Groundwater Pollution Prevention and Control Assessment in the Beijing-Tianjin-Hebei Region

Groundwater is the lifeline of the Beijing-Tianjin-Hebei region, supplying a substantial share of municipal, industrial, and agricultural water demand across northern China. This article presents a professional technical overview of groundwater pollution prevention and control assessment in the region, covering the regulatory framework, sampling design, testing parameters, analytical methods, and evaluation workflows. It is intended for environmental consultants, industrial operators, and regulatory professionals involved in groundwater protection, site investigation, and remediation projects.

Technical Overview

The Beijing-Tianjin-Hebei region, situated on the eastern North China Plain and the adjacent foothill and coastal zones of the Haihe River Basin, relies on groundwater for more than half of its total water supply. Decades of intensive abstraction have produced one of the largest groundwater depression cones in the world, triggering land subsidence, aquitard compaction, and seawater intrusion along the Bohai coastal belt of Tianjin and eastern Hebei. At the same time, shallow Quaternary aquifers are widely affected by nitrate and ammonia nitrogen from agricultural non-point sources, heavy metals and organic contaminants from legacy industrial sites, chemical parks, gas stations, and landfills. Groundwater pollution prevention and control assessment therefore combines water quality evaluation, source identification, vulnerability analysis, and human health risk assessment into an integrated decision-support process.

The assessment is anchored in national policy instruments, including the Water Pollution Prevention and Control Action Plan, the Groundwater Pollution Prevention and Control Implementation Plan, the Groundwater Management Regulation issued by the State Council, and the groundwater quality objectives of the 14th Five-Year Plan period. Within the region, assessments typically follow the dual-source supervision model, which targets both centralized groundwater drinking water sources and key pollution sources such as industrial enterprises, hazardous waste disposal facilities, landfills, and mining areas.

Assessment Objectives

• Establish baseline groundwater quality conditions and long-term trends for shallow and deep aquifers.
• Classify groundwater quality against the national groundwater quality standard and identify exceedance indicators.
• Identify, score, and rank potential pollution sources and their release pathways.
• Delineate contaminant plumes in three dimensions and evaluate migration behavior.
• Quantify carcinogenic and non-carcinogenic health risks for exposed populations.
• Support remediation design, risk control zoning, and post-remediation effectiveness verification.

Regulatory and Technical Basis

• GB/T 14848-2017, Groundwater Quality Standard, which defines 93 indicators and five quality classes.
• HJ 164-2020, Technical Specification for Groundwater Environmental Monitoring, governing well layout, sampling, and preservation.
• HJ 25.1-2019, HJ 25.2-2019, and HJ 25.3-2019, covering site investigation, monitoring, and risk assessment for development land.
• The Groundwater Management Regulation, which mandates pollution investigation, risk zoning, and source control obligations.
• National and industry standards for monitoring well drilling, well completion, and hydrogeological testing.

Testing Samples

Groundwater Samples

Groundwater is collected from newly installed monitoring wells screened at targeted depth intervals, typically the shallow unconfined aquifer within 30 to 60 meters for near-surface contamination screening, and deeper confined aquifers used for water supply. Existing municipal supply wells, industrial production wells, agricultural irrigation wells, and domestic wells are also sampled to map regional quality conditions. Multi-level monitoring clusters are used where vertical leakage between aquifers is suspected.

Soil and Vadose Zone Samples

Continuous borehole cores are recovered to characterize lithology, hydraulic conductivity, and organic carbon content, which control contaminant retardation and migration. Soil samples from suspected source zones are analyzed to define the vertical and lateral extent of contamination and to construct conceptual site models.

Source and Ancillary Samples

Depending on the site, sampling may include industrial wastewater, landfill leachate, treatment sludge, free-phase product, sediments from recharge channels, and hydraulically connected surface water. These samples confirm source signatures and support source-pathway-receptor analysis.

Testing Items

Testing portfolios are configured according to GB/T 14848-2017 and the sensitivity of nearby receptors, and typically comprise the following groups.

Routine Physicochemical Indicators

These include pH, turbidity, total dissolved solids, total hardness, sulfate, chloride, iron, manganese, permanganate index, ammonia nitrogen, fluoride, nitrate, nitrite, and dissolved solids balance parameters, reflecting the 39 routine indicators of the national standard.

Inorganic and Toxicological Indicators

Heavy metals and metalloids such as arsenic, cadmium, lead, mercury, selenium, hexavalent chromium, copper, zinc, nickel, and aluminum are quantified, together with cyanide and iodide, which are regionally relevant in the North China Plain.

Organic Indicators

Volatile organic compounds include benzene, toluene, ethylbenzene, xylenes, chloroform, carbon tetrachloride, trichloroethylene, and tetrachloroethylene. Semi-volatile compounds include polycyclic aromatic hydrocarbons, phenols, phthalate esters, nitrobenzenes, and anilines. Organochlorine pesticides, total petroleum hydrocarbons, and emerging contaminants such as per- and polyfluoroalkyl substances are added where source history warrants.

Microbiological and Supplementary Indicators

Total coliforms and fecal coliforms are tested for sources influenced by sewage. Stable isotopes of hydrogen, oxygen, and nitrogen, along with hydrochemical facies analysis, are applied to distinguish geogenic background from anthropogenic inputs and to trace nitrate origins.

