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Childhood lead poisoning in the U.S. continues to be a major unresolved child public health issue. One barrier to solving the problem of lead poisoning concerns current child blood lead level (BLL) monitoring practices. In most states, one or two BLL tests administered in early childhood are used to rule out lead exposure. Current knowledge, however, regarding the multiple, complex biological mechanisms that underlie lead absorption and distribution during development suggests that child BLLs should be assumed to be an informative but necessarily fluctuating metric of current child lead exposure. We review some key mechanisms and pathways that influence lead absorption, lead distribution, and the stability of lead in red blood cells. We also consider how each of these factors and their development are likely to drive fluctuations in child BLLs over time. The goal of this special report is to provide a starting point for change in current child BLL testing practices. Solving the problem of child lead exposure will require new approaches to child BLL testing that take into account likely fluctuations in child BLLs., Introduction Lead poisoning in U.S. children continues at staggering rates in selected sectors, particularly among those living in under-resourced communities where older unrenovated housing and lead paint are still major [...]

Pollution from animal wastes is a threat to water resources. Insufficient treatment and disposal of animal manure results in potential runoff and transport of waste into surface and groundwater and ultimately contaminating drinking water in many rural areas. The goal of this research is to assess the efficiency of an innovative configuration of anaerobic membrane bioreactor (AnMBR) and constructed wetlands (CWs) to treat animal waste, providing a sustainable, resilient management system for agricultural wastewaters. Numerical simulations were conducted to assess the capacity of CWs to remove nutrients from AnMBR permeate with varying ammonium (NH4+), phosphorus (P), and chemical oxygen demand (COD) concentrations and temperature conditions (10°C, 20°C, 30°C, and 40°C). The simulations were conducted using HYDRUS software with the Constructed Wetland 2D (CW2D) module. The results supported the assumption that CWs can be an efficient polishing step for AnMBR permeate, removing more than 90% of NH4+ and P, which was further confirmed with experimental measurements. The effectiveness of this design relies on the natural processes for nutrient removal that can be optimized by altering nutrient and COD loading rates from the AnMBR system. When AnMBR systems face unexpected failures or technical issues, the integration of CWs provides a reliable contingency plan, ensuring a practical and resilient wastewater treatment process. The findings from this research offer significant promise for developing cost-effective and environmentally friendly solutions for the treatment and reuse of concentrated animal feeding operations (CAFOs) wastewater through a hybrid treatment configuration, contributing to the broader goals of decentralized wastewater treatment and agricultural practices. [ABSTRACT FROM AUTHOR]

Direct evidence-based approaches are vital to evaluating newly proposed theories on the persistence of soil organic carbon and establishing the contributions of abiotic and biotic controls. Our primary goal was to directly identify the mechanisms of organic carbon stabilization in native-state, free soil microaggregates without disrupting the aggregate microstructure using scanning transmission x-ray microscopy coupled with near edge x-ray absorption fine structure spectroscopy (STXM-NEXAFS). The influence of soil management practices on microaggregate associated-carbon was also assessed. Free, stable soil microaggregates were collected from a tropical agro-ecosystem in Cruz Alta, Brazil. The long-term experimental plots (>25 years) comparing two tillage systems: no-till and till with a complex crop rotation. Based on simultaneously collected multi-elemental associations and speciation, STXM-NEXAFS successfully provided submicron level information on organo-mineral associations. Simple organic carbon sources were found preserved within microaggregates; some still possessing original morphology, suggesting that their stabilization was not entirely governed by the substrate chemistry. Bulk analysis showed higher and younger organic carbon in microaggregates from no-till systems than tilled systems. These results provide direct submicron level evidence that the surrounding environment is involved in stabilizing organic carbon, thus favoring newly proposed concepts on the persistence of soil organic carbon.

