Assessment of the Environmental Risk of Pesticides Leaching at the Watershed Scale under Arid Climatic Conditions and Low Recharge Rates

The assessment of the vulnerability of soil and groundwater resources to pesticide contamination is important to reduce the risk of environmental pollution. The applicability of the expanded attenuation factor (EAF) to assess leaching potential of 30 pesticides was investigated under four recharge rates (0.0003–0.002 m d−1) in the arid environment of the Jazan watershed. EAF results revealed that Picloram, Carbofuran, Monocrotophos, and 2,4-D pesticides showed high leaching potential, mainly because of their low K O C , and relatively longer t 1 / 2 . In addition, medium leaching potential was observed with six more pesticides (Atrazine, Aldicarb, Simazine, Methomyl, Oxamyl, and Lindane). Regardless of the recharge rate, all other pesticides showed a very low leaching potential in the Jazan watershed. Sensitivity analysis revealed that the output of the EAF index is most sensitive to the fraction of organic carbon ( f o c ) , water content at field capacity ( θ F C ) , recharge rate ( q ) , and partition coefficient ( K O C ) , and least sensitive to soil bulk density ( ρ b ) and air-filled porosity ( n a ). The areal extent of areas with larger leaching potential in the Jazan watershed was consistent with soils having f o c < 0.3, θ F C > 10 m3 m−3, and ρ b < 1450 kg m−3, and were mostly associated with the loamy sand soils, followed by the sand and silt loam soils. EAF index model performed well in assessing relative rankings of leaching potential and delineating areas that are more susceptible to pesticide leaching. At the lowest recharge rate, general risk maps showed that the risk of leaching potential was very low for all pesticides in the entire area of the Jazan watershed. On the other hand, under the worst case scenario (0.002 m d−1), only Picloram and Carbofuran showed very high leaching potential in areas that represented 10.8 and 8.2% from the total area of the Jazan watershed, respectively. The information gained from this research can help farmers and decision-makers to implement regulations and best management practices to reduce the risk of environmental pollution, and protect soil and groundwater resources in Jazan watershed.

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Modeling the impact of nitrate fertilizers on groundwater quality in the southern part of the Nile Delta, Egypt

Water Science & Technology Water Supply ◽

10.2166/ws.2016.162 ◽

2016 ◽

Vol 17 (2) ◽

pp. 561-570 ◽

Cited By ~ 6

Author(s):

Mohamed Galal Eltarabily ◽

Abdelazim M. Negm ◽

Chihiro Yoshimura ◽

Oliver C. Saavedra

Keyword(s):

Groundwater Contamination ◽

Nitrogen Fertilizer ◽

Best Management Practices ◽

Management Practices ◽

Groundwater Modeling ◽

Nile Delta ◽

Groundwater Resources ◽

Shallow Groundwater ◽

Water Source ◽

The Impact

The use of fertilizers in agriculture in Egypt, especially nitrogen, has increased significantly in the last decade, resulting in nonpoint contamination of the groundwater resources. This study investigated the effect of using nitrogen fertilizer on groundwater contamination with nitrate in the central southern part of the Nile Delta. NO3− concentrations in shallow groundwater were assessed based on the applied urea dose (the common nitrogen fertilizer used) in year 2014. A groundwater modeling system (GMS) comprising MODFLOW and MT3D was used to simulate the three-dimensional groundwater flow and NO3− transportation processes in El-Menoufia Governorate, located in the central region of the Nile Delta aquifer. Calibration for MODFLOW was conducted to match known head configurations to minimize the water balance differences. Calibration of MT3D was accomplished by fitting the model to the measured NO3− concentrations during the year 2014. The results highlighted areas of groundwater contamination by NO3−, which occurred at shallow depths (40 m) due to the significant loads of nitrogen fertilizer application and the flood irrigation method. While the results suggested one approach was to avoid using contaminated shallow groundwater as a water source, a more sustainable approach would be to implement best management practices to reduce and control the amount of nitrate leaching into the shallow groundwater system in the future.

