Chemical fraction, leachability, and bioaccessibility of heavy metals in contaminated soils, Northeast China

Heavy metals in urban soils may pose risks to both urban environment and human health. However, only a fraction of heavy metals in soil is mobile and/or bioavailable for plant uptake and human ingestion. This study evaluates the chemical fraction and potential mobility and bioaccessibility of heavy metals (Cd, Cr, Cu, Pb, and Zn) in the contaminated urban topsoils from steel-industrial city (Anshan), Northeastern China. Chemical forms of heavy metals in soils are determined using Tessier sequential extraction technique. The toxicity characteristic leaching procedure (TCLP), ethylenediaminetetraacetic acid (EDTA), and US Pharmacopeia methodology (USPM) are used to determine the operationally defined potentially mobile and bioaccessible metal fractions, respectively. Sequential extraction results show that Cd has the highest percentage of exchangeable form, whereas Cr primarily exists in residual form. The non-residual fraction of heavy metals increases in the order of Cr < Cu < Pb < Zn < Cd. The leachability of heavy metals evaluated by TCLP test indicates that Cd, Zn, Cu, and Pb have much higher mobile than Cr. The bioavailability of heavy metals determined by EDTA extraction decreases in the order of Pb > Cu ≅ Zn > Cd > Cr. The order of bioaccessibility determined by USPM extraction is Pb = Cu > Zn > Cd > Cr. The Cr exhibits the lowest leachability and bioaccessibility among the investigated metals. The Pb has the highest bioaccessibility, indicating higher potential hazard for the human health. There are significant relationships between the EDTA- and USPM-extractable metals (Cd, Cu, Pb, and Zn) and the sum of first three steps of sequential extraction. Highly significant correlation is found between amounts of EDTA-extractable Cd, Cu, Pb, and Zn and USPM-extractable metals. The result suggests that EDTA extraction can be helpful to estimate the bioaccessibility of heavy metals for human ingestion. Introduction of mobile and human bioaccessible concentrations into risk assessments can give more realistic implications for urban environmental management.

Polishing surgical metal pieces, granulomatosis and mineralogical analysis

This report describes the case of a 44-year-old man with pulmonary nodules whose histological analysis initially suggested tuberculosis. The Mycobacterium tuberculosis (MT) culture was negative and a questionnaire revealed a professional activity of brushing and polishing surgical instruments without any protection for 7 years.  A mineralogical analysis by optical and electron microscopy was performed on both a healthy lung tissue biopsy and a lung nodule in a paraffin block. Electron microscopy analysis revealed the presence of metal particles (iron oxide, titanium oxide, aluminum oxide and steel) in both samples. This study suggests that mineralogical analysis combined with a questionnaire on dust exposure could help redirect the diagnosis of a dust-related disease.

[Metal fume fever, often unrecognized]

BACKGROUND

Metal fume fever is an occupational disease caused by inhalation of volatile metal oxides. Clinically there is a strong resemblance to influenza. It is thought that metal fume fever occurs much more frequently than it is reported. The symptoms are self-limiting without treatment, disappearing within 24-48 hours without residual symptoms.

CASE DESCRIPTION

A male 35-year-old construction worker had cut galvanized steel plates in a closed environment. He had a flu-like illness with fever, leucocytosis and hypoxemia. The symptoms resolved completely without treatment within 18 hours.

CONCLUSION

Metal fume fever is a frequently occurring disease but is often overlooked. It is important to ask about exposure to metal fumes in certain occupational groups in order to make the correct diagnosis. In this way measures can be taken to avoid exposure to metal oxides and to prevent recurrence of the disease.

Incomplete left bundle branch block as an artefact caused by the Nuss procedure for pectus excavatum

AIMS

Nuss procedure is an established and well approved minimally invasive technique for the correction of pectus excavatum. Hereby an individually curved steel bar is inserted to stabilize the thorax. This study aimed to describe ECG changes associated with this procedure.

METHODS AND RESULTS

Electrocardiographs of 65 patients who underwent Nuss procedure in our Hospital were evaluated before and after bar implantation as well as after bar removal. In the Goldberger leads, there was a consistent reduction in the QRS amplitude in lead I. In the Wilson leads, the most prominent change was a reduction in the QRS amplitude and a novel r' wave forming a slightly elevated J-point in the left lateral leads. Additionally, we noticed the loss of the former small and physiological q wave in the same leads, typical for an incomplete left bundle branch block (ILBBB). These changes resolved after bar removal.

