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At least 19 recordsLinked to original sources

Urban soil multifunctionality and seasonal variability of carbon-linked soil traits.

Urban soils can play a significant role in climate change mitigation due to their capacity to store carbon (C) and support microbial biodiversity. In this context, this study evaluated the effects of different fertilization strategies on soil quality, greenhouse gas emissions, and microbial communities in two urban green areas located in the Campania region (Southern Italy) over a three-year period. Mineral fertilization (MIN), micronized vermicompost (CMP), micronized biochar (BCH), vermicompost plus biochar (CMP + BCH) were compared to an unfertilized control (CNT). The results showed that soil physicochemical properties were mainly influenced by site-specific conditions and temporal variability, whereas cation exchange capacity was the soil parameter most responsive to fertilization treatments. The QBS-ar index, used as an indicator of soil biological quality based on soil arthropods, was primarily affected by seasonality, with higher values recorded during spring-summer and no significant effects attributable to fertilization treatments. Vermicompost, BCH, and their combination were associated with lower net soil-vegetation CO2 fluxes and smaller temporal increases in the measured flux compared with the control and mineral fertilization treatments. All treatments exhibited a negative estimated annualized net C balance, indicating that, under the adopted temporal upscaling procedure, the estimated gaseous exchanges exceeded the annual increase in soil organic carbon stocks. Nevertheless, BCH showed the least negative estimated annualized balance. Analyses of microbial diversity revealed that bacterial and fungal communities were mainly shaped by temporal and seasonal factors, while fertilization treatments had limited effects on microbial diversity and community composition. Overall, the findings indicate that biochar showed the most favorable estimated carbon balance and the lowest measured net CO2 fluxes under the conditions investigated. However, its effects on soil biological and microbial properties were limited in the short term, and none of the tested treatments achieved net carbon sequestration. These results suggest that biochar may contribute to climate change mitigation as part of long-term, site-specific management strategies rather than as a standalone solution for improving soil multifunctionality.

Biochar

Monitoring pesticides in agricultural and urban soils of the United States.

Organochlorine pesticides were monitored annually in the major agricultural areas of the United States from 1968 to 1973. Results show that agricultural soils are widely contaminated with low levels of organochlorine residues. Residue concentrations are decreasing as applications of the compounds decrease. Annual monitoring of urban areas since 1969 has demonstrated that urban soils generally have higher pesticide residue concentrations than do agricultural soils in the same locations. High concentrations of mercury, cadmium, and lead have also been observed in urban soils.

Cadmium

Pesticide residue concentrations in soils of five United States cities, 1971--urban soils monitoring program.

Soil samples from five metropolitan areas including Baltimore, Maryland; Gadsden, Alabama; Hartford, Connecticut; Macon, Georgia; and Newport News, Virginia were analyzed for elemental arsenic, organochlorine pesticides, and polychlorinated biphenyls (PCBs). A representative number of samples were analyzed for organophosphorus pesticides, but none was detected. All areas exhibited heavy soil concentrations of organochlorine pesticides including sigma DDT, aldrin, dieldrin, photodieldrin, chlordane, heptachlor, heptachlor epoxide, endrin, endrin ketone, and endosulfan sulfate. PCBs were detected in three of the five metropolitan areas. Within the metropolitan areas, samples from the urban, or core city, locations generally had higher pesticide concentrations than did samples from suburban locations. Finally, pesticide residue concentrations were generally higher in soils of metropolitan areas than in nearby agricultural soils.

Arsenic

Environmental coupling between metal resistance genes and bacterial communities in Beijing urban green-space soils.

