Tanning
INTRODUCTION
This Industry Profile Fact Sheet is presented by the EPA Region 3 to assist state, local, and municipal agencies, and private groups in the initial planning and evaluation of sites being considered for remediation, redevelopment or reuse. It is intended to provide a general description of site conditions and contaminants which may be encountered at specific industrial facilities. This fact sheet is presented for informational purposes only, and should not be construed as a federal policy or directive.
INDUSTRY, PROCESS, OR SITE DESCRIPTION
Tanning is the process of manufacturing leathers from animal hides. Before shipping to the tanning facility, animal hides are preserved with a brine solution. A typical tanning facility consists of three sections: the beam house, tanning room, and finishing area. In the beam, house salt and hair are removed from the hide. The hides are then pickled with sulfuric acid to a pH of less than 3. During the tanning process the tanning solution is allowed to fully penetrate the hide. The most common tanning solution is trivalent chromium sulfate solution. The pH is then raised slowly with sodium bicarbonate and dried. In the finishing area, the hide surface is treated and dyed as required.
CHARACTERISTIC RAW MATERIALS
This industry typically uses chemicals for dehairing, liming, deliming, tanning and curing. The following chemicals are/were commonly utilized in tanning industries:
- Trivalent chromium sulfate
- Sodium bicarbonate
- Sodium sulfide or sodium sulfhydrate
- Arsenic or cyanide as sharpening agent
- Ammonium sulfate
- Sulfuric acid
- Lime
- Aniline dyes
WASTE STREAMS AND POTENTIALLY AFFECTED ENVIRONMENTAL MEDIA
On-site waste piles, pits and vats were common treatment/storage techniques prior to the promulgation and enforcement of the Resource Conservation and Recovery Act of 1976 (RCRA). Common waste products encountered at Superfund assessment and remediation projects include solid and liquid wastes containing trivalent chromium sulfate, corrosive liquids and sludges, volatile organic compounds, metals, cyanides, and sulfides, in addition to unused raw materials. These compounds often are absorbed into building walls, floors, ceilings and underlying soils.
SAMPLING STRATEGIES
All raw materials encountered on site should be visually identified and confirmed using immuno-assay, qualitative indicators, or wet chemistry field screening techniques. It should be noted that many of the raw materials containing corrosive and cyanide compounds may represent a significant direct contact and/or inhalation hazard to assessment personnel. Visually identified contaminated areas, waste piles and storage tanks should be characterized by collecting several samples for laboratory analysis. Surface and subsurface soil sampling should be performed from the suspected contaminated areas outward to the suspected clean areas. Once the primary contaminants are established, grid or random sampling may be performed to confirm suspected clean areas. Application of non-intrusive subsurface geophysics should be evaluated to detect underground burial pits, process lines and storage tanks.
Additionally, contaminated buildings and the associated demolition debris may be encountered at abandoned or inactive sites. Decontamination and wipe testing of this material may be required prior to off-site landfill disposal.
Nearby surface water, on-site and local wells may be sampled if surface or groundwater is an environmental concern.
SUGGESTED ANALYTICAL PARAMETERS
Arsenic Analysis
Cyanide Analysis
Chromium (hexavalent/total) Analysis
pH analysis
Sodium Analysis
Sulfides Analysis
Target Compound List (TCL) Analysis
Priority Pollutant Organics Analysis (volatile, semivolatile, pesticide/PCBs)
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