Peri-urban Sites Research Articles

Ambient BTEX Concentrations during the COVID-19 Lockdown in a Peri-Urban Environment (Orléans, France)

During the period from 17 March to 10 May 2020, France saw dramatic shifts in domestic, industrial and transport activities as a national lockdown was introduced. So far, studies have generally focused on urban settings, by contrast, this work reports data for a peri-urban location. Air samples were collected and analyzed using a fully automated GC-MS-FID system in an air quality monitoring station situated in the suburbs of Orléans, France. Average concentrations of BTEX (benzene, toluene, ethylbenzene, and xylenes) before, during, and after lockdown, were 402 ± 143, 800 ± 378 and 851 ± 445 pptv, respectively. Diurnal variation in BTEX and correlations between each of its components were analyzed to determine its various sources. The toluene/benzene (T/B) and m,p-xylene/ethylbenzene (MP/E) ratios, photochemical ages were used to explore whether the BTEX were from local or more distant sources. Together with a host of complementary measurements including NOx, O3, black carbon, meteorological parameters, and anthropogenic activities, we were able to make some inferences on the sources of BTEX. The results suggest that although anomalous local anthropogenic activity can lead to significant changes in BTEX concentrations, pollution levels in Orléans are mostly dependent on meteorological conditions, specifically whether the winds are coming from the Paris region. It appears, based on these measurements, that the pollution in the Orléans area is very much tied to the nearby megacity of Paris, this may be true for other peri-urban sites with implications for city planning and pollution mitigation strategies.

Aedes Mosquito Distribution along a Transect from Rural to Urban Settings in Yaoundé, Cameroon.

Simple SummaryVector surveillance is key for the prevention of arbovirus disease outbreaks. In the present study, the distribution of the Aedes vector population between the city centre and a close rural setting was assessed. Larval mosquito collections were undertaken from November 2019 to November 2020 along a transect from the rural area to the city centre. All containers with water were inspected. Some entomological indices evaluating transmission risk were estimated. A total of 6332 mosquito larvae were collected. Different Aedes species were recorded, including Ae. albopictus, Ae. aegytpi, Ae. simpsoni and Aedes spp. The density of mosquitoes collected during the rainy season (4706) was high compared to the dry season (1626). Ae. albopictus was the most abundant Aedes species in the urban (96.89%) and peri-urban (95.09%) sites while Ae. aegypti was the most abundant species in rural settings (68.56%). Ae. Albopictus preferred breeding habitats were discarded tires (42.51%), whereas Ae. aegypti was more prevalent in plastic containers used for storing water (65.87%). High stegomyia indexes traducing a high arbovirus transmission risk were recorded. The study suggests a high frequency of Aedes species in Yaoundé and its neighbourhood and stresses the need for urgent action to control Aedes populations in the city of Yaoundé.Introduction: The surveillance of mosquito vectors is important for the control of arboviruses diseases worldwide. Detailed information on the bionomics and distribution of their main vectors, Aedes aegypti and Aedes albopictus, is essential for assessing disease transmission risk and for better planning of control interventions. Methods: Entomological surveys were carried out from November 2019 to November 2020 in six localities of Yaoundé city following a transect from urban to rural settings: two urban (Obili, Mvan), two peri-urban (Simbock, Ahala) and two rural areas (Lendom, Elig-essomballa)—during rainy and dry seasons. All water containers were inspected. Aedes mosquito abundance, species distribution and seasonal distribution patterns were compared using generalized linear models. Stegomyia indexes were estimated to determine the risk of arbovirus transmission. Results: A total of 6332 mosquitoes larvae were collected (2342 in urban areas, 1694 in peri-urban areas and 2296 in rural sites). Aedes species recorded included Ae. albopictus, Ae. aegytpi, Ae. simpsoni and Aedes spp. High mosquito abundance was registered in the rainy season (4706) compared to the dry season (1626) (p < 0.0001). Ae. albopictus was the most abundant Aedes species in urban (96.89%) and peri-urban (95.09%) sites whereas Ae. aegypti was more prevalent in rural sites (68.56%) (p < 0.0001). Both species were found together in 71 larval habitats. Ae. albopictus was mostly found in discarded tires (42.51%), whereas Ae. aegypti was more prevalent in plastic containers used for storing water (65.87%). The majority of Aedes mosquitoes’ breeding places were situated close to human dwellings (0–10 m). Conclusion: Uncontrolled urbanization seems to greatly favour the presence of Aedes mosquito species around human dwellings in Yaoundé. Controlling Aedes mosquito distribution is becoming urgent to reduce the risk of arbovirus outbreaks in the city of Yaoundé.

