOC and physicochemical properties can explain much of the soil distribution characteristics of the POPs. The background levels of POPs were estimated in conjunction with the global soil database. It led to the proposition that the stable soil carbon pools are key controlling factors affecting the ultimate global distribution of POPs, so that the dynamic cycling of soil carbon acts to counteract the cold-trapping effects. In the future, soil carbon pool composition should be fully considered in a multimedia environmental model of POPs, and the risk of secondary release of POPs in soils under conditions such as climate change can be further assessed with soil organic carbon models.

2023 Outstanding Papers published in the Environmental Science journals of the Royal Society of Chemistry

The Editors-in-Chief of the Environmental Science journals introduce the Outstanding Papers of 2023.

Comprehensive Assessment of Environmental Emissions, Fate, and Risks of Veterinary Antibiotics in China: An Environmental Fate Modeling Approach

China is one of the major global consumers of veterinary antibiotics. Insufficient recognition of emissions and environmental contamination hamper global efforts to prevent antibiotic resistance development. This pioneering study combined empirical data and modeling approaches to predict total 2010-2020 emissions of 80 veterinary antibiotics ranging from 23,110 to 40,850 tonnes/year, after 36-50% antibiotic removal by manure treatment. Following an initial increase of 10% from 2010 to 2015, emissions declined thereafter by 43%. While 85% of emissions discharged into soils, approximately 56%, 23%, and 18% of environmental residue were ultimately distributed in soils, freshwaters, and seawaters under steady-state conditions. In 2020, 657 (319-1470) tonnes entered the ocean from inland freshwaters. Median ∑antibiotics concentrations were estimated at 4.7 × 103 ng/L in freshwaters and 2.9 ng/g in soils, with tetracyclines and sulfonamides as the predominant components. We identified 44 veterinary antibiotics potentially posing high risks of resistance development in freshwaters, with seven exhibiting high risks in >10% of Chinese freshwater areas. Tetracyclines were the category with the most antibiotics exhibiting elevated risks; however, sulfamethylthiazole demonstrated the highest individual compound risk. The Haihe River Basin displayed the highest susceptibility overall. The findings offer valuable support for control of veterinary antibiotic contamination in China.

Development and validation of an in situ high-resolution technique for measuring antibiotics in sediments

Important biogeochemical processes occur in sediments at fine scales. Sampling techniques capable of yielding information with high resolution are therefore needed to investigate chemical distributions and fluxes and to elucidate key processes affecting chemical fates. In this study, a high-resolution diffusive gradients in thin-films (DGT) technique was systematically developed and tested in a controlled sediment system to measure organic contaminants, antibiotics, for the first time. The DGT probe was used to resolve compound distributions at the mm scale. It also reflected the fluxes from the sediment pore-water and remobilization from the solid phase, providing more dynamic information. Through the fine scale detection, a reduction of re-supply was observed over time, which was concentration and location dependent. Compared to the Rhizon sampling method, antibiotic concentrations obtained by DGT probes were less than the pore-water concentrations, as DGT measures the labile fraction of the compounds. The DGT probe was also tested on an intact sediment core sampled from a lake in China and used to measure the distribution of labile antibiotics with depth in the core at the mm scale. ENVIRONMENTAL IMPLICATION: The abuse of antibiotics and widespread of their residues influences the ecosystem, induces the generation of super-bacteria, and finally poses threat to human health. Sediments adsorbs pollutants from the aquatic environment, while may also release them back to the environment. We systematically developed DGT probe approach for measuring antibiotics in sediment in situ in high resolving power, it provides information at fine scale to help us investigate biogeochemical processes take place in sediment and sediment-water interface.

Evaluating the Current State of Epilepsy Care in the Province of Ontario

There are numerous challenges pertaining to epilepsy care across Ontario, including Epilepsy Monitoring Unit (EMU) bed pressures, surgical access and community supports. We sampled the current clinical, community and operational state of Ontario epilepsy centres and community epilepsy agencies post COVID-19 pandemic. A 44-item survey was distributed to all 11 district and regional adult and paediatric Ontario epilepsy centres. Qualitative responses were collected from community epilepsy agencies. Results revealed ongoing gaps in epilepsy care across Ontario, with EMU bed pressures and labour shortages being limiting factors. A clinical network advising the Ontario Ministry of Health will improve access to epilepsy care.

Emerging and legacy plasticisers in coastal and estuarine environments: A review

The occurrence of plastic waste in the environment is an emerging and ongoing concern. In addition to the physical impacts of macroplastics and microplastics on organisms, the chemical effects of plastic additives such as plasticisers have also received increasing attention. Research concerning plasticiser pollution in estuaries and coastal environments has been a particular focus, as these environments are the primary entry point for anthropogenic contaminants into the wider marine environment. Additionally, the conditions in estuarine environments favour the sedimentation of suspended particulate matter, with which plasticisers are strongly associated. Hence, estuary systems may be where some of the highest concentrations of these pollutants are seen in freshwater and marine environments. Recent studies have confirmed emerging plasticisers and phthalates as pollutants in estuaries, with the relative abundance of these compounds controlled primarily by patterns of use, source intensity, and fate. Plasticiser profiles are typically dominated by mid-high molecular weight compounds such as DnBP, DiBP, and DEHP. Plasticisers may be taken up by estuarine and marine organisms, and some phthalates can cause negative impacts in marine organisms, although further research is required to assess the impacts of emerging plasticisers. This review provides an overview of the processes controlling the release and partitioning of emerging and legacy plasticisers in aqueous environments, in addition to the sources of plasticisers in estuarine and coastal environments. This is followed by a quantitative analysis and discussion of literature concerning the (co-)occurrence and concentrations of emerging plasticisers and phthalates in these environments. We end this review with a discussion the fate (degradation and uptake by biota) of these compounds, in addition to identification of knowledge gaps and recommendations for future research.

Indirect Emissions from Organophosphite Antioxidants Result in Significant Organophosphate Ester Contamination in China

Organophosphite antioxidants (OPAs) have been seriously neglected as potential sources of organophosphate esters (OPEs) in environments. This study utilizes a modeling approach to quantify for the first time national emissions and multimedia distributions of triphenyl phosphate (TPHP)─a well-known flame retardant─and three novel OPEs: tris(2,4-ditert-butylphenyl) phosphate (AO168═O), bis(2,4-ditert-butylphenyl) pentaerythritol diphosphate (AO626═O2), and trisnonylphenol phosphate (TNPP). Emphasis is on the quantitative assessment of OPA source in China. TPHP has 1.1-9.7 times higher emission (300 Mg/year in 2019 with half from OPA sources) than AO168═O (278 Mg/year), AO626═O2 (53 Mg/year), and TNPP (32 Mg/year), but AO168═O is predominant in environments (63-79%) except freshwaters. About 72-99% of the studied OPEs are emitted via air, with 88-99% ultimately distributed into soils as the major sink. OPA-source emissions contribute 9.5-57% and 4.7-56% of TPHP masses and concentrations (except in sediments) in different media, respectively. Both AO168═O and AO626═O2 exhibit high overall persistence ranging between 2 and 11 years. Source emissions and environmental concentrations are elevated in economically developed areas, while persistence is higher in northern areas, where precipitation and temperature are lower. This study shows the significance of the sources of OPA to OPE contamination, which supports chemical management of these substances.

Gaseous elemental mercury emissions from informal E-Waste recycling facilities in Pakistan

Detrimental effects of mercury (Hg) on ecosystems and human health have been well-documented. Whereas emissions of gaseous elemental mercury (GEM) from e-waste recycling have been reported in developed countries, much less is known about the situation in the Global South. Using a total of 132 passive air samplers, seasonally resolved concentrations of GEM in air were measured continuously at 32 informal e-waste recycling facilities and background location in Pakistan for a period of one year between September 2020 and December 2021. Annual average GEM concentrations at the studied locations ranged from 1.8 to 92 ng m-3. Among the studied cities, higher concentrations were measured in Karachi (mean ± s.d: 17 ± 22, range: 4.2-92 ng m-3), Lahore (16 ± 4.2, 8.2-22 ng m-3) and Peshawar (15 ± 17, 4.9-80 ng m-3), while lower levels were measured in Hyderabad (6.9 ± 6.2, 3.1-25 ng m-3), consistent with a higher rate of informal recycling activities in metropolitan areas. Seasonally, higher GEM levels occurred during autumn (15 ± 16: 3.3-92 ng m-3) and summer (13 ± 8.7: 1.8-80 ng m-3) than in winter (12 ± 8.4: 2.5-49 ng m-3) and spring (9.2 ± 7.3: 1.8-80 ng m-3), possibly reflecting enhanced volatilization at higher temperatures and/or varying magnitude of recycling operations in different seasons. Policies and strict regulations related to e-waste management should be developed and implemented urgently in the country.