Direct evidence-based approaches are vital in understanding the involvement of abiotic/biotic factors and evaluating the newly proposed theories on soil carbon (C) stabilization. Microaggregates (150–250 μm) collected from a corn system (>22 years; Kansas, USA), which had been under no-till with different nitrogen (N) treatments were analyzed (N treatments: manure/compost, urea, zero fertilizer). We studied C stabilization in free soil microaggregates (with preserved aggregate architecture), directly using scanning transmission X-ray microscopy coupled with near edge X-ray absorption fine structure (STXM-NEXAFS) spectroscopy. Submicron scale findings were complemented with bulk chemical analysis. The STXM-NEXAFS analysis revealed soil organic carbon (SOC) preservation inside nano- and micro-pores and organo–mineral association, various degrees of humification, and high molecular diversity. The presence of microbial-derived C was found in manure-/compost-added microaggregates highlighting the contribution of organic amendments in facilitating microbial diversity. The incidence of aragonite-like minerals suggested the biologically/chemically active nature of microaggregate cores. Bulk analysis of free microaggregates showed a higher concentration of SOC (6.5%), ammonium oxalate extractable Fe/Al/Si), and higher aliphaticity of humic acid in manure-/compost-added soils compared to inorganic fertilizer (3% SOC) and control (2.7% SOC) treatments. The co-existence of elements (calcium [Ca]/C, iron [Fe]/N, Fe/C, aluminum [Al]/C, and silicon [Si]/C) was partially supported by bulk chemical analysis that indicated a strong association between ammonium oxalate extractable Fe/Al/Si and SOC (R² = 0.63—0.77). Overall, our study provided direct/indirect evidence for the complex and interactive involvement of chemical, mineralogical, and biological mechanisms that may have been stimulated by the long-term addition of compost/manure in stabilizing SOC. [ABSTRACT FROM AUTHOR]

Peculiarities of metals uptake by the biofuel crop Miscanthus x giganteus were explored during plant growth at soil from the military site (Sliač, Slovakia). The experiment was carried out in greenhouse during two vegetation seasons. Research soil was predominantly elevated in Fe and Ti, while other metals (As, Cu, Mn, Sr, Zn and Zr) were presented at order of magnitude lower concentrations. No inhibition of plant growth was observed. The calculated Bioconcentration Factor showed that levels of metals’ accumulation by plant roots, stems and leaves were independent of metals’ concentrations in the soil. The accumulation of metals by stems and leaves was much lower than by roots. As, Zr, Ti were almost not accumulated by stems and leaves during both seasons; accumulation of Cu, Fe, Mn, Zn and Sr was not essential which confirmed that biomass of M. x giganteus might be processed for the energy purpose.

Solutions to simultaneously meet crop phosphorus (P) demand and reduce P loss from agricultural systems are required to improve the sustainability of our production. Our objective was to determine the effect of cover crop addition (with cover crop [CC], and without cover crop [NC]) and P fertilizer management (zero P control [CN], fall broadcast [FB], and spring injected [SI]) on P cycling, agronomic P use efficiency (PUE), and environmental P use efficiency (EPUE), measured as the percent of P lost in runoff water, in a no‐till corn (Zea mays)–soybean [Glycine max (L.) Merr.] rotation. The experiment was a 2 × 3 factorial. Both FB and SI increased P cycling through the main crop and cover crop tissue, compared to the CN. Cover crop did not affect main crop P uptake, removal in grain, or return to soil in crop residue, but CC treatment increased total P uptake and return in the system. Cover crop effects on P uptake, removal, and return were the same regardless of P fertilization treatments. Phosphorus fertilizer and CC treatments did not affect PUE. Both FB and SI P fertilizer management decreased EPUE, although SI tended to decrease EPUE less than FB. Cover crop significantly improved EPUE only in 2019, when CC reduced erosion losses. Therefore, cover crops were not consistently beneficial for reducing the environmental effects of P fertilization, and their use cannot replace the importance of sound P fertilizer stewardship, including sub‐surface P placement. However, cover crops play an important role in improving EPUE in years with high erosion loss potential. Core Ideas: Cover crops increased total P return to the soil surface by 30%.Agronomic phosphorus use efficiency was not affected by cover crops or phosphorus fertilizer management.Cover crops had variable effects on environmental phosphorus use efficiency.Reducing P loss is the most important factor for improving environmental P use efficiency. [ABSTRACT FROM AUTHOR]