Parasitological and molecular search for Leishmania natural infection in phlebotomine sand flies in peri-urban and rural sites of an Argentinean area endemic for tegumentary leishmaniasis

Leishmaniases are neglected tropical diseases caused by Leishmania spp. parasites transmitted by the bite of phlebotomine sand flies. In Argentina, the most endemic area of American tegumentary leishmaniasis (ATL) has been Orán department, Province of Salta, where Leishmania (Viannia) braziliensis prevails and Nyssomyia neivai is considered as its vector, although there is no accurate and sufficient information in this regard. The aim of this work was to search for natural infection by Leishmania spp. in sand flies from peri-urban and rural sites with ATL background in Orán department. For this, sand flies were caught at five sites; female sand flies captured with Shannon trap were dissected to microscopically examine their gut contents, while females captured with CDC traps were molecularly analyzed by duplex PCR with two primer pairs to simultaneously amplify kinetoplast DNA (kDNA) and mammalian actin. A total of 1921 females were captured, with Ny. neivai being the most abundant species (89%), followed by Migonemyia migonei (6%) and cortelezzii complex (3%). No natural infection was found in any of them neither by dissection nor by PCR, although the detection limit of kDNA PCR was up to 25 promastigotes. The absence of infected females in peri-urban sites suggest that the transmission did not take place in those environments during the study period. Future searches for natural infection should focus on rural settings to deepen knowledge and elucidate the role of the circulating sand fly species as all have been linked to ATL transmission at other sites.

Antibiotic Resistance and Sewage-Associated Marker Genes in Untreated Sewage and a River Characterized During Baseflow and Stormflow.

Since sewage is a hotspot for antibiotic resistance genes (ARGs), the identification of ARGs in environmental waters impacted by sewage, and their correlation to fecal indicators, is necessary to implement management strategies. In this study, sewage treatment plant (STP) influent samples were collected and analyzed using quantitative polymerase chain reaction (qPCR) to investigate the abundance and correlations between sewage-associated markers (i.e., Bacteroides HF183, Lachnospiraceae Lachno3, crAssphage) and ARGs indicating resistance to nine antibiotics (belonging to aminoglycosides, beta-lactams, sulfonamides, macrolides, and tetracyclines). All ARGs, except blaVIM, and sewage-associated marker genes were always detected in untreated sewage, and ermF and sul1 were detected in the greatest abundances. intl1 was also highly abundant in untreated sewage samples. Significant correlations were identified between sewage-associated marker genes, ARGs and the intl1 in untreated sewage (τ = 0.488, p = 0.0125). Of the three sewage-associated marker genes, the BIO-ENV procedure identified that HF183 alone best maximized correlations to ARGs and intl1 (τ = 0.590). Additionally, grab samples were collected from peri-urban and urban sites along the Brisbane River system during base and stormflow conditions, and analyzed for Escherichia coli, ARGs, the intl1, and sewage-associated marker genes using quantitative polymerase chain reaction (qPCR). Significant correlations were identified between E. coli, ARGs, and intl1 (τ = 0.0893, p = 0.0032), as well as with sewage-associated marker genes in water samples from the Brisbane River system (τ = 0.3229, p = 0.0001). Of the sewage-associated marker genes and E. coli, the BIO-ENV procedure identified that crAssphage alone maximized correlations with ARGs and intl1 in river samples (τ = 0.4148). Significant differences in E. coli, ARGs, intl1, and sewage-associated marker genes, and by flow condition (i.e., base vs. storm), and site types (peri-urban vs. urban) combined were identified (R = 0.3668, p = 0.0001), where percent dissimilarities between the multi-factorial groups ranged between 20.8 and 11.2%. Results from this study suggest increased levels of certain ARGs and sewage-associated marker genes in stormflow river water samples compared to base flow conditions. E. coli, HF183 and crAssphage may serve as potential indicators of sewage-derived ARGs under stormflow conditions, and this merits further investigation. Data presented in this study will be valuable to water quality managers to understand the links between sewage pollution and ARGs in urban environments.