Genetics and SUDEP: Challenges and Future Directions

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of epilepsy-related deaths in children and adults with epilepsy. The incidence of SUDEP in children and adults is equal, approximately 1.2 per 1000-person years. Although inroads have been made in our understanding of SUDEP, its pathophysiology remains unknown. The most important risk factor for SUDEP is the presence of tonic-clonic seizures. Recently there has been growing interest in the contribution of genetic risk factors to SUDEP deaths. Pathogenic variants in epilepsy-related and cardiac genes have been found in some cases of SUDEP post-mortem. Pleiotropy may occur in which a single gene when altered may cause multiple phenotypes (i.e., epilepsy and cardiac arrhythmia). Recently it has been shown that some developmental and epileptic encephalopathies (DEEs) may also be at heightened risk of SUDEP. In addition, polygenic risk has been postulated to effect SUDEP risk with current models evaluating the additive effect of variants in multiple genes. However, the mechanisms underpinning polygenic risk in SUDEP are likely more complex than this. Some preliminary studies also highlight the feasibility of detecting genetic variants in brain tissue post-mortem. Despite the advances in the field of SUDEP genetics, the use of molecular autopsy remains underutilized in SUDEP cases. Several challenges exist concerning genetic testing post-mortem in SUDEP cases, such as interpretation, cost of testing, and availability. In this focused review, we highlight the current landscape of genetic testing in SUDEP cases, its challenges, and future directions.

Co-occurrence of macroplastics, microplastics, and legacy and emerging plasticisers in UK soils

Despite a theoretical link between plastic and plasticiser occurrence in the terrestrial environment, there are few empirical studies of the relationship between these contaminants in soils. We carried out a field study to assess the co-occurrence of plastic waste, and legacy and emerging plasticisers in UK soils (n = 19) from various land uses (woodlands, urban roadsides, urban parklands, landfill-associated). Surface plastics and soil microplastics were quantified and characterised using ATR-FTIR and μ-FTIR. Eight legacy (phthalate) and three emerging (adipate, citrate, trimellitate) plasticisers were quantified using GC-MS. Surface plastics were found at higher prevalence at landfill-associated and urban roadside sites, with levels significantly (2 orders of magnitude) greater than in woodlands. Microplastics were detected in landfill-associated (mean 12.3 particles g^-1 dw), urban roadside (17.3 particles g^-1 dw) and urban parkland (15.7 particles g^-1 dw) soils, but not in woodland soils. The most commonly detected polymers were polyethene, polypropene and polystyrene. Mean ∑plasticiser concentration in urban roadside soils (3111 ng g^-1 dw) was significantly higher than in woodlands (134 ng g^-1 dw). No significant difference was found between landfill-associated (318 ng g^-1 dw) and urban parkland (193 ng g^-1 dw) soils and woodlands. Di-n-butyl phthalate (94.7% detection frequency) and the emerging plasticiser trioctyl trimellitate (89.5%) were the most commonly detected plasticisers, with diethylhexyl phthalate (493 ng g^-1 dw) and di-iso-decyl phthalate (96.7 ng g^-1 dw) present at the highest concentrations. ∑plasticiser concentrations were significantly correlated with surface plastic (R² = 0.23), but not with soil microplastic concentrations. Whilst plastic litter seems a fundamental source of plasticisers in soils, mechanisms such as airborne transport from source areas may be as important. Based on the data from this study, phthalates remain the dominant plasticisers in soils, but emerging plasticisers are already widespread, as reflected by their presence in all land uses studied.

The genetic landscape of developmental and epileptic encephalopathy with spike-and-wave activation in sleep

OBJECTIVE

Epileptic Encephalopathy / Developmental Epileptic Encephalopathy with spike-and-wave activation in sleep (EE/DEE-SWAS) is defined as an epilepsy syndrome characterized by neurodevelopmental regression temporally related to the emergence of significant activation of spike-wave discharges in EEG during sleep. The availability of genetic testing has made it evident that monogenic and chromosomal abnormalities play an aetiological role in the development of EE/DEE-SWAS. We sought to review the literature to better understand the genetic landscape of EE/DEE-SWAS.

METHODS

In this systematic review, we reviewed cases of EE/DEE-SWAS associated with a genetic aetiology, collecting information related to the underlying aetiology, onset, management, and EEG patterns.

RESULTS

One hundred and seventy-two cases of EE/DEE-SWAS were identified. Genetic causes of note included pathogenic variants in GRIN2A, ZEB2, CNKSR2 and chromosome 17q21.31 deletions, each of which demonstrated unique clinical characteristics, EEG patterns, and age of onset. Factors identified to raise suspicion of a potential genetic aetiology included the presentation of DEE-SWAS and onset of SWAS under the age of five years. Treatment of EE/DEE-SWAS due to genetic causes was diverse, including a combination of anti-seizure medications, steroids, and other clinical strategies, with no clear consensus on a preferred or superior treatment. Data collected was significantly heterogeneous, with a lack of consistent use of neuropsychology testing, EEG patterns, or use of established clinical definitions.

CONCLUSIONS

Uniformity concerning the new definition of EE/DEE-SWAS, guidelines for management and more frequent genetic screening will be needed to guide best practices for the treatment of patients with EE/DEE-SWAS.

SUDEP: Living with the knowledge

OBJECTIVE

To understand how knowledge of sudden unexpected death in epilepsy (SUDEP) impacted the lives of adult persons with epilepsy (PWE) and primary caregivers of both adults and children with epilepsy.

METHODS

The principles of fundamental qualitative description guided this descriptive and exploratory qualitative study to document patients' and caregivers' perceptions and experiences. A purposeful sample of individuals (18 years or older) diagnosed with epilepsy or primary caregivers of PWE completed a single in-depth, semi-structured, one-to-one telephone interview. Categories of findings were developed using directed content analysis.

RESULTS

A total of twenty-seven participants completed the study. This consisted of eight adult females and six adult males with epilepsy, ten female caregivers, and three male caregivers of PWE. All participants had become aware of SUDEP at least 12 months before their interview. Most were not informed about SUDEP by their treating neurologist and instead learned about SUDEP via alternative sources (e.g., the internet). All participants believed that knowledge of SUDEP outweighed the risks of being informed about it. Anxiety/fear related to SUDEP disclosure was generally not long-lasting. Caregivers of PWE were more directly impacted by SUDEP disclosure than adult PWE. Caregivers were more likely to make lifestyle/management changes due to learning about SUDEP (e.g., increased supervision and co-sleeping). Participants agreed that follow-up clinical support should be provided after SUDEP disclosure.

CONCLUSIONS

Disclosure of SUDEP risk may have more significant impacts on caregivers of PWE than adult PWE in the form of lifestyle changes and epilepsy management. After SUDEP disclosure, follow-up support should be offered to PWE and their caregivers, which should be incorporated into future guidelines.

A bibliometric analysis and assessment of priorities for heavy metal bioavailability research and risk management in contaminated land

Risk assessment has been recognized as an important tool for evaluating heavy metal pollution and providing risk-based information for decision makers. In order to accurately assess the risk of heavy metals in contaminated soil to human health, it is necessary to conduct bioavailability studies on heavy metals in soil. Bioavailability of heavy metals in soils and the implications for risk assessment and land management/remediation has evolved over the decades and now has considerable practical and economic implications internationally. This article aims to explore its evolution by undertaking a bibliometric analysis of the research fields which have addressed heavy metal bioavailability in soils, with a focus on the risk assessment of contaminated land and human exposure to soil-borne metals. Bibliometric analysis techniques are applied to monitor and assess the changing research literature on the bioavailability of heavy metals in contaminated soils. Over 5000 articles were found for the period 1979-2020. The purpose was not to perform an exhaustive literature review, but to draw out trends and patterns in the literature, and to make observations on past and current priorities. Key words were extracted from the analysis and the roles of different countries in driving the research literature identified. Three phases in literature/subject development were identified. Between 1979 and 2000 (initial phase, 213 articles), studies used extraction procedures and solubility studies to investigate the roles of soil properties on metal form/speciation and focused on bioavailability to (crop) plants in agricultural soils. Between 2001 and 2010 (slow development phase, 1105 articles), attention switched to metals introduced in soil amendments and wastes, metal impacts on soil microbial processes, and incorporating bioavailability in risk assessment. More rigorous techniques were being used, such as the diffusive gradients in thin films technique, to better understand kinetic and metal speciation in soils and the quantitative relationship to bioavailability. By 2011-2020 (rapid development phase, 3137 articles), research was being conducted in many countries (site specific, often industrially contaminated and urban sites), with a focus shift to health risk assessment, remediation, and bioavailability to various ecological receptors (e.g., humans and animals), with the development of many methods of bioavailability (e.g., simulated gastrointestinal tract enzymolysis methods). Some priorities for research on soil heavy metal bioavailability are identified.