CONCLUSION

We describe the common finding of a reversible incomplete ILBBB after Nuss surgery. The reason for these ECG changes remain unclear. Since cardiac ischaemia, damage, or perioperative irritation of the pericardium is improbable and the alteration of the anatomic thoracic situation remains after bar explantation, we suspect an artefact through alteration of the electric field by the steel bar. Practitioners dealing with patients after Nuss procedure should be aware of this most probably harmless finding.

Effects of inhalable particulate matter on blood coagulation

BACKGROUND

Particulate matter (PM) exposure has been linked to increased risk of cardiovascular disease, possibly resulting from hypercoagulability and thrombosis. Lung and systemic inflammation resulting from PM inhalation may activate blood coagulation, but mechanisms for PM-related hypercoagulability are still largely unknown.

OBJECTIVES

To identify coagulation mechanisms activated by PM in a population with well-characterized exposure.

METHODS

We measured prothrombin time (PT), activated partial thromboplastin time, endogenous thrombin potentials (ETPs) with/without exogenous triggers and with/without soluble thrombomodulin, tissue-type plasminogen activator (t-PA) antigen, D-dimer and C-reactive protein (CRP) in 37 workers in a steel production plant with well-characterized exposure to PM with aerodynamic diameter of < 1 mum (PM(1)) and coarse PM (PM(10) - PM(1)). Blood samples were collected from each subject on the first (baseline) and last (postexposure) day of a 4-day work week. We analyzed differences between baseline and postexposure levels using a paired Student's t-test. We fitted multivariate mixed-regression models to estimate the associations of interquartile range PM(1) and coarse PM exposure with parameter levels.

RESULTS

None of the parameters showed any significant changes from baseline in postexposure samples. However, exposure levels were associated with shorter PT (beta[PM(1)] = -0.33 s, P = 0.08; beta[PM(coarse)] = - 0.33 s, P = 0.01), and higher ETP without exogenous triggers and with thrombomodulin (beta[PM(1)] = + 99 nm min, P = 0.02; beta[PM(coarse)] = + 66 nm min, P = 0.05), t-PA (beta[PM(1)] = + 0.72 ng mL(-1), P = 0.01; beta[PM(coarse)] = + 0.88 ng mL(-1), P = 0.04), and CRP (beta[PM(1)] = + 0.59 mg L(-1), P = 0.03; beta[PM(coarse)] = + 0.48 mg L(-1), P = 0.01).

CONCLUSIONS

PM exposure did not show any short-term effect within the week of the study. The association of PM exposure with PT, ETP and CRP provides some evidence of long-term effects on inflammation and coagulation.

Speciation of Cd and Pb in dust emitted from sinter plant

Many studies have provided evidence of the impact of heavy metals in atmospheric emission. Sinter plants represent the first step in steel production, and are important emitters of Cd and Pb. The toxicity of these two metals depends above all on their speciation. Particles collected before and after the filtration system were analysed to determine the Cd- and Pb-bearing phases, using analytical tools such as XRF, EXAFS or ICP-AES and chemical leaching (sequential extractions adapted to steel dusts). Results show that Pb is associated with carbonate and Cd with chloride. These two types of speciation lead to high solubility under common environmental conditions, which may produce impacts on the environment and health.

Employment as a Welder and Parkinson Disease Among Heavy Equipment Manufacturing Workers

OBJECTIVE

We investigated whether employment as a welder with potential exposure to manganese and other substances is associated with Parkinson disease (PD), parkinsonism or related neurological disorders, or accelerates the age of onset of PD.

METHODS

We selected cases and controls from 12,595 persons ever employed at three Caterpillar Inc. (CAT) plants between 1976 and 2004 with potential to make a medical insurance claim between 1998 and 2004. Cases had filed a claim for 1) PD, 2) "secondary parkinsonism", 3) "other degenerative diseases of the basal ganglia" or 4) "essential and other specific forms of tremor". Cases were grouped by claims: Group 1-claims 1 and 2 and Group 2-claims 1 to 4, and as study period incident (SPI) or prevalent. Each case was matched to two series of 10 controls each on date of case's first claim, year of birth, race and sex. Series I was also matched on plant.

RESULTS

Odds ratios (OR) and 95% confidence intervals (CI) for the variable, "ever welder in any CAT plant" were: Group 1-SPI Cases: Series I (OR = .76, CI = .26-2.19), Series II (OR = .81, CI = .29-2.25); Group 1- Prevalent Cases: Series I (OR = .82, CI = .36-1.86), Series II (OR = .97, CI = .42-2.23); Group 2- SPI Cases: Series I (OR = 1.03, CI = .57-1.87), Series II (OR = 1.21, CI = .67-2.20) Group 2-Prevalent Cases: Series I (OR = 1.02, CI = .62-1.71), Series II (OR = .86, CI = .51-1.43). Our finding of no statistically significant associations for welding employment was maintained following adjustment for potential confounding and evaluation of possible effect modification. Employment as a welder did not accelerate the age of onset of PD.

