Distribution of arsenic in shallow aquifers of Guangzhou region, China: natural and anthropogenic impacts

2014 ◽  
Vol 49 (4) ◽  
pp. 354-371 ◽  
Author(s):  
Fan Liu ◽  
Guanxing Huang ◽  
Jichao Sun ◽  
Jihong Jing ◽  
Ying Zhang

To elucidate the distribution of arsenic in shallow aquifers of the Guangzhou region (South China), 85 groundwater samples were collected and 18 chemical parameters of them were analyzed. The arsenic concentration of groundwater ranged from below detection limit to 0.13 mg/L. The results showed that those areas with high arsenic concentration were characterized by porous aquifers, low-lying, relief topography and close proximity to fault belt and rivers. The reductive dissolution of Fe (hydr)oxides is the main control mechanism for arsenic enrichment in the river delta region where groundwater is mainly characterized by a reducing environment. This mechanism was well embodied in the areas with these geological and geographical features. Agricultural fertilizer could produce high levels of nitrate in groundwater and the reduction of it could restrain the enrichment of arsenic. Industrial effluents, sewage irrigation and the probable leakage from sewers could promote the arsenic content in groundwater by lateral flow and infiltration. In addition, the effect of ion competition between phosphate and arsenic occurred in sewer leakage areas characterized by middle-high construction leading to the elevation of arsenic concentrations. The arsenic distribution in groundwater was caused by these natural and anthropogenic factors jointly.

2021 ◽  
Vol 63 (11) ◽  
pp. 19-23
Author(s):  
Thi Duyen Vu ◽  
◽  
Thi Mai Tran ◽  
Thi Kim Trang Pham ◽  
Mai Lan Vi ◽  
...  

Arsenic contamination in groundwater is commonly found in alluvial plains of major river basins, in which the Red river delta has also been reported to be contaminated with high levels of arsenic. In this study, groundwater from 50 household wells was collected to study the spatial distribution of arsenic in northwestern Hanoi. The results showed that arsenic concentration in groundwater varied in a wide range of less than 5 to 334 μg/l, of which up 62% of the wells exceeded the WHO guideline value of 10 μg/l for arsenic content in drinking water. Arsenic groundwater in this area is unevenly distributed throughout the area, high arsenic concentrations are found in a narrow band between Red river and Day river. This pattern of arsenic distribution is strongly related to the sediment age, sedimentary processes, and it is also modified by local groundwater flow parts and the occurrence of hydraulic connection between aquifers, which are observed in the study area. Arsenic is released into the groundwater during the reductive dissolution of arsenic-bearing minerals under the presence of organic matter.


Author(s):  
M. I. Dzhalalova ◽  
A. B. Biarslanov ◽  
D. B. Asgerova

The state of plant communities in areas located in the Tersko-Sulak lowland was studied by assessing phytocenotic indicators: the structure of vegetation cover, projective cover, species diversity, species abundance and elevated production, as well as automated decoding methods. There are almost no virgin soils and natural phytocenoses here; all of them have been transformed into agrocenoses (irrigated arable lands and hayfields, rice-trees and pastures). The long-term impact on pasture ecosystems of natural and anthropogenic factors leads to significant changes in the indigenous communities of this region. Phytocenoses are formed mainly by dry-steppe types of cereals with the participation of feather grass, forbs and ephemera, a semi-desert haloxerophytic shrub - Taurida wormwood. At the base of the grass stand is common coastal wormwood and Taurida wormwood - species resistant to anthropogenic influences. Anthropogenic impacts have led to a decrease in the number of species of feed-rich grain crops and a decrease in the overall productivity of pastures. Plant communities in all areas are littered with ruderal species. The seasonal dynamics of the land cover of the sites was estimated by the methods of automatic decoding of satellite images of the Landsat8 OLI series satellite for 2015, dated by the periods: spring - May 20, summer - July 23, autumn - October 20. Satellite imagery data obtained by Landsat satellite with a resolution in the multispectral image of 30 m per pixel, and in the panchromatic image - 10 m per pixel, which correspond to the requirements for satellite imagery to assess the dynamics of soil and vegetation cover. Lower resolution data, for example, NDVI MODIS, does not provide a reliable reflection of the state of soil and vegetation cover under arid conditions. In this regard, remote sensing data obtained from the Internet resource https://earthexplorer.usgs.gov/ was used.