The Epilepsy Phenotype of ST3GAL3-related Developmental and Epileptic Encephalopathy

OBJECTIVE

ST3GAL3-related developmental and epileptic encephalopathy (DEE-15) is an autosomal recessive condition characterized by intellectual disability, language and motor impairments, behavioural difficulties, stereotypies and epilepsy. Only a few cases have been reported, and the epilepsy phenotype is not fully elucidated.

METHODS

A retrospective chart review of two siblings with ST3GAL3-related DEE was completed. In addition, we reviewed all published cases of ST3GAL3-related congenital disorder of glycosylation.

RESULTS

Two brothers presented with global developmental delay, motor and language impairment, hypotonia, and childhood-onset seizures. Seizures started between 2.5-5 years and had tonic components. Both siblings had prolonged periods of seizure freedom on carbamazepine. Tremor was present in the younger sibling. Whole exome sequencing revealed two novel pathogenic variants in ST3GAL3, 1) c.302del, p.Phe102Serfs*34 and 2) c.781C>T, p.Arg261*, which were inherited in trans. MRI showed T2 hyperintensities and restricted diffusion in the brainstem and middle cerebellar peduncle in the older sibling, also described in two reported cases. A review of the literature revealed 24 cases of ST3GAL3-related CDG. Twelve cases had information about seizures, and epilepsy was diagnosed in 8 (67%). The median age of seizure onset was 5.5 months. Epileptic spasms were most common (67%). Four children were diagnosed with Infantile Epileptic Spasms syndrome and Lennox Gastaut syndrome (57%). Most children (n=6, 75%) had seizures despite anti-seizure medication treatment.

SIGNIFICANCE

Seizures related to ST3GAL3-related DEE often occur in infancy and may present as epileptic spasms. However, seizure onset may also occur outside of infancy with mixed seizure types and show good response to treatment with prolonged seizure freedom. Tremor may also be uniquely observed in this condition.

SUDEP Counseling: Where do we stand?

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of epilepsy-related death in children and adults living with epilepsy. Several recent clinical practice guidelines have recommended that all individuals living with epilepsy and their caregivers be informed about SUDEP as a part of routine epilepsy counseling. Further, several studies over the last two decades have explored the state of SUDEP counseling. Patients with epilepsy and their families want to be informed about the risk of SUDEP at or near the time of diagnosis and preferably in person. Despite guideline recommendations, many pediatric and adult neurologists do not routinely inform individuals with epilepsy and their families about SUDEP. Some neurologists discuss SUDEP with only a subset of patients with epilepsy, such as those with risk factors like frequent generalized or focal to bilateral tonic-clonic seizures, nocturnal seizures, non-compliance, or medically refractory epilepsy. Proponents of routine SUDEP counseling argue that patients with epilepsy and their families have a "right to know" and that counseling may positively impact epilepsy self-management (i.e., behavioral modification and risk reduction). Some neurologists still believe that SUDEP counseling may cause unnecessary stress and anxiety for patients and their families (although this is erroneous) and that they also have a "right not to know." This narrative review explores the current gaps in SUDEP counseling, patients' and caregivers' perspectives of SUDEP counseling, and SUDEP prevention.

Epilepsy surgery outcomes in patients with GATOR1 gene complex variants: Report of new cases and review of literature

AIM

To report seizure outcomes in children with GATOR1 gene complex disorders who underwent epilepsy surgery and perform a systematic literature search to study the available evidence.

METHODS

The records of children with pathogenic/likely pathogenic variants in GATOR1 gene complex who underwent epilepsy surgery were reviewed. Clinical, radiological, neurophysiological, and histological data were extracted/summarized. The systematic review included all case series/reports and observational studies reporting on children or adults with genetic (germline or somatic) variants in the GATOR1 complex genes (DEPDC5, NPRL2, NPRL3) with focal epilepsy with/without focal cortical dysplasia who underwent epilepsy surgery; seizure outcomes were analyzed.

RESULTS

Eight children with pathogenic/likely pathogenic variants in GATOR1 complex genes were included. All had drug-resistant epilepsy. Six children had significant neurodevelopmental delay. Epilepsy surgery was performed in all; clinical seizure freedom was noted in 4 children (50%). Systematic literature search identified 17 eligible articles; additional 30 cases with patient-level data were studied. Lesional MRI brain was seen in 80% cases. The pooled rate of seizure freedom following surgery was 60%; FCD IIa was the most encountered pathology.

INTERPRETATION

Epilepsy surgery may be effective in some children with GATOR1 complex gene variants. Seizure outcomes may be compromised by extensive epileptogenic zones.

Life after SUDEP: Experiences of traumatic loss and growth

PURPOSE

To understand the experiences of bereaved relatives of individuals who passed due to sudden unexpected death in epilepsy (SUDEP) and to explore the impacts of death in their lives.

METHODS

The principles of fundamental qualitative description informed all design decisions. Stratified purposeful sampling included 21 bereaved relatives (parent, sibling, or spouse/partner), aged at least 18 years, of persons who passed away because of SUDEP. In-depth one-to-one interviews were conducted. Directed content analysis was used to code, categorize, and synthesize the interview data.

RESULTS

There was some criticism of emergency response and medical professionals involved in providing insensitive or poor care immediately after SUDEP occurred. Personal hardships described by participants following SUDEP included loss of personal identity, feeling depressed, experiencing guilt, having panic attacks, requiring therapy, as well as having difficulty with anniversaries, dates, and cleaning up a child's room. Bereaved spouses and parents in particular spoke of experiencing challenges in maintaining other relationships following the death. Some participants spoke of experiencing increased financial hardships. Ways of coping included keeping oneself busy, honoring the memory of the loved one, relying on friends and families, and engaging in advocacy/community work, including raising awareness on epilepsy and SUDEP.

CONCLUSIONS

Sudden unexpected death in epilepsy affected several aspects of the day-to-day lives of bereaved relatives. Though methods of coping were similar to the usual strategies adopted by all bereaved relatives, advocacy work related to raising awareness about epilepsy and SUDEP was unique to this group. Guidelines on SUDEP should ideally include recommendations for trauma-informed support and assessment for depression and anxiety to the bereaved relatives as well.

The neuroimaging spectrum of SLC13A5 related developmental and epileptic encephalopathy

BACKGROUND

SLC13A5 related developmental and epileptic encephalopathy (DEE) is an autosomal recessive condition characterized by neonatal seizures, fever sensitivity, status epilepticus, developmental delay and tooth anomalies. The neuroimaging spectrum of SLC13A5 related DEE is not fully known. We present a case of SLC13A5 related DEE with distinct neuroimaging findings and review the neuroimaging findings of all published cases of SLC13A5 related DEE.

METHODS

A retrospective case review and focused review of the literature was completed.

RESULTS

A 16-month-old male with a clinical phenotype consistent with SLC13A5 related DEE and a previously reported pathogenic variant in SLC13A5, c.655G>A, p.Gly219Arg and a novel likely pathogenic variant in SLC13A5, c.202C>T, p.Pro68Ser was identified. MRI at day 5 of life revealed wide spread punctate white matter lesions (PWMLs) affecting the subcortical white matter, periventricular white matter, splenium of the corpus callosum, posterior limb of the internal capsule, corticospinal tracts, midbrain, pons and medulla, mimicking a metabolic/infectious etiology. MRI at one month showed atrophy and evolution of white matter necrosis. One hundred and five cases of SLC13A5 related DEE were identified. Initial MRI was completed in 62 cases (59%). MRI was normal in 41 cases (66%) and abnormal in 21 (34%). White matter abnormalities were most common (n=15, 71%); PWMLs occurred in 8 cases (38%).

