قارن الطرق

	نمذجة تلوث المياه الجوفية	تحديد الأنواع الكيميائية للمعادن الثقيلة
المجال	الهندسة البيئية	الهندسة البيئية
العائلة	Process / pipeline	Process / pipeline
سنة النشأة	1988	1979
صاحب الطريقة	USGS and hydrogeology researchers	Tessier and hydrogeochemists
النوع	numerical simulation pipeline	analytical and geochemical modeling pipeline
المصدر التأسيسي	Fetter, C. W., Boving, T. B., & Kreamer, D. K. (2018). Contaminant Hydrogeology (3rd ed.). Waveland Press. ISBN: 978-1478625315	Tessier, A., Campbell, P. G. C., & Bisson, M. (1979). Sequential Extraction Procedure for the Speciation of Particulate Trace Metals. Analytical Chemistry, 51(7), 844–851.
الأسماء البديلة	groundwater transport, contaminant plume modeling, subsurface flow and transport, GWHC modeling	metal speciation, metal partitioning, bioavailability assessment, speciation analysis
ذات صلة	3	3
الملخص	Groundwater contamination modeling is a quantitative approach to predict the migration of dissolved and suspended contaminants (chemical spills, landfill leachate, petroleum, radionuclides) through subsurface aquifers and toward receptors (drinking water wells, surface water bodies, ecosystems). Developed systematically in the 1980s–1990s by the USGS and hydrogeologists, these models couple flow equations (Darcy's law) with advection-dispersion transport and geochemical reactions to forecast contaminant arrival times and plume extent.	Heavy metal speciation is the analytical and geochemical determination of the chemical forms (species) and partitioning of toxic metals (lead, cadmium, chromium, zinc, copper) in soil, sediment, and water. Metal bioavailability—the fraction accessible to organisms—depends critically on speciation: metal bound to soil organic matter or iron oxides is immobile and non-bioavailable; dissolved or exchangeable metal is highly bioavailable and toxic. Speciation assessment informs remediation design, risk assessment, and contaminant fate prediction.