Determination of organo-zinc based fungicides in timber treatments employing gas chromatographic analysis with mass selective detection and/or inductively coupled plasma atomic emission spectroscopy.

A method for the determination of zinc octoate (zinc 2-ethylhexanoate) and acypetacs zinc in occupational hygiene samples and wood treatments formulations is described. The zinc carboxylates are liquid-liquid partitioned between toluene and 1 M HCl, with the liberated acids being extracted into the toluene and zinc (chloride) into the acid. The carboxylic acids are then methylated using trimethylsilyldiazomethane-methanol and the resultant methyl esters are selectively and sensitively analysed by gas chromatography with mass selective detection (GC-MS). Alternatively, the zinc content of the acid extract can be analysed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). GC-MS is the preferred method of analysis for zinc octoate, where a single analyte (methyl-2-ethylhexanoate) is produced for analysis. Because acypetacs zinc contains a complex mixture of carboxylates, quantitative GC-MS analysis of the methyl esters produced is impractical and ICP-AES is the preferred method for quantitation. In this case, GC-MS can be used to confirm the identity of the product used. The analysis of occupational hygiene samples (cotton pads, gloves and socks as well as Tenax tubes and GF/A filters) spiked with metal carboxylates is demonstrated. Recoveries around 70-90% and reproducibilities of 5-23% (n=6-8) were typically achieved for the determination of tin octoate (a surrogate for zinc octoate) at spiking levels ranging from 4 to 190 microg per sampling device. Recoveries around 102-106% and reproducibilities of 10-12% (n=5-6) were typically achieved for acypetacs zinc at spiking levels ranging from 100 mg per sampling device. Reaction yields for the octoate methylation reaction were in the region of 85-87%. The method was used to monitor for occupational exposure to zinc octoate and acypetacs zinc during the application of wood treatments to fences.

Hygienists and operating auxiliaries: the opinions of New Zealand dental practitioners.

A postal survey was sent to the 1,122 members of the New Zealand Dental Association holding practising certificates in 1989. Replies were received from 53 percent, of whom 80 percent were general dental practitioners, and 45 percent had previously experienced working overseas with hygienists. Only 1 percent of respondents were opposed to any type of auxiliary working in New Zealand. At the time of the survey, 16 percent were already employing auxiliaries under Section 11 of the 1988 Dental Act. Six percent were employing hygienists and 10 percent were employing NZDA operating auxiliaries. A further 16 percent wanted to employ hygienists in the near future and 10 percent would consider employing NZDA operating auxiliaries. Altogether, 42 percent were employing or wished to employ auxiliaries (22 percent hygienist and 19 percent NZDA operating auxiliary). Dentists responding in this survey spent little time pursuing important hygienist-type duties themselves, but indicated that these were the tasks most likely to be delegated to auxiliaries. Most respondents thought that hygienists should be trained in New Zealand, and 60 percent felt the training should be at the School of Dentistry. The majority were of the opinion that the course should last 18-24 months. Eighty-one percent of respondents thought that former school dental nurses required additional training before being allowed to become auxiliaries, and 42 percent thought such additional training should be up to 3 months long and comprise a block course. Eighty-five percent thought there should be an examination at its completion. Approximately one-third of respondents were not prepared to be involved in training a person to perform auxiliary clinical duties.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhalation exposure in secondary aluminium smelting.

Inhalation exposure at seven UK secondary aluminium smelters was investigated to quantify the main exposures and identify their sources. The substances monitored were gases (carbon monoxide, hydrogen sulphide and nitrogen dioxide), total inhalable dust, metals, ammonia, polycyclic aromatic hydrocarbons (PAHs), particulate fluoride salts and acids. The results showed that people were exposed to a range of workplace air pollutants. Personal exposure results for total inhalable dust were between 700 and 5600 microg x m(-3) and the maximum personal exposure result for particulate fluoride salts was 690 microg x m(-3) (as F). The maximum aluminium, total PAH and lead personal exposure results were 900, 19 and 18 microg x m(-3) respectively. The average proportion of aluminium in total inhalable dust samples was 13% and rotary furnace processes generated the most dust. Particulate fluoride salt exposure was more widespread than hydrofluoric acid exposure. The source of the salt exposure was fluoride containing fluxes. The lead exposure source was lead solder contamination in the furnace charge.