Health risk assessment via ingestion and inhalation of soil PTE of an urban area

Potentially Toxic Elements (PTE) are common soil contaminants and pose a significant risk to human health. In this study, ingestion (<150 μm) and inhalation (<10 μm) bioaccessibility and human health risk due to PTE were investigated in soils of the urban and peri-urban area of Torino. Lead, Cd, Cu, and Zn were observed to be the most soluble elements in simulated gastric and lung fluids. Higher bioaccessible concentrations of Pb, Ni, Co and Sb were observed in the inhalable size fraction (<10 μm) compared to ingestible one probably because of the higher concentration in fine soil size fraction. Conversely, the relative bioaccessibility of Pb, Cu, Cd, Zn and As was lower, due to the different extracting conditions and to the presumable different elemental speciation. Average values suggested that PTE would be more bioavailable if ingested than inhaled, particularly in urban areas, were the bioaccessible percentages were always higher than in peri-urban sites. Health risk assessment was conducted using bioaccessible concentrations and their corresponding toxicities via ingestion and inhalation exposures. Unacceptable non-carcinogenic risk (HQ > 1) was found through ingestion exposure for children in some urban sites and Pb was the most hazardous elements. Carcinogenic risks were under the threshold levels for every soil (CR < 10−4), with Cr and As being the dominant contributors to risk. Therefore, necessary soil remediation activities are needed to reduce the risks of human, especially for children, exposure to Pb.

Land use in urban areas impacts the composition of soil bacterial communities involved in nitrogen cycling. A case study from Lefkosia (Nicosia) Cyprus

The different types of land-use and soil lithology in urban and peri-urban areas of modern cities compose a complex mosaic of soil ecosystems. It is largely unknown how these differences result in changes in bacterial community composition and structure as well as in functional guilds involved in N cycling. To investigate the bacterial composition and the proportion of denitrifiers in agricultural, forested, schoolyard and industrial areas, 24 samples were collected from urban and peri-urban sites of Lefkosia. Bacterial diversity and the proportion of denitrifiers were assessed by NGS and qPCR, respectively. Proteobacteria, Actinobacteria, Bacteriodetes, Chloroflexi, Acidobacteria and Planctomycetes were identified as the most dominant phyla across all sites, while agricultural sites exhibited the highest bacterial diversity. Heavy metals such as Co, Pb, V and Al were identified as key factors shaping bacterial composition in industrial and schoolyard sites, while the bacterial assemblages in agricultural and forested sites were associated with Ca. Variance partitioning analysis showed that 10.2% of the bacterial community variation was explained by land use management, 5.1% by chemical elements due to soil lithology, and 1.4% by sampling location. The proportion of denitrifiers varied with land use management. In industrial and schoolyard sites, the abundance of the nosZII bacterial community increased while nirK abundance declined. Our data showed that land use and lithology have a moderate impact on the bacterial assemblages in urban and peri-urban areas of Lefkosia. As the nosZII bacterial community is important to the N2O sink capacity of soils, it would be interesting to elucidate the factors contributing to the proliferation of the nosZII clade in these soils.

The relationship between childhood trauma, socioeconomic status, and maternal depression among pregnant women in a South African birth cohort study.

BackgroundMaternal depression is an important cause of morbidity and mortality. Experiences of childhood trauma contribute to maternal depression, potentially causing adult socio-economic disparities in mental health. We investigate whether adult socioeconomic status (SES) mediates the relationship between childhood trauma and antenatal depression.MethodsWe analyzed data from two sociodemographically distinct peri-urban sites in the Western Cape, South Africa in a birth cohort study, the Drakenstein Child Health Study: Mbekweni (N = 510) and TC Newman (N = 413). Data were collected from pregnant women between 28 and 32 weeks’ gestation.ResultsAssociations between trauma and depressive symptoms differed by site (=2163.6, df = 1419, p < 0.01); direct effects of trauma on depression were 0.24 mean increased symptoms in Mbekweni (p < 0.01) and 0.47 in TC Newman (p < 0.01). Trauma was differentially associated with SES (Mbekweni: −0.10, p = 0.07; TC Newman: −0.05, p = 0.37) and SES with depression (Mbekweni: −0.18, p < 0.01; TC Newman: −0.02, p = 0.62) across both sites. Indirect effects of trauma on depression through SES were 0.018 (95% C.I. −0.002-0.039) in Mbekweni and 0.001 (95% C.I. −0.004-0.006) in TC Newman, suggesting mediation was not supported. SES was a stronger indicator of depression risk in relatively poorer Mbekweni.ConclusionNeighborhood-level effects and poverty are potentially important modifiers, and points of intervention, for maternal mental health outcomes.

