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1.
Environ Monit Assess ; 191(9): 582, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31435833

RESUMO

Non-point source (NPS) pollution, including fertilizer and manure application, sediment erosion, and haphazard discharge of wastewater, has led to a wide range of water pollution problems in the Miyun Reservoir, the most important drinking water source in Beijing. In this study, the Soil and Water Assessment Tool (SWAT) model was used to evaluate NPS pollution loads and the effectiveness of best management practices (BMPs) in the two subwatersheds within the Miyun Reservoir Watershed (MRW). Spatial distributions of soil types and land uses, and changes in precipitation and fertilizer application, were analysed to elucidate the distribution of pollution in this watershed from 1990 to 2010. The results demonstrated that the nutrient losses were significantly affected by soil properties and higher in both agricultural land and barren land. The temporal distribution of pollutant loads was consistent with that of precipitation. Soil erosion and nutrient losses would increase risks of water eutrophication and ecosystem degradation in the Miyun Reservoir. The well-calibrated SWAT model was used to assess the effects of several Best Management Practices (BMPs), including filter strips, grassed waterways, constructed wetlands, detention basins, converting farmland to forest, soil nutrient management, conservation tillage, contour farming, and strip cropping. The removal rates of those BMPs ranged from 1.03 to 38.40% and from 1.36 to 39.34% for total nitrogen (TN) and total phosphorus (TP) loads, respectively. The efficiency of BMPs was dependent on design parameters and local factors and varied in different sub-basins. This study revealed that no single BMP could achieve the water quality improvement targets and highlighted the importance of optimal configuration of BMP combinations at sub-basin scale. The findings presented here provide valuable information for developing the sustainable watershed management strategies.


Assuntos
Conservação dos Recursos Hídricos , Monitoramento Ambiental , Poluição Difusa/análise , Agricultura/métodos , Pequim , China , Ecossistema , Eutrofização , Fertilizantes , Florestas , Esterco , Nitrogênio/análise , Poluição Difusa/estatística & dados numéricos , Fósforo/análise , Solo , Qualidade da Água
2.
Environ Sci Pollut Res Int ; 26(26): 27073-27086, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31317434

RESUMO

Assessing the potential impacts of nonpoint source (NPS) pollution and proposing sound control strategies are significant global challenges. However, few studies have provided insights into the quantitative risk analysis and efficient management of NPS pollution. This study formulated four evaluation criteria to characterize both the generation and migration of diffuse phosphorus. Multicriteria analysis and the technique for order preference by similarity to ideal solution were combined to develop a NPS pollution risk index model for the evaluation of the potential phosphorus loss at the basin scale. The proposed model is a simple and efficient tool that considers most factors that affect diffuse phosphorus. In the GIS environment, the spatial distribution of the risk index of diffuse phosphorus could be mapped and visualized in the Huai River Basin. With the natural breaks classification method, the study area was divided into the following five regions: a potentially polluted region (3.5%), a lightly polluted region (15.4%), a moderately polluted region (40.7%), a highly polluted region (31.5%), and a seriously polluted region (8.9%). Based on land use composition, geographical location, and sources of diffuse phosphorus of these five regions, corresponding prevention measures were introduced, thus facilitating the management of NPS pollution for policy makers.


Assuntos
Modelos Teóricos , Poluição Difusa/análise , Fósforo/análise , Poluição Química da Água/análise , China , Visualização de Dados , Monitoramento Ambiental/métodos , Sistemas de Informação Geográfica , Rios
3.
Mar Pollut Bull ; 142: 76-84, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31232351

RESUMO

Stable isotopes and geochemical proxies (TOC/TN and Chla/TOC) in sediments can be used to distinguish organic matter sources (anthropogenic, terrestrial, or marine). This study aims to characterize organic matter (OM) in superficial sediments from three sectors of central Chile (33°S) that are highly influenced by urban and industrial development. Our results show that a substantial fraction of these OM in Quintero Bay is anthropogenic, from industrial and domestic wastewater sources. In contrast, a mixture of terrestrial and anthropogenic OM dominates the isotopic signal of surface sediments from Concón, derived from non-point industrial and agriculture sources associated with the Aconcagua River basin, while Ritoque exhibited a mixture of different OM sources. However, deposition of allochthonous OM in our study area depends on coastal topography, which influences the local currents and well-ventilated waters, promoting the dispersion and assimilation of OM and thus providing an environment with a high capacity for natural remediation.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Compostos Orgânicos/análise , Poluentes Químicos da Água/análise , Agricultura , Chile , Isótopos/análise , Poluição Difusa/análise , Compostos Orgânicos/química , Poluentes Químicos da Água/química
4.
J Environ Qual ; 48(2): 330-339, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30951112

