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PubMed2002

Incorporation of toxicity tests into the Turkish industrial discharge monitoring systems.

A toxicity evaluation is an important parameter in wastewater quality and in the monitoring of discharged effluents. Some organic and inorganic compounds at toxic levels have been detected in industrial discharges, resulting in plant upsets and discharge permit violations. In some cases, even though the effluent does not exceed the chemical-specific discharge limits, the results of toxicity tests show potential toxicity. Knowledge of the toxicity of effluents can benefit treatment plant operators in optimizing plant operation, protecting receiving water quality, and establishing sewer discharge permits. In the Turkish regulations only toxicity dilution factor with fish is part of the toxicity monitoring program of permissible wastewater discharge. This study investigated the acute toxicity of pulp-paper, leather, and petrochemical industry wastewaters by traditional and enrichment toxicity tests and emphasized the importance of toxicity tests in wastewater discharge regulations. The enrichment toxicity tests are novel applications indicating whether there is potential toxicity or stimulation conditions. Different organisms were used, including bacteria (Floc and Coliform bacteria) algae (Chlorella sp.), fish (Lepistes sp.), and protozoan species (Vorticella sp.) to represent four trophic levels. The toxicity test results were compared with chemical analyses to identify the pollutants responsible for the toxicity in the effluent wastewater samples. Toxicity of the effluents could not be explained by using physicochemical analyses in five cases for the leather and four cases for the pulp-paper and petrochemical industries. The results clearly showed that the use of bioassay tests produce additional information about the toxicity potential of industrial discharges and effluents.

Animals↗

PubMed2004

Hormetic versus toxic effects of vegetable tannin in a multitest study.

Tannin from mimosa trees (Acacia sp.) utilized in traditional leather tanning was tested for toxicity in sea urchin (Sphaerechinus granularis and Paracentrotus lividus) embryos and sperm, marine, and freshwater algae (Selenastrum capricornutum and Dunaliella tertiolecta), and Daphnia magna. Based on a two-step tanning procedure used in traditional tanneries, two mimosa tannin preparations, i.e., fresh tannin (FT) and used tannin (UT), were tested as suspensions. The early results in S. granularis embryos showed that UT exerted lower acute toxicity than FT, namely, 1 vs 100 mg/L, to obtain 100% mortality, respectively. Subsequent bioassays were conducted on fresh tannin water extracts (TWE) corresponding to nominal tannin concentrations ranging from 0.1 to 30 mg/L. Developmental toxicity, up to embryonic mortality was exerted by TWE at levels > 1 mg/L, S. granularis being more sensitive than P. lividus embryos/larvae. At the concentration of 0.1 mg/L, the frequencies of larval malformations were significantly lower than in controls. This positive stimulatory effect (currently termed as hormesis) was observed in extended numbers of culture replicates (up to 14) and was significant in the embryo cultures characterized by a relatively poor control quality (with < 70% viable larvae in controls), whereas this effect was not observed in good-quality cultures (with > or = 70% viable larvae in controls). Cytogenetic analysis of S. granularis embryos reared in FT or UT suspensions (1 mg/L to 1 g/L) showed mitotoxic effects (decrease in active mitoses per embryo) in FT-exposed, but not in UT-exposed embryos. Mitotic aberrations were significantly increased by 10 mg/L UT. Sperm fertilization success in both sea urchin species showed an increasing fertilization rate (FR) up to 0.3 mg/L TWE and a dose-related decrease in FR up to 30 mg/L. Again, the offspring of P. lividus sperm exposed to TWE (0.1 and 0.3 mg/L) showed a decrease in larval malformations compared to controls, whereas a dose-related increase in developmental defects was observed in the offspring of P. lividus sperm exposed to higher TWE levels (1 to 30 mg/L). Algal cell growth bioassays in two species (S. capricornutum and D. tertiolecta) also showed a maximum growth at TWE levels ranging from 0.3 to 3 mg/L and a subsequent decline up to 30 mg/L TWE. D. magna bioassays resulted in daphnid immobilization by TWE concentrations ranging from 100 to 300 mg/L. The results demonstrate that tannins utilized in traditional leather tanning industry may raise concern of environmental damage at relatively high concentrations, whereas low-level tannins may result in hormetic effects. The present study also points to the need for bioassay design that should rely on adequate criteria in control quality, allowing to detect both inhibitory and hormetic effects.