In March of 2009, Mr. John Holloway and his neighbors in the Harmony Park district of Kansas City, MO, were excited to begin gardening on a vacant city lot in their neighborhood. The neighborhood, like many in urban areas, had once been residential interspersed with small establishments including restaurants, shops, and businesses such as auto body shops and gas stations. The under-utilized lot had once had multiple abandoned houses on it that had been torn down about two decades earlier, but since then the lot had been empty, overgrown with weeds, and a neighborhood eyesore. Mr. Holloway, a leader in his community, hoped that a community garden would not only improve the aesthetics of his neighborhood, but also provide a local, inexpensive source of fresh fruits and vegetables for his neighborhood, which is located in a food desert. When concerns arose about soil contaminants on the site, Mr. Holloway grew panicked that a community garden on a brownfield site would do more harm than good in his neighborhood. This case focuses on Mr. Holloway's decision of whether to continue gardening on the brownfield site in Harmony Park. The decision requires that students evaluate environmental, agronomic, human health, social, and economic issues related to the problem Mr. Holloway faces. Objectives of this case are for students to analyze and discuss data and concepts related to gardening on brownfield sites, urban soil contamination, urban food deserts, and human health.

Participation in urban agriculture is growing throughout the United States; however, potential soil contaminants in urban environments present challenges. Individuals in direct contact with urban soil should be aware of urban soil quality and soil contamination issues to minimize environmental and human health risks. The study reported here assessed the needs of urban gardeners and farmers throughout the United States with respect to soil contamination. Our results suggest that urban gardeners and farmers need and want information and guidance on best management practices for safely growing food crops on mildly contaminated urban soils.

Current child blood lead (Pb) screening guidelines assume that blood lead levels (BLLs) are relatively stable over time, and that only youngest children are vulnerable to the damaging effects of lower-range BLLs. This study aimed to test the stability of lower-range (≤ 10 μg/dL) child BLLs over time, and whether lower-range BLLs diminished with age among children aged 6 months to 16 years living in a lower-income neighborhood with a density of pre-1986 housing and legacy contamination. Age, sex, family income, age of residence, and/or residence proximity to point sources of Pb, were tested as potential additional factors. Capillary blood samples from 193 children were analyzed by inductively coupled plasma mass spectrometry (ICPMS). Multiple imputation was used to simulate missing data for 3 blood tests for each child. Integrated Growth Curve models with Test Wave as a random effect were used to test BLL variability over time. Among N = 193 children tested, at Time 1 testing, 8.7% had the BLLs ≥ 5 μg/dL (CDC "elevated" BLL reference value at the time of data collection) and 16.8% had BLLs ≥ 3.5 μg/dL (2021 CDC "elevated" BLL reference value). Modeling with time as a random effect showed that the variability of BLLs were attributable to changes within children. Moreover, time was not a significant predictor of child BLLs over 18 months. A sex by age interaction suggested that BLLs diminished with age only among males. Of the additional environmental factors tested, only proximity to a major source of industrial or vehicle exhaust pollution predicted child BLL variability, and was associated with a small, but significant BLL increase (0.22 μg/dL). These findings suggest that one or two BLL tests for only infants or toddlers are insufficient for identifying children with Pb poisoning. [ABSTRACT FROM AUTHOR]

Organic nutrient sources are an effective way to improve soil fertility and increase crop yield. Bio-slurry provides tremendous nutrient potential for the vegetative and reproductive growth of field crops and its long-term sustainability. Application of the bioslurry on the field can help to reduce fertilizer use, maintain productivity, and improve soil health. Soil enzyme activity was enhanced by swine slurry. Enzyme activity following fertilization takes precedence over microbial biomass in the short term. The study aimed (1) to study the effect of bio-slurry and chemical fertilizer on soil enzymes activity, and (2) to compare the biomass growth of corn using bio-slurry and chemical fertilizer. The research was conducted from November to December 2022 at the Throckmorton Plant Sciences Center, Department of Agronomy, Kansas State University, United States. The experiment was conducted in pots under greenhouse conditions with 5 treatments, including Treatment 1: Control (without fertilizer), Treatment 2: bio-slurry, Treatment 3: urea, Treatment 4: NH4NO3 and Treatment 5: KNO3+NaNO3. Each treatment was conducted in 3 replications with 1 pot per replication and 2 seeds per pot. The activities of soil enzymes, biomass of corn above ground and root were collected and analyzed. Corn plants treated with bio-slurry and inorganic fertilizer were found to have a non-significant growth of corn soil β-glucosidase enzyme with 4.41 mg/L, 3.83 mg/L, 4.23 mg/L, 4.11 mg/L, and 4.14 mg/L, respectively. With regard to aboveground and belowground biomass, no significant differences between the control and other treatments were observed. The results showed that bio-slurry released low amounts of enzyme activity to the soil and provided good growth conditions to corn. [ABSTRACT FROM AUTHOR]