RESUMO

Over the past four decades, riparian buffers have proven effective in retaining nutrients and sediment from agricultural runoff. Many grass species have been used with variable success in riparian buffers to improve the water quality of runoff. However, limited information is available on the effectiveness of giant cane [ (Walt.) Muhl] in improving surface water quality compared with grass species such as Kentucky bluegrass ( L.) and orchardgrass ( L.). Therefore, the objective of our study was to determine the quality of runoff leaving vegetative buffer plots planted with giant cane, Kentucky bluegrass, and orchardgrass. Additionally, a bare-ground control and continuous corn ( L.) was also monitored for comparison of runoff with vegetative buffers. The giant cane treatment had significantly greater infiltration rates (38.18 mm h, < 0.05) than bare ground (1.61 mm h), corn (5.75 mm h), Kentucky bluegrass (12.30 mm h), and orchardgrass (4.21 mm h) treatments. Dissolved reactive P in runoff was ranked as follows: corn > giant cane = Kentucky bluegrass = orchardgrass > bare ground. The total P from the corn treatment (1.70 mg L, < 0.05) was significantly higher than for bare ground (1.22 mg L), giant cane (0.69 mg L), Kentucky bluegrass (0.86 mg L), and orchardgrass (0.54 mg L). Giant cane, Kentucky bluegrass, and orchardgrass significantly reduced the total P concentration more than bare ground and corn. Results from this study demonstrate the utility of giant cane as a vegetated buffer to reduce nutrient and sediment concentrations in agricultural runoff.


Assuntos
Agricultura , Biodegradação Ambiental , Poluição Difusa/prevenção & controle , Rios , Poluição Difusa/análise
5.
J Environ Qual ; 48(2): 352-361, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30951125

RESUMO

Riparian buffer strips (RBS) are encouraged to control agricultural diffuse pollution. In Quebec Province, Canada, a policy promotes 3-m-wide RBS. Abiding farmers minimally maintain herbaceous vegetation, but nutrient retention efficiency could be improved with woody biomass. This work aimed to assess if fast-growing willows ( Seemen 'SX64') could reduce nutrient loads to a stream, in addition to yielding biomass. Triplicate treatments of two stem densities and a herbaceous control plot were monitored from 2011 to 2013 in a randomized block design on agricultural fields of the St. Lawrence Lowlands with sandy loam (Saint-Roch-de-l'Achigan [SR]) and organic-rich (Boisbriand [BB]) soils. Runoff, interstitial water, and water from the saturated zone were sampled 16 (SR) and 14 (BB) times to quantify nutrient buffering (NO, NH, P, and K). Sampling campaigns followed (i) snowmelt or ≥15-mm natural precipitation events after (ii) fertilization and (iii) glyphosate-based herbicide applications. Concentration reduction before and after the RBS was highest for nitrates (77-81% in runoff at BB, 92-98% at 35- to 70-cm depth at SR) just after fertilization, when edge-of-field concentrations peaked. Total P removal was observed in runoff after fertilization at SR, and K removal was punctually witnessed at BB. Riparian buffer strips were inefficient for NH and dissolved P removal, and RBS effluents exceeded aquatic life protection standards. plantations, irrespective of stem density, were not more efficient than herbaceous RBS. This shows that without fertilizer input reductions, narrow RBS are insufficient to protect streams from excess nutrients in corn ( L.) and soybean [ (L.) Merr.] crops.