Acacia↗

PubMed2006

Microbial keratinases and their prospective applications: an overview.

Microbial keratinases have become biotechnologically important since they target the hydrolysis of highly rigid, strongly cross-linked structural polypeptide "keratin" recalcitrant to the commonly known proteolytic enzymes trypsin, pepsin and papain. These enzymes are largely produced in the presence of keratinous substrates in the form of hair, feather, wool, nail, horn etc. during their degradation. The complex mechanism of keratinolysis involves cooperative action of sulfitolytic and proteolytic systems. Keratinases are robust enzymes with a wide temperature and pH activity range and are largely serine or metallo proteases. Sequence homologies of keratinases indicate their relatedness to subtilisin family of serine proteases. They stand out among proteases since they attack the keratin residues and hence find application in developing cost-effective feather by-products for feed and fertilizers. Their application can also be extended to detergent and leather industries where they serve as specialty enzymes. Besides, they also find application in wool and silk cleaning; in the leather industry, better dehairing potential of these enzymes has led to the development of greener hair-saving dehairing technology and personal care products. Further, their prospective application in the challenging field of prion degradation would revolutionize the protease world in the near future.

Bacteria↗

PubMed2005

Occupational risk factors for kidney cancer: a cohort study in Sweden.

Although many studies have examined the associations between occupational exposures and kidney cancer, the evidence is not consistent. To examine the risk of occupational exposures on kidney cancer, we carried out a follow-up study on the economically active Swedish population, based on the latest update of the Swedish Family-Cancer Database. We calculated standardized incidence ratios (SIR) and 95% confidence intervals (CIs) for different occupational groups, adjusted for age, period, and socioeconomic status. The reference group was all the economically active population. An increased risk of renal parenchymal cancer was observed for miners and quarry workers, drivers, sales agents, transport workers, and public safety and protection workers among men, and launderers and dry cleaners among women. Significantly increased SIRs of renal pelvical cancer were also observed for the food manufacture workers among men, and journalists and shoe and leather industry workers among women. Male forestry workers, smelters, and metal foundry workers had increased risk for unspecified kidney cancer. Although smoking may explain some of these results, exposure to gasoline, diesel, their exposure products, some metal and chemicals in shoe and leather works, and dry-cleaning products may be associated with kidney cancer.

Confidence Intervals↗

PubMed2006

Environmental monitoring of occupational exposure to N,N-dimethylformamide: comparison between active and diffusive sampling.

OBJECTIVES: The objective of this study is to optimize the evaluation of the exposure to N,N-dimethylformamide (DMF) in synthetic leather factories by diffusive samplers. The DMF exposure was monitored in synthetic leather factories by two sampler types: active and diffusive. METHODS: Air measurements were carried out using two different personal air samplers, a diffusive and an active one. The diffusive sampling method, TK200 with charcoal filters, was examined in comparison with pumping through NIOSH silica gel tubes workplace air as with the currently available "gold standard". The evaluation was carried out, in two different years but in the same season, for all the duration of the shift, i.e. 8 h on workers employed in five different factories in the district of Florence and Prato (Italy). RESULTS: The statistical and graphical analysis of data show a good correlation between active and passive samplers (r = 0.96, P < 0.001, n = 91), a good linear regression (DMF(diffusive )= 0.95 DMF(active) + 0.15, R (2) = 0.92), a not statistically significant difference between data (tested by paired t test and non-parametric Wilcoxon test). Moreover, all these results are confirmed for data lower and higher than TLV-TWA, in particular we found a significant Pearson correlation (r = 0.92, P < 0.001, n = 83; r = 0.92, P < 0.05, n = 8, respectively) and a significant linear regression (DMF(diffusive )= 0.88 DMF(active) + 0.73, R (2 )= 0.86; DMF(diffusive )= 0.90 DMF(active) + 3.76, R (2 )= 0.85). Besides, the analysis of graphical representations confirmed the previous evidences. Finally, we can not find a significant difference between different types of job. CONCLUSIONS: Due to the good agreement between the two groups of data, the TK200 samplers can be considered as a simpler approach than the pump for screening worker exposures to DMF.