Urban green spaces are intensively managed ecosystems exposed to chronic, multisource, low-intensity anthropogenic inputs. These inputs may alter soil microbial communities and influence the distribution of metal resistance genes (MRGs). However, MRG distributions and their relationships with environmental conditions and bacterial communities remain unclear under the complex, non-extreme pollution conditions typical of these ecosystems. We investigated Beijing urban green spaces as a representative system using metagenomic sequencing and metagenome-assembled genome (MAG) analysis. We characterized soil MRG composition, its environmental associations, and the distribution of potential hosts. MRG composition differed significantly among ecological conservation (EC), transitional urban (TU), and central urban (CU) zones. These differences were closely associated with soil physicochemical properties and bacterial community structure. Available phosphorus (AP) was significantly associated with variation in both bacterial community structure and MRG composition. MAG-based analysis identified distinct potential-host compositions across the three functional zones. Proteobacteria were more frequently represented among dereplicated MAGs from EC soils, whereas Actinobacteria were more frequent in TU and CU soils. Heavy metal concentrations correlated with MRG composition. However, variation partitioning analysis did not identify an independent contribution from heavy metals after accounting for soil physicochemical properties and bacterial community structure. These findings indicate that urban green-space soil monitoring should incorporate environmental conditions and microbial community characteristics rather than rely solely on total metal concentrations.

Soil Microbiology

Serum zinc concentrations in Finns.

Serum zinc concentrations were measured in 1416 Finns aged 15 years and above and belonging to 18 population groups living in various parts of the country. The mean serum zinc concentration was for men 12.7 mumol/l (82 microgram/100 ml) and for women 11.7 mumol/l (77 microgram/100 ml). Zinc levels varied with sex, age, length of fast, time of day and geographic area. It is noted that the incidence of coronary heart disease, the occurrence of a number of elements in soil and water, and the zinc level in human sera can in a statistical sence be linked to soil composition in Finland. Causal relationships, however, remain obscure.

Adult

Oxantel-pyrantel in various regimens for the treatment of soil transmitted helminthiasis in rural and urban communities.

204 individuals from a rural community were given a single dose of oxantel-pyrantel at 15mg/kg bodyweight and if still infected, 20mg/kg bodyweight, with cure rates of 100%, 53% and 71% for ascariasis, trichuriasis and hookworm infection, respectively. From an urban community, 124 patients were given the same drug either as 15mg/kg bodyweight given twice in one day, with an interval of about 12 hours, or 20mg/kg bodyweight given daily for 2 days. Cure rates obtained were 100% in both groups for ascariasis; 89.2% of those given the first regimen were cured of trichuriasis compared with 71.2% of those on the second. For trichuriasis, oxantel-pyrantel given twice, 12 hours apart, appears to be the best treatment schedule and further clinical trials using this regimen are suggested.

Adolescent

Concurrent stimulation of diflufenican biodegradation and changes in the active microbiome in gravel revealed by Total RNA.

The use of slowly degraded pesticides poses a particular problem when these are applied to urban areas such as gravel paths. The urban gravel provides an environment very different from agricultural soils; i.e., it is both lower in carbon and microbial activity. We, therefore, endeavored to stimulate the degradation of the pesticide diflufenican added to urban gravel microcosms amended with dry alfalfa to increase microbial activity. In the present study, alfalfa addition significantly increased the formation of diflufenican's primary metabolite, 2-[3-(trifluoromethyl)phenoxy]nicotinic acid (AE-B), indicating stimulated biotransformation. The concurrent changes of the active microbial communities within the gravel were explored using shotgun metatranscriptomic sequencing of ribosomal RNA and messenger RNA. Although bacterial taxa remained dominant (87.0%-98.5% relative abundance), the alfalfa treatment led to a 4-5-fold increase in eukaryotic groups, including fungi and microbial grazers. Several microbial taxa potentially involved in the degradation of complex carbon compounds and aromatic pollutants-including Bacteroidetes, Verrucomicrobia, Sordariomycetes, Mortierellales, Tremellales, Sphingopyxis, and Phenylobacterium-increased in relative abundance following alfalfa amendment. Functional gene profiling revealed elevated expression of genes related to microbial activity and biomass production. Genes with potential roles in the breakdown of complex carbon structures (e.g., xylanases/chitin deacetylases) and in the transformation of aromatic compounds (e.g., ring-cleaving dioxygenases) were revealed. We conclude that complex carbon amendments can enhance the microbial activity, promoting the biotransformation of diflufenican in urban gravel environments. These findings provide new insights into the interactions between microbial community dynamics, gene expression profiles, and pesticide biotransformation in non-agricultural matrices.IMPORTANCEPesticides used on urban areas, e.g., gravel paths, are likely to have different effects and fates than when these are used on agricultural soils. Hence, studies into the degradation of pesticides applied to urban matrices are needed. We have previously shown that metabolites of the persistent pesticide diflufenican are even more persistent in urban soils, and it has also previously been shown that these metabolites leach from gravel surfaces. The reasons behind this are that the urban gravel provides an environment very different from agricultural soils; i.e., it is both lower in carbon and microbial activity. In the present study, we, therefore, endeavored to stimulate the degradation of the pesticide diflufenican added to urban gravel microcosms amended with dry alfalfa to increase microbial activity, concurrently studying the changes in the active microbiome by Total RNA-metatranscriptomics.