Assuntos
Biodegradação Ambiental , Monitoramento Ambiental , Nitrogênio/análise , Poluição Difusa/prevenção & controle , Fósforo/análise , Agricultura , Poluição Difusa/análise , Poaceae , Quebeque , Salix , Soja , Zea mays
6.
J Environ Qual ; 48(2): 510-517, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30951133

RESUMO

Computer models are commonly used for predicting risks of runoff P loss from agricultural fields by enabling simulation of various management practices and climatic scenarios. For P loss models to be useful tools, however, they must accurately predict P loss for a wide range of climatic, physiographic, and land management conditions. A complicating factor in developing and evaluating P loss models is the relative scarcity of available measured field data that adequately capture P losses before and after implementing management practices in a variety of physiographic settings. Here, we describe the development of the P Loss in runoff Events from Agricultural fields Database (PLEAD)-a compilation of event-based, field-scale dissolved and/or total P loss runoff loadings from agricultural fields collected at various research sites located in the US Heartland and southern United States. The database also includes runoff and erosion rates; soil-test P; tillage practices; planting and harvesting rates and practices; fertilizer application rate, method, and timing; manure application rate, method, and timing; and livestock grazing density and timing. In total, >1800 individual runoff events-ranging in duration from 0.4 to 97 h-have been included in the database. Event runoff P losses ranged from <0.05 to 1.3 and 3.0 kg P ha for dissolved and total P, respectively. The data contained in this database have been used in multiple research studies to address important modeling questions relevant to P management planning. We provide these data to encourage additional studies by other researchers. The PLEAD database is available at .


Assuntos
Agricultura , Monitoramento Ambiental/métodos , Poluição Difusa/estatística & dados numéricos , Fósforo/análise , Poluentes Químicos da Água/análise , Fertilizantes , Poluição Difusa/análise , Poluição Difusa/prevenção & controle
7.
Environ Sci Pollut Res Int ; 26(10): 10363-10373, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30761497

RESUMO

It is the key point to reveal the effect of irrigation water and fertilization conditions on the agriculture non-point pollution in the paddy field. In this study, the estimation model of agricultural non-point source pollution loads at field scale was established on the basis of agricultural drainage irrigation model and combined with pollutant concentration predication model. Based on the estimation model of agricultural non-point source pollution in the field and experimental data, the load of agricultural non-point source pollution in different irrigate amount and fertilization schedule in paddy field was calculated. The results showed that the variation of field drainage varies greatly under different irrigation conditions, and there is an "inflection point" between the irrigation water amount and field drainage amount. The non-point pollution load increased with the increase of irrigation water and showed a significant power correlation. Under the different irrigation condition, the increase amplitude of non-point pollution load with the increase of irrigation water was different. When the irrigation water is smaller, the non-point pollution load increase relatively less, and when the irrigation water increased to inflection point, the non-point pollution load will increase considerably. In addition, there was a positive correlation between the fertilization and non-point pollution load. The non-point pollution load had obvious difference in different fertilization schedule even with same fertilization level, in which the fertilizer pollution load increased the most in the period of turning green to tillering. The results provide some basis for the field control and management of agricultural non-point source pollution.


Assuntos
Irrigação Agrícola/métodos , Poluição Difusa/análise , Oryza/crescimento & desenvolvimento , Agricultura/métodos , Poluição Ambiental , Fertilizantes , Nitrogênio/análise , Fósforo , Água , Movimentos da Água , Poluentes Químicos da Água/análise
8.
Bioresour Technol ; 280: 295-302, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30776656

RESUMO

Storing multipond constructed wetlands, dispersed in the areas of rural lake or river basins, are unique and alternative conventional treatment systems for non-point source pollution. However, the sustainable operation and successful application of these systems remain a challenge. This study aimed to assess the seasonal variations of performance, identify operational factors of nutrients removal and fill the knowledge gap of field-scale storing multipond constructed wetlands application in a plateau lake watershed. Preferable performances for pollutant purification and operation parameters were achieved in different water seasons. Highly related to the performance of wastewater treatment, operational parameters including temperature, mass loading rate, hydraulic loading rate, hydraulic retention time and water depth were analyzed through first-order kinetics model, Spearman's rank correlation and redundancy analysis. Optimized parameters obtained through different analyzing methods revealed that appropriate hydraulic loading rate and mass loading rate would give better purification performances in wet season.


