Services / Hazardous WasteServices / Hazardous Waste

Hazardous Waste

North Coast Laboratories can assist you in determining whether your waste has excessive contaminants, primarily heavy metals, under state and federal guidelines. If the material is hazardous, then it must be recycled, treated, stored, or disposed at a proper hazardous waste facility. TTLC and STLC analyses are used to determine whether solid wastes are hazardous under state regulations (Title 22 of the California Code of Regulations). TCLP analyses are waste characterizations based on federal regulations. STLC and TCLP procedures are designed to simulate what happens to a waste material in a landfill using artificial leachates.

Test Parameters Method
TTLC Requirements
CAM 17 Metals Various
Chromium VI EPA 7196
Fluoride EPA 300.0 Mod.
2,4-D and 2,4,5-TP Silvex EPA 8151A
Organochlorine Pesticides and PCBs EPA 8081 & 8082
Pentachlorophenol (PCP) CPAR
Trichloroethylene (TCE) EPA 8260B
STLC Requirements
CA Waste Extraction Test (WET) CCR Title 22
WET using DI Water – Chromium VI only CCR Title 22
CAM 17 Metals Various
Toxicity Characteristic Leaching Procedure (TCLP)
Extraction for Metals, Herbicides, Pesticides & Semivolatiles EPA 1311
Metals (As, Ba, Cd, Cr, Pb, Hg, Se, Ag) Various
Phenoxy Herbicides (2,4-D & 2,4,5-TP Silvex) EPA 8151A
Organochlorine Pesticides EPA 8081

Metals Extractions


TTLC stands for Total Threshold Limit Concentration. This is how metals results are normally expressed for solid samples. If you do not specify a special extraction procedure on your chain of custody your metals will be reported as TTLC values.


STLC stand for Soluble Threshold Limit Concentration. This extraction is used to determine whether certain leachable compounds are present in large enough amounts in a given material that the material need to be dealt with as hazardous waste. The extraction procedure mimics what will happen to a given material as it is exposed to normal climatic conditions in a landfill over time. When this extraction is used solid matrices will be reported in liquid units.


TCLP stands for Toxicity Characteristic Leaching Procedure. This extraction is one of four characteristics used to identify hazardous waste; the other three are Ignitabilty, Corrosivity and Reactivity. The TCLP extraction is designed to simulate the climatic leaching action expected to occur in landfills. It identifies and quantifies 8 metals and 25 organic compounds (pesticides, herbicides, etc.) with the potential to leach into ground water. When this extraction is used solid matrices will be reported in liquid units.

When to Do a STLC Extraction

The limits for STLC and TTLC metals are listed below along with the range of TTLC concentrations for which a STLC extraction must be done.

Substance STLC (mg/L) Range of TTLC Values
for Which an STLC Must Be Done
Wet Weight
TTLC (mg/kg)
Antimony 15 ≥ 150 mg/kg 500
Arsenic* 5 ≥ 50 mg/kg 500
Barium* 100 ≥ 1000 mg/kg 10,000
Beryllium 0.75 ≥ 7.5 mg/kg 75
Cadmium* 1 ≥ 10 mg/kg 100
Chromium 6* 5 ≥ 50 mg/kg 500
Chromium* 5 ≥ 50 mg/kg 2,500
Cobalt 80 ≥ 800 mg/kg 8,000
Copper 25 ≥ 250 mg/kg 2,500
Lead* 5 ≥ 50 mg/kg 1,000
Mercury* 0.2 ≥ 2 mg/kg 20
Molybdenum 350 ≥ 3,500 mg/kg 3,500
Nickel 20 ≥ 200 mg/kg 2,000
Selenium* 1 ≥ 10 mg/kg 100
Silver* 5 ≥ 50 mg/kg 500
Thallium 7 ≥ 70 mg/kg 700
Vanadium 24 ≥ 240 mg/kg 2,400
Zinc 250 ≥ 2,500 mg/kg 5,000
*TCLP Metals
If you have a solid sample analyzed for metals (TTLC) you must do an STLC for those metals that are 10 times or greater than the STLC limit. For example – The TTLC limit for antimony is 500 mg/kg and the STLC limit is 15 mg/L. If your TTLC result is 150 mg/kg or higher they you must do an STLC for antimony.

Go to our Analyte Search page »