High Diversity, Prevalence, and Co-infection Rates of Tick-Borne Pathogens in Ticks and Wildlife Hosts in an Urban Area in Romania.

Despite the increasingly recognized eco-epidemiological importance of ticks as vectors for numerous zoonotic pathogens in urban areas, data regarding the pathogen diversity and co-infection rates in ticks and wildlife hosts in urban and peri-urban Romania are scanty. We aimed to establish the risk of human exposure to co-infected ticks in Cluj-Napoca, a major city in Romania. DNA was isolated from 151 questing ticks: Ixodes ricinus (n = 95), Haemaphysalis punctata (n = 53), Dermacentor reticulatus (n = 2), and Dermacentor marginatus (n = 1); 222 engorged ticks: I. ricinus (n = 164), I. hexagonus (n = 36), H. punctata (n = 16), H. concinna (n = 6), and 70 tissue samples collected from wildlife hosts during 2018 in five urban, and two peri-urban sites. Using a pre-designed Fluidigm real-time PCR dynamic array, all DNA samples were individually screened for the presence of 44 vector-borne pathogens. Subsequently, conventional PCRs were performed for a selection of samples to allow validation and sequencing. In total, 15 pathogens were identified to species and 6 to genus level. In questing ticks, single infections were more common than co-infections. Seven Borrelia spp. were detected in questing I. ricinus, and three in H. punctata ticks. An overall high prevalence 26.35% (95% CI: 19.46–34.22) and diversity of Borrelia burgdorferi sensu lato was seen in urban questing ticks. Other pathogens of the order Rickettsiales were present with variable prevalence. Co-infections occurred in 27.4% (95% CI: 18.72-37.48) of all infected questing ticks. In engorged ticks the overall Bo. burgdorferi sensu lato prevalence was 35.6% (95% CI: 29.29–42.27), with five species present. Pathogens of the order Rickettsiales were also frequently detected. We report for the first time in Romania the presence of Rickettsia aeschlimannii and Rickettsia felis. Overall, from the infected engorged ticks, 69.2% showcased co-infections. In Ixodes spp., dual co-infections, namely Borrelia spp. and Anaplasma phagocytophilum, and Rickettsia helvetica and A. phagocytophilum were the most prevalent. Given the outcome, we underline the need to establish proper tick-surveillance programs in cities and include co-infections in the management plan of tick-borne diseases in Romania.

The canid pest ejector challenge: controlling urban foxes while keeping domestic dogs safe

Abstract Context It is widely recognised that red foxes (Vulpes vulpes) are abundant within urban areas; however, it is difficult to apply lethal control measures using poison baits in cities because of concerns about the safety of domestic pets, particularly dogs (Canis familiaris). Aims We tested canid pest ejectors (CPEs) as a potential method of fox control by measuring visitation and activation behaviour of foxes and other wildlife while assessing non-target risk to domestic dogs. Methods We compared eight urban and eight peri-urban sites in Sydney, with half of the sites having restricted access for domestic dogs. We allocated five camera traps and ejectors per site. Through generalised linear mixed models, we compared the probability of ejector activation between foxes and dogs. We also assessed the relationship between dog visitation and distance to habitation and dog restrictions as measures of dog safety. Key results Both species of canids were equally likely to pull the ejector (P = 0.26). As expected, dog visitation was significantly lower in sites with dog restrictions (P &lt; 0.001). However, it was not related to distance from habitation. Only two non-canid species were recorded pulling the ejector, suggesting high target-specificity for canids. Conclusions In sites with dog restrictions, the risk of dog casualties from CPEs is minimal. However, distance from habitation does not increase dog safety, at least within 250 m. The ejector is highly specific for canids. Implications We provide specific recommendations for the design of a potential fox control program using CPEs in urban and peri-urban areas. The ejector may be a safe method for fox control in cities when deployed at places without domestic dogs.