Measurement of short-term exposure to airborne soluble platinum in the platinum industry.

A number of cases of respiratory sensitization to soluble platinum have arisen in the U.K. over the last few years, despite measured 8 h TWA exposure levels below the current long-term exposure limit in most cases. One possible cause of sensitization may be as a result of high exposures over short periods. Short-term sampling has been hampered by inadequate sampling and analysis techniques. This investigation has used two types of personal inhalable sampler, with ICPMS analysis, to take 15 min TWA soluble platinum exposure measurements at three sites. The lower detection limit for soluble platinum salts was approximately 0.01 microgram m-3 for 15 min samples, allowing exposures two orders of magnitude below the exposure limit to be measured. It was found that the majority of short-term exposure levels were significantly below 0.006 mg m-3. No evidence was found for altered work practices during sampling, indicating that either sensitization is occurring at airborne exposure levels below the exposure limit, or there is an alternate route of exposure.

Monitoring intensive care unit performance using statistical quality control charts.

This paper discusses results of a study in which mortality rates and APACHE II severity of illness scores of Intensive Care Unit (ICU) patients were monitored for a five-year period (1986-1990) using statistical quality control charts. The purpose of the study was to determine whether severity of illness of patients and mortality rates had changed significantly over this time horizon. The results show that the Intensive Care Unit process is stable and in statistical control. There is no apparent trend in the severity of illness scores nor mortality rates measured both at ten days and six months from the last ICU admission. Quality control charts, which have been used extensively to detect changes in industrial processes on a short term basis, provide a simple method of monitoring the ICU process over an extended time horizon.

Occupational exposure to metalworking fluid mist and sump fluid contaminants.

This paper summarizes the analytical and occupational hygiene findings from a recent survey of occupational exposure to metalworking fluids (MWFs) in the engineering industry. The aim of the survey was to link MWF mist exposure measurements with particular engineering processes and controls, and utilize the data obtained to develop exposure standards. At the same time the opportunity was taken to assess fluid management and control, including bacterial and fines contamination in the machine sumps. In general, occupational exposure to mineral oil MWF mist was controlled to <3 mg/m(3) (8 h time-weighted average) and to <1 mg/m(3) for water-mix MWF mist (in terms of the concentrate). These exposure values do not necessarily represent best practice, but are believed to be achievable and representative of industry as a whole. Gravimetric analysis of the total inhalable particulate was found to be a good predictor of mineral oil MWF mist but not for water-mix MWF mist. Grinding and drilling operations produced higher exposures than turning and milling for water-mix fluids. There were insufficient data to compare machining operations for mineral oil MWFs. On the whole, fluid management was found to be poor, with most sites failing to meet industry good practice or Health & Safety Executive (HSE) standards. Some of the operating procedures utilized were deficient or unsatisfactory. Poor standards of fluid management were found at all sizes of company. High levels of bacteria, endotoxin and fines were found in sumps, and control of other factors, such as water-mix fluid concentration, was often poor. Mineral oils had higher levels of fines than water-mix fluids (medians of 395 and 18 mg/l, respectively), and grinding produced high levels of fines in both types of MWF. Many water-mix sumps contained bacterial levels of >1 x 10(6) CFU/ml, and endotoxin levels of >100 000 EU/ml were not uncommon. The median values were 109 000 CFU/ml and 8039 EU/ml, respectively. Mists could potentially contain extensive contamination from bacteria and endotoxin. Analysis of the data suggests that sumps operating under typical conditions for machining (a temperature of 20 degrees C, a pH of 9 and a fluid strength below 10%), also appear to provide optimum conditions for the proliferation of bacteria. Low levels of benzo[a]pyrene (median 0.03 micro g/g) were found in the mineral oils, and low levels of N-nitrosodiethanolamine (median 0.4 micro g/ml) were found in the water-mix MWFs. The results of this work will contribute to guidance from the HSE, setting out accepted industry good practice, including guide values for MWF mist and sump fluid contaminants, with significant emphasis on sump fluid management (maintenance and monitoring), as well as control issues.