Testing Methods

Field Sampling and On-Site Measurement

Sampling follows HJ 164-2020 using low-flow purging with minimal drawdown, typically below 0.3 liters per minute, until turbidity and field parameters stabilize over consecutive readings. Field measurements cover pH, electrical conductivity, dissolved oxygen, oxidation-reduction potential, turbidity, and temperature. Samples for dissolved metals are filtered through 0.45 micrometer membranes, preserved with appropriate reagents, held at 4 degrees Celsius, and transported under strict chain-of-custody procedures within method-specified holding times.

Laboratory Analytical Techniques

• Metals and metalloids by inductively coupled plasma mass spectrometry in accordance with HJ 700-2014.
• Anions such as sulfate, chloride, nitrate, and fluoride by ion chromatography in accordance with HJ 84-2016.
• Ammonia nitrogen by salicylate spectrophotometry in accordance with HJ 535-2009.
• Volatile organic compounds by purge-and-trap gas chromatography-mass spectrometry in accordance with HJ 639-2012.
• Semi-volatile organic compounds by gas chromatography-mass spectrometry or high-performance liquid chromatography following validated national methods.
• Hexavalent chromium by diphenylcarbohydrazide spectrophotometry, and petroleum hydrocarbons by gas chromatography with flame ionization detection.
• Microbiological indicators by membrane filtration or enzyme substrate techniques, and isotope ratios by isotope ratio mass spectrometry.

Quality Assurance and Data Validation

• All analyses performed by laboratories accredited under CMA and CNAS schemes.
• Field quality control comprising trip blanks, field blanks, equipment rinsates, and duplicate samples at no less than 10 percent frequency.
• Laboratory quality control with method blanks, matrix spikes, certified reference materials, and calibration verification.
• Method detection limits set below the most stringent evaluation thresholds of GB/T 14848-2017.
• Systematic data validation covering holding times, blank contamination, recoveries, and duplicate precision before reporting.

Assessment and Modeling Techniques

Water quality is classified using single-factor evaluation complemented by comprehensive index methods. Intrinsic vulnerability is mapped with the DRASTIC model, which is overlaid with source hazard scores to generate pollution risk zoning. Groundwater flow and solute transport models, commonly built on MODFLOW and MT3DMS platforms, are calibrated against observed heads and concentrations to predict plume evolution. Health risk assessment follows the source-pathway-receptor paradigm, quantifying ingestion and dermal exposure risks with acceptable carcinogenic risk generally between 1E-06 and 1E-04 and hazard quotients not exceeding 1.

Applications

• Compliance assessment and source registration for key pollution sources under regional groundwater supervision programs.
• Safety evaluation and protection zone refinement for centralized groundwater drinking water sources.
• Environmental due diligence and brownfield investigation for land redevelopment along Beijing-Tianjin and Beijing-Hebei industrial corridors.
• Baseline definition and remediation effectiveness verification for contaminated plumes at chemical plants, chrome slag sites, and fuel storage facilities.
• Environmental performance monitoring for municipal landfills and hazardous waste disposal sites.
• Diagnostic studies of agricultural nitrate non-point source pollution and managed recharge water quality control.
• Integration of water level and water quality monitoring to support regional over-abstraction control and ecological restoration targets.
• Data support for regional pollution prevention zoning maps and digital groundwater management platforms.

FAQ

What do the five quality classes in GB/T 14848-2017 mean?

Class I and Class II reflect natural background conditions. Class III is suitable for centralized drinking water supply and is the key compliance benchmark. Class IV is suitable for agricultural and certain industrial uses with appropriate treatment. Class V is unsuitable for direct use and indicates serious degradation requiring management intervention.

Which aquifers in the region are most vulnerable to pollution?

The shallow unconfined Quaternary aquifer is the most vulnerable because it receives direct recharge from precipitation and irrigation return flow. Long-term over-abstraction of deep aquifers can also increase vulnerability by inducing downward leakage through weakened aquitards, which is why multi-level monitoring is recommended.

How many monitoring wells are required for a typical source site?

For a single pollution source, a common minimum configuration is one upgradient well and at least two downgradient wells, with additional wells added based on plume geometry, hydrogeological heterogeneity, and receptor proximity. Regional assessments use grid-based or stratified layouts combined with existing national monitoring network wells.

How frequently should groundwater be sampled?

Routine monitoring is generally quarterly or semi-annual, while drinking water sources may require monthly sampling. Remediation projects often require monthly or event-based sampling to track performance, and at least one full seasonal cycle is recommended for baseline characterization.

How is geogenic background distinguished from anthropogenic pollution?

Regionally elevated iron, manganese, fluoride, arsenic, and total dissolved solids often reflect natural hydrogeochemical conditions. Statistical baseline analysis, hydrochemical facies evaluation, vertical concentration profiling, and isotope tracing are combined to separate natural enrichment from contamination attributable to human activities.

What deliverables does an assessment typically produce?

Core deliverables include an investigation report with hydrogeological characterization, a laboratory data package with full quality control records, a water quality assessment report, a human health and environmental risk assessment, a monitoring plan, and where required, a remediation or risk control proposal.

How long does a complete assessment take?

A phased initial screening with existing wells can often be completed within one to three months. A detailed assessment involving well installation, seasonal sampling rounds, laboratory analysis, modeling, and risk evaluation typically requires six to twelve months, depending on site complexity.