210Pb, 210Po, 226Ra, U and Th in arable crops and ovine liver: variations in concentrations in the United Kingdom and resultant doses.

Concentrations of a range of naturally occurring radionuclides have been determined in the same crops grown at two sites in the UK. Ovine liver has also been studied. One site was in an area where concentrations in soil are typical of the UK (the 'control' site) and the other in an area where levels were well above average (the 'test' site). For an average adult consumer of all of the foodstuffs studied, the doses from consumption for the test site were about 4 times higher than those for the control site. However, the differences were small compared with the variability in overall doses from natural background across the UK. 210Pb and 210Po were important contributors to doses for both sites, but at the test site the contribution from 226Ra was also significant. Of the foodstuffs studied, consumption of leafy vegetables and liver gave the highest doses. The doses from leafy vegetables were sensitive to the weather conditions prior to harvesting. Consequently, rigorous monitoring programmes should be based on several samples collected throughout the year; extrapolations based on a single annual sample are unlikely to be reliable.

Concerns of the dry-cleaning industry: a qualitative investigation of labor and management.

BACKGROUND: Occupational scientists agree there are hazards associated with dry-cleaning, but do dry-cleaning owners and workers concur? Knowledge of owners' and workers' perceptions can help guide intervention efforts to reduce worker exposure. To better understand these issues, a qualitative study was conducted using focus group methodology and constant comparative analysis. METHODS: Two owner and four worker focus groups were held. RESULTS: Findings suggest that overall, health and safety issues were not of great concern. Owners were primarily concerned with the economic impact of regulations. Workers did express some anxiety about solvent exposure and burns, but most felt that these hazards were "just part of the job." Also, other than the installation of air-conditioning in the shops and the provision of health benefits, workers could not think of ways health and safety on the job could be improved. CONCLUSIONS: These findings will be used to develop comprehensive safety and health interventions (e.g., engineering plus education and training) in dry-cleaning shops.

Investigations of the potential bioavailability of 210Po in some foodstuffs.

Extraction of 210Po from lamb's liver, pig's kidneys, mussel flesh and brown crabmeat with a series of solvent systems has been used to gain some insight into the uncertainty about the gastrointestinal absorption factor for Po incorporated into foodstuffs. By extracting the tissues with diethyldithiocarbamate dissolved in chloroform, and also in methanol, it has been shown that 210Po is more effectively extracted from lamb's liver and crabmeat than it is from each of the other tissues. A similar pattern of extractability is also evident for aqueous solutions of citric acid on crabmeat and mussel flesh. Of particular note is the low extractability by dimethylsulphoxide (3%) of 210Po in mussel flesh as opposed to 24% extractability of 210Po from crabmeat. 210Po-binding macromolecules of about 10 kDa have been released from crabmeat and mussel flesh by digestion with pepsin.

Clean-up of lead in household carpet and floor dust.

Methods to remove lead-containing dust were tested on carpets from homes of children with high blood lead and on new carpets artificially contaminated in the laboratory. The household carpets could not be cleaned effectively by repetitive vacuuming with HEPA-filtered cleaners. The lead concentration in the removed dust remained about the same from the initial cleaning (1 min/m2) to the final cleaning (total cleaning time of 10 min/m2). The lead loading on the surface of the carpets often increased during cleaning because vacuuming brought lead from deeper in the carpet to the surface. Over 95% of the total dust was removed from bare wooden floors by dry vacuuming (5 min/m2). For linoleum, more than 75% was removed by vacuuming for 5 min/m2. However, little was removed in vacuuming after the initial two minutes and about 20% was removed in a final wet-washing step. HEPA-vacuuming of the laboratory-contaminated carpets revealed that two of the commercially available vacuum cleaners tested were essentially equivalent and each removed significantly more dust than a third vacuum during a total cleaning time of 10 min/m2. Cleaning for 6 min/m2 was necessary to remove more than 70% of the embedded dust by the two more efficient vacuums. Cleaning efficiencies were about the same for short pile and sculptured carpets. It was concluded that it may be more practical to replace rather than clean carpets. HEPA-vacuum cleaning of carpets was shown to increase lead dust on the surface under some conditions.