Assuntos
Lagos/química , Poluição Difusa/análise , Águas Residuárias/química , Áreas Alagadas , Estações do Ano , Poluentes Químicos da Água/análise
9.
Environ Pollut ; 245: 965-974, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30682753

RESUMO

At present, the study of microplastic sources is in a relatively preliminary stage due to the complexity of microplastic features in the environment. Based on a literature review, we developed a source-specific classification system for the quantitative analysis of microplastic sources. The classification system includes ten types of microplastics based on morphology and composition and can identify their main sources and the associated probabilities. To reflect the complexity of types and sources in the regional combination of microplastics, we first propose a microplastic diversity index (D1-D'(MP)). We use the South China Sea as an example to carry out quantitative source analysis and calculate the diversity index. Eight types of microplastics were found, mainly consisting of maritime coatings (type "Gran_coat") (33.0%) and synthetic fibers (type "Fib_thin") (29.6%). We also found that the diversity increased with offshore distance. In addition, we partitioned surface microplastics globally according to a two-dimensional microplastic abundance-diversity index. We believe that these indicators can effectively reflect pollution status and ultimately lead to different types of control measures. In the future, additional indicators for the characterization of microplastics must be included in the classification system to establish a one-to-one source analysis system for microplastic characteristics and source apportionment. In general, our study may provide new insights into the establishment of more accurate and quantitative source apportionment techniques and effective pollution control.


Assuntos
Monitoramento Ambiental/métodos , Poluição Difusa/análise , Plásticos/análise , Água do Mar/química , Poluentes Químicos da Água/análise , China , Oceanos e Mares , Plásticos/classificação , Poluentes Químicos da Água/classificação
10.
Environ Sci Pollut Res Int ; 26(2): 1487-1506, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30430446

RESUMO

The water quality in many Midwestern streams and lakes is negatively impacted by agricultural activities. Although the agricultural inputs that degrade water quality are well known, the impact of these inputs varies as a function of geologic and topographic parameters. To better understand how a range of land use, geologic, and topographic factors affect water quality in Midwestern watersheds, we sampled surface water quality parameters, including nitrate, phosphate, dissolved oxygen, turbidity, bacteria, pH, specific conductance, temperature, and biotic index (BI) in 35 independent sub-watersheds within the Lower Grand River Watershed in northern Missouri. For each sub-watershed, the land use/land cover, soil texture, depth to bedrock, depth to the water table, recent precipitation area, total stream length, watershed shape/relief ratio, topographic complexity, mean elevation, and slope were determined. Water quality sampling was conducted twice: in the spring and in the late summer/early fall. A pairwise comparison of water quality parameters acquired in the fall and spring showed that each of these factors varies considerably with season, suggesting that the timing is critical when comparing water quality indicators. Correlation analysis between water quality indicators and watershed characteristics revealed that both geologic and land use characteristics correlated significantly with water quality parameters. The water quality index had the highest correlation with the biotic index during the spring, implying that the lower water quality conditions observed in the spring might be more representative of the longer-term water quality conditions in these watersheds than the higher quality conditions observed in the fall. An assessment of macroinvertebrates indicated that the biotic index was primarily influenced by nutrient loading due to excessive amounts of phosphorus (P) and nitrogen (N) discharge from agricultural land uses. The PCA analysis found a correlation between turbidity, E. coli, and BI, suggesting that livestock grazing may adversely affect the water quality in this watershed. Moreover, this analysis found that N, P, and SC contribute greatly to the observed water quality variability. The results of this study can be used to improve decision-making strategies to improve water quality for the entire river basin.


Assuntos
Poluição Difusa/análise , Poluição da Água/análise , Qualidade da Água , Agricultura , Animais , Bactérias/isolamento & purificação , Monitoramento Ambiental/métodos , Monitoramento Ambiental/estatística & dados numéricos , Escherichia coli/isolamento & purificação , Invertebrados , Missouri , Nitratos/análise , Nitrogênio/análise , Poluição Difusa/estatística & dados numéricos , Fosfatos/análise , Fósforo/análise , Rios , Estações do Ano , Solo/química , Microbiologia da Água
11.
Environ Sci Pollut Res Int ; 26(1): 464-472, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30406587

RESUMO

Agricultural non-point source pollution causes global warming and the deterioration of air and water quality. It is difficult to identify and monitor the emission sources of agricultural pollution due to the large number of farms in China. Many studies focus on the technological aspect of achieving agricultural sustainability, but its socioeconomic aspect is poorly understood. Here, we report how group size (number of farms in a certain region) affects agricultural pollution governance through conducting a social science experiment. We found that when communication was allowed among group members, a small group size facilitated cooperation. Although deviations from the cooperation equilibrium occurred with time in all groups, the smaller the group size, the slower the cooperation equilibrium became frangible. These findings suggest that reducing number of farms and extending the length of farm property rights can benefit the mitigation of agricultural non-point pollution in China. Social science experiments can be a useful tool to understand the socioeconomic aspect of agricultural sustainability.