Performance of Xpert® MTB/RIF and Determine™ TB-LAM Ag in HIV-infected adults in peri-urban sites in Zambia.

Peri-urban health facilities providing HIV and TB care in Zambia. To evaluate 1) the impact of Xpert® MTB/RIF on time-to-diagnosis, treatment initiation, and outcomes among adult people living with HIV (PLHIV) on antiretroviral therapy (ART); and 2) the diagnostic performance of Xpert and Determine™ TB-LAM Ag assays. Quasi-experimental study design with the first cohort evaluated per standard-of-care (SOC; first sputum tested using smear microscopy) and the second cohort per an algorithm using Xpert as initial test (intervention phase; IP). Xpert testing was provided onsite in Chongwe District, while samples were transported 5-10 km in Kafue District. TB was confirmed using mycobacterial culture. Among 1350 PLHIV enrolled, 156 (15.4%) had confirmed TB. Time from TB evaluation to diagnosis (P = 0.018), and from evaluation to treatment initiation (P = 0.03) was significantly shorter for IP than for SOC. There was no difference in all-cause mortality (7.0% vs. 8.6%). TB-LAM Ag showed higher sensitivity with lower CD4 cell count: 81.8% at CD4 < 50 cells/mm3 vs. 31.7% overall. Xpert improved time to diagnosis and treatment initiation, but there was no difference in all-cause mortality. High sensitivity of Determine TB-LAM Ag at lower CD4 count supports increased use in settings providing care to PLHIV, particularly with advanced HIV disease.

Postneonatal under-5 mortality in peri-urban and rural Eastern Uganda, 2005–2015

IntroductionCommunity and individual sociodemographic characteristics play an important role in child survival. However, a question remains how urbanisation and demographic changes in sub-Saharan Africa affect community-level determinants for child survival.MethodsLongitudinal...

Spatial-temporal patterns and influence of land-use and socioeconomic factors on fine particulate matter pollution in Accra, Ghana

Background: Air pollution levels in cities in Sub-Saharan Africa (SSA), the world’s most rapidly urbanizing region, are among the highest globally due to influences from diverse local and regional sources. However, very little is known about within-city disparities at fine spatial-temporal resolution. We examined the space-time patterns of fine particle pollution (PM2.5) in relation to land-use variables and socioeconomic factors in Accra, Ghana, and evaluated trends over a decade.Methods: We measured and analysed weekly gravimetric and minute-by-minute PM2.5 (optical sensor) concentrations from 150 unique locations (10 fixed [1-year] and 140 weekly [7-day] sites) covering a range of land-use, socioeconomic features and source influences.Results: PM2.5 concentrations were highest between December - February, during the “Harmattan” when transported dust and changes in regional and local meteorology affect Accra. In this period, levels were as high as 267 μg/m3 (mean 94.1 μg/m3), compared to annual PM2.5 concentrations ranging from 14.4 to 31.3 μg/m3 at fixed sites. Across all 150 sites, weekly concentrations ranged from &lt;10 μg/m3 to &gt;250 μg/m3. Sites near roadsides had the highest overall mean PM2.5 (43 μg/m3), followed by high-density (poor) and low-density (affluent) residential sites; peri-urban background sites had the lowest levels. By time of day, daily PM2.5 at all sites rose at dawn and peaked at daybreak, followed by a gradual decline till afternoon and a modest evening peak. There were indications of decreased PM2.5 concentrations at residential sites when compared to matching data from a decade ago (39 vs 25 μg/m3), suggesting likely reductions in biomass emissions.Conclusion: Fine particle pollution in Accra may be decreasing over time but remains 2 to 4-fold higher than the WHO guideline with significant variations in relation to spatial, socioeconomic, and land-use factors. Equitable local policies and interventions are needed to reduce air pollution levels and protect the vulnerable.

