Parkinson's disease and brain levels of organochlorine pesticides.

Epidemiological studies have suggested an etiologic relationship between pesticide exposure and Parkinson's disease (PD). Organochlorine pesticides were assayed in postmortem brain samples from 20 PD, 7 Alzheimer's disease (AD), and 14 nonneurological control cases. The three groups were similar in age at death, sex, and demographic variables. Only two of 16 pesticide residues screened were detected. A long-lasting residue of DDT (pp-DDE) was found in the majority of cases of PD and AD, as well as in all the control cases; pp-DDT was significantly more likely to be found in AD controls than the PD cases (Fisher's exact two-tailed, p = 0.04). Dieldrin was detected in 6 of 20 PD brains, 1 of 7 AD, and in none of 14 control samples. Despite the relatively small number of brains assayed, the association between Dieldrin and the diagnosis of PD was highly significant (p = 0.03). Dieldrin, a lipid-soluble, long-lasting mitochondrial poison, should be investigated as a potential etiological agent of Parkinsonism.

The role of the laboratory in pesticide management

The chemical laboratory plays a pivotal role in pesticide management. Without the ability to identify and measure the chemicals, it is difficult to formulate, assess residues, or monitor for contamination. The chemistry laboratory is capable of providing information on environmental behavior, persistence, hazards and residues. There are many methods of analyses, but the most commonly employed are thin-layer chromatography, gas chromatography and liquid chromatography. Thin-layer chromatography is cheap, rapid and easy to learn. It offers many advantages where resources are scarce and the ultimate in sensitivity are not required. A laboratory equipped with gas chromatography and other instruments can serve as a backup for many of the primary laboratories using simpler analyses (AU)

Behaviour of synthetic absorbable sutures with and without synergistic enteric infection.

The behaviour of synthetic absorbable sutures, polyglycolic acid (PGA) and polydioxanone (PDS), has been tested in an experimental guinea pig model utilising synergistic enteric bacteria. Braided PDS gave a wound sepsis rate of 42%, monofilament PDS 36%, and PGA 26%, while sepsis rate in the controls was 30%. The dissolution characteristics of PGA and monofilament PDS appeared to be unaffected by the presence of infection, while that of braided PDS was significantly increased. Braided PDS also showed more rapid dissolution characteristics than PGA.

Development and application of methodology for determining 1,2-dibromo-3-chloropropane (DBCP) in ambient air.

A method previously described by Mann et al. for the determination of hexachlorobenzene in air was modified to detect DBCP in air at the level of 0.02 ppb (by volume). The method utilizes Chromosorb 101 as a trapping medium with subsequent analysis of the eluted DBCP by electron capture--gas chromatography. The procedure was tested using air flows of 1 1/min to 5 1/min for sampling periods of 30 min to 3 hr. Recoveries of greater than 90% wer obtained for DBCP levels ranging from 0.07 ppb to 20 ppm. More than 90% of the DBCP stored on Chromosorb 101 at ambient temperature for one month was recovered. A one-half acre field plot was sprayed with DBCP using the drench method. Air samples were taken from the breathing zone of the applicator during the mixing, spraying and clean-up procedures. Air samples were also taken periodically around the perimeter of the plot for up to 7 days after spraying.

Evaluation pf methodology for determining 1,2-dibromoethane (EDB) in ambient air.

EDB (ethylene dibromide) is of regulatory interest because it has cancer inducing properties and is a causative agent of aspermia. Methodology used in determining the extent of exposure of workers to EDB in a citrus fumigation facility was evaluated. The purpose of this effort was to develop and/or evaluate the methodology. A number of solid adsorbents were evaluated for trapping EDB. Charcoal was found to be the most efficient for this application. The influence of a number of factors, e.g., humidity, biphenyl concentration and solvents, on trapping and elution efficiency was determined. The level of sensitivity attained in these studies exceeds that necessary to monitor the proposed standard of a maximum of 1 mg/m3 for a 15 min occupational exposure.

Field application of evaluated methodology for determining 1,2-dibromoethane, EDB, in ambient air.

EDB (ethylene dibromide) is of regulatory interest because it has cancer inducing properties and is a causative agent of aspermia. Previously evaluated methodology was used to determine the extent of exposure of workers to EDB in citrus fumigation stations and a warehouse used as a holding site before shipment. The purpose of this effort was to carry out environmental sampling, and to determine the exposure level of workers and related administrative personnel at two citrus fumigation centers and at a warehouse.

Analytical methodology for the determination of Kepone residues in fish, shellfish, and Hi-Vol air filters.

The recent discovery of the pollution of the environment with Kepone has resulted in a tremendous interest in the development of residue methodology for the compound. Current multiresidue methods for the determination of the common organochlorinated pesticides do not yield good quantitative analytical results for Kepone. The extracting solvents are usually of insufficient polarity to extract Kepone from the various media. This article describes some of the recently developed methodology for Kepone in air filters, finfish, finfish livers and entrails, shellfish, and archival oyster samples. The finfish and archival oyster samples were Soxhlet extracted using diethyl ether/petroleum ether (1:1 v/v) as the extracting solvent. The finfish livers and entrails were macerated in a Duall tissue grinder containing acetonitrile followed by partitioning of the Kepone into benzene. Shellfish samples were analyzed after extracting the sample with acetonitrile and partitioning the Kepone into benzene. The Hi-Vol air samples were extracted with methanol/benzene (1:1 v/v). The coextracting contaminants were removed by micro-Florisil column chromatography and/or acid digestion. The procedural recovery of Kepone from fortified samples averaged 82%.