OBJECTIVEExposure to polychlorinated biphenyls (PCBs) is considered to have culminated between 1950 and 1970 in Japan, and exposure through diet, the major exposure route, has decreased significantly over the last 10 years. The primary goal of the present study was to investigate the long-term trends and congener profiles of serum and dietary levels of PCBs using historical samples.

METHODSUsing banked samples collected in 1980, 1995, and 2003 surveys, we determined the daily intakes and serum concentrations of 13 PCB congeners (#74, #99, #118, #138, #146, #153, #156, #163, #164, #170, #180, #182, and #187) in women.

RESULTSThe total daily PCB intake [ng/day, geometric mean (geometric standard deviation)] decreased significantly from 523 (2.5) in 1980 to 63 (3.2) in 2003. The serum total PCB level (ng/g lipid) in women <40 years of age decreased significantly from 185 (1.8) in 1980 to 68 (1.8) in 2003. In contrast, the level in women >50 years of age increased significantly from 125 (1.7) in 1980 to 242 (1.7) in 2003. Specifically, the serum concentrations of hexa (#138, #146, #153, #156, #163, and #164) and hepta (#170, #180, #182, and #187) congeners increased significantly. A comparison of the serum PCB levels of women born from 1940 to 1953 revealed that their serum total PCB level was significantly higher in the 2003 survey [242 (1.7), n = 9] than in the 1995 [128 (2.0), n = 17] surveys. This increase in the total PCB level was attributable to increases in the hepta congener groups.

CONCLUSIONPresent results suggest a decreased rate of elimination of hepta congeners with aging in females, rather than a birth-generation phenomenon.

In order to protect farmers from health hazards posed by soil fumigation with methyl bromide in greenhouses, the authors monitored the concentrations of the fumigant inside greenhouses, before and after fumigation and measured occupational exposures. In the meantime, a questionnaire survey was conducted to find out the facts about working conditions, health effects and personal protective equipment in 1996.
As environmental concentrations of methyl bromide decreased from 2200ppm to 1100ppm gradually in three days, two farmers were exposed to 57ppm and 25ppm, in opening up the greenhouses, respectively, which are above ACGIH's TLV-TWA (1ppm) and OSHA's PEL-C (20ppm). The questionnaire survey (n=164) found that about 80% of the respondents have fumigated inside the whole greenhouse without mulch, above 90% have opened up greenhouses within 5 days, and that only 10% have worn effective gas masks and clothes. Regarding subjective symptoms after fumigation, 2%-6% of respondents complained about eye and respiratory tract irritation.
These results suggest that farmers might be exposed to high concentrations of methyl bromide in opening up greenhouses. In order to prevent health hazards of methyl bromide, education programs on toxic information and health effects of methyl bromide, and safety training in soil fumigation should be provided to farmers.

Agriculture has been reported as one of the most dangerous industries, but there are a very few statistical reports about agricultural injuries and accidents in Japan. The authors conducted analyses of agricultural injuries and accidents data from 1992 to 1995 (n=333) in Kochi, in order to discuss issues of agricultural safety and health, and the characteristics of agricultural injuries and accidents among aged farmers.
The average age of 333 patients, including 13 deaths, was 57.1 years old, and 174 patients (52.3%) were over 60 years old. One hundred and thirty seven accidents (41.4%) occurred during the period from July to September. Injuries resulting from falls topped the list with 101 patients (30.3%), followed by pinchs and involvements with 58 (17.4%), cuts and lacerations with 54 (16.2%), and slips with 36 (10.8%). The injury causes were agricultural machinery in 134 patients (40.2%), agricultural facilities in 34 (10.2%), motor vehcles in 27 (8.1%), and farm animals in 18 (5.4%). The rate of fall accidents was significantly higher among people over 60 years old than among those under 60 years old (p<0.001). The rate of serious injuries and accidents was significantly higher among people over the age of 60 than among those under the age of 60 (p<0.01).
Considering these results, effective and feasible preventions for agricultural injuies and accidents must be safety education and training, safety procedure manuals, which should be easy to understand for aged farmers, and improvements of agricultural machinery and eqiupments.