Assuntos
Agricultura/estatística & dados numéricos , Monitoramento Ambiental , Poluição Difusa/estatística & dados numéricos , Agricultura/métodos , China , Poluição Ambiental , Fazendas , Poluição Difusa/análise , Poluentes Químicos da Água/análise , Poluição da Água
12.
Chemosphere ; 216: 213-223, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30368086

RESUMO

Antibiotics in surface waters and soils are growing public health concerns and treated wastewater has often been identified as the main source of antibiotics. However, few studies have been conducted to evaluate the occurrence and concentrations of antibiotics in coastal cities without direct impact of wastewater discharge. In this study, the occurrence of 14 antibiotics including four macrolides, three sulfonamides, three ß-lactams, lincomycin, chloramphenicol, furazolidon, and monensin in surface waters and soils in Singapore were analyzed with SPE-LC-ESI-MS/MS. The detected concentrations of antibiotics were all below 82.5 ng/L in surface waters and below 80.6 ng/g dry wt in soils. These concentrations were significantly lower than other cities that were under the impact of treated wastewater discharge, suggesting that reduction of treated wastewater discharge reduces occurrence of antibiotics in the environment. However, the wide occurrence of trace levels of antibiotics suggest that other factors may have contributed to detected environmental antibiotics. Population density was positively correlated with concentrations of clarithromycin, lincomycin, azithromycin, and sulfamethoxazole in surface waters, suggesting that non-point source pollution due to anthropogenic pressure may contribute to the wide detection of trace levels of antibiotics. The potential impact of antibiotic use, natural production, and half-lives of antibiotics were further discussed. Further studies are needed to evaluate how anthropogenic activities other than wastewater discharge may contribute to the occurrence of trace level antibiotics and their associated health risks in urban environments.


Assuntos
Antibacterianos/análise , Monitoramento Ambiental , Poluição Difusa/análise , Poluentes do Solo/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Singapura
13.
J Environ Manage ; 228: 197-204, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30223178

RESUMO

Agricultural nonpoint source pollution is the leading source of water quality degradation in United States, which has led to the development of programs that aim to mitigate this pollution. One common approach to mitigating nonpoint source pollution is the use of best management practices (BMPs). However, it can be challenging to evaluate the effectiveness of implemented BMPs due to polices that limit data sharing. In this study, the uncertainty introduced by data sharing limitations is quantified through the use of a watershed model. Results indicated that BMP implementation improved the overall water quality in the region (up to ∼15% pollution reduction) and that increasing the area of BMP implementation resulted in higher pollution reduction. However, the model outputs also indicated that uncertainty caused by data sharing limitations resulted in variabilities ranging from -160% to 140%. This shows the importance of data sharing among agencies to better guide current and future conservation programs.


Assuntos
Incerteza , Agricultura/métodos , Poluição Difusa/análise , Poluição da Água/análise , Qualidade da Água
14.
Water Environ Res ; 90(10): 1872-1898, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30180923

RESUMO

A review of the literature published during year 2017 on topics relating to nonpoint source pollution (NPS) is presented. This article is written with a view to cater the need of nonpoint source pollution research and to summarize the new advancements in NPS control. Research developments on assessing, monitoring, and controlling the nonpoint source pollution are the main focus of this review. Future research topics related to NPS are also recommended.


Assuntos
Poluição Difusa , Monitoramento Ambiental , Poluição Difusa/análise , Poluição Difusa/prevenção & controle , Poluição Difusa/estatística & dados numéricos
15.
Artigo em Inglês | MEDLINE | ID: mdl-30060454

RESUMO

Changes in landscape patterns in a river basin play a crucial role in the change on load of non-point source pollution. The spatial distribution of various land use types affects the transmission of non-point source pollutants on the basis of source-sink theory in landscape ecology. Jiulong River basin in southeast of China was selected as the study area in this paper. Aiming to analyze the correlation between changing landscape patterns and load of non-point source pollution in this area, traditional landscape metrics and the improved location-weighted landscape contrast index based on the minimum hydrological response unit (HRULCI) were applied in this study, in combination with remote sensing and geographic information system (GIS) technique. The results of the landscape metrics showed the enhanced fragmentation extent and the decreasing polymerization degree of the overall landscape in the watershed. High values of HRULCI were concentrated in cultivated land, while low HRULCI values mostly appeared in forestland, indicating that cultivated land substantially enhanced non-point source pollution, while forestland inhibited the pollution process.