Air Pollutants, Occupational↗

PubMed2001

Determination of residual dentine caries after conventional mechanical and chemomechanical caries removal with Carisolv.

The aim of the study was to assess the efficacy of removing dentine caries chemomechanically with Carisolv and with round burs. In 24 extracted permanent teeth each, caries removal with Carisolv or rotating round burs was monitored by checking the hardness of the dentine with a dental explorer and stopped at 12 teeth in each group when either (a) a leather-hard texture was reached or (b) a sharp scratching sound was heard. After embedding and sectioning (400 microm), caries activity of the remaining dentine was assessed using methyl red dye. In microscope images (7x) of the samples, the mean depth of the pink (caries-active, pH<5.5) and yellow (pH>5.5) staining of each carious lesion was calculated. Using a round bur, the depth of caries-active and -inactive lesions was significantly greater when a leather-hard texture (51-58 microm) was reached than when a sharp scratching sound was reached (19-25 microm, t-test, P<0.05). For teeth treated with Carisolv, only the depth of the caries-inactive dentine differed significantly. Regardless of the clinical criterion for caries removal, Carisolv treatment resulted in higher mean depths of caries-active dentine (71-78 microm) than conventional caries removal using the round bur (19-51 microm), while the mean depths of the caries-inactive dentine differed minimally. Thus, caries removal with Carisolv leaves up to a mean of 50 microm more carious dentine than round burs.

Azo Compounds↗

PubMed1982

Technical notes on long-term vascular access for more than 12 months in conscious dogs.

A method for the implantation of catheters into carotid, jugular, and femoral vessels that allows long-term access in conscious dogs has been described. The vascular catheters, especially when introduced into the femoral vessels, remain patent for more than 12 months. This improved patency may result from the solving of several methodological problems: 1. firm securing of the catheters to the vessels with a simple polyethylene perivascular muff that is rapidly prepared and introduced; 2. a 5 cm long replaceable catheter connected to the free end of the intravascular tubing prevents the need to replace the entire implantation after crushing; 3. a leather jacket, together with a large leather collar in some cases, prevents the animal from damaging the free ends of the catheters that lie longitudinally along the back. In addition, they allow rapid healing of the incisions, particularly in the thigh.

Animals↗

PubMed1982

Toxic effects of chromic sulphate on the common carp, Cyprinus carpio.

The effects of chromic sulphate, which is commonly used in the tanning of leather, on the common carp, Cyprinus carpio and the bighead, Aristichthys nobilis, were studied. C. carpio was found to be more susceptible than A. nobilis to chromic sulphate at the lowest concentration tested (100 mg/l) whereas results obtained at other concentration were similar for both species. Damage to the gills, liver and intestine was observed by histopathological examination. A wide range of chemicals is used in the different stages of treating leather and a possible treatment of the effluent from the tanneries is suggested.

Animals↗

PubMed1998

Case-control study of risk factors of Creutzfeldt-Jakob disease in Europe during 1993-95. European Union (EU) Collaborative Study Group of Creutzfeldt-Jakob disease (CJD).