2019 ◽  
Vol 70 (7) ◽  
pp. 2330-2334
Author(s):  
Mihaela Ciopec ◽  
Adina Negrea ◽  
Narcis Duteanu ◽  
Corneliu Mircea Davidescu ◽  
Iosif Hulka ◽  
...  

Arsenic content in groundwater�s present a wide range of concentration, ranging from hundreds of micrograms to thousands of micrograms of arsenic per litter, while the maximum permitted arsenic concentration established by World Health Organization (WHO) is 10 mg L-1. According to the WHO all people, regardless of their stage of development and their social economic condition, have the right to have access to adequate drinking water. The most efficient and economic technique used for arsenic removal is represented by adsorption. In order to make this remediation technique more affordable and environmentally friendly is important to new materials with advance adsorbent properties. Novelty of present paper is represented by the usage of a new adsorbent material obtained by physical - chemical modification of Amberlite XAD polymers using crown ethers followed by iron doping, due to well-known affinity of arsenic for iron ions. Present paper aims to test the obtained modified Amberlite polymer for arsenic removal from real groundwater by using adsorption in a fixed bed column, establishing in this way a mechanism for the adsorption process. During experimental work was studied the influence of competing ions from real water into the arsenic adsorption process.


2015 ◽  
Vol 12 (2) ◽  
pp. 74-82 ◽  
Author(s):  
Md. Habibur Rahman ◽  
Md. Mohashin Farazi ◽  
Kohinoor Begum ◽  
Md. Serazul Islam

Rice (Oryza sativa L.) is one of the major food crops in many countries. As the cultivation of rice requires huge volume of water, long term use of Arsenic contaminated groundwater for irrigation may result in the increase of arsenic concentration in the agricultural soil and eventually accumulation in rice grains. A micro level study was conducted to investigate the transfer of arsenic from irrigation water and soil to rice plants in the arsenic affected 8 unions of Chandina upazilla, Comilla district. The level of arsenic in irrigation water (0.12±0.08 and 0.67±0.07 mg l-1) was much above the WHO permissible limit of 0.01 mg l-1 for drinking water and FAO permissible limit of 0.10 mg l-1 for irrigation water. The total soil arsenic concentrations ranged from 3.21±0.80 to 8.74±2.83 mg kg-1 dry weight of soil, which was below the maximum acceptable limit for agricultural soil of 20.0 mg kg-1 as recommended by the European Community. The accumulation of arsenic in the grain ranged from 0.12±0.04 to 0.58±0.06 mg kg-1 in Boro and 0.16±0.04 to 1.06±0.20 mg kg-1 in T. Aman. Except grain sample (T. Aman) of one union, the grains in both Boro and T. Aman of all unions did not exceed 1.0 mg kg-1 dry weight of arsenic (the permissible limit of arsenic in rice according to WHO recommendation). Thus, till now rice has remained harmless for consumption in the study area. The results clearly showed that the arsenic content in the grains of Boro rice is correlated to the intensity of arsenic contamination of irrigation water and soil. The Agriculturists 2014; 12(2) 74-82


2017 ◽  
Vol 7 (1) ◽  
pp. 105-111
Author(s):  
Jay Narayan Shrestha

The anthropogenic impact on Keshalia river, especially on fish diversity, is very high. Over fishing with unconventional fishing methods, disposal of domestic and industrial effluents, excess use of pesticides, dumping sites of municipalities, dam construction without fish ladder across the river and mining of sands and gravels are major anthropogenic impacts on the river.


Water Policy ◽  
2009 ◽  
Vol 11 (3) ◽  
pp. 362-378 ◽  
Author(s):  
N. Nahar

In attempting to eliminate disease caused by drinking polluted surface water, millions of tube-wells were drilled in Bangladesh. However, owing to arsenic in groundwater, the availability of safe drinking water has declined from earlier achievement of 97% to 51.2%. This article reviews the causes and distribution of arsenic concentration in rural Bangladesh from a wide variety of literature. Scientists have converged to two hypotheses for causes of arsenic in groundwater: the pyrite oxidation hypothesis and the oxy-hydroxide reduction hypothesis. There is a positive correlation between arsenic content in irrigated groundwater and arsenic contained in soils. There is a significant presence of arsenic in rice and leafy vegetables. Today, arsenic is causing toxicity to human health and creating major social problems. This finding implies that, had there been a precautionary measure taken when a new technology tube-well was being introduced, in the form of testing water for harmful metals, the risk that the rural population is facing now could have been drastically reduced. This lack of precautionary measure, before starting a mass installation of tube-wells for drinking and irrigation should be seen as a “human error” and avoided in future water policy and planning.


