Chromium leather industry

Factor 2 results from the discharge of chromium by the leather industry and corresponds to the element pattern in the water. Factor 3, of geogenic origin, is caused by inflows from some small tributaries (Sormitz, Loquitz, Schwarza). 

Gasification of Leather Offal. Chrome-leather tanning scraps or offal are a waste product of the tanning and leather industries. These wastes are usually the result of trimming operations and contain 3.5 wt % chromium and about 50 wt % water. The wastes cannot be incinerated because malodorous substances and carcinogenic chromium-containing particulates are formed. Landfill disposal is presently used. 

Environmental problems in the leather industry due to chromium pollution can be solved, but are expensive and the alternatives are not without their own problems. 

Potassium dichromate is the principal active ingredient in purgative solutions the indications for its use are broad and may encompass any complaint. The substance is toxic in the hexavalent state but metallic chromium is inert. It is used in the leather industry for tanning, as an industrial cleaning agent and in electroplating. It is a bright yellow crystalline substance in its natural state. 

Integrated membrane process for chromium recovery in the leather industry. UF = ultrafiltration NF= nanofiltration. 

Fregert S, Gruvberger B (1979) Chromium in industrial leather gloves. Contact Dermatitis 5 189... 

In contrast, an analysis of approved occupational diseases from 1978 to 1984 in Germany revealed that none of the 941 cases of allergic contact dermatitis due to chromium salts occurred in the leather industry (Wardenbach et al. 1989). A similar development in France was stated by Cavelier and Foussereau (1995). 

Das M, Misra MP, Kumar A, Kumar P, Ahmed S, Chandra SV (1989) Chronic chromium poisoning with dermatitis in the leather industry. Contact Dermatitis 20 221-222 Dyro FM (1978) Methyl ethyl ketone polyneuropathy in shoe factory workers. Clin Toxicol 13 371-376 Estlander T, Kanerva L, Jolanki R (1990) Occupational allergic dermatoses from textile, leather, and fur dyes. Am J Contact Dermat 1 13-20... 

Chromium Liver, kidney, digestive system effects 0.1 Natural mineral deposits, metal finishing, textile and leather industries... 

Taylor M.M., Diefendorf E.J., Thompson C.J., Brown E.M, and Marmer W.N. (1994) Extraction and Characterization of Chrome Free Protein from Chromium-Containing Collagenous Waste Generated in the Leather Industry, In Polymer from Agricultural Coproducts, M.L.Fishman, R.B. Friedman, S.J.Huang (eds.) ACS Symp.Ser. 575, pp.171-187. 

A fine example of a closed water cycle is the application of nanofiltrafion in the leather industry (Cassano et al., 2001). Wastewater contains large eoneentrations of tannins or chromium after pretreatment by ultrafiltration, the chemieals used in the baths can be recovered in the concentrate fraction (Molinari et al., 2004), whereas the permeate can be reused for other purposes, for example, in the pickling step (Cassano et al., 1999). 

Chrome Tanning. The original chrome tanning was a two-bath process. The unhaired hides, delimed and bated, were treated with a solution of sodium bichromate [10588-01-9]. The amount of bichromate used was about 3—5% based on the weight of the hides. The bichromate was absorbed or adsorbed into the hide, the solution drained, and the hides refloated. Sodium bisulfite was added and two important reactions resulted in the formation of a basic chromium and coUoidal sulfur in the hide. This gave a chrome taimage and also helped to fiH the hide with the soHd sulfur. This cmde system, which continued in the industry in some types of leather for over 50 years, is obsolete. 

Leather Tanning and Textiles. Although chromium (VT) compounds are the most important commercially, the bulk of the appHcations in the textile and tanning industries depend on the abiUty of Cr(III) to form stable complexes with proteins, ceUulosic materials, dyestuffs, and various synthetic polymers. The chemistry is complex and not well understood in many cases, but a common denominator is the coordinating abiUty of chromium (ITT) (see LEATHER Textiles). 

The broad spectrum of the raw goods occurring in the leather and fur industry [95] necessitates various wet treatment processes in which surfactants and emulsifiers play a big role, e.g., in the regeneration of raw goods, which are preserved with salt, or by drying short-chain sulfosuccinates. To achieve hydro-phobizing effects, sulfosuccinate as emulsifiers are fixed on the surface by salts of aluminum or chromium. 

Chromium(lll) sulfate is used as the electrolyte for obtaining pure chromium metal. It is used for chrome plating of other metals for protective and decorative purposes. Other important applications of this compound are as a mordant in the textile industry in tanning leather to dissolve gelatin to impart green color to paints, varnishes, inks, and ceramic glazes and as a catalyst. 

Chromium compounds, mostly in chromium(III) or chromium(VT) forms, produced by the chemical industry are used for chrome plating, the manufacture of dyes and pigments, leather tanning, and wood preserving. Smaller amounts are used in drilling muds, rust and corrosion inhibitors, textiles, and toner for copying machines. For more information on the physical and chemical properties and on the production and use of chromium, see Chapters 3 and 4. 

Cement-producing plants, because cement contains chromium Industrial cooling towers that previously used chromium as a rust inhibitor Waterways that receive industrial discharges from electroplating, leather tanning, and textile industries... 

Occupational exposure to chromium(VI) compounds in a number of industries has been associated with increased risk of respiratory system cancers, primarily bronchogenic and nasal. Among the industries investigated in retrospective mortality studies are chromate production, chromate pigment production and use, chrome plating, stainless steel welding, ferrochromium alloy production, and leather tanning. 

Studies of chromate production workers, who are exposed to a variety of chromium compounds both hexavalent and trivalent, and chromate pigment industries, where exposure is mainly to chromium(VI), have consistently demonstrated an association with respiratory system cancer. Studies in chrome platers, who are exposed to chromium(VI) and other agents, including nickel, generally support the conclusion that certain chromium(VI) compounds are carcinogenic. Studies in stainless steel welders exposed to chromium(VI) and other chemicals, and in ferrochromium alloy workers, who are exposed mainly to chromium(O) and chromium(III), but also to some chromium(VI), were inconclusive. Studies in leather tanners, who are exposed to chromium(III), were consistently negative. 

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