CONCLUSION

Neuroimaging abnormalities may exist in a third of SLC13A5 related DEE cases. White matter abnormalities such as PWMLs appear most common. It remains unknown why some are susceptible to these lesions and how they affect long-term neurodevelopmental outcomes in SLC13A5 related DEE.

Does freeze-thaw action affect the extractability and bioavailability of Pb and As in contaminated soils?

As global warming intensifies, there will be increased uncertainty as to the environmental behavior and risks from heavy metals in industrial/legacy contaminated sites in permafrost regions. Bioavailability has been increasingly used for human health risk assessment of heavy metals in contaminated soils. Soil heavy metal bioavailability depends on soil physicochemical properties, and freeze-thaw affects soil physical, chemical and biological processes. However it is not clear whether freeze-thaw has an effect on the bioavailability of soil heavy metals. In this study, soils contaminated with Pb and As were collected from 10 industrial sites in northeast China. Extractability and bioavailability of soil Pb and As were determined by the Tessier sequential extraction method and four in vitro gastron-intestinal simulation methods under control and freeze-thaw treatments. The aims were: to compare the results of extraction and bioavailability from laboratory experiments which artificially simulate freeze-thaw conditions against control soils; to explore the correlation between bioavailability of Pb/As and soil properties. Freeze-thaw significantly decreased soil pH, and increased the soil weight surface area. Freeze-thaw decreased the percentage in the residual fraction, and increased the percentage of Pb and As in the exchangeable fraction, carbonate-bound fraction, Fe-Mn oxides-bound fraction and organic-bound fraction, relative to control soils. Freeze-thaw significantly increased Pb and As bioavailability compared to the controls. Pb and As released in the gastric phase of the four methods was significantly higher than that in the intestinal phase. Further analysis of correlations between Pb and As bioavailability and soil properties indicated that total concentrations of Al, Fe and Mn, particle size, and weight surface area significantly correlated to Pb and As bioavailability. Overall, this study demonstrated that freeze-thaw did influence the bioavailability of soil heavy metals. It suggests the freeze-thaw action should be comprehensively considered in the human risk assessment of soil pollutants in permafrost regions.

Evaluation and Application of a Novel Diffusive Gradients in Thin-Films Technique for In Situ Monitoring of Glucocorticoids in Natural Waters

The potential environmental risks of glucocorticoids (GCs) have attracted attention in the past few decades. In this study, a novel diffusive gradients in thin-films (DGT) device and analytical technique based on the second generation of polar enhanced phase (PEP-2), PEP-2-DGT, were developed for sampling and quantifying natural and synthetic GCs in aquatic systems. The capacity of PEP-2 gels for accumulating all target compounds was >600 μg per disc, sufficient for long-term passive sampling of selected GCs, even in wastewaters. Systematic tests were carried out to verify the application of DGT in natural waters and wastewaters. The performance of PEP-2-DGT devices was independent (C_DGT/C_soln was in the acceptable range of 0.9-1.1) of a wide range of environmental conditions: ionic strength (0.001-0.5 mol L^-1), dissolved organic matter (0-20 mg L^-1), and pH (3.06-9.02). It was tested for various diffusive layer thicknesses (0.565-2.065 mm) and different deployment times (10-168 h). Diffusion coefficients (D) of selected GCs through an agarose-based diffusive gel were determined for the first time (3.80-4.85 × 10^-6 cm^-2 s ^-1 at 25 °C). Linear correlations between D and log K_ow were established for three groups of target GCs (R² = 0.96-0.99). This could enable prediction of D values for other GCs with similar structures in the future, which will help for rapid screening and emergency monitoring. Concentrations and distribution patterns of analytes obtained by PEP-2-DGT devices in five rivers after 7- and 14-day deployments were in accordance with those measured from grab samples, with total GC concentrations ranging from 7 to 27 ng L^-1 at all sampling sites, confirming the reliability and robustness of the DGT devices for monitoring GCs in natural waters. The development of the new DGT technique will help improve understanding of the behavior and fate of these compounds in the aquatic environments.

Impact of short-term control measures on air quality: A case study during the 7th Military World Games in central China

The 7th Military World Games held in Wuhan (WH) in Oct 2019 provided an opportunity to clarify the impact of short-term control measures on air quality. Fine particulate matters (PM_2.5) were collected in WH, Huangshi (HS), and Huanggang (HG) during the control (Oct 13-28, 2019) and non-control periods (Oct 29- Nov 5, 2019). The results showed that air quality was good during the control period, with the concentrations of PM_2.5 and gaseous pollutants being below the Grade Ⅱ of China Ambient Air Quality Standard. Concentrations of PM_2.5 and its major chemical components in the control period were significantly lower than those in the non-control period, with reductions ranging from 17% (trace elements) to 46% (elemental carbon). However, higher contributions of secondary components such as SO₄^2-, NO₃^-, NH₄⁺ and secondary organic carbon (SOC) to PM_2.5 were observed during the control period, suggesting the important role of secondary transformation. Potential source contribution function (PSCF) of PM_2.5 showed that the main source regions were potentially located in surrounding cities Hubei Province, but regional transport can't be ignored. Six sources were identified by positive matrix factorization (PMF) for both control and non-control period. The contributions of combustion emissions and vehicle emissions were amplified in the control period, while the contribution of construction dust increased significantly when the control measures ended. Emission reductions contributed more to PM_2.5 concentration decrease in WH (55%) than that in HS (51%) and HG (49%), which was consistent with the stricter control measures implemented in WH. These results indicated that short-term controls were effective at lowering PM_2.5 concentration. However, the elevated contributions of secondary aerosols and the influence of regional transport on the study areas also need to be paid attention for air quality improvement in the future.

Assessing the Impact of Atrazine on the Availability of Arsenic in Soils Using DGT Technique

Arsenic (As) has been observed to co-exist with atrazine (ATR) in soils worldwide. ATR, as an organic chemical, may affect the availability of As and further influence its uptake by organisms. Here we used a novel passive sampling technique, DGT (diffusive gradients in thin-films), to compare with other two conventional sampling approaches (soil solution extraction and 'Olsen As' measurement) to investigate the influence of ATR addition (normal recommended level and contaminated level) on the availability of As in soils, to further interpret the potential risk of As in soil environment. The effect of adding ATR on the behaviour of As in soils was limited. When the concentration of ATR was much higher, the availability of As in soils was supressed, the labile pool size was also affected, but the R value did not change much. The properties of the soils also played an important role by affecting the states of the compounds.

Distribution, sources and transport of polycyclic aromatic hydrocarbons (PAHs) in karst spring systems from Western Hubei, Central China

Karst groundwater is an important water resource but it is vulnerable to contaminants, due to the distinctive geological features of abundant transmissive fractures and conduits in the karst area which connect the surface to the underground systems. Anthropogenic activity-derived polycyclic aromatic hydrocarbons (PAHs) on the surface environment could enter groundwater easily and rapidly and threaten water security in karst areas. Samples in the multimedia environment from 10 specific karst spring systems from Western Hubei of Central China were collected to analyze 16 priority PAHs and to investigate their transport in these karst spring systems. The total concentrations of PAHs in the soil, river water, river sediments, spring water, and spring sediments ranged between 6.04 and 67.7 ng g^-1, 4.56 and 11.4 ng L^-1, 29.9 and 1041 ng g^-1, 4.09 and 222 ng L^-1, and 5.88 and 83.0 ng g^-1, respectively. Levels of PAHs in this area were relatively low when compared to other karst areas. Proportions of low-molecular-weight (LMW)-PAHs in the water, sediments and soil (average 58.2-78.8%) were much higher than those of high-molecular-weight (HMW)-PAHs. The proportion of LMW-PAHs in the sediments (especially in river sediments) was higher than that in the soil. Characteristic ratio analysis and principal component analysis showed that PAHs were from high-temperature combustion of the mixture of coal and biomass, and vehicle emission, where coal and biomass combustion were the dominant sources. Significant correlations of PAH compositions in different media of karst spring systems were observed, especially in the Yuquangdong (YQD)-Migongquan (MGQ), Jiuzhenziquan (JZZQ), Xianyudong (XYD) and Fengdong (FD) karst spring systems, indicating the rapid PAH transport from the recharge area soil to the discharge area of spring water and sediments.