CONCLUSIONS

Our study supported the conclusion that employment as a welder is not associated with Parkinson disease, parkinsonism or a related neurological disorder.

Occupational exposures to polycyclic aromatic hydrocarbons, and respiratory and urinary tract cancers: a quantitative review to 2005

BACKGROUND

Exposure to polycyclic aromatic hydrocarbons (PAHs) has been reported in several industries, including those of the aluminum production, coal gasification, coke production, iron and steel foundries, coal tar and related products, carbon black and carbon electrodes production.

PATIENTS AND METHODS

This paper reviews the results from cohort studies conducted on workers exposed to PAHs in these industries, with a focus on cancers of the respiratory and urinary tract.

RESULTS

An excess risk from lung/respiratory cancers was found in most industries, the pooled relative risk (RR) being 2.58 (95% CI 2.28-2.92) for coal gasification, 1.58 (95% CI 1.47-1.69) for coke production, 1.40 (95% CI 1.31-1.49) for iron and steel foundries, 1.51 (95% CI 1.28-1.78) for roofers and 1.30 (95% CI 1.06-1.59) for carbon black production. The evidence for cancers of the bladder and of the urinary system is less consistent, with a significant increased risk only for workers in aluminum production (pooled RR = 1.29, 95% CI 1.12-1.49), coal gasification (pooled RR = 2.39, 95% CI 1.36-4.21), and iron and steel foundries (pooled RR = 1.29, 95% CI 1.06-1.57).

CONCLUSIONS

Increased risks from lung and bladder cancers were found in PAH-related occupations. These were modest in most industries, apart from those for coal gasification, and whether they are due at least partially to some bias or confounding remains open to discussion.

Endovascular Therapy for Management of Oral Hemorrhage in Malignant Head and Neck Tumors

PURPOSE

To evaluate the efficacy and safety of endovascular therapy in oral hemorrhage from malignant head and neck tumors.

METHODS

Ten patients (mean age 56 years) with oral hemorrhage caused by malignant head and neck tumors underwent a total of 13 emergency embolization procedures using gelatin sponge particles, steel and/or platinum coils, or a combination of these embolic materials. Angiographic abnormalities, technical success rate, clinical success rate, recurrence rate, complications, hemostatic period, hospital days, survival days, and patient outcome were all analyzed.

RESULTS

Angiographic abnormalities were identified during 85% of procedures (11/13). The technical success rate was 100% (13/13 procedures). The primary and secondary clinical success rates were 77% (10/13 procedures) and 67% (2/3 procedures), respectively. The overall clinical success rate was 92%, and the recurrence rate was 22% (2/9 procedures) in patients whom we were able to observe during the 1-month period after embolization. No major complications occurred. Several patients in whom gelatin sponge particles had been used complained of transient local pain after the procedure. The median hemostatic period was 71 days (range 0-518 days). Median hospital and survival days were 59 days (range 3-209 days) and 141 days (range 4-518 days), respectively. Three patients survived and 7 patients died during the observation period. Only 1 of these 7 patients died from hemorrhage.

CONCLUSION

In conclusion, our findings suggest that endovascular therapy is an effective, safe, and repeatable treatment for oral hemorrhage caused by malignant head and neck tumors.

[Striated muscle microvascular response to implants with sol-gel calcium phosphate coating. A comparative in vivo study]

AIM

Local microvascular perfusion plays an important role in reparative processes and the pathogenesis of infection. The impairment of skeletal muscle microcirculation by a biomaterial may therefore have profound consequences. The aim of our study was to determine whether the biological acceptance of the widely utilised implant material stainless steel can be improved by a coating of sol-gel calcium phosphate.

METHODS

Using the hamster dorsal skinfold chamber preparation and intravital microscopy, we quantified nutritive perfusion and leukocyte-endothelium interaction in skeletal muscle after implantation of sol-gel calcium phosphate-coated stainless steel- and commercial pure titanium implants, and compared these results to those obtained with uncoated stainless steel and titanium.

RESULTS

Within the first 24 h after implantation, animals with calcium phosphate coated stainless steel showed a significantly lower inflammatory response than did those with an uncoated stainless steel implant. After 24 h the quantified microcirculatory parameters deteriorated for animals with a calcium phosphate-coated stainless steel plate, indicating that, for as yet unknown reasons, the shielding mechanism of the calcium phosphate seems to deteriorate. Although not as inert as pure titanium, we found a relatively low inflammatory response for calcium phosphate coated titanium over the whole observation period, suggesting that the coating as such is well tolerated by the skeletal muscle microcirculation.

