Contribution Of Anthropogenic Activities Research Articles

Source apportionment of soil PTE in a northern industrial county using PMF model: Partitioning strategies and uncertainty analysis

Positive matrix factorization (PMF) has commonly been applied for source apportionment of potentially toxic elements (PTE) in agricultural soil, however, spatial heterogeneity of PTE significantly undermines the accuracy and reliability of PMF results. In this study, a representative industrial-agricultural hub in North China (Xuanhua district, Zhangjiakou City) was selected as the research subject, multiple partition processing (PP) strategies and uncertainty analyses were integrated to advance the PMF modeling and associated algorithm mechanisms were comparatively discussed. Specifically, we adopted three methods to split the research area into several subzones according to industrial density (PP-1), population density (PP-2), and the ecological risk index (PP-3) respectively, to rectify the spatial bias phenomenon of PTE concentrations and to achieve a more interpretable result. Our results indicated that the obvious enrichment of Cd, Pb, and Zn was found in the agricultural soil, with Hg and Cd accounted for 83.49% of the overall potential ecological risk. Combining proper PP with PMF can significantly improve the modelling accuracy. Uncertainty analysis showed that interval ratios of tracer species (Cd, Pb, Hg, and Zn) calculated by PP-3 were consistently lower than that of PP-1 and PP-2, indicating that PP-3 coupled PMF can afford the optimal modeling results. It suggested that natural sources, fertilizers and pesticides, atmosphere deposition, mining, and smelting were recognized as the major contributor for the soil PTE contamination. The contribution of anthropogenic activities, specifically fertilizers and pesticides, and atmosphere deposition, increased by 1.64% and 5.91% compared to PMF results. These findings demonstrate that integration of proper partitioning processing into PMF can effectively improve the accuracy of the model even at the case of soil PTE contamination with high heterogeneity, offering support to subsequently implement directional control strategies.

Spatiotemporal Dynamics and Drivers of Wind Erosion during 1990–2020 in the Yarlung Zangbo River Basin, Southern Tibetan Plateau

Wind erosion is recognized as one of the main environmental issues and seriously threatens ecosystem services in the Yarlung Zangbo River basin (YZRB), southern Tibetan Plateau. Exploring the spatiotemporal dynamics and drivers of wind erosion is crucial for improving regional ecosystem services and sustainable development. This study was conducted to examine the spatiotemporal patterns of soil wind erosion modulus (SWEM) in YZRB from 1990 to 2020 by using the revised wind erosion equation (RWEQ) and to identify the influence of climate change and anthropogenic activities on wind erosion dynamics. The results showed that temporally, the overall SWEM presented a significant downward trend (−0.912 t·hm−2·a−1) and a continuous downward trend in the key implementation areas of ecological engineering. Spatially, the severe area of wind erosion is mainly concentrated in the flat and broad river valley, where sand sources are widely distributed. Significant SWEM differences were found among various land use/cover (LULC) types. Exceeding 90% reduction rates in SWEM occurred in forests, grasslands, and cultivated land. Additionally, the influence analysis showed that climate change was the dominant factor driving the variations in wind erosion due to the reduction of wind speed. By contrast, the contribution of anthropogenic activities is relatively less, accounting for 43.50% of wind erosion change, which closely matches the transfer of LULC to grassland and forest land with the implementation area of ecological engineering projects. This study provides useful information on the driving mechanism of wind erosion, prevention service changes, and determining priority zones for desertification prevention in YZRB. We suggest that eco-restoration activities should be endorsed in the future, as well as the adaptive management that is required to control wind erosion and improve ecosystem services and human well-being for people in the YZRB region.

Elemental Characteristics of Respirable Particulate Matter in the Urban Atmosphere of Dehradun, Uttrakhand, India