BACKGROUND: Creutzfeldt-Jakob disease (CJD) is a transmissible spongiform encephalopathy. Genetic and iatrogenic forms have been recognised but most are sporadic and of unknown cause. We have studied risk factors for CJD as part of the 1993-95 European Union collaborative studies of CJD in Europe. METHODS: The 405 patients with definite or probable CJD who took part in our study had taken part in population-based studies done between 1993 and 1995 in Belgium, France, Germany, Italy, the Netherlands, and the UK. Data on putative risk factors from these patients were compared with data from 405 controls. FINDINGS: We found evidence for familial aggregation of CJD with dementia due to causes other than CJD (relative risk [RR] 2.26, 95% CI 1.31-3.90). No significant increased risk of CJD in relation to a history of surgery and blood transfusion was shown. There was no evidence for an association between the risk of CJD and the consumption of beef, veal, lamb, cheese, or milk. No association was found with occupational exposure to animals or leather. The few positive findings of the study include increased risk in relation to consumption of raw meat (RR 1.63 [95% CI 1.18-2.23]) and brain (1.68 [1.18-2.39]), frequent exposure to leather products (1.94 [1.13-3.33]), and exposure to fertiliser consisting of hoofs and horns (2.32 [1.38-2.91]). Additional analyses, for example stratification by country and of exposures pre-1985 and post-1985, suggest that these results should be interpreted with great caution. INTERPRETATION: Within the limits of the retrospective design of the study, our findings suggest that genetic factors other than the known CJD mutations may play an important part in CJD. Iatrogenic transmission of disease seems rare in this large population-based sample of patients with CJD. There is little evidence for an association between the risk of CJD and either animal exposure, or consumption of processed bovine meat or milk products for the period studied.

Adult↗

PubMed2005

[Chromium-induced vasculitis-like purpuric allergic contact dermatitis].

INTRODUCTION: Purpuric allergic contact dermatitis is a rare and poorly understood condition. CASE REPORT: A 27-year-old male patient with a personal history of atopic dermatitis since childhood consulted for chronic papular-purpuric rash present for 7 years. Moderate pruritus was seen. Profuse lesions were observed on the palms and soles and on the upper and lower limbs, with sparing of the trunk. These lesions consisted of purpuric papules, in some cases with crusts, forming large plaques. The clinical picture was initially suggestive of vasculitis, but this diagnosis was ruled out by histological examination and laboratory tests. Skin patch tests were evocative of chromium-induced contact dermatitis. Retrospective directed history-taking confirmed the relevance of the latter test since it revealed regular wearing of leather clothing. Lasting cure was achieved following eradication of the allergen. DISCUSSION: Reports of contact purpuric dermatitis are rare. This condition has been described principally for allergens consisting of rubber or dyes used in clothing. Our case was notable on account of the severity of the lesions, mimicking vasculitis, as well as the novelty of the incriminated allergen, chromium, found in leather garments. It underlines the value of routine skin patch tests in the event of chronic non-specific dermatitis. To our knowledge, this is the first reported case of chromium-induced purpuric allergic contact dermatitis.

Adult↗

PubMed1979

Penetration resistance of dental injection needles.

A laboratory test of the sharpness and penetration resistance of different brands of dental needles was undertaken. Both properties are essential when pain during injection is discussed. Using a Strograph in combination with a piece of stretched chamois leather resembling the mucous membrane, graphs were obtained for each needle tested and evaluated with reference to maximum penetration resistance at the actual point of puncture and to the smoothness of the further insertion through the leather. The findings gave a relative characteristic of each product based on a trial of 20 needles selected at random from each batch of 100 needles.

Dental Instruments↗

PubMed1997

Chrome tannage using high-intensity ultrasonic field.

The process time in chrome tannage in leather making, using an elastic compression cycle followed by irradiation by high-intensity ultrasound, is quite short lasting only a few minutes, compared with a process time of several hours in modern chrome tannage. After ultrasonic irradiation, samples were basified in 17 h in chrome liquor at a pH of 4.0 and the shrinkage temperature was measured. The determination of the efficiency for the chrome liquor penetrating into the hides can be based on the steepness of the shrinkage temperature-processing time curve. An approximate value of 20 degrees C min(-1) can be evaluated for the initial slope of the curve when elastic compression and high-intensity ultrasonic irradiation is used, and a processing time of 2 min is required in chrome liquor (plus 17 h basification and 24 h storage time) to obtain leather stable to boiling. Usually, hides are kept in chrome liquor for 2 h.