Field comparison between moss and lichen PAHs uptake abilities based on deposition fluxes and diagnostic ratios

In the present work, PAH uptake ability was tested in oven-devitalized moss (Hypnum cupressiforme) and lichen (Pseudevernia furfuracea) exposed in bags for six weeks in 9 periurban sites of Campania region (southern Italy). Based on a previous pilot work, aims of the study were to verify: i) whether the lichen showed higher PAH uptake and flux; ii) whether the two biomonitors evidenced similar pollution trends over the study area; iii) whether the two biomonitors highlighted similar pollution sources based on specific diagnostic ratios. For most PAHs, the accumulation was significantly higher in the lichen compared to moss, likely due to the ability of the first to entrap PAHs in the thallus and preserve these compounds from degradation during the exposure. In both biomonitors 4-rings PAHs prevailed, followed by 2–3-rings, both in lichen and in moss, whereas a limited accumulation of 5–6-rings PAHs was observed. The better performance of the lichen directly reflected on PAH deposition fluxes, which were significantly higher in the lichen also due to its lower specific leaf area. Despite the different sensitivity of the two species, they provided similar information in all sites, describing the same trend of pollution over the study area. According to diagnostic ratios, both moss and lichen highlighted pyrogenic emissions occurred during the six-week exposure.

Addressing Uptake of HIV Testing and Linkage to Care Among Men in Côte d'Ivoire: An Evaluation of the Brothers for Life Program Implementation.

Historically, men in sub-Saharan Africa have worse outcomes along the HIV care continuum than women. Brothers for Life (BFL) is a community-based behavior change intervention for men, adapted for Côte d'Ivoire, involving group discussions that address salient gender norms and promote HIV prevention, testing, and linkage to care with support from peer navigators. The goal of this study was to describe the BFL program as implemented in Côte d'Ivoire, evaluate program implementation, and report uptake of HIV testing and treatment among BFL participants. Three urban and periurban sites in Côte d'Ivoire. The implementation evaluation assessed the fidelity and acceptability of the BFL program and the reach of program completion, testing and peer navigation using qualitative and quantitative approaches. BFL facilitation fidelity and content fidelity were high. Semistructured interviews with BFL participants indicated that men appreciated the format and content and that the BFL program helped some participants overcome their fears and adopt more positive attitudes and behaviors around testing and treatment. Assessments of reach showed that, of the 7187 BFL participants, 81% tested for HIV as part of BFL and 2.3% (135) tested HIV-positive. Of those, 76% (102) accepted peer navigator support, and 97% (131) initiated treatment. After 6 months, 100% of the 131 men who initiated treatment remained in care. The implementation of BFL in Côte d'Ivoire successfully achieved the goals of engaging participants in discussions around HIV prevention, encouraging HIV testing, and achieving linkage to care, treatment initiation, and retention.

Survival of people aged 50\xa0years and older by HIV and HIV treatment status: findings from three waves of the SAGE-Wellbeing of Older People Study (SAGE-WOPS) in Uganda

BackgroundData on the survival status of older adults on antiretroviral treatment (ART) are scarce in sub-Saharan Africa. The objective of this study was to determine the survival status of people aged 50 years and older who were HIV-negative, HIV-positive not on ART, and HIV-positive on ART.MethodsWe used three waves of data from the World Health Organisation Study on Global Ageing and adult health- Well Being of Older People Study cohort in Uganda, conducted in 2009, 2012–2013 and 2015–2016. The cohort included HIV-negative and HIV-positive persons aged 50 years and older recruited from multiple rural and peri-urban sites in Uganda. Data were collected using interviewer-administered questionnaire. Time-dependent ART data were collected from medical records using a data-abstraction form. This study was conducted before the universal test and treat policy came into effect. We fitted Cox survival models to estimate hazard ratios to compare the risk of death between groups, adjusted for age, sex, marital status and hypertension.ResultsOf 623 participants, 517 (82.9%) of respondents had follow-up data and were included in this analysis. We observed 1571 person-years of follow-up from 274 people who were HIV-negative, and 1252 from 243 who were HIV-positive. The estimated mortality adjusted hazard ratio (aHR) was 1.89 (95% CI 1.0–3.4; p = 0.04) among people living with HIV compared to HIV-negative people. The aHR for mortality among people receiving ART compared with HIV-negative people was 1.75 (95% CI 0.9–3.5). People who were HIV-positive and not receiving ART had the greatest risk of death (aHR = 2.09, 95% CI 1.0–4.4 compared with HIV negative participants). The aHR for HIV-positive people not receiving ART, compared to those who were on treatment, was 1.19 (95% CI 0.6–2.5).ConclusionOlder adults living with HIV on ART had a risk of mortality that was nearly twice as high as HIV-negative adults. Further analyses of longitudinal data should be done to understand factors that affect the survival of older adults on ART.