Redevelopment of urban brownfield sites in China: Motivation, history, policies and improved management

Rapid urbanisation in China has resulted in an increased demand for land in towns and cities. To upgrade and modernise, China has also moved many major industries from urban centres to less populated areas. With the high economic value of urban land, the transformation and utilisation of brownfield areas have become important economically and socially. The Chinese government has recognised the need for strong frameworks to safeguard soil and groundwater quality, with brownfield sites a key category for management. Strong scientific, regulatory and decision-making frameworks are needed and being adopted to ensure practical, careful and wise use of central and localised government resources, to manage the reuse and regeneration of these brownfield sites. This paper reviews the context, policies and management procedures of developing brownfield sites in countries with a history of brownfield management and discusses China's current situation and priorities for brownfield governance and redevelopment. These include (1) clarification of brownfield site soil contamination risk control standards and risk assessment procedures, (2) the responsibilities of different national and local agencies, (3) the establishment of a national expert committee to advise on best practices, policy and process, (4) the use of registered brownfield databases at national, provincial, municipal and county levels, and (5) the set up of soil pollution prevention fund at the provincial level.

Critical assessment of an equilibrium-based method to study the binding of waterborne organic contaminants to natural dissolved organic matter (DOM)

Dissolved organic matter (DOM) can play a major role in determining availability of pollutants to aquatic biota. Equilibrium dialysis is the most commonly used method to assess the interaction between DOM and organic contaminants. However, results obtained through this method can be affected by confounding factors linked to the diffusion of DOM through the membrane or the interaction of DOM and/or the compounds with the membrane itself. In this study, we propose an improved experimental approach, where highly hydrophilic cellulose-ester membranes with small molecular cut-off (100-500 Da) were used to overcome some of these hindrances. The performance of the method to determine the binding of a commonly used moderately hydrophobic herbicide (Isoproturon - ISU) with natural DOM was critically evaluated through a set of quality assurance criteria, across a range of DOM concentrations and pH conditions. DOM trans-membrane diffusion was prevented by the smaller pore size of the dialysis membrane. Good measurement reproducibility, mass balance closure, and successful trans-membrane equilibrium of ISU were obtained. ISU showed relatively low affinity with DOM (log K_DOC 1-2 L g^-1), which was significantly influenced by varying pH and DOM concentration. An alternative membrane may be needed for higher pH conditions as the greater adsorption effect blurred the observation of trans-membrane equilibrium and confounding mass balance closure. The paper makes recommendations on how to avoid measurement artefacts, while considering criteria for the expected mass distribution of compounds at equilibrium and for sorption onto the membrane and surfaces of the experimental units.

Low density electrical source imaging of the ictal onset zone in the surgical evaluation of children with epilepsy

PURPOSE

To investigate the utility of Low Density (LD) Electrical Source Imaging (ESI) to model the ictal onset zone (IOZ) for the surgical work up of children with medically refractory epilepsy.

METHODS

This was a retrospective review of 12 patients from a district and regional pediatric epilepsy center, who underwent focal resections between 2014 and 2019. ESI was generated using the Curry 8 software, incorporating T1 Magnetic Resonance Imaging (MRI) scans and scalp electroencephalogram (EEG) recordings. Concordance of the ictal LD-ESI localizations to the epileptogenic zone was assessed by comparing the location of the ictal LD-ESI to the focal resection margins on neuroimaging and noting the post-operative outcomes at one year. Localizations determined by ictal LD-ESI were also compared to interictal LD-ESI, positron emission tomography (FDG-PET) and interictal magnetoencephalography (MEG).

RESULTS

Ictal ESI correctly localized the ictal onset zone in 4/6 patients, with all four being seizure free at one year. Similarly, interictal ESI localized the irritative zone in 7/9 patients with focal resections, with 6/7 being seizure free at one year. Additionally, we observed ictal ESI to be concordant to interictal ESI in 5/6 patients. Ictal ESI and interictal ESI were concordant to interictal MEG in 3/6 patients. Ictal ESI was concordant with FDG-PET in 6/7 cases.

CONCLUSION

IOZ source localization through LD-ESI is a promising complementary method of assessing the epileptogenic focus in children. These findings may support the inclusion of ictal LD-ESI within the pre-surgical evaluation of children to supplement current diagnostic tools.

Chemical pollution: A growing peril and potential catastrophic risk to humanity

Anthropogenic chemical pollution has the potential to pose one of the largest environmental threats to humanity, but global understanding of the issue remains fragmented. This article presents a comprehensive perspective of the threat of chemical pollution to humanity, emphasising male fertility, cognitive health and food security. There are serious gaps in our understanding of the scale of the threat and the risks posed by the dispersal, mixture and recombination of chemicals in the wider environment. Although some pollution control measures exist they are often not being adopted at the rate needed to avoid chronic and acute effects on human health now and in coming decades. There is an urgent need for enhanced global awareness and scientific scrutiny of the overall scale of risk posed by chemical usage, dispersal and disposal.

Evaluating the simulated toxicities of metal mixtures and hydrocarbons using the alkane degrading bioreporter Acinetobacter baylyi ADPWH_recA

Oil spillages lead to the formation of hydrocarbon and metal mixtures possessing effects on alkane-degrading bacteria that are responsible for the bioremediation of oil-contaminated soils and waters. Studies of bacterial responses to the mixture of petroleum and metal can inform appropriate strategies for bioremediation. We employed a luminescent bioreporter Acinetobacter baylyi ADPWH_recA with alkane degradation capability to evaluate the combined effects from heavy metals (Cd, Pb and Cu) and alkanes (dodecane, tetradecane, hexadecane and octadecane). Bioluminescent ratios of ADPWH_recA in single Cd or Pb treatments ranged from 0.25 to 1.98, indicating both genotoxicity and cytotoxicity of these two metals, while ratios < 1.0 postexposure to Cu showed its cytotoxic impacts on ADPWH_recA bioreporter. Metal mixtures exhibited enhanced antagonistic effects (Ti>4.0) determined by the Toxic Unit model. With 100 mg/L alkane, the morbidity of ADPWH-recA reduced to < 20%, showing the inhibition of alkanes on Cd toxicity. Exposed to the metal mixture containing 10 mg/L Cu, the weak binding affinity of Cu with alkanes contributed to a high morbidity of > 85% in ADPWH_recA cells. This study provides a new way to understand the toxicity of mixture contaminants, which can help to optimize treatment efficiencies of bacterial remediation for oil contamination.

Modeling of Flame Retardants in Typical Urban Indoor Environments in China during 2010-2030: Influence of Policy and Decoration and Implications for Human Exposure

Novel flame retardants (FRs) are of increasing concern, given growing evidence of health effects and use to replace polybrominated diphenyl ethers (PBDEs). This study modeled combined effects of use policies and decoration on indoor FRs and human exposure for 18 widely used PBDEs, organophosphate esters (OPEs), and novel brominated flame retardants in typical urban indoor environments in China. The current estimated indoor emission rates and average concentrations in air and dust of the 18 FRs were 10²-10³ ng/h, 561 ng/m³, and 1.5 × 10⁴ ng/g, respectively, with seven OPEs dominant (>69%). Different use patterns exist between China and the US and Europe. Scenarios modeled over 2010-2030 suggested that decoration would affect indoor concentrations of FRs more than use policies, and use policies were mainly responsible for shifts of FR composition. Additional use of hexabromobenzene and 2,3,4,5,6-pentabromotoluene and removal of BDE-209 would make the total human exposure to the modeled FR mixture increase after the restriction of penta- and octa-BDE but decrease after deca-BDE was banned. Better knowledge of the toxicity of substitutes is needed for a complete understanding of the health implications of such changes. Toddlers may be more affected by use changes than adults. Such studies are supportive to the management of FR use.

Binding of waterborne pharmaceutical and personal care products to natural dissolved organic matter

Information on how key environmental conditions such as natural dissolved organic matter (DOM) and water pH alter the possible risks posed by pharmaceuticals (PPCPs) is still scarce. In our previous study, the presence of natural DOM at high pH reduced the toxicity of a mix of waterborne PPCPs to algae. DOM-complexation and pH effect on speciation of the more hydrophobic and neutral compounds of the mix was suggested to be driving this behaviour. However, the study design did not allow the verification of this hypothesis. Here, the DOM- PPCPs interaction at different pH was investigated for 6 PPCPs through equilibrium dialysis, under the same conditions of DOM and pH as our previous study. Association with DOM was confirmed for the more hydrophobic PPCPs at high pH. The results suggest the binding was driven by i) the presence of carboxylic groups of PPCPs, ii) high pH shifting the structural configuration of DOM, making it more suited to bind some of the PPCPs. A non-linear change of binding capacity with increasing DOM concentration was also observed among the tested PPCPs.