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Determination of solute leaching potential within a hummocky agricultural landscape

Canadian Journal of Soil Science ◽

10.4141/cjss07018 ◽

2007 ◽

Vol 87 (5) ◽

pp. 541-549 ◽

Cited By ~ 5

Author(s):

J. Thibodeau ◽

L G Fuller ◽

D S Chanasyk

Keyword(s):

Best Management Practices ◽

Management Practices ◽

Agricultural Landscape ◽

Soil Classification ◽

Agricultural Landscapes ◽

Water Soluble ◽

Soil Horizon ◽

Leaching Potential ◽

Potential Index ◽

Curvature Measurements

Leaching of water-soluble contaminants has resulted in degradation of groundwater quality. This research project examined the long-term spatial variability of leaching processes within two hummocky, agricultural landscapes near Bittern Lake, in central Alberta. Analysing the distribution of soil profiles within a landscape, we created a leaching potential index based on a soil profile index (SPI) and plan curvature measurements. The index accurately differentiated locations of very high and high leaching potential from low and very low leaching potential. This index may become a useful tool to determine the variability of leaching within an agricultural landscape, to identify areas of high leaching potential, to determine agricultural best management practices, and to minimize contamination of groundwater. Key words: Soil-landscape, soil horizon, soil classification, sulphate, electrical conductivity, leaching

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Assessment of groundwater resource vulnerability to over-exploitation in a tropical, agricultural basin

10.5194/egusphere-egu2020-12951 ◽

2020 ◽

Author(s):

Okke Batelaan ◽

Daniel Partington ◽

Manh Hai Vu ◽

Margaret Shanafield

Keyword(s):

Land Use ◽

Local Knowledge ◽

Best Management Practices ◽

Management Practices ◽

Groundwater Resources ◽

Groundwater Resource ◽

Balance Model ◽

Groundwater Extraction ◽

Groundwater Levels ◽

Basin Scale

<p>In many parts of the world, groundwater extraction for agriculture is strongly increasing, causing severe stress on groundwater resources and associated ecosystems. Understanding how groundwater flow systems support extractions is therefore essential. However, particularly in developing, rural, tropical regions, monitoring of groundwater levels, chemistry and extractions is poorly regulated, resulting in a lack of data. Hence, alternative approaches are necessary to develop best management practices in these groundwater basins. In this study, catchment-scale groundwater extraction is indirectly estimated by two &#8220;soft data&#8221; approaches: (1) using local knowledge through a qualitative field survey of groundwater level fluctuations and groundwater withdrawals; and (2) land-use/population data combined with local knowledge on cropping/water use practices. Spatially distributed recharge is simulated on the basis of a monthly water balance model, which requires widely available topographic, soil, land-use and meteorological data. Extractions and recharge force a simple, basin-scale groundwater model for assessment of impact of irrigation practices. Agricultural scenarios are developed and modelling procedures are designed to test the temporal and spatial vulnerability over a 100 yr time span of the groundwater resource. The approaches are tested and applied for the agricultural La Vi River basin, Vietnam, where the livelihood of the local farmers requires development of new agricultural and hydrological techniques. The typical cash-crops are cultivated on sandy soils and irrigated in the dry season from thousands of private shallow wells. The tropical climate and strong seasonal rainfall pattern produces a strong fluctuation in groundwater levels. The modelling shows significant spatio-temporal unmet pumping demand dependent on the agricultural development scenario, indicating the need and opportunity for planning of groundwater based irrigation development. Overall, the multi-method comprehensive approach supports basin-scale sustainable groundwater resource development and only requires relatively easily accessible data.</p>

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Homeowner Best Management Practices for the Home Lawn

EDIS ◽

10.32473/edis-ep236-2009 ◽

2009 ◽

Vol 2009 (5) ◽

Author(s):

Laurie E. Trenholm

Keyword(s):

Best Management Practices ◽

Management Practices ◽

Groundwater Resources ◽

Fact Sheet ◽

Best Management

Revised! ENH-979, a 5-page illustrated fact sheet by Laurie E. Trenholm, provides easy-to-follow tips for maintaining a healthy, Florida-Friendly lawn without polluting surface or groundwater resources. Published by the UF Department of Environmental Horticulture, June 2009. ENH979/EP236: Homeowner Best Management Practices for the Home Lawn (ufl.edu)

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