Biodegradation, Environmental

Manganese pollution in the city environment and its relationship to traffic density.

As lead is phased out of gasoline, other additives with anti-knock properties, particularly organic manganese compounds, are being substituted. Unavoidably, such compounds go through the combustion process, are eliminated in exhaust gases, and become part of the city environment. To obtain some indication of the extent of this new pollution street soils from various locations in a heavily trafficked city (Newark, NJ) were analyzed for manganese and lead by atomic absorption. Highly signigicant inverse relationships were found between the concentrations of both contaminants and distances from major traffic arteries. Strong circumstantial evidence is thus provided that: 1) manganese pollution is occurring, along with lead, in the city environment; 2) this new pollution is related to traffic density; and 3) the most likely sources are automobile exhausts. This suspicion is further strengthened by the significant correlations observed between manganese and lead contents in children's blood, suggesting a common source for both. Substantiation of the safety of this practice of adding manganese to gasoline is needed.

Automobile Driving

Persistent antimicrobial resistance during soil remediation driven by residual heavy metal co-selection.

Remediation of heavy metal-contaminated soil is a global priority, particularly as reclaimed land increasingly intersects with urban development and human exposure. However, the ecological consequences of soil remediation, especially its impact on antimicrobial resistance (AMR) as a global health threat, have remained poorly understood. Here, we combined single-cell Raman-D₂O probing with genome-resolved metagenomics to monitor the dynamics of phenotypic and genotypic resistance to metals and antibiotics during a 120-day remediation of soils with three contamination levels from a lead-zinc smelting site. Although chemical remediation substantially reduced bioavailable metals (by 42%-65%), AMR was not diminished. Instead, both phenotypic activity and gene abundance of metal- and antibiotic-resistant microorganisms increased, resulting in a two- to three-fold increase in AMR-associated health risks. Among 76 metagenome assembled genomes (MAGs) from phenotypic resistance communities, all Cd resistance-associated MAGs harbored multidrug resistance genes, half of which were colocalized with metal resistance determinants, and their prevalence continued to rise with remediation. These findings reveal that although remediation alleviates acute metal toxicity, residual low-concentration bioavailable metals sustain evolutionary selection for resistance, highlighting a disconnect between chemical recovery and biological safety. Moreover, the improved soil nutrient and physiochemical properties of remediated soils further promoted the proliferation of antibiotic-resistant bacteria. This study offers new ecological insights into the unintended consequences of anthropogenic interventions, underscoring the need to integrate biological safety into soil health and safety assessments.

Soil Microbiology

Environmental transport and transformation of automotive-emitted lead.

The use of a mass balance equation assists in clarifying the contribution of automotive-emitted lead to the regional and global problems of the distribution of this element, by taking into account the physicochemical transformation processes operating on the lead during its transport along the various environmental pathways. The technical factors which govern the emission of such lead from automobile engines and which affect its subsequent dispersion through the environment are described.