CONCLUSIONS

Our in vivo results suggest that the biological acceptance of a conventional stainless steel implant can be improved over a short term by a sol-gel coating of calcium phosphate. Concerning tolerance by the local vascular system, commercially pure titanium currently remains unsurpassed.

[Changes in the local nonspecific immune response to post-traumatic inflammation during treatment]

Clinical investigation have been done in adult patients with broken mandible during 3 weeks of conservative treatment with aluminum splints (1st group, n = 17) or steel splints (2nd group, n = 16) in comparison with health adults (control group, n = 18). The neutrophil emigration into alterative locus and their degranulation as well as phagocytic activity of peripheral blood neutrophils were tested. It was found that aluminum splint application caused the intensive inflammation and then the depression of local host defense reactions. Treatment with steel splints did not lead to neutrophil function depletion or to hyper-intensification of inflammatory reaction in patients. The increased values of neutrophil reactions were normalized in this group at the final period of the treatment. The examined trial ensures our accurate method in treatment of patients with broken mandible. The determination of local host defense state may be proposed as preferable simple express-method of evaluation of immune status, treatment efficiency and prognosis in these patients.

Ten-year update on mortality among mild-steel welders

OBJECTIVES

This study is an update on the lung cancer risk of mild-steel welders with no asbestos exposure using a cohort of nonwelders for comparison.

METHODS

The subjects came from three United States (US) plants that manufactured heavy equipment. The follow-up was extended from 1988 to 1998. The welders were not exposed to asbestos (typical of shipyard welders) or to chromium or nickel (present in stainless steel).

RESULTS

There were 108 lung cancer deaths among the welders and 128 such deaths among the nonwelders (double the previous number of lung cancer deaths). The standardized mortality ratio (SMR) for lung cancer was 1.46 [95% confidence interval (95% CI 1.20-1.76] for the welders and 1.18 (95% CI 0.98-1.40) for the nonwelders, both in comparison with the US general population. Direct comparison between the welders and nonwelders yielded a rate ratio of 1.22 (95% CI 0.93-1.59). Analyses using a 15-year lag time did not differ greatly from those of an unlagged analysis. There were no marked trends for lung cancer risk by duration of exposure or latency. Evidence from cross-sectional data from a sample of the cohort indicated that the welders smoked somewhat more than the US population and more than the nonwelders. An approximate adjustment of the rate ratios for possible confounding by smoking suggested that smoking may have accounted for about half of the excess lung cancer observed among the welders versus that of either reference population. CONCLUSIONS These data provide suggestive but not conclusive evidence of a modest lung cancer risk from mild-steel welding.

Recovery of an impalement and transfixion chest injury by a reinforced steel bar

A 36-year-old man was admitted to our hospital because of impalement injury due to a downwards fall upon some reinforced steel rods. An emergency operation was performed using percutaneous cardiopulmonary support (PCPS). The steel rods were taken out in the operating room. The heart, great vessels, vertebrae, and spinal cord were not involved in the impalement wounds. We performed a bronchoplasty of the torn and separated right main bronchus, and repaired the impaled left lung without any pulmonary resection. He recuperated without sequelae.

Risk of lung cancer in workers producing stainless steel and metallic alloys

OBJECTIVES

The mortality of workers involved in the production of stainless and alloyed steel from 1968 to 1992 was studied, in order to investigate the risk of lung cancer due to exposure to metals, i.e. iron oxides, chromium and/or nickel compounds.

METHODS

The study design was a historical cohort mortality study and a nested case-control study concerning lung cancer. Standardized mortality ratios (SMRs) were computed using regional mortality rates as an external reference for comparing observed and expected numbers of deaths, adjusting for age, sex and calendar time. Conditional logistic regression was used to estimate odds ratios (ORs). Occupational exposure was assessed through the complete job histories of cases and controls and a specific job-exposure matrix.

RESULTS

The cohort comprised 4,288 male and 609 female workers. The observed overall mortality was significantly lower than expected [649 deaths; SMR = 0.91; 95% confidence interval (CI) 0.84-0.98]. No significant SMR was observed for mortality from lung cancer (54 deaths; SMR = 1.19; CI 0.88-1.55). The case-control study was based on 54 cases and 162 individually matched controls. Smoking habits were available for 71%. No lung cancer excess was observed for exposure to (1) metals and/or their compounds, i.e. iron (OR = 0.94, CI 0.48-1.86), chromium and/or nickel (OR = 1.18, CI 0.62-2.25), and cobalt (OR =0.64, CI 0.33-1.25), (2) acid mists (OR = 0.43, CI 0.17-1.10), and (3) asbestos (OR = 1.00, CI 0.54-1.86). With respect to exposure to polycyclic aromatic hydrocarbons (PAHs) and silica, which are often found together in workplaces, (1) high and statistically significant lung cancer excesses were observed, the ORs being 1.95 (CI 1.03-3.72) and 2.47 (CI 1.28-4.77) respectively, (2) quantitative exposure parameters revealed upward trends reaching statistical significance (P < 0.05), and (3) adjustments for tobacco consumption did not reveal any confounding factors from smoking.

