Beijing-Tianjin-Hebei Soil Remediation Risk Control Testing: Standards, Samples, Methods and Applica

Beijing-Tianjin-Hebei soil remediation risk control testing provides the analytical foundation for investigating, assessing, and closing out contaminated land projects across China's most intensively redeveloped industrial region. Guided by GB 36600-2018 and the HJ 25 technical guideline series, accredited laboratories deliver defensible data for site investigation, risk assessment, remediation design, effect evaluation, and regulatory acceptance. This article explains the sample types, testing items, analytical methods, and applications that underpin soil and groundwater compliance for development land and agricultural land in the Jing-Jin-Ji region.

Technical Overview

The Beijing-Tianjin-Hebei region (Jing-Jin-Ji) concentrates decades of iron and steel production, coking, petrochemical refining, electroplating, pesticide manufacturing, and gasworks operation. Under the national coordinated development strategy, large-scale enterprise relocation, steel capacity reduction, and urban renewal have transferred extensive tracts of former industrial land into residential and commercial use. As a result, soil pollution investigation, risk assessment, risk control, remediation, and effect evaluation have become regulatory preconditions for land redevelopment throughout the region.

The legal framework rests on the Soil Pollution Prevention and Control Action Plan (2016) and the Soil Pollution Prevention and Control Law of the People's Republic of China, effective January 1, 2019. Any change of land use toward sensitive development on suspect land requires a soil pollution status investigation. Where unacceptable risk is confirmed, risk control or remediation must be completed and its effect evaluated and filed with the local ecological environment authority before the land enters the supply market or construction begins. Third-party testing supplies the quantitative basis at every stage of this lifecycle.

• GB 36600-2018: Soil environmental quality - Risk control standard for soil contamination of development land, establishing screening values and intervention values for 85 indicators under Category I (sensitive) and Category II (non-sensitive) land uses
• GB 15618-2018: Risk control standard for soil contamination of agricultural land, with screening and control values for basic and other contaminants
• HJ 25.1-2019, HJ 25.2-2019, HJ 25.3-2019 and HJ 25.4-2019: Technical guidelines for site investigation, risk assessment, risk control and remediation, and effect evaluation of development land
• HJ 25.5-2018: Technical guideline for risk control and remediation of agricultural land
• HJ/T 166-2004 and HJ 164-2020: Technical specifications for soil and groundwater environmental monitoring
• GB/T 14848-2017: Groundwater quality standard used to interpret monitoring well data
• HJ 1019-2019: Technical specification for self-monitoring of soil and groundwater by key industrial enterprises

The decision logic is value-driven. Where contaminant concentrations fall below the GB 36600 screening values, risk is generally acceptable and the investigation may conclude. Where concentrations lie between screening and intervention values, a site-specific human health risk assessment under HJ 25.2 is performed to derive remediation target values. Where concentrations exceed intervention values, risk control or remediation is generally mandatory. Testing laboratories therefore support investigators, remediation contractors, environmental consultants, and regulators from initial screening through acceptance and long-term monitoring.

Testing Samples

Soil Samples

Soil sampling programs combine judgmental placement at former process areas, tanks, drains, and storage zones with systematic grid coverage. Under HJ 25.1-2019, preliminary investigation typically applies grids no larger than 40 m x 40 m (1,600 square meters per point), while detailed investigation densifies to 20 m x 20 m (400 square meters per point), adjusted according to the conceptual site model. Sample types include:

• Surface grab samples from 0 to 0.5 m for human contact and inhalation exposure assessment
• Subsurface interval samples from boreholes advanced through fill and native strata until unaffected horizons are documented
• Undisturbed core subsamples for volatile organic compounds, collected rapidly with syringes or EnCore-type samplers, sealed without headspace, and preserved at 4 degrees Celsius in the dark
• Split portions for metals, semi-volatiles, and physical-chemical parameters, with lithological logging of every core

Groundwater Samples

Monitoring wells are designed and installed in accordance with HJ 164-2020, with screens positioned to intersect the water table so that light non-aqueous phase liquids can be detected. Low-flow, minimal-drawdown purging is applied until field parameters such as pH, electrical conductivity, dissolved oxygen, oxidation-reduction potential, turbidity, and temperature stabilize. Filtered and unfiltered aliquots are preserved appropriately, including nitric acid acidification for dissolved metals and chilled zero-headspace vials for volatile organics.