Journal Article↗

PubMedDate not supplied

Mercury intrusion porosimetry, nitrogen adsorption, and scanning electron microscopy analysis of pores in skin.

Stability of collagenous matrixes such as skin and leather with respect to changes in their dimensions on heating has long been correlated with degree and type of cross links formed and short-range ordering in angstrom unit scales. Macroscopic dimensional changes may be expected to involve alterations in the long-range order as well as supramolecular assemblies in skin and leather. This study relates thermal shrinkage of skin matrixes with alterations observed in micro-, meso-, and macroporic structures. Changes in the pore structure of skin associated with thermal shrinkage have been studied using nitrogen adsorption and mercury intrusion porosimetry measurements. A comparison of results obtained using both techniques has been made. These results indicate that although the percentage porosity of the matrix decreases, the BET specific surface area increases on shrinkage. An insight into the changes in the pore systems of skin induced by thermal shrinkage has been gained.

Adsorption↗

PubMed2002

Green route for the utilization of chrome shavings (chromium-containing solid waste) in tanning industry.

Chromium-containing wastes from various industrial sectors are under critical review. Leather processing is one such industrial activity that generates chromium-bearing wastes in different forms. One of them is chrome shavings, and this contributes to an extent of 10% of the quantum of raw skins/hides processed, amounting to 0.8 million ton globally. In this study, the high protein content of chrome shavings has been utilized for reduction of chromium(VI) in the preparation of chrome tanning agent. This approach has been exploited for the development of two products: one with chrome shavings alone as reducing agent and the other with equal proportion of chrome shavings and molasses. The developed products exhibit more masking due to the formation of intermediate organic oligopeptides. This has been corroborated through the spectral, hydrolysis, and species-wise distribution studies. The formation of these organic masking agents helps in chrome tanning by shifting the precipitation point of chromium to relatively higher pH levels. Hence, the developed products find use as chrome tanning agents for leather processing, thus providing a means for better utilization of chrome shaving wastes.

Carcinogens, Environmental↗

PubMed2003

Use of DSC to detect the heterogeneity of hydrothermal stability in the polyphenol-treated collagen matrix.

The hydrothermal stability of the collagen matrixes treated with plant polyphenols (tannins) depends on not only the strength of the polyphenol-collagen interactions but also the distribution uniformity of polyphenolic molecules within the collagen fibrils. Traditional methods of uniformity tests rely heavily on the expertise of workers and are thus subjective. This paper describes a differential scanning calorimetry (DSC) study of the sheepskin collagen samples treated with hydrolyzable tannins, including two commercial tannins' extracts (chestnut and valonea), two pure ellagitannins (vescalagin and castalagin), and six synthetic gallotannins (di-galloyl-ethylene glycol (DGE), tri-galloyl-glycerol, tetra-galloyl-meso-erythritol, penta-galloyl-adonitol, penta-galloyl-glucose, and hexa-galloyl-ducitol). The collagen sample without polyphenol treatment and the sample treated with DGE showed a single sharp peak in their DSC thermogram with a full peak width at half height (fwhh) of 3-4 degrees C. The samples treated with other tannins all showed multiple peak DSC profiles with the fwhh of each peak at about 3-4 degrees C. These multiple peak profiles imply that in these polyphenol-treated samples, there is a distribution of collagen molecules having different hydrothermal stability. The results have demonstrated that DSC offers an objective method to detect the stability heterogeneity of collagen matrixes in the solid state, providing a useful tool for the leather industry to evaluate the uniformity of leather tanning.

Animals↗

PubMed2002

Sinonasal cancer and occupational exposures: a pooled analysis of 12 case-control studies.