CONCLUSION

This study failed to detect any relationship between lung cancer and exposure to iron, chromium, nickel and/or their compounds. High and statistically significant relative risks, along with increasing trends, were observed for simultaneous exposure to PAHs and silica.

Pulmonary fibrosis in a steel mill worker

We report a case of pulmonary fibrosis in a 32-year-old man, who had worked at a steel mill and who died of respiratory failure due to interstitial fibrosis despite vigorous treatment. He showed SLE-associated symptoms, such as pleural effusion, malar rashes, discoid rashes, arthritis, leukopenia, and positive antinuclear antibody and anti-histone antibody. However, he did not present anti-DNA antibody. A thoracoscopic lung biopsy showed interstitial fibrosis, chronic inflammation and a small non-caseating granuloma in lung tissues, which could be induced by external agents such as metals. The manganese concentration in the lung tissue was 4.64 microg/g compared to 0.42-0.7 microg/g in the controls. The levels of other metals, such as iron, nickel, cobalt and zinc in patient's lung tissue were higher than those in the controls. The patient was probably exposed to Si and various metal dusts, and the lung fibrosis was related to these exposures. Exposure to Si and metal dusts should be sought in the history of any patient with SLE, especially in a male with pulmonary signs, and if present, exposure should be stopped. In the meantime, steps should be taken to ensure that workers exposure to Si and metal dusts in all environments have adequate protection.

Striated muscle microvascular response to silver implants: A comparative in vivo study with titanium and stainless steel

Local microvascular perfusion is the primary line of defense of tissue against microorganisms and plays a considerable role in reparative processes. The impairment of the microcirculation by a biomaterial may therefore have profound consequences. Silver is known to have excellent antimicrobial activity and, although regional and systemic toxic effects have been described, silver is regularly discussed as an implant material in bone surgery. Because little is known about the influence of silver implants on the adjacent host tissue microvasculature, we studied in vivo nutritive perfusion and leukocytic response, and compared these results with those of the conventionally used materials titanium and stainless steel. Using the hamster dorsal skinfold chamber preparation and intravital microscopy, the implantation of a commercially pure silver sample led to a distinct and persistent activation of leukocytes combined with a marked disruption of the microvascular endothelial integrity, massive leukocyte extravasation, and considerable venular dilation. Whereas animals with stainless-steel implants showed a moderate increase in these parameters with a tendency to recuperate, titanium implants caused only a transient increase of leukocyte-endothelial cell interaction within the first 120 min and no significant change in macromolecular leakage, leukocyte extravasation and venular diameter. After 3 days, five of six preparations with silver samples showed severe inflammation and massive edema. Thus, the use of silver as an implant material should be critically judged despite its bactericidal properties. The implant material titanium seems to be well tolerated by the local vascular system and currently represents the golden standard.

No risk of metal toxicity in combined spinal-epidural anesthesia

Using the single level needle-through-needle technique for combined spinal-epidural anesthesia (CSE) may introduce very fine metal particles abraded by the spinal needle from the inner ground edge of the Tuohy needle into the patient. Either the local anesthetic administered epidurally or the peridural catheter may also pass intrathecally through the hole in the dura made by the spinal needle. To examine these concerns, the needle-through-needle technique was simulated in an in vitro model (18-gauge Tuohy needle; 27- or 29-gauge Quincke needle). The presence of abraded metal particles was identified by atomic absorption spectrography (AAS). The needles were then examined under an electron microscope. Metal particles could not be identified by using AAS in the needle-through-needle technique after normal clinical use, nor could traces of use be revealed by using an electron microscope to examine the Tuohy needle. With intentionally rough handling and caudal orientation of the spinal needle tip, minimal scratches could be seen by using an electron microscope, but there were no metal particles detected by AAS. In an anatomical preparation, the possible passage of the epidural catheter anesthetic through the dural puncture hole into the cerebrospinal fluid compartment was investigated endoscopically. Neither passage of dyed epidural local anesthetic nor penetration of the epidural catheter into the cerebrospinal fluid compartment could be demonstrated by endoscopy. We conclude that the needle-through-needle-technique is an acceptable way of performing CSE anesthesia. Endangering the patient by an unintentionally intrathecal misplacement of the epidural catheter seems to be very unlikely based on our in vitro model if small spinal needles (27- or 29-gauge) are used.