Development and Applications of Novel DGT Passive Samplers for Measuring 12 Per- and Polyfluoroalkyl Substances in Natural Waters and Wastewaters

Extensive and long-term use of per- and polyfluoroalkyl substances (PFASs) has caused their widespread distribution in aquatic systems. A new diffusive gradients in thin-films (DGT) passive sampling method based on weak anion exchanger (WAX) binding layer is developed here for monitoring five perfluoroalkyl carboxylic acids (PFCAs), five perfluoroalkanesulfonic acids (PFSAs) and two PFASs (6:2 FTSA and GenX) in waters. Performance of WAX-DGTs was independent of environmental conditions, namely pH (3.03-8.96), ionic strength (1-500 mM), and DOM content (4-30 mg L^-1). Diffusion coefficients (D) of the 12 PFASs in the diffusive gels were measured, 9 for the first time. Linear correlations between D and perfluoroalkyl chain lengths (CF₂) were established to obtain D for congener chemicals with the similar functional group and structure. The binding capacity of the WAX-DGT sampler was at least 440 μg PFASs per sampler, sufficient for applications in waters across a wide range of conditions and PFASs concentrations. Successful applications of WAX based DGT samplers in a wastewater treatment plant (WWTP) and three rivers has demonstrated that DGT is a powerful tool for monitoring, surveillance and research of these 12 PFASs in aquatic systems, and can be extended to wider suites of PFs in future.

Selected Persistent Organic Pollutants in Ambient Air in Turkey: Regional Sources and Controlling Factors

As a result of its unique location, Turkey receives air masses from Europe, Russia, Middle East, and Africa, making it an important place in terms of long-range atmospheric transport (LRT) of contaminants. Atmospheric levels of 22 organochlorine pesticides (OCPs), 45 polychlorinated biphenyls (PCBs), and 14 polybrominated diphenyl ethers (PBDEs) were measured in two metropolitan cities, Istanbul and Izmir, on a weekly basis from May 2014 to May 2015. Dichlorodiphenyltrichloroethane (DDT) and its derivatives were dominant OCP species, followed by isomers of hexachlorocyclohexane (HCH) at both sites. The annual mean concentration of ∑DDX (sum of o,p'-DDT, p,p'-DDT, o,p'-DDD, p,p'-DDD, o,p'-DDE, and p,p'-DDE) was 82 pg/m³ for Istanbul and 89 pg/m³ for Izmir, while these levels were about 46 pg/m³ for ∑HCHs (sum of α-, β-, γ-, and δ-HCH) at both of the sites. At both stations, tri- and tetra-PCBs and tetra- and penta-PBDEs were dominant congeners. The temperature dependence indicates that both LRT and local contaminated areas contribute to the elevated levels. A Lagrangian particle dispersion model (FLEXPART) showed a few potential source regions in northern Africa and Middle East, southern-southwestern and eastern Europe including Russia, as well as from local domestic metropolitan areas.

Use of the Dynamic Technique DGT to Determine the Labile Pool Size and Kinetic Resupply of Pesticides in Soils and Sediments

The diffusive gradients in thin films (DGT) technique has been successfully and widely applied to investigate the labile fractions of inorganic contaminants in soils and sediments, but there have been almost no applications to organic contaminants. Here we developed and tested the approach for the pesticide Atrazine (ATR) in a controlled soil experiment and in situ in an intact lake sediment core. The soil study explored the relationships between soil solution, DGT measured labile ATR and solvent extractable ATR in dosed soils of different organic matter, pH status and incubation times. The results are further interpreted using the DIFS (DGT-induced fluxes in soils and sediments) model. Resupply of ATR to the soil solution was partially sustained by the solid phase in all the soils. This was due to small labile pool size and slow kinetics, with soil pH being an important controlling factor. The in situ sediment study successfully used a DGT probe to examine labile ATR distribution through the core on the subcm scale. It demonstrated-for the first time-an easy to use in situ technique to investigate the effects of redox on resupply kinetics and biogeochemical processes of trace organic contaminants in sediments.

Persistent Organic Pollutants (POPs) and Related Chemicals in the Global Environment: Some Personal Reflections

Persistent organic pollutants (POPs) and related chemicals are fascinating because of their combination of physical-chemical properties and complex effects. Most are man-made, but some also have natural origins. They are persistent in the environment, but they can be broken down variously by biodegradation, atmospheric reactions, and abiotic transformations. They can exist in the gas or particle phases, or both, in the atmosphere and in the dissolved or particulate phases, or both, in water. These combinations mean that they may undergo long-range transport in the atmosphere or oceans, or they may stay close to sources. Hence, emissions from one country are frequently a source of contamination to another country. They are also usually lipophilic, so-combined with persistence-this means they can accumulate in organisms and biomagnify through food chains. We all have a baseline of POPs residues in our tissues, even the unborn fetus via placental transfer and the newly born baby via mother's milk. POPs in biological systems occur in mixtures, so confirming effects caused by POPs on humans and other top predators is never straightforward. Depending on which papers you read, POPs may be relatively benign, or they could be responsible for key subchronic and chronic effects on reproductive potential, on immune response, as carcinogens, and on a range of behavioral and cognitive end points. They could be a factor behind diseases and conditions which have been increasingly reported and studied in modern societies. In short, they are endlessly fascinating to scientists and a nightmare to regulators and policy makers.

First surveillance of SARS-CoV-2 and organic tracers in community wastewater during post lockdown in Chennai, South India: Methods, occurrence and concurrence

Surveillance of SARS-CoV-2 and organic tracers (OTs) were conducted in the community wastewater of Chennai city and the suburbs, South India, during partial and post lockdown phases (August-September 2020) as a response to the coronavirus disease 2019 (COVID-19) pandemic. Wastewater samples were collected from four sewage treatment plants (STPs), five sewage pumping stations (SPSs) and at different time intervals from a suburban hospital wastewater (HWW). Four different methods of wastewater concentrations viz., composite (COM), supernatant (SUP), sediment (SED), and syringe filtration (SYR) were subjected to quantitative real time-polymerase chain reaction (qRT-PCR). Unlike HWW, STP inlet, sludge and SPS samples were found with higher loading of SARS-CoV-2 by SED followed by SUP method. Given the higher levels of dissolved and suspended solids in STPs and SPSs over HWW, we suspect that this enveloped virus might exhibit the tendency of higher partitioning in solid phase. Cycle threshold (C_t) values were < 30 in 50% of the HWW samples indicating higher viral load from the COVID-19 infected patients. In the STP outlets, a strict decline of biochemical oxygen demand, >95% removal of caffeine, and absence of viral copies reflect the efficiency of the treatment plants in Chennai city. Among the detected OTs, a combination of maximum dynamic range and high concurrence percentage was observed for caffeine and N1 gene of SARS-CoV-2. Hence, we suggest that caffeine can be used as an indicator for the removal of SARS-CoV-2 by STPs. Our predicted estimated number of cases are in line with the available clinical data from the catchments. Densely distributed population of the Koyambedu catchment could be partly responsible for the high proportion of estimated infected individuals during the study period.

The application of land use regression model to investigate spatiotemporal variations of PM2.5 in Guangzhou, China: Implications for the public health benefits of PM2.5 reduction

Understanding the intra-city variation of PM_2.5 is important for air quality management and exposure assessment. In this study, to investigate the spatiotemporal variation of PM_2.5 in Guangzhou, we developed land use regression (LUR) models using data from 49 routine air quality monitoring stations. The R², adjust R² and 10-fold cross validation R² for the annual PM_2.5 LUR model were 0.78, 0.72 and 0.66, respectively, indicating the robustness of the model. In all the LUR models, traffic variables (e.g., length of main road and the distance to nearest ancillary) were the most common variables in the LUR models, suggesting vehicle emission was the most important contributor to PM_2.5 and controlling vehicle emissions would be an effective way to reduce PM_2.5. The predicted PM_2.5 exhibited significant variations with different land uses, with the highest value for impervious surfaces, followed by green land, cropland, forest and water areas. Guangzhou as the third largest city that PM_2.5 concentration has achieved CAAQS Grade II guideline in China, it represents a useful case study city to examine the health and economic benefits of further reduction of PM_2.5 to the lower concentration ranges. So, the health and economic benefits of reducing PM_2.5 in Guangzhou was further estimated using the BenMAP model, based on the annual PM_2.5 concentration predicted by the LUR model. The results showed that the avoided all cause mortalities were 992 cases (95% CI: 221-2140) and the corresponding economic benefits were 1478 million CNY (95% CI: 257-2524) (willingness to pay approach) if the annual PM_2.5 concentration can be reduced to the annual CAAQS Grade I guideline value of 15 μg/m³. Our results are expected to provide valuable information for further air pollution control strategies in China.

