Effect of soil treatments and amendments on the nematode community under miscanthus growing in a lead contaminated military site

Applying phytotechnologies with energy crops on lands contaminated with trace elements provides cellulosic biomass and improves soil health. The process can be reflected in changes in the soil nematode community structure. This study assessed the nematode community composition of soil with Miscanthus grown with different agronomic practices. The research was onducted at Fort Riley, Kansas, USA, in soil with aged contamination by Pb at 1000 to 1500 mg/kg. The experimental design was a randomized complete block composed of four replications of five treatments: Control-undisturbed mixed plant cover and four conditions of Miscanthus growth,which consisted of No-till, Till (immediately before planting), Till + P, and Till + biosolids. Analysis of abundance, diversity, and community functional status indicators showed di�erential sensitivity of nematode taxa to agronomic treatments. Significant transformations in the nematode trophic group structure occurred under Miscanthus cultivation compared with the undisturbed mixed plant cover. Shannon and Pielou index response to agronomic treatments illustrated decreasing nematode community diversity with all Miscanthus agronomic conditions. However, agronomic practices led to increasing nematode community maturity, but those e�ects varied between spring and fall seasons. Increasing herbivores and omnivore-predators were the primary drivers of the observed changes in the nematode community due to planting Miscanthus. The nematode ecological structure indicators suggested that growth in Pb-contaminated land using different agronomical practices likely affects essential soil processes. More study is needed to define the effects of pre-plant tillage and amendments to soil nematode communities and Miscanthus yield over multiple growing seasons of this perennial crop

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

Background: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. Methods: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. Findings: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. Interpretation: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic. Funding: Bill & Melinda Gates Foundation

Iron oxides minimize arsenic mobility in soil material saturated with saline wastewater

The soil material in constructed wetlands is effective in retaining Se from flue-gas desulfurization (FGD) wastewater (WW), but reducing conditions can enhance native-soil As mobility. A laboratory-based soil column experiment was performed to assess the effectiveness of ferrihydrite (Fh) in minimizing the mobility of native-soil As in water-saturated soil material. A saline FGD WW mixture (i.e., influent) was delivered to columns of untreated and Fh-treated soil for 60 d. One untreated column and one Fh-treated column were then subjected to drying, followed by an additional 30 d of influent delivery. Although the influent was low in As (∼1 μg L⁻¹) and the soil As level was normal, the total dissolved As concentration of effluent from the untreated columns increased with time, from ∼1 μg L⁻¹ to a maximum of ∼27 μg L⁻¹. In contrast, effluent from the Fh-treated columns remained low in As (i.e., <5 μg L⁻¹). The strong correlation between total dissolved Fe and As in the effluent suggested that reductive dissolution of native-soil Fe minerals was responsible for releasing As into solution. Results from X-ray absorption spectroscopy showed newly precipitated Fe minerals in the Fh-treated soil, and the remaining As was mainly As(V) species in both the untreated and Fh-treated soils. Thus, native-soil As mobilized under saturated conditions can be sequestered by adding poorly crystalline Fe oxides to soil prior to saturation. Furthermore, results obtained by drying and rewetting the columns showed that saturated conditions must be maintained to minimize the remobilization of sequestered As and retained Se.Madhubhashini B. Galkaduwa, Ganga M. Hettiarachchi, Gerard J. Kluitenberg, and Stacy L. Hutchinso

Copper lability in soils subjected to intermittent submergence

Reducing conditions in soils can have significant influences on the availability of nutrient and toxic metals, through their remobilization, their release through reductive dissolution of oxide phases, and from the formation of precipitates. In the literature, contrasting results are reported on the effects of temporary waterlogging conditions on the availability of metals. In the present study, changes in the "labile" or "potentially available" pool of copper (Cu) in soils as a consequence of up to three intermittent soil submergence cycles was investigated using isotopic dilution. The soils (an Oxisol and an Inceprisol) selected were amended in the field with both biosolids-Cu and salt-Cu. Intermittent soil submergence was found to have a significant effect on the lability of Cu in soils, with E(total) values generally increasing in all the treatments with the different submergence cycles, the highest lability of Cu observed in the Cu-salt treatment. The presence of nonexchangeable colloidal forms of Cu, influenced by treatments and submergence cycles, was also reported.M. Biasioli, J. K. Kirby, G. M. Hettiarachchi, F. Ajmone-Marsan, M. J. McLaughli

Field demonstration of reduction of lead availability in soil and cabbage (Brassica Chinensis L.) contaminated by mining tailings using phosphorus fertilizers

A field demonstration of reduction of lead availability in a soil and cabbage (Brassica Chinensis L.) contaminated by mining tailings, located in Shaoxing, China was carried out to evaluate the effects of applications of phosphorus fertilizers on Pb fractionation and Pb phytoavailability in the soil. It was found that the addition of all three P fertilizers including single super phosphate (SSP), phosphate rock (PR), and calcium magnesium phosphate (CMP) significantly decreased the percentage of water-soluble and exchangeable (WE) soil Pb and then reduced the uptake of Pb, Cd, and Zn by the cabbage compared to the control (CK). The results showed that the level of 300 g P/m(2) soil was the most cost-effective application rate of P fertilizers for reducing Pb availability at the first stage of remediation, and that at this P level, the effect of WE fraction of Pb in the soil decreased by three phosphorus fertilizers followed the order: CMP (79%)>SSP (41%)>PR (23%); Effectiveness on the reduction of Pb uptake by cabbage was in the order: CMP (53%)>SSP (41%)>PR (30%). Therefore our field trial demonstrated that it was effective and feasible to reduce Pb availability in soil and cabbage contaminated by mining tailings using P fertilizers in China and PR would be a most cost-effective amendment