IMPLICATIONS

Atomic absorption spectrography shows no contamination of the intrathecal compartment by abraded metal particles from the Tuohy needle by combined spinal-epidural anesthesia with the needle-through-needle technique. In vitro, neither passage of dyed epidural local anesthetic nor penetration of the epidural catheter into the cerebrospinal fluid compartment could be demonstrated by endoscopy.

A nested case-control study of bladder cancer incidence in a steel manufacturing plant

BACKGROUND

A surveillance study of bladder cancer incidence in northwestern Illinois detected a number of cases who had worked in a large steel manufacturing plant. To investigate these cancers further, a nested case-control study of bladder cancer was conducted at this plant.

METHODS

Cases from the surveillance study were matched to company personnel files. Four controls per case were selected from company files and frequency matched on age (cases and controls were all white males). Employment histories were abstracted from company records and odds ratios calculated according to job titles and departments worked. Cases and controls who held only white collar jobs were excluded from the analysis.

RESULTS

Results for 16 cases and 75 controls showed elevated odds ratios for heaters (OR = 21.1, 95% cCI = 2.2-205.8) based on three cases. Heaters monitored electric reheat furnaces and may have been exposed to polycyclic aromatic hydrocarbons. Previous studies have shown moderate risks for bladder cancer among furnace operators, but most of these studies were also based on a small number of cases.

CONCLUSIONS

Additional studies of furnace operators' exposures and cancer risks are needed to investigate these results further.

Long-term monitoring of the immune reactivity of stainless steel welders

The immune reactivity of stainless steel welders (n = 22-53) was evaluated in a three year's study. The results (phagocytic activity, cellular and humoral immunity) were statistically compared with those in control group of non-exposed persons from the same plant (n = 14-23) and with long-term laboratory reference values (LRV) (n = 14-311). In welders several changes were found when compared to the LRV: in humoral response there were higher prealbumin, lysozyme, circulating immune complexes and lower IgG. In phagocytic tests there were lower ingestion, bactericidal activity and higher metabolic activity of peripheral mononuclear leucocytes. In cellular immunity the marked lymphocytosis, higher counts of T-lymphocytes, CD4+ and CD8+ lymphocytes were noticed. After lowering the concentrations of metals in the working area there were trends to normal values in some parameters [relative numbers of T-lymphocytes, relative number of CD4+ lymphocytes, phagocytic activity, metabolic activity of leucocytes (INT index), IgA, complement C3, transferrin]. The extent and the length of the exposure to welding fumes, smoking and changed conditions at working place were followed as well.

Deaths and tumours among workers grinding stainless steel: a follow up

OBJECTIVE

To study cause specific mortality and cancer morbidity in workers exposed to the dust of grinding materials, grinding agents, and stainless steel, especially with regard to a possibly increased risk of respiratory, stomach, and colorectal cancer.

METHODS

Retrospective cohort study, using reference cohorts of blue collar workers and population rates for comparison. The exposed cohort comprises workers with at least 12 months employment time at two plants, producing stainless steel sinks and saucepans (n = 727). Also, reference cohorts of other industrial workers (n = 3965) and fishermen (n = 8092) were analysed. The observation period began 15 years after the start of employment. Standardised mortality or incidence ratios (SMRs, SIRs; county reference rates) were calculated for cause-specific mortality between 1952 and 1993, and for cancer morbidity between 1958 and 1992.

RESULTS

In the exposed cohort, overall mortality, cardiovascular mortality, and all malignant mortality and morbidity were slightly lower than expected. Also, the risk estimates for cancer in the upper and lower respiratory tracts and for stomach cancer were lower than expected. There was an increase in morbidity from colon cancer, which was explained by an excess of tumours in the sigmoid part only. Here, the risk estimates were higher in workers with long employment time (1-14 years: four observed cases, SIR 1.7, 95% confidence interval (95% CI) 0.4 to 4.5; > or = 15 years: three observed cases, SIR 4.3, 95% CI 0.9 to 13) and the increased risk was especially pronounced among those first employed before 1942. A slight nominal excess of rectal cancers (nine observed cases, SIR 1.4, 95% CI 0.6 to 2.6), and a significant excess of prostate cancer morbidity (36 observed cases, SIR 1.7, 95% CI 1.2 to 2.4) were found. These risk estimates did not, however, increase with employment time.