Soil Gas and Indoor Air Samples

Temporary probes, permanent soil gas points, and sub-slab vapor installations support vapor intrusion pathway evaluation, particularly where chlorinated solvents or petroleum hydrocarbons are present beneath or adjacent to existing or planned buildings. Paired sub-slab, indoor air, and outdoor air samples allow background correction in risk assessments.

Backfill Soil, Solid Waste, and Remediation Byproducts

Imported backfill soil is verified against GB 36600 screening values before placement. Solidified or stabilized monoliths are tested for unconfined compressive strength and leachability using HJ/T 299 (sulfuric and nitric acid extraction) or HJ 557 (horizontal vibration method). Excavated spoil destined for off-site management is classified against the GB 5085 hazardous waste identification standards.

Testing Items

The default analytical scope mirrors the 45 basic items of GB 36600-2018 and is expanded with site-specific indicators derived from historical process review, raw material and product inventories, and preliminary screening data.

Heavy Metals and Inorganic Contaminants

Basic items include arsenic, cadmium, chromium(VI), copper, lead, mercury, and nickel. Depending on site history, the scope extends to antimony, beryllium, cobalt, molybdenum, zinc, thallium, manganese, vanadium, selenium, total chromium, fluoride, and total and easily-released cyanide, the latter being critical for former gasworks, coking, and metallurgical sites common in the region.

Volatile Organic Compounds

The 27 basic VOCs cover benzene, toluene, ethylbenzene, xylenes, and styrene, along with chlorinated solvents frequently encountered at chemical and electronics sites, including vinyl chloride, cis- and trans-1,2-dichloroethene, trichloroethene, tetrachloroethene, 1,1- and 1,2-dichloroethane, 1,1,1- and 1,1,2-trichloroethane, methylene chloride, chloroform, carbon tetrachloride, chlorobenzene, dichlorobenzenes, and dichloropropane.

Semi-Volatile Organic Compounds and Other Organics

Basic SVOCs include nitrobenzene, aniline, 2-chlorophenol, naphthalene, and the carcinogenic polycyclic aromatic hydrocarbons: benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, and dibenzo[a,h]anthracene. The other 40 GB 36600 items cover additional halogenated aromatics, phthalates, organochlorine pesticides, total polychlorinated biphenyls, petroleum hydrocarbons C10-C40, and dioxins and furans.

Groundwater and Supporting Parameters

Groundwater suites track the soil contaminant list and add routine indicators of GB/T 14848-2017, such as pH, total dissolved solids, chlorides, sulfates, ammonia nitrogen, nitrate, nitrite, fluoride, iron, manganese, and total hardness. Soil supporting parameters, including pH (HJ 962), organic carbon, moisture, particle-size distribution, and cation exchange capacity, feed fate and transport models and remediation process design such as oxidant dosing and amendment selection.

Testing Methods

Sample Preparation and Preservation

VOC samples are analyzed as received to prevent volatilization losses, while metals samples are air-dried, crushed, and sieved to method-specified fractions. Holding times are strictly enforced, commonly seven days for volatiles, ten to fourteen days for semi-volatiles and petroleum hydrocarbons, and longer for metals, with cold chain and chain-of-custody documentation maintained from field to bench.

Instrumental Analysis

• HJ 605-2011 purge-and-trap GC-MS, or HJ 642-2013 headspace GC-MS, for volatile organic compounds
• HJ 834-2017 GC-MS for semi-volatile organic compounds and HJ 784-2016 high-performance liquid chromatography for polycyclic aromatic hydrocarbons
• HJ 835-2017 GC-MS for organochlorine pesticides and HJ 743-2015 GC-MS for polychlorinated biphenyls
• HJ 1021-2019 GC-FID for total petroleum hydrocarbons C10-C40
• HJ 803-2016 aqua regia extraction ICP-MS or HJ 700-2014 microwave digestion ICP-MS for metals, HJ 680-2013 atomic fluorescence for mercury and arsenic, and HJ 1082-2019 alkaline extraction for chromium(VI)
• Isotope dilution high-resolution GC-MS for dioxins and furans
• HJ 780-2015 wavelength-dispersive X-ray fluorescence for rapid on-site metals determination

Field Screening

Handheld X-ray fluorescence analyzers and photoionization or flame ionization detectors provide real-time data for adaptive investigation, guiding sampling depths, excavation boundaries, hotspot delineation, and worker health and safety classifications. Field results are confirmatory-analyzed in the laboratory before any compliance decision is made.