OBJECTIVE: In order to examine the associations between sinonasal cancer and occupational exposures other than wood dust and leather dust, the data from 12 case-control studies conducted in seven countries were pooled and reanalyzed. METHODS: The pooled data set included 195 adenocarcinoma cases (169 men and 26 women), 432 squamous cell carcinomas (330 men and 102 women), and 3136 controls (2349 men and 787 women). Occupational exposures to formaldehyde, silica dust, textile dust, coal dust, flour dust, asbestos, and man-made vitreous fibers were assessed with a job-exposure matrix. Odds ratios (ORs) were adjusted for age, study, wood dust, and leather dust, or other occupational exposures when relevant. 95% confidence intervals (CIs) were estimated by unconditional logistic regression. RESULTS: A significantly increased risk of adenocarcinoma was associated with exposure to formaldehyde. The ORs for the highest level of exposure were 3.0 (Cl = 1.5-5.7) among men and 6.2 (CI=2.0-19.7) among women. An elevated risk of squamous cell carcinoma was observed among men (OR=2.5, CI=0.6-10.1) and women (OR = 3.5, CI = 1.2-10.5) with a high probability of exposure to formaldehyde. Exposure to textile dust was associated with non-significantly elevated risk of adenocarcinoma, among women only: the OR for the high level of cumulative exposure was 2.5 (CI = 0.7-9.0). High level of asbestos exposure was associated with a significantly increased risk of squamous cell carcinoma among men (OR = 1.6, CI = 1.1-2.3). CONCLUSIONS: The results of this pooled analysis support the hypothesis that occupational exposure to formaldehyde increases the risk of sinonasal cancer, particularly of adenocarcinoma. They also indicate an elevated risk of adenocarcinoma among women exposed to textile dust, and suggest that exposure to asbestos may increase the risk of squamous cell carcinoma.

Adenocarcinoma↗

PubMed1982

Nasal cancer in the Northamptonshire boot and shoe industry: is it declining?

This paper reports a survey of nasal cancer in Northamptonshire during the period 1950-79. An increased risk of various histological types of nasal tumour has been observed within the footwear manufacturing industry, which seems to be limited to the minority of men and women exposed to the dust of leather soles and heels. In Northamptonshire this exposure has usually occurred in the preparation, press and finishing rooms of factories making boots and shoes by the welted process. This type of leather is tanned by treatment with vegetable extracts, not chrome salts. Although the population of workers involved has diminished over the period of the study there has been no evidence of a decline in incidence of these tumours within it.

Aged↗

PubMed2003

Common allergens in shoe dermatitis: our experience in Lahore, Pakistan.

BACKGROUND: Shoe dermatitis is a form of contact dermatitis resulting from exposure to shoes. Different chemicals, in conjunction with a hot and humid environment within the shoe, give rise to allergic or irritant dermatitis. Allergic shoe dermatitis is commonly caused by constituents of rubber, leather, adhesives, and rarely by linings and dyes. AIM: To determine the frequency of various allergens in shoe dermatitis in our patients. METHODS: One hundred and nine patients suspected of having contact dermatitis due to shoe allergens were included. All patients were patch tested with the Shoe series and European Standard series. Patches were applied on the upper back and removed after 48 h. Results were read at 48, 72, and 120 h and interpreted according to International Contact Dermatitis Research Group (ICDRG) criteria. RESULTS: Of the 119 patients, 87 (73%) reacted positively to various allergens, 48% of whom showed polysensitivity. Glues (33.6%), particularly para-tert-butylphenol formaldehyde resin (PTBP-FR) (26.9%), were the leading cause of shoe dermatitis. Other allergens were leather chemicals (26.4%), potassium dichromate (16.18%), rubber allergens (7.6%), and dyes (7.6%). Shoe scrapings tested positive in 26.3% of patients. Other common allergens were nickel sulfate (22.7%), neomycin sulfate (10.1%), and cobalt chloride (8.4%). CONCLUSIONS: Considering the diversity of allergens, all patients presenting with shoe dermatitis should be patch tested with the Shoe series and a standard series to determine the etiologic allergens.

Adhesives↗