Soils with strong texture-contrast between A and B horizons dominate the agricultural zones of the west and south of Australia. The B horizon is often sodic and of much finer texture than the A (or E) horizon above, and can have a bulk density as high as 2 g [cm.sup.-3]. When dry, these B horizons may severely impede the root growth of annual cereal crops. The objective of this study was to characterise the mineralogy and chemistry of fine pores at the interface of an E and a sodic B horizon of an Alfisol (Sodosol). Micro-X-ray fluorescence spectroscopy (μ-XRF) was used to locate the distribution of calcium (Ca), manganese (Mn), iron (Fe), zinc (Zn), and copper (Cu), and μ-X-ray absorption near edge structure (μ-XANES) spectroscopy or μ-X-ray absorption fine structure (μ-XAFS) spectroscopy to investigate speciation of Fe, Mn, Zn, and Cu around a pore. Both natural aggregates and thin sections were employed but measurements from thin sections were more useful because of the smaller thickness of the sample. The distribution maps showed that Ca was present in the pores but the other elements were not. Copper, Mn, and Zn were concentrated around the micropore. Manganese was always well correlated with Fe. Manganese was found in reduced form, i.e. Mn(II), and associated with phosphates, whereas Fe was in oxidised form and mostly associated with oxides. Zinc was mostly associated with carbonates (C[O.sub.3]), sulfates (S[O.sub.4]), and silicates (Si[O.sub.4]). The results were then compared with measurements by laser ablation inductively coupled plasmamass spectrometry (LA-ICP-MS). Only some of the observations made by μ-XRF were confirmed by LA-ICP-MS, most probably because of the superior detection limits of synchrotron-based μ-XRF., Introduction Soils with strong texture-contrast between surface and B horizons, called duplex soils in Australia, dominate the agricultural zones of the west and south of Australia. The A and E [...]

The potential availability (E) and partitioning ([K.sub.d]) of Se added to three soils as elemental Se ([Se.sup.0]), sodium selenite ([MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]), and sodium selenate ([MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]) were measured by isotopic dilution using either [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]. The soils were kept either submerged or at 80% water-holding capacity for either 15 or 60 d. Both [K.sub.d] and E values were controlled by the type of Se, soil moisture content, and time after application. The [K.sub.d] values for [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] were largely controlled by soil type, with the soil having the lowest pH and highest concentrations ofoxalate-extractable Al and Fe having the highest [K.sub.d] values. The [K.sub.d] values for [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], on the other hand, were largely influenced by the incubation period, and to a lesser extent soil type and moisture conditions. Selenate [K.sub.d] values decreased with incubation and were higher under submerged conditions. The availability of [Se.sup.0] as measured by concentrations of labile Se species was low due to limited oxidation to [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]. Elemental Se is therefore not suitable for preplant Se fertilization of lowland rice (O*Tza satit,a L.) because it is not readily oxidized. In the submerged soils, concentrations of labile [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] and [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] were also low, with >80% of the Se added as either [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] or [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] being fixed into nonlabile pools, probably through reduction to [Se.sup.0]. Rates of oxidation of [Se.sup.0] will play a critical role in determining whether reduced [Se.sup.0] formed in submerged soils after fertilization will contribute to plant Se uptake through oxidation either during field drainage before harvest or in the rice rhizosphere. doi: 10.2136/sssaj2009.0416