Short-term personal PM2.5 exposure and change in DNA methylation of imprinted genes: Panel study of healthy young adults in Guangzhou city, China

DNA methylation (DNAm) plays a significant role in deleterious health effects inflicted by fine particulate matter (PM_2.5) on the human body. Recent studies have reported that DNAm of imprinted control regions (ICRs) in imprinted genes may be a sensitive biomarker of environmental exposure. Less is known about specific biomarkers of imprinted genes after PM_2.5 exposure. The relationship between PM_2.5 and its chemical constituents and DNAm of ICRs in imprinted genes after short-term exposure was investigated to determine specific human biomarkers of its adverse health effects. A panel study was carried out in healthy young people in Guangzhou, China. Mixed-effects models were used to evaluate the influence of PM_2.5 and its constituent exposure on DNAm while controlling for potential confounders. There was no significant correlation between DNAm and personal PM_2.5 exposure mass. DNAm changes in eight ICRs (L3MBTL1, NNAT, PEG10, GNAS Ex1A, MCTS2, SNURF/SNRPN, IGF2R, and RB1) and a non-imprinted gene (CYP1B1) were significantly associated with PM_2.5 constituents. Compared to non-imprinted genes, imprinted gene methylation was more susceptible to interference with PM_2.5 constituent exposure. Among those genes, L3MBTL1 was the most sensitive to personal PM_2.5 constituent exposure. Moreover, transition metals derived from traffic sources (Cd, Fe, Mn, and Ni) significantly influenced DNAm of the imprinted genes, suggesting the importance of more targeted measures to reduce toxic constituents. Bioinformatics analysis indicated that imprinted genes (RB1) may be correlated with pathways and diseases (non-small cell lung cancer, glioma, and bladder cancer). The present study suggests that screening the imprinted gene for DNAm can be used as a sensitive biomarker of PM_2.5 exposure. The results will provide data for prevention of PM_2.5 exposure and a novel perspective on potential mechanisms on an epigenetic level.

Ecological Memory of Historical Contamination Influences the Response of Phytoplankton Communities

Ecological memory (EM) recognizes the importance of previous stress encounters in promoting community tolerance and thereby enhances ecosystem stability, provided that gained tolerances are preserved during non-stress periods. Drawing from this concept, we hypothesized that the recruitment of tolerant species can be facilitated by imposing an initial sorting process (conditioning) during the early stages of community assembly, which should result in higher production (biomass development and photosynthetic efficiency) and stable community composition. To test this, phytoplankton resting stages were germinated from lake sediments originating from two catchments that differed in contamination history: one impacted by long-term herbicides and pesticides exposures (historically contaminated lake) from an agricultural catchment compared to a low-impacted one (near-pristine lake) from a forested catchment. Conditioning was achieved by adding an herbicide (Isoproturon, which was commonly used in the catchment of the historically contaminated lake) during germination. Afterward, the communities obtained from germination were exposed to an increasing gradient of Isoproturon. As hypothesized, upon conditioning, the phytoplankton assemblages from the historically contaminated lake were able to rapidly restore photosynthetic efficiency (p > 0.01) and became structurally (community composition) more resistant to Isoproturon. The communities of the near-pristine lake did not yield these positive effects regardless of conditioning, supporting that EM was a unique attribute of the historically stressed ecosystem. Moreover, assemblages that displayed higher structural resistance concurrently yielded lower biomass, indicating that benefits of EM in increasing structural stability may trade-off with production. Our results clearly indicate that EM can foster ecosystem stability to a recurring stressor.

DNA Methylation Biomarkers of IQ Reduction are Associated with Long-term Lead Exposure in School Aged Children in Southern China

Although lead associated with intelligence decline in children has long been reported, studies combining intelligence determination, molecular mechanisms exploration, and biomarker screen are quite rare. In this study, based on 333 children aged 9-11, we determined the role of DNA methylation (DNAm) in the relationship of lead exposure with children's intelligence. DNAm was measured from children's blood DNA specimens, and mediation analysis was performed to identify DNAm biomarkers mediating the lead-intelligence relationship. We identified forty-three differentially methylated regions (DMRs), and two fragments (FAM50B1 and PTCHD3) significantly mediated the lead-intelligence relationship, with contribution rates of 30.36% (p = 0.010) and 60.36% (p < 0.001), respectively. In addition, blood lead levels (BLLs) lower than 100 μg/L still adversely affected children's IQs and DNAm of the two fragments. Our data suggests that DNAm mediates lead-associated cognitive delay in children and blood lead reference value for school-aged children (100 μg/L) should be revised, and the candidate biomarkers can be used in related neurological diseases in future.

Applying Raman Microspectroscopy to Evaluate the Effects of Nutrient Cations on Alkane Bioavailability to Acinetobacter baylyi ADP1

Contamination with petroleum hydrocarbons causes extensive damage to ecological systems. On oil-contaminated sites, alkanes are major components; many indigenous bacteria can access and/or degrade alkanes. However, their ability to do so is affected by external properties of the soil, including nutrient cations. This study used Raman microspectroscopy to study how nutrient cations affect alkanes' bioavailability to Acinetobacter baylyi ADP1 (a known degrader). Treated with Na, K, Mg, and Ca at 10 mM, A. baylyi was exposed to seven n-alkanes (decane, dodecane, tetradecane, hexadecane, nonadecane, eicosane, and tetracosane) and one alkane mixture (mineral oil). Raman spectral analysis indicated that bioavailability of alkanes varied with carbon chain lengths, and additional cations altered the bacterial response to n-alkanes. Sodium significantly increased the bacterial affinity toward decane and dodecane, and K and Mg enhanced the bioavailability of tetradecane and hexadecane. In contrast, the bacterial response was inhibited by Ca for all alkanes. Similar results were observed in mineral oil exposure. Our study employed Raman spectral assay to offer a deep insight into how nutrient cations affect the bioavailability of alkanes, suggesting that nutrient cations can play a key role in influencing the harmful effects of hydrocarbons and could be optimized to enhance the bioremediation strategy.

How efficiently can HEPA purifiers remove priority fine and ultrafine particles from indoor air?

More than 1 million premature deaths in Asia annually are estimated to be associated with indoor air quality. HEPA (high-efficiency particulate air) filter air purifiers (APs) are widely used in urban Chinese residences by the growing middle class, as public awareness of air pollution increases. Currently, understanding of how particle size affects particle removal is inconsistent, and the rate at which different particle types are removed remains largely unknown. Therefore, this investigation aimed to determine the relationship between particle size and the removal efficiency of particles, and how efficiently ambient air is filtered compared to particle types which are typically used in standard tests (tobacco smoke, dust and pollen). Three of the most popular AP models in China were tested in China's largest indoor controlled chamber laboratory and the removal efficiencies of particles in the 18-514 nm range were identified. Each AP had a distinct profile of removal efficiency against particle size, but the three APs shared similarities in performance, with removal efficiency consistently lowest at 200-250 nm. This size fraction is important in an exposure context as these particles are abundant in ambient air in mega-cities, can penetrate through building shells effectively, remain airborne for long periods of time and can penetrate the deepest areas of the lungs. Ambient air particles were removed at a similar rate to test particles; this confirms that the Association of Home Appliance Manufacturers' (AHAM) standards are a suitable proxy for "real world" performance.