Assuntos
Modelos Teóricos , Poluição Difusa/análise , China , Monitoramento Ambiental , Florestas , Sistemas de Informação Geográfica , Rios
16.
Chemosphere ; 211: 557-565, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30092536

RESUMO

Understanding pollutant transport process and source apportionment is critical to urban stormwater pollution mitigation. Previous studies have investigated transport and sources of road deposited sediments (RDS) and sewer sediments individually, and most of these studies focused on stormwater pollution in combined sewer systems. However, studies about pollutant transport and source apportionment of the entire urban non-point source pollution process in separate sewer systems are lacking. This study analyzed particle size distribution and chemical pollutants in five media during the entire pollutant process including RDS, roof runoff, road runoff, sewer sediments, and sewer runoff. The outcomes found that mass percentage of fine particles became greater during pollutant transport in stormwater runoff. According to transport characteristics, particles were grouped into three types: particles <20 µm, 20-105 µm, and >105 µm. Particles <20 µm had the highest mobility capacity and particles >105 µm had the lowest mobility capacity, while mobility capacity of particles 20-105 µm was uncertain. Pollutant concentrations in road runoff were significantly influenced by rainfall intensity and pollutant concentrations in sewer runoff could become lower during rainy seasons ignoring rainfall intensity. RDS was the main contributor of heavy metals while organic matter and nutrients were primarily contributed by sewer sediments. Roof runoff, road runoff and sewer sediments contributed 5.35%, 69.24% and 25.41% particles to urban receiving water, respectively. Based on the outcomes, several suggestions were given for stormwater management.


Assuntos
Monitoramento Ambiental/métodos , Poluição Ambiental/análise , Poluição Difusa/análise , Esgotos/química
17.
Environ Sci Pollut Res Int ; 25(21): 20946-20955, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29766427

RESUMO

To control non-point source (NPS) pollution, it is important to estimate NPS pollution exports and identify sources of pollution. Precipitation and terrain have large impacts on the export and transport of NPS pollutants. We established an improved export coefficient model (IECM) to estimate the amount of agricultural and rural NPS total phosphorus (TP) exported from the Luanhe River Basin (LRB) in northern China. The TP concentrations of rivers from 35 selected catchments in the LRB were used to test the model's explanation capacity and accuracy. The simulation results showed that, in 2013, the average TP export was 57.20 t at the catchment scale. The mean TP export intensity in the LRB was 289.40 kg/km2, which was much higher than those of other basins in China. In the LRB topographic regions, the TP export intensity was the highest in the south Yanshan Mountains and was followed by the plain area, the north Yanshan Mountains, and the Bashang Plateau. Among the three pollution categories, the contribution ratios to TP export were, from high to low, the rural population (59.44%), livestock husbandry (22.24%), and land-use types (18.32%). Among all ten pollution sources, the contribution ratios from the rural population (59.44%), pigs (14.40%), and arable land (10.52%) ranked as the top three sources. This study provides information that decision makers and planners can use to develop sustainable measures for the prevention and control of NPS pollution in semi-arid regions.


Assuntos
Monitoramento Ambiental/métodos , Modelos Teóricos , Poluição Difusa/análise , Fósforo/análise , Rios/química , Poluentes Químicos da Água/análise , Agricultura , Animais , China , Clima Desértico , Humanos
18.
Water Res ; 139: 311-320, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29660620