CONCLUSIONS

The finding of an increased risk of cancer in the sigmoid part of the colon, which was not found in the reference cohorts, and with indication of a relation between duration of employment and response, is consistent with a causal relation. The limited size of the exposed cohort makes a detailed exposure-response analysis unstable, and the confidence limits are wide. Albeit slightly raised, the risk estimate for rectal cancer in the exposed cohort was not different from the estimate among the other industrial workers.

60Co contamination in recycled steel resulting in elevated civilian radiation doses: causes and challenges

Since late 1992, more than 100 building complexes containing public and private schools and nearly 1,000 apartments have been identified in Taiwan with elevated levels of gamma-radiation from construction steel contaminated with 60Co. Due to improper handling of 60Co contaminated scrap steel in late 1982 and 1983, contaminated construction materials have been widely distributed throughout the country. These contaminated construction materials have generated elevated radiation exposures to members of the public in Taiwan. As of early 1996, more than 4,000 people, including young students, have been identified as receiving more than 1 mSv y(-1) above the local background for up to 12 y. This report provides a detailed discussion of the sources of the 60Co contamination in construction steel, its discovery in the building complexes, and preliminary evaluation and remediation activities.

Asthma, lung function, and bronchial responsiveness in welders

The incidence of asthma was compared in welders welding in stainless steel (SS) or mild steel (MS). The study was comprised of welders who had been welding for at least 6 months during the preceding 10 year period in four companies, but who had not been welding occupationally prior to this time. The inclusion criteria were met by 42 SS welders with a total welding time of 196 years. Sixteen of these had left work, six because of airway symptoms. Eighty-five MS welders with a total welding time of 403 years were included. Forty-eight of these had left work, 10 citing airway symptoms as a main reason for leaving work, according to responses in a mailed questionnaire. Ex-welders with airway symptoms were in some cases further investigated with spirometry and bronchial provocation tests. In other cases, medical records gave a clear diagnosis. In addition, bronchial responsiveness and lung function were measured and airway symptoms were recorded in presently active welders. Twenty-three of the 26 active SS steel welders and 23 of the 37 active MS steel welders were examined, together with a reference group of 26 (out of 30 invited) vehicle assemblers. There was no difference in the incidence of welding-associated asthma (5% for SS, 7% for MS welders per 1,000 welding-years). Bronchial responsiveness and lung function in active welders was normal and did not differ between MS and SS welders or between welders and a reference group of vehicle fitters. Welders had a significantly higher prevalence of airway symptoms as compared to vehicle fitters.

Erythrocyte antioxidant system and serum ceruloplasmin levels in welders

The erythrocyte antioxidant system (superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione) and serum ceruloplasmin were studied in workers chronically exposed to welding fumes and gases, which are thought to be oxidant pollutants. Fifty-four healthy men using two electric arc welding processes (manual metal arc on stainless steel and mild steel, and metal inert gas on mild steel) were studied. The possible effects of cigarette smoking were also considered. The erythrocyte antioxidant system was in the normal range for all welders. Serum ceruloplasmin was significantly enhanced only in smoking welders and higher in manual metal arc than in metal inert gas welders, suggesting that the increase is related to the severity of the oxidant threat, which is more stressful for the workers using the manual metal arc technique because of the presence of stainless steel particles in the fumes. Although cigarette smoking alone did not increase serum ceruloplasmin levels, it affected the response to oxidant stress in welders.

[Medical ENT endoscopic studies in the iron and steel industry]

461 chromium- and nickel-exposed steelworkers were otolaryngologically examined by endoscopy. Besides chronic inflammatory diseases of the ear, nose and paranasal sinuses, the clinical diagnosis of leukoplakia and hyperplastic laryngitis was made for 30 workers. In no case a lesion suspicious of cancer was found. Office staff showing no such occupational risk factors served as the control group. It was found that in both groups smoking has to be assumed as the decisive factor for the development of chronic inflammation and precancerous changes in the oral cavity and the larynx.

Corrosion potential of steel bird shot in dogs

Each year many dogs are accidentally or purposely wounded with shotguns. When lead pellets were used exclusively in the past, clinical problems from chronically embedded shot seldom developed except for rare cases of lead toxicosis. However, because expended lead shot ingested unintentionally by waterfowl and other avian species is fatal, the US Fish and Wildlife Service mandated exclusive use of steel shot for waterfowl hunting beginning in 1991. To discover the effects of implanted steel shot in a biological system, in vitro and in vivo studies were performed. Severe surface corrosion was evident when steel shot was placed in physiologic saline solution and sterile canine plasma. Eight laboratory dogs were surgically implanted with sterile steel shot in various superficial locations for intervals of 2 to 26 weeks. Corrosion of implants and tissue inflammation was observed in all biopsy specimens examined. It has been shown that steel shot embedded in tissues will corrode and result in a severe inflammatory response. If the accompanying inflammation is complicated by bacterial contamination, foreign body reactions resulting in infected, draining tracts could develop. Veterinarians and dog owners should be aware that treatment and prognosis for wounds caused by steel shot may differ from those for similar wounds caused by lead shot.