2021 ◽  
Vol 1 (2) ◽  
pp. 50-58
Author(s):  
Ikenna Uzonu

This work examined the effects of industrial effluents on surface water used for vegetable irrigation in Kano City of Kano State. As the population of Kano increases, more demand is placed on these industries for products thus leading to the generation of large volumes of effluents that are discharged directly into nearby streams without treatment. The usage of this surface water for vegetable irrigation by a significant number of vegetable farmers is a matter of major concern due to the presence of pollutants. Some of the field measurements were carried out insitu while others were taken to the laboratory for analysis. Groundwater samples were taken from a borehole and two hand-dug wells while surface water was taken from point of discharge and two other points along the Challawa River which is the main source of water for vegetable irrigation. Composite soil samples were taken from four points within the vegetable farms. The Federal Environmental Protection Agency and the Federal Ministry of Environment standards were used as baseline standards for limits. Results show that presence of Fe, Pb, Mn, Cr and Cd were found to be above the FMEnv limits in the soil, the presence of SO4, Cu and K were also found to be above the FMEnv limits as well in groundwater while BOD, NO2 and Cr were above the FEPA limit for surface water. Some of the recommendations include constant monitoring for the presence of heavy metals in soils and irrigation water and that the need for the construction of both primary and secondary treatment plants has become essential.


2005 ◽  
Vol 5 ◽  
pp. 646-651 ◽  
Author(s):  
Dilip Kumar Das ◽  
T. K. Garai ◽  
S. Sarkar ◽  
Pintu Sur

A laboratory experiment on an Inceptisol with pH 7.6, organic carbon 6.8 g kg–1, and 0.5MNaHCO3extractable arsenic 0.4 mg kg–1was conducted to study the interaction effect of graded levels of arsenic (0, 5, and 10 mg kg–1) with zinc (0, 10, and 20 mg kg–1) and organics (0, 1, and 2% on soil weight basis) separately on the mobilization of arsenic in soils.The results show that the amount of 0.5MNaHCO3extractable arsenic at pH 8.5 increased with the progress of submergence up to 35 days. However, the increase in arsenic concentration was correlated with decreasing application of graded levels of Zn as zinc sulfate. The intensity of reduction varied with varying levels of Zn, being higher (0.73–2.72 mg kg–1) in the treatment where Zn was at 10 mg kg–1and lower (0.70–1.08 mg kg–1) with Zn at 20 mg kg–1application.The amount of arsenic content in the soil significantly decreased with the application of varying levels of organics. However, such depressive effect was found more pronounced with well-decomposed farm yard manure than that of vermicompost. The results of field experiments showed that the grain yield between continuous flooding (4.84 t ha–1) and intermittent flooding up to 40 days after transplanting then continuous flooding (4.83 t ha–1) with the application of ZnSO4at 25 kg ha–1did not vary. The lowest grain yield (3.65 t ha–1) was recorded in the treatment where intermittent flooding was maintained throughout the growth period without the application of Zn. The amount of arsenic content was, however, recorded much lower in the treatment where intermittent flooding throughout the growth period was maintained with ZnSO4.


2016 ◽  
Vol 28 (4) ◽  
pp. 305-312 ◽  
Author(s):  
Hua Rong ◽  
Hou Shugui ◽  
Li Yuansheng ◽  
Pang Hongxi ◽  
Paul Mayewski ◽  
...  

AbstractThis study presents an arsenic concentration time series from 1964–2009 at Dome Argus, Antarctica. The data show a very large increase in arsenic concentration from the mid-1980s to the late-1990s (by a factor of~22) compared with the values before the mid-1980s. This increase is likely to be related to the increased copper smelting in South America. Arsenic concentration then decreased in the late-1990s, most probably as a result of environmental regulations in South America. The sudden increase in arsenic concentration observed at Dome Argus coincides with similar increases observed at Dome Fuji and in Antarctica Ice Core-6 (IC-6) at the same time, suggesting that arsenic pollution during the period from the mid-1980s to the late-1990s was a regional phenomenon in Antarctica. Investigations of arsenic concentrations at these three Antarctic locations show that, during this time, regional arsenic distribution followed dust transport pathways associated with general climate models with South America as a major source region for the half of Antarctica facing the Atlantic and Indian oceans.


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