A comparative study of the phagovars, antimicrobial susceptibility patterns, and plasmid profiles of 119 strains of Salmonella Enteritidis isolated from food poisoning was carried out to determine the most adequate markers in epidemiological investigations. An epidemiological pattern (consisting of a phagovar 4 and 60kb plasmid) emerged as the predominant pattern in Nagano prefecture during the study period.

Characteristics of the components of suspended particulate mater (SPM) were investigated, as well as their seasonal variations and compositions in the mountainous and urban areas. The mountainous sampling site was Happo Ridge at an altitude of 1850m and the urban site was the city area in Nagano, the both being in the central mountainous region in inland area of Japan. SPM was sampled by filtering air on a quartz fiber filter set in a low volume air sampler, with a flow rate of 20 1 min E-1 and for a period of one month. In the mountainous area, SO42- concentrations were much higher in spring and summer than those in fall and winter. Almost all of SO42- were considered to be produced by the photooxidation of SO2 and transported for a long distance into that area. Ca2+ concentration increased particularly in March and April in which yellow sand from the Asia Continent arrived at those sites. The seasonal variation of elemental carbon (EC) concentration was small, while organic carbon (OC) increased in spring and summer. This suggested that OC in spring and summer was produced by photochemical reaction. In the urban area, SO42- concentration increased in spring and summer. This seasonal variation was similar to that in the mountainous area, but that level was smaller. Ca2+ concentration increased in winter as a result of the road dust raised by cars. SO42- was most abundant in the mountainous area and attained more than 10 % of the SPM. EC, OC and SO42- were abundant in the urban area and all these components, respectively, were more than 10 % of the SPM. The total concentrations of chemical components analyzed attained 43 % and 68% of SPM in the mountainous and urban areas, respectively. Secondary components occupied 41% and 34% of the total components in the mountainous and urban areas, respectively. The contribution of secondary components in the mountainous area is larger than that in the urban area.

The Working Party finalized a review of chlorinated hydrocarbon substances in the African aquatic environment; the review is annexed to this report. The Working Group concluded that it had achieved its major goal to evaluate the state of the African aquatic environment and to review major groups of pollutants that could have negative impacts on aquatic life and fishery resources, i.e. organic matter, metals and organochlorine substances. Future studies could concentrate on phosphorus loads causing eutrophication and on the state of specific types of water bodies in Africa. The Working Party discussed its potential role in the preparations for the CIFA Seminar on African inland fisheries, aquaculture and the environment, scheduled for December 1994, and made suggestions for major inputs it could provide to the seminar.