RESUMO

The formation and transportation processes of non-point source (NPS) pollution varied among the studied watersheds in the Northeastern China, so we hypothesized that the driving force behind NPS pollution followed the spatial scale effect. With a watershed outlet sedimentary flux analysis and a distributed NPS pollution loading model, we investigated the temporal dynamics of NPS and the differences in driving forces. Sediment core samples were collected from two adjacent watersheds, the smaller Abujiao watershed and the larger Naoli watershed. The natural climatic conditions, long-term variations in the distribution of land use, soil properties and tillage practices were the same in the two watersheds. The vertical distributions of total nitrogen, total phosphorus, Zn and As at 1-cm intervals in the section showed clear differences between the watersheds. There were higher concentrations of total nitrogen and total phosphorus in the larger watershed, but the heavy metals were more concentrated in the smaller watershed. Lead-210 (210Pb) analyses and the constant rate of supply model provided a dated sedimentary flux, which was correlated with the corresponding yearly loading of NPS total nitrogen and total phosphorus in the two watersheds. The total phosphorus showed a stable relationship in both watersheds with an R2 value that ranged from 0.503 to 0.682. A rose figure comparison also demonstrated that the pollutant flux in the sediment was very different in the two watersheds, which had similar territorial conditions and different hydrological patterns. Redundancy analysis further indicated that expanding paddy areas had a large impact on the sedimentary flux of nitrogen and phosphorus in the smaller watershed, but precipitation had a direct impact on NPS loading in the larger watershed. We concluded that the spatial scale effect affected the NPS pollution via the transport processes in the waterway, which was mainly influenced by branch length and drainage density.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/análise , Poluição Difusa/análise , Rios , China , Radioisótopos de Chumbo , Metais Pesados/análise , Nitrogênio/análise , Fósforo/análise , Poluentes Químicos da Água/análise
19.
Environ Sci Pollut Res Int ; 25(15): 15120-15132, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29556978

RESUMO

We measured the occurrence and seasonal variations of glyphosate and its metabolite, aminomethylphosphonic acid (AMPA), in different environmental compartments within the limits of an agricultural basin. This topic is of high relevance since glyphosate is the most applied pesticide in agricultural systems worldwide. We were able to quantify the seasonal variations of glyphosate that result mainly from endo-drift inputs, that is, from direct spraying either onto genetically modified (GM) crops (i.e., soybean and maize) or onto weeds in no-till practices. We found that both glyphosate and AMPA accumulate in soil, but the metabolite accumulates to a greater extent due to its higher persistence. Knowing that glyphosate and AMPA were present in soils (> 93% of detection for both compounds), we aimed to study the dispersion to other environmental compartments (surface water, stream sediments, and groundwater), in order to establish the degree of non-point source pollution. Also, we assessed the relationship between the water-table depth and glyphosate and AMPA levels in groundwater. All of the studied compartments had variable levels of glyphosate and AMPA. The highest frequency of detections was found in the stream sediments samples (glyphosate 95%, AMPA 100%), followed by surface water (glyphosate 28%, AMPA 50%) and then groundwater (glyphosate 24%, AMPA 33%). Despite glyphosate being considered a molecule with low vertical mobility in soils, we found that its detection in groundwater was strongly associated with the month where glyphosate concentration in soil was the highest. However, we did not find a direct relation between groundwater table depth and glyphosate or AMPA detections. This is the first simultaneous study of glyphosate and AMPA seasonal variations in soil, groundwater, surface water, and sediments within a rural basin.


Assuntos
Monitoramento Ambiental/métodos , Glicina/análogos & derivados , Herbicidas/análise , Isoxazóis/análise , Poluição Difusa/análise , Poluentes do Solo/análise , Tetrazóis/análise , Argentina , Produtos Agrícolas/crescimento & desenvolvimento , Sedimentos Geológicos/química , Glicina/análise , Água Subterrânea/química , Rios/química , Solo/química
20.
Environ Sci Pollut Res Int ; 25(10): 9849-9860, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29372527

RESUMO

Due to limits on available data, the effects of urban sprawl on regional nonpoint source pollution (NPS) have not been investigated over long time periods. In this paper, the characteristics of urban sprawl from 1999 to 2014 in Beijing were explored by analyzing historical land-use data. The Event Mean Concentration data have been collected from all available references, which were used to estimate the variation in urban NPSs. Moreover, the impacts of variation in urban sprawl on regional NPSs were qualified. The results indicated that the urbanization process showed different influences on pollutants, while COD and TN were identified as key NPS pollutants. Residential areas contributed more NPS pollutants than did roads, which played a tremendous role in the control of urban NPS. The results also suggested in part that the impact of urban sprawl on the variation of COD decreased while TN increased in Beijing during the study period. These results would provide insight into the impacts of urban sprawl on NPS variation over a long period, as well as the reference for reasonable urban planning directives.


Assuntos
Planejamento de Cidades , Monitoramento Ambiental/métodos , Poluição Difusa/análise , Urbanização , Pequim
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