To evaluate the ambient air quality of the Dehradun city, respirable particulate matter was collected using respirable dust sampler (RDS) and analysed for the heavy metal content using atomic absorption spectroscopy (AAS). The morphology of particulates were determined using scanning electron microscope (SEM) and the elemental composition was determined through SEM- energy dispersive spectroscopy (EDS). Particulate matter mass concentration ranged from 65.00 µg m-3 to 337.33 µg m-3. Quantified heavy metals in particulate matter were Copper (Cu), Zinc (Zn), Cobalt (Co), Manganese (Mn), Iron (Fe), Nickel (Ni), Chromium (Cr), Lead (Pb) and Cadmium (Cd). The order of concentration of heavy metals were found to be in the trend of Fe>Zn>Cu>Pb>Cr>Ni>Mn>Co>Cd. Maximum concentration of PM10 was found at commercial site during summer, winter and monsoon season. Enrichment factor analysis showed substantial contribution of anthropogenic activities on PM10. Source apportionment (varimax rotated factor analysis method) showed dominance of incineration and uncontrolled burning of waste and refuses, resuspended dust with vehicular emission and crustal sources as the dominant sources in Dehradun. Plantation drive strategy have major role in ambient particulate matter mitigation measures and carbon sequestration from climate change and global problem worldwide. This study will be help to mitigate or decrease the load of air pollution by the using of various trees for sustainable human development on the marvellous earth planet.

Atmospheric CO2 consumption by rock weathering over a five year period in a large non-perennial tropical river basin of southern India

Rivers engage in carbon cycle by transporting the dissolved products of weathering of rocks to the oceans, and this process is sensitive to the global climatic changes. The present study was carried out with an objective of estimating the spatial and temporal variation in carbon consumption due to rock weathering in Cauvery, which is a major non-perennial tropical river in the peninsular India. The samples of all the rock types of this river basin were collected and subjected to mineralogical analysis. The water samples from this river were collected three times a year from 2013 to 2017 at 28 locations and were analysed for pH, EC and major ions. The spatiotemporal variations in the chemistry of river water were used to understand the amount of carbon dioxide consumed by rock weathering. The contribution of weathering to dissolved load of the river was higher followed by the contribution of anthropogenic activities and rainfall. The contribution of silicate weathering is dominant during the high river flow, whereas during low flow time periods, the contribution of carbonate weathering is on par with silicate weathering. The carbon consumption due to weathering in the Cauvery river was higher when the flow was significant, and it was lower during summer months. It is also evident that the carbon consumption is high in the upper and middle regions of the basin due to the weathering of gneissic and granodiorite rocks. Thus, the carbon consumption and flux in this basin are dynamic, both spatially and temporally. The east flowing rivers draining through the peninsular India, which is mostly composed of massive rocks, also functions as carbon sink, thus benefitting the environment by reducing the excess CO2 in the atmosphere.

Diffuse sources dominate the sulfate load into Finnish surface waters

Sulfate (SO42−) affects the cycling of ecologically important substances, such as carbon, nutrients and metals, but the contribution of anthropogenic activities in sulfate load entering aquatic systems is poorly known. We calculate specific sulfate loads for land cover types, atmospheric deposition and point sources, and then estimate the source-specific flux of sulfate to Finnish surface waters. The largest sulfate flux, entering mostly the Baltic Sea, originates from agricultural fields on acid sulfate soil (24% of total flux). Forests on mineral soil, which cover 67% of the country's surface area, form the second largest source (21%). Additionally, agricultural fields on non-acid soil cause noticeable sulfate flux (16%). Pulp and paper mills were the key point sources (20%) for sulfate. We find that anthropogenic activities contribute to elevated sulfate levels in waters potentially affecting the cycling of nutrients, metals and formation of greenhouse gases in naturally sulfate-poor freshwaters. Based on these findings, sulfate should be systematically included in monitoring and pollution control measures.

Biogenic components and trace elements in the sediments of river mouths and accumulation areas of the Curonian Lagoon (south-eastern Baltic Sea)

The main suppliers of sedimentary matter into the large coastal freshwater lagoon of the southeastern Baltic (Curonian Lagoon) are the Neman River including the sleeves Atmata, Skirvytė and Razliv, as well as Matrosovka and Deima rivers. Large catchment area of the rivers densely populated and characterized by intensive industrial and agricultural activities, which are regarded as potential suppliers of biogenic and chemical elements. Elevated amounts of biogenic components (nitrogen and phosphorus) as well as arsenic recorded in sediments from the river mouth areas suggest serious contribution of anthropogenic activities (use of fertilizers and pesticides in the agricultural activities) on the general sediment quality in the investigated area. Newly obtained data clarify the patterns of biogenic and trace element distribution in sediments located in close vicinity of potential pollution sources.