Air Pollutants

Biomass burning contributions to Mexico City's atmospheric CO2 estimated using a multi-isotope approach.

Fossil fuel combustion dominates anthropogenic emissions worldwide; however, special attention should be addressed to biomass burning, since it is an increasingly important contributor under warmer, drier fire-weather conditions exacerbated by climate change. These emissions could impact the atmospheric composition of heavily urbanized environments. To assess the influence of biomass burning, along with fossil fuels combustion and soil and plant respiration on Mexico City's atmospheric composition, we conducted a year-long (December 2023-December 2024) isotopic monitoring of atmospheric CO2, combining radiocarbon (&#x394;14C), CO2 stable isotopes (&#x3b4;13C, &#x3b4;18O), and CO/CO2 ratios. Once defined the isotopic signatures and the characteristic CO/CO2 that describe the sources, we performed Monte Carlo simulations under two tracer modalities (&#x394;14C + CO/CO2 and &#x394;14C + CO2 stable isotopes) for source apportionment. Results show that during the dry season, particularly in March-April, atmospheric &#x394;14C values approached and overlapped background levels despite Mexico City's fossil-fuel dominance, indicating enhanced non-fossil inputs. Moreover, backward HYSPLIT trajectories supported that these elevated &#x394;14C values coincided with regional wildfire activity. Monte Carlo results attributed up to &#x223c;34 %-60 % of local CO2 to biomass burning in April, followed by March with contributions of &#x223c;31 %-49 %. Since these biomass burning figures contrast with the official emissions inventory of Mexico City metropolitan area, which assigns <1 % of total CO2 emissions to biomass burning, this study could exhibit the emissions inventory underestimation of this source, and thus, the need to reassess and incorporate top-down isotopic constraints in fire-affected urban regions.

Mexico

The identification and elimination of a potential lead hazard in an urban park.

During development of a park in Oakland, California, a potential public helath hazard due to lead in the soil (approximately 1,000 to 100,000 ppm) was identified through cooperative sampling and analysis efforts of the staffs at the county and state health departments. Analysis of samples collected at various locations and depths in the park, coupled with a three-dimensional model of the lead values obtained, indicated steps necessary to eliminate the hazard. The county undertook the abatement program, and with the elimination of the health hazard, the park development has been completed. Concomitant blood lead screening of neighborhood children failed to establish the park as a source of elevated lead in any of the children tested.

Child, Preschool

An urban epidemic of North American blastomycosis.

Five culturally proved cases of blastomycosis occurred in a 9-month period during 1974 and 1975 in a western suburb of Chicago. All patients lived within a 1-mile radius of the center of Westmont, Ill. (population, 12,000). Three of these patients lived in adjacent buildings in the same apartment complex. None of the patients had significant outdoor exposure. Dust from a nearby construction site was postulated as a possible common source, although soil cultures from the area were negative. This is the third chronologic epidemic of the blastomycosis; a fourth one has been reported. It is the only outbreak to occur in a major metropolitan area.

Adult

Intestinal parasitic infestation in urban and rural Xhosa children. A comparative study.

Evidence of helminthic intestinal parasites was found in 97,0% of stools of 544 Xhosa schoolchildren living in Cape Town. The commonest parasite was Trichuris trichiura, which infested 89,9% of the children. In contrast, only 9,8% of 387 Xhosa children living in the Tsolo district, Transkei, had evidence of intestinal parasites in their stools, Hymenolepis nana being the commonest. In spite of the unsatisfactory sanitary conditions in the Tsolo area compared with those in Guguletu, Cape Town, where all sewage is waterborne, few rural children were infested. The high prevalence of infestation in the Guguletu children suggests extensive contamination of the soil in the area by parasitic ova. In view of the magnitude of the extent of parasitic infestation in the Guguletu children, a vigorous and sustained programme of medication and education will have to be undertaken if the problem is to be resolved.

Black or African American