Seasonal and meteorological effects on the cooling magnitude of trees in subtropical climate

The cooling effect of trees is one of the most important ecosystem services offered by natural components in cities. However, the large variations in cooling magnitudes reported in different studies call for deeper understanding of the underlying mechanisms. This study investigated the seasonal and meteorological effects on the cooling magnitude of trees in the humid subtropical climate. The meteorological conditions at four peri-urban woodland sites and a rooftop control site were continuously monitored for one year. The annual mean (±SD) cooling magnitudes were 0.9 ± 0.5, 2.5 ± 1.4 and 1.6 ± 0.8 °C in air temperature (Ta), physiological equivalent temperature (PET) and universal thermal climate index (UTCI) respectively with notable seasonal and diurnal variations. The daily total incoming shortwave radiation (S_in) explained 24.7, 39.2 and 35.7% of the variability in cooling magnitudes in Ta, PET and UTCI respectively. For every 1 MJ/m2 increase in S_in in a day, the daily mean cooling magnitude increased by 0.03, 0.16 and 0.08 °C in Ta, PET and UTCI respectively. The cooling magnitude measured in Ta could increase by 0.05 °C for every 1 °C rise in background Ta. The monthly mean interception of S_in was generally over 80% with an annual mean of 82.3%, which allowed the cooling benefit of trees to extend to the transitional season. Future studies are suggested to conduct a continuous measurement for at least 24 h under sunny and cloudy conditions in both hot and cold seasons with a ground-level control site to capture a more complete picture of the fluctuations in cooling magnitude.

Urban Rivers as Dispersal Corridors: Which Factors Are Important for the Spread of Alien Woody Species along the Danube?

Cities are hotspots of invasions, and this is particularly the case for urban rivers, which are known to serve as corridors for the spread of alien plant species to floodplain forests. Here, we present a case study on woody (shrubs, trees) species invasions across a gradient from a metropolis (Vienna) to rural regions along the Danube River in eastern Austria. In total, we identified 44 native and 25 alien woody species in 75 plots. Five alien woody species occur in at least 10 plots. The most wide-spread ones were species of floodplain forests (Acer negundo, Fraxinus pennsylvanica, and Populus x canadensis), while Ailanthus altissima and Robinia pseudoacacia—which prefer dry sites—were recorded substantially less often. The average level of invasion—i.e., the relative proportion of alien to native woody species in plots—was high across all three study regions. Still, there was a moderate decline of alien woody species richness along the urban—peri-urban—rural gradient. Generalized Linear Mixed Models showed that population density and the proportion of urban habitats in the environs of the plots is significantly positively correlated with the presence of Acer negundo and Ailanthus altissima. Conversely, the occurrence of Robinia pseudoacacia is negatively correlated with surrounding population density and urban habitats. Occurrence of Acer negundo is positively correlated with urban habitats. For Fraxinus pennsylvanica, we found no significant relationships. Our results confirm that gallery forests at river banks are highly susceptible to invasions. We argue that managing alien woody species in urban and peri-urban sites is not appropriate and useful, given that re-invasion is likely in most cases (from adjacent urban green spaces). We acknowledge that this recommendation entails the implicit recognition that gallery forests along urban sections of the Danube will contain a substantial—and likely further increasing—proportion of alien woody species.

Assessment of potentially toxic elements in vegetables cultivated in urban and peri-urban sites in the Kurdistan region of Iraq and implications for human health.