A new method to diagnose the contribution of anthropogenic activities to temperature: temperature tagging

Abstract. This study presents a new methodology, called temperature tagging. It keeps track of the contributions of individual processes to temperature within a climate model simulation. As a first step and as a test bed, a simple box climate model is regarded. The model consists of an atmosphere, which absorbs and emits radiation, and of a surface, which reflects, absorbs and emits radiation. The tagging methodology is used to investigate the impact of the atmosphere on surface temperature. Four processes are investigated in more detail and their contribution to the surface temperature quantified: (i) shortwave influx and shortwave atmospheric absorption ("sw"), (ii) longwave atmospheric absorption due to non-CO2 greenhouse gases ("nC"), (iii) due to a base case CO2 concentration ("bC"), and (iv) due to an enhanced CO2 concentration ("eC"). The differential equation for the temperature in the box climate model is decomposed into four equations for the tagged temperatures. This method is applied to investigate the contribution of longwave absorption to the surface temperature (greenhouse effect), which is calculated to be 68 K. This estimate contrasts an alternative calculation of the greenhouse effect of slightly more than 30 K based on the difference of the surface temperature with and without an atmosphere. The difference of the two estimates is due to a shortwave cooling effect and a reduced contribution of the shortwave to the total downward flux: the shortwave absorption of the atmosphere results in a reduced net shortwave flux at the surface of 192 W m−2, leading to a cooling of the surface by 14 K. Introducing an atmosphere results in a downward longwave flux at the surface due to atmospheric absorption of 189 W m−2, which roughly equals the net shortwave flux of 192 W m−2. This longwave flux is a result of both the radiation due to atmospheric temperatures and its longwave absorption. Hence the longwave absorption roughly accounts for 91 W m−2 out of a total of 381 W m−2 (roughly 25%) and therefore accounts for a temperature change of 68 K. In a second experiment, the CO2 concentration is doubled, which leads to an increase in surface temperature of 1.2 K, resulting from a temperature increase due to CO2 of 1.9 K, due to non-CO2 greenhouse gases of 0.6 K and a cooling of 1.3 K due to a reduced importance of the solar heating for the surface and atmospheric temperatures. These two experiments show the feasibility of temperature tagging and its potential as a diagnostic for climate simulations.

Chemical characteristics of rainwater in northeast China, a case study of Dalian

The samples of rainwater were collected at two urban sites and one rural site in Dalian from January to December 2007, and precipitation pH, conductivity, and main chemical components were analyzed. The dominant ions in rainwater were SO42−, NO3−, NH4+, Cl−, Ca2+ and Na+, which accounted for 92.03% of the total ions. Winter and spring had high concentrations of chemical components, while autumn and summer had relative low values. The dominant neutralization substances were NH4+, Ca2+, and Mg2+, and presented relatively lower neutralization capability than the other major acid rain city in north China. This caused precipitation was typically acidic with pH 4.79. Downtown has obvious lower precipitation pH, higher electrical conductivity value, higher concentrations of chemical components, and higher neutralizing capability than rural area. Furthermore, the possible common sources of major ions were identified based on backward trajectory analysis, correlation analysis, and source contribution. It presented that the chemical ion concentrations were influenced not only by local emissions but also transferred materials by wind from remote areas. SO42−, NO3−, and NH4+ were mainly from human activities, Ca2+, Mg2+, and K+ were soil derived, Na+ and Cl− were marine source, and the contribution of anthropogenic activities was also considerable for Cl−.

Plant diversity in relation to anthropogenic trace metals in soils of selected sites in Nigeria's Guinea Savanna

Studies on the contributions of anthropogenic activities to trace metal contamination in the soils of the West African sub-region, and their effects on the biodiversity of the area, are scanty. The effect of the trace metal content of soil, contributed by some anthropogenic activities (cultivation, vehicular traffic and industrial activity), on the plant diversity and vegetation structure in each of four sites in Nigeria's Guinea Savanna was evaluated. Soil contents of Pb, Br, Nb, V, Co, and Rb analysed by energy dispersive X-ray Fluorescence (ED-XRF) were generally higher in all the polluted sites than in the control site, except in the low traffic site (B). Co was lower than in the control site and Rb in the industrial site (D) was lower than in the control site. The mean number of plant species was significantly higher in site A (control) than in all the other three sites.