Quality Assurance and Quality Control

Laboratories operate under China Metrology Accreditation (CMA) and CNAS ISO/IEC 17025 accreditation with capability scopes covering the relevant matrices and methods. Quality controls include method blanks, laboratory control samples, matrix spikes and duplicates with relative percent difference limits, surrogate standards, and continuing calibration verification. Data packages undergo internal review and independent validation so that results withstand expert panel scrutiny and regulatory filing in Beijing, Tianjin, and Hebei jurisdictions.

Applications

Testing services in this field directly support the regulatory and commercial milestones of land redevelopment and industrial compliance across the Jing-Jin-Ji region:

• Due diligence and regulatory filing for land transfer of former industrial, gasworks, coking, chemical, and electroplating sites
• Verification of ex-situ remediation technologies such as soil washing, thermal desorption, cement kiln co-processing, and solidification and stabilization, including pit-bottom and treated backfill confirmation sampling
• Performance verification of in-situ remedies including chemical oxidation and reduction, enhanced bioremediation, permeable reactive barriers, and monitored natural attenuation
• Effect evaluation and long-term monitoring for engineering risk controls such as caps and cut-off walls, together with institutional land use controls
• Key-industry enterprise self-monitoring and hidden hazard investigation under HJ 1019-2019
• Agricultural land category delineation and safe utilization verification, correlated with food contaminant limits under GB 2762
• Compliance testing of treated groundwater and remediation wastewater against local discharge standards such as DB11/307 in Beijing
• Emergency response, pollution incident forensics, and investigation of illegal dumping or burial of hazardous waste

FAQ

When is soil remediation risk control testing legally required?

Testing is required before any change of land use or land supply on former industrial, mining, or otherwise suspect sites; after risk control or remediation activities to demonstrate that effect evaluation criteria are met; and periodically by key enterprises for mandatory soil and groundwater self-monitoring. Under the Soil Pollution Prevention and Control Law, land cannot be supplied for development until relevant reports are completed and filed.

What is the difference between risk control and remediation?

Remediation reduces contaminant mass or concentration in soil or groundwater through treatment or removal. Risk control instead breaks exposure pathways using engineered measures such as capping, vertical barriers, or clean soil cover, combined with use restrictions and long-term monitoring. Both approaches require effect evaluation, but risk control sites typically carry ongoing monitoring obligations.

How do screening values and intervention values drive decisions?

Under GB 36600-2018, results below screening values generally close the assessment with no further action. Results between screening and intervention values trigger a site-specific risk assessment under HJ 25.2 to calculate remediation targets. Results above intervention values indicate that risk control or remediation is generally necessary before the land can be used for its intended purpose.

What sample density applies to site investigation?

HJ 25.1-2019 specifies systematic grids, commonly one point per 1,600 square meters for preliminary sampling and one point per 400 square meters for detailed sampling, adjusted based on the conceptual site model. Groundwater wells are positioned hydraulically upgradient and downgradient of suspected sources, and borings extend until uncontaminated strata are documented.

How quickly are results available?

Field programs for a typical site require one to four weeks depending on scale and access. Standard laboratory turnaround is approximately ten to fifteen working days, with expedited schedules available. Because volatile organics carry short holding times, sample scheduling and courier logistics are managed to protect data validity.

Which laboratories are qualified to perform this testing?

Laboratories must hold CMA accreditation with capability scopes explicitly covering the soil, groundwater, and method standards involved. CNAS accreditation to ISO/IEC 17025 provides additional international recognition. Reports from accredited laboratories are accepted for regulatory filing, expert panel review, and effect evaluation acceptance across Beijing, Tianjin, and Hebei.

Does agricultural land testing differ from development land testing?

Yes. Agricultural land is assessed against GB 15618-2018, with emphasis on cadmium and other heavy metals linked to crop safety. Safe utilization measures such as soil passivation, adjusted fertilization, and crop substitution are verified through combined soil and crop testing, whereas development land assessment under GB 36600-2018 is driven by human health exposure scenarios for the planned land use.