Microscopic haematuria as a predictor of urological diseases among steel workers

A cohort of 501 workers in a steel mill in Ontario, Canada was followed up from 1974 to 1986 for 13 years. Results indicate that the 13-year cumulative incidence of urological diseases among workers who had a positive urinalysis result of microscopic haematuria at the beginning of the follow-up period (1974) was 1.3 times that of those who had a negative urinalysis result (95% confidence interval 0.6-2.8). This relative risk remained the same after adjusting for age and smoking. This indicates that there is a possibility that urinary screening for microscopic haematuria could be a useful predictor of urological disease occurrence. However, the benefits of early detection and management were difficult to demonstrate. Serious urological diseases, particularly urinary cancers, were not detected earlier as a result of the urinary screening test in this study. Several studies have been done to validate the test in the past. More work to validate the test and to determine the predictive accuracy is recommended.

Comparison of the reaction of the cornea to nylon and stainless steel sutures: an animal study

In 11 rabbits a comparison was made between the reactions of the cornea to nylon and to stainless steel sutures, macroscopically and by means of scanning electron-microscopy (SEM). Macroscopically, the wounds sutured with steel thread showed much less reaction than the wounds sutured with nylon. Vascularization was never encountered in the wounds sutured with steel thread. SEM examination also showed clear differences, which became noticeable within a short time. Both on the suture and round the opening in the cornea extensive deposits of material are seen within a short time (1 week) in the case of nylon, in the case of stainless steel this reaction is much less marked. A few weeks later deposits also appear on the steel thread, but these have a different composition and contain no material suggestive of an inflammatory reaction.

Tissue reaction to suture materials in infected surgical wounds--a histopathologic evaluation

Suture materials are foreign bodies which induce and prolong tissue reaction in the wound area. Cellular responses to infected wounds containing 7 suture materials (braided polyglycolic acid [BPGA, Dexon], multifilament stainless steel, monofilament nylon, black braided silk, braided Dacron [Mersilene], and plain and chromic catgut) were studied at 6, 10, 20, and 40 days. Cellular reaction varied with different suture materials. In general, neutrophils were the predominant cells in acute infection, but later, macrophages and fibroblasts predominated. Occasionally, plasma cells, lymphocytes, eosinophils, and giant cells were present. In the infected wounds with implants of plain catgut, chromic catgut, silk, and braided Dacron, there were large numbers of neutrophils even in chronic implantation, indicating persistence of local infection. With nylon, steel, and BPGA, the number of neutrophils rapidly decreased. Although BPGA induced intense acute reaction, the response was mild in chronic implantation. It appeared to be absorbed more slowly than plain or chromic catgut, and tissue reaction was minimal in the absorption stages. A reaction similar to the Splendore-Hoeppli phenomenon was seen around multifilament silk strands in chronic stages of implantation.

Chronic vascular reactions to steel coil occlusion devices

Original Gianturco steel coil vascular embolization devices and two modifications were compared for their occlusive effects and for the degree of adverse reaction in the surrounding vessel wall. Modifications consisted of silk or Ivalon replacing the wool strands of the original device. Single coils were placed into the left renal artery of nine mixed breed swine and restudied 3 months later. The bare coils did not occlude the vessels nor lead to significant foreign body reaction. Wool, silk, and Ivalon coils produced prompt and sustained renal artery occlusion. Upon histologic examination of the vessel wall, foreign body and chronic inflammatory reaction was found to be strongest against wool. This reaction was less with silk and markedly diminished with Ivalon. The results indicate that silk and Ivalon coils, while having the same occlusive effect, are preferable to wool coils if less local reaction is desired.

[Prevalence of penumoconiosis in a steel-plant (author's transl)]

Chest X-rays of 483 steel workers employed in the same factory were examined by the authors and classified according to the ILO U/C 1971 classification for pneumoconiosis. The prevalence of pneumoconiosis was found to be 8.4%. The majority of the positive cases were detected among the furnace workers and then among presse and rolling-mill workers. Only one positive case was found among the workers of the other foremen. It is stated that the furnace is the main source of pollution and that the lack of protective systems spreads the risk also to the surrounding working sites. No significant differences were found as for the opacity features.