Decadal shifts in soil pH and organic matter differ between land uses in contrasting regions in China

Soil organic matter (SOM) and pH are critical soil properties strongly linked to carbon storage, nutrient cycling and crop productivity. Land use is known to have a dominant impact on these key soil properties, but we often lack the ability to examine temporal trajectories across extensive spatial scales. Large-scale monitoring programmes provide the data to evaluate these longer-term changes, and under different climatic conditions. This study used data from Chinese soil surveys to examine changes in soil pH and SOM across different land uses (dry farmland, paddy fields, grassland, woodland, unused land), with surface soil (0-20 cm) collected in the periods 1985-90 (Survey 1; 890 samples) and 2006-10 (Survey 2; 5005 samples) from two contrasting areas. In the southern part of China the mean pH of paddy soils fell sharply over the two decades between surveys - from pH 5.81 to 5.19 (p < 0.001), while dry farmlands in the northern sampling area fell slightly (from pH 8.15 to 7.82; p < 0.001). The mean SOM content of dry farmland soil rose in both areas and the mean SOM of paddy fields in the southern area also rose (all p < 0.001). Woodland soil pH in the south showed an increase from 4.71 to 5.29 (p < 0.001) but no significant difference was measured in the woodlands of the northern area, although the trend increased. The SOM content of woodland top soils rose in the northern (p = 0.003) and southern (p < 0.001) study areas. The implications and potential causes of these changes over the two decade timespan between surveys are discussed and suggestions made as to how large scale soil sampling campaigns can be designed to monitor for changes and potential controlling factors.

A year-long passive sampling of phenolic endocrine disrupting chemicals in the East River, South China

The occurrence of endocrine disrupting chemicals (EDCs) in the aquatic environment is a global concern. In this study, we employed two different passive samplers Diffusive Gradients in Thin-films (DGT) and Chemcatcher for in situ measurement of 8 phenolic EDCs in the East River of the Pearl River system over one-year. These data were assessed alongside results from traditional grab sampling. Six chemicals (4tOP, 4NP, BPA, E1, EE2 and DES) were regularly detected in the water samples, of which the three phenols (i.e. 4tOP, 4NP and BPA) were in all samples and at high concentrations (0.4-1040 ng/L for 4tOP, 2.6-58500 ng/L for NP and 11.4-123300 ng/L for BPA). Fewer target chemicals were detected in both passive samplers, with only 4tOP, 4NP and BPA found in most samplers; E1 and DES were occasionally measurable above detection limits. The higher (by about a factor of 2-3) measurements provided by DGT compared to Chemcatcher could be attributed to the effect of the diffusive boundary layer on Chemcatcher uptake or the strong adsorption of target chemicals on the Chemcatcher PES filter. The temporal trends of EDC monthly loadings indicated that they were from different sources and that WWTPs were not effective in EDC removal and/or there was still some untreated wastewater discharged into the rivers.

In Situ Catchment Scale Sampling of Emerging Contaminants Using Diffusive Gradients in Thin Films (DGT) and Traditional Grab Sampling: A Case Study of the River Thames, UK

The in situ passive sampling technique, diffusive gradients in thin films (DGT), confronts many of the challenges associated with current sampling methods used for emerging contaminants (ECs) in aquatic systems. This study compared DGT and grab sampling for their suitability to screen and monitor ECs at the catchment scale in the River Thames system (U.K.) and explored their sources and environmental fate. The ubiquitous presence of endocrine disrupting chemicals, parabens, and their metabolites is of concern. This study is the first to report organophosphate esters (OPEs) in the study area. TEP (summer 13-160 and winter 18-46, ng/L) and TCPP (summer 242-4282 and winter 215-854, ng/L) were the main OPEs. For chemicals which were relatively stable in the rivers, DGT and grab sampling were in good agreement. For chemicals which showed high variation in water bodies, DGT provided a better integral of loadings and exposure than grab sampling. DGT was not as sensitive as grab sampling under the procedures employed here, but there are several options to improve it to give comparable/better performance. DGT samples require shorter preparation time for analysis in the laboratory than grab samples. Overall, DGT can be a powerful tool to characterize ECs throughout a large dynamic water system.

Scatter imaging during lung stereotactic body radiation therapy characterized with phantom studies

By collecting photons scattered out of the therapy beam, scatter imaging creates images of the treated volume. Two phantoms were used to assess the possible application of scatter imaging for markerless tracking of lung tumors during stereotactic body radiation therapy (SBRT) treatment. A scatter-imaging camera was assembled with a CsI flat-panel detector and a 5 mm diameter pinhole collimator. Scatter images were collected during the irradiation of phantoms with megavoltage photons. To assess scatter image quality, spherical phantom lung tumors of 2.1-2.8 cm diameters were placed inside a static, anthropomorphic phantom. To show the efficacy of the technique with a moving target (3 cm diameter), the position of a simulated tumor was tracked in scatter images during sinusoidal motion (15 mm amplitude, 0.25 Hz frequency) in a dynamic lung phantom in open-field, dynamic conformal arc (DCA), and volumetric modulated arc therapy (VMAT) deliveries. Anatomical features are identifiable on static phantom scatter images collected with 10 MU of delivered dose (2.1 cm diameter lung tumor contrast-to-noise ratio of 4.4). The contrast-to-noise ratio increases with tumor size and delivered dose. During dynamic motion, the position of the 3.0 cm diameter lung tumor was identified with a root-mean-square error of 0.8, 1.2, and 2.9 mm for open field (0.3 s frame integration), DCA (0.5 s), and VMAT (0.5 s), respectively. Based on phantom studies, scatter imaging is a potential technique for markerless lung tumor tracking during SBRT without additional imaging dose. Quality scatter images may be collected at low, clinically relevant doses (10 MU). Scatter images are capable of sub-millimeter tracking precision, but modulation decreases accuracy.

Interrogating cadmium and lead biosorption mechanisms by Simplicillium chinense via infrared spectroscopy

Fungi-associated phytoremediation is an environmentally friendly and cost-efficient approach to remove potential toxic elements (PTEs) from contaminated soils. Many fungal strains have been reported to possess PTE-biosorption behaviour which benefits phytoremediation performance. Nevertheless, most studies are limited in rich or defined medium, far away from the real-world scenarios where nutrients are deficient. Understanding fungal PTE-biosorption performance and influential factors in soil environment can expand their application potential and is urgently needed. This study applied attenuated total reflection Fourier-transform infrared (ATR-FTIR) coupled with phenotypic microarrays to study the biospectral alterations of a fungal strain Simplicillium chinense QD10 and explore the mechanisms of Cd and Pb biosorption. Both Cd and Pb were efficiently adsorbed by S. chinense QD10 cultivated with 48 different carbon sources and the biosorption efficiency achieved >90%. As the first study using spectroscopic tools to analyse PTE-biosorption by fungal cells in a high-throughput manner, our results indicated that spectral biomarkers associated with phosphor-lipids and proteins (1745 cm^-1, 1456 cm^-1 and 1396 cm^-1) were significantly correlated with Cd biosorption, suggesting the cell wall components of S. chinense QD10 as the primary interactive targets. In contrast, there was no any spectral biomarker associated with Pb biosorption. Addtionally, adsorption isotherms evidenced a Langmuir model for Cd biosorption but a Freundlich model for Pb biosorption. Accordingly, Pb and Cd biosorption by S. chinense QD10 followed discriminating mechanisms, specific adsorption on cell membrane for Cd and unspecific extracellular precipitation for Pb. This work lends new insights into the mechanisms of PTE-biosorption via IR spectrochemical tools, which provide more comprehensive clues for biosorption behaviour with a nondestructive and high-throughput manner solving the traditional technical barrier regarding the real-world scenarios.

Establishing the relationship between molecular biomarkers and biotransformation rates: Extension of knowledge for dechlorination of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs)

Anaerobic reductive treatment technologies offer cost-effective and large-scale treatment of chlorinated compounds, including polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs). The information about the degradation rates of these compounds in natural settings is critical but difficult to obtain because of slow degradation processes. Establishing a relationship between biotransformation rate and abundance of biomarkers is one of the most critical challenges faced by the bioremediation industry. When solved for a given contaminant, it may result in significant cost savings because of serving as a basis for action. In the current review, we have summarized the studies highlighting the use of biomarkers, particularly DNA and RNA, as a proxy for reductive dechlorination of chlorinated ethenes. As the use of biomarkers for predicting biotransformation rates has not yet been executed for PCDD/Fs, we propose the extension of the same knowledge for dioxins, where slow degradation rates further necessitate the need for developing the biomarker-rate relationship. For this, we have first retrieved and calculated the bioremediation rates of different PCDD/Fs and then highlighted the key sequences that can be used as potential biomarkers. We have also discussed the implications and hurdles in developing such a relationship. Improvements in current techniques and collaboration with some other fields, such as biokinetic modeling, can improve the predictive capability of the biomarkers so that they can be used for effectively predicting biotransformation rates of dioxins and related compounds. In the future, a valid and established relationship between biomarkers and biotransformation rates of dioxin may result in significant cost savings, whilst also serving as a basis for action.