Vegetable fields in and around urban areas in the Kurdistan region of Iraq may have higher than background concentrations of potentially toxic elements (PTEs) from contamination sources including municipal waste disposal and wastewater used for irrigation. The purpose of this study was to assess PTE concentrations in soils and the edible parts of field-grown vegetables to quantify potential health risks to the local population. In this survey, 174 soils and 26 different vegetable and fruit types were sampled from 15 areas around Sulaymaniyah and Halabja cities. Sampling was undertaken from fields in urban, peri-urban and rural locations including sites close to areas of waste disposal. The soils are calcareous (pH 7.67-8.21) and classified as silty loam, sandy or silty clay with organic matter content between 6.62 and 11.4%. Concentrations of PTEs were typically higher in waste disposal areas compared with urban, peri-urban and rural areas. Pollution load indices suggested that agricultural soils near waste disposal sites were contaminated with some trace elements. Potentially toxic element concentrations in vegetables were highly variable. Higher total concentrations of PTEs were measured in vegetables from the waste areas with decreasing concentrations in urban, peri-urban and rural areas. Risks to human health were assessed using hazard quotients (HQ). Vegetable consumption poses no risk for adults, whereas children might be exposed to Ni, As and Cd. Although HQs suggest elevated risk for children from consumption of some vegetables, these risks are likely to be lower when realistic dietary consumption levels are considered.

Quantification and risk assessment of heavy metal build-up in soil-plant system after irrigation with untreated city wastewater in Vehari, Pakistan.

In peri-urban areas of district Vehari, farmers are using untreated city wastewater for crop irrigation owing to the scarcity of good-quality irrigation water. This practice may pose severe environmental and health issues to local inhabitants attributed to the high levels of potentially toxic metals in wastewater. The present study evaluated the potential impacts of wastewater irrigation on metals (Cd, Cr, Cu, Fe, Ni, Mn, Pb and Zn) build-up in the soil-plant continuum and associated health risks. In this study, wastewater (n = 17), soil (n = 108) and plant (n = 65) samples were collected from 15 peri-urban sites of three tehsils of district Vehari. Results showed that the mean concentration (mg/L) of Cd (0.02), Mn (0.25) and Fe (1.57) in wastewater samples was higher than their respective threshold values. Similarly, Cd, Mn and Fe concentration in soil was beyond the permissible limits of agricultural soil receiving wastewater irrigation. However, plants showed high accumulation of Pb, Cr and Fe than their respective limits depending on the vegetable/crop species. The health risk parameters showed that Pb and Cd are the major toxic chemical substances to human health, and the daily intake of crop plants can pose a potential health threat due to wastewater-irrigated crop consumption. Results highlighted the necessity of wastewater pretreatment to avoid the soil and vegetable contamination by wastewater irrigation and to reduce the associated health risks.

Women\u2019s freedom of movement and participation in psychosocial support groups: qualitative study in northern India

BackgroundDepression, the world’s leading cause of disability, disproportionately affects women. Women in India, one of the most gender unequal countries worldwide, face systemic gender disadvantage that significantly increases the risk of common mental disorders. This study’s objective was to examine the factors influencing women’s participation in psychosocial support groups, within an approach where community members work together to collectively strengthen their community’s mental health.MethodsThis community-based qualitative study was conducted from May to July 2016, across three peri-urban sites in Dehradun district, Uttarakhand, Northern India. Set within an NGO-run mental health project, data were collected through focus group discussions with individuals involved in psychosocial support groups including women with psychosocial disabilities as well as caregivers (N = 10, representing 59 women), and key informant interviews (N = 8) with community members and mental health professionals. Data were analyzed using a thematic analysis approach.ResultsThe principal barrier to participating in psychosocial support groups was restrictions on women’s freedom of movement. Women in the community are not normally permitted to leave home, unless going to market or work, making it difficult for women to leave their home to participate in the groups. The restrictions emanated from the overall community’s attitude toward gender relations, the women’s own internalized gender expectations, and most significantly, the decision-making power of husbands and mothers-in-law. Other factors including employment and education shaped women’s ability to participate in psychosocial support groups; however, the role of these additional factors must be understood in connection to a gender order limiting women’s freedom of movement.ConclusionsMental health access and gender inequality are inseparable in the context of Northern India, and women’s mental health cannot be addressed without first addressing underlying gender relations. Community-based mental health programs are an effective tool and can be used to strengthen communities collectively; however, attention towards the gender constraints that restrict women’s freedom of movement and their ability to access care is required. To our knowledge, this is the first study to clearly document and analyze the connection between access to community mental health services in South Asia and women’s freedom of movement.