In 1982 a further study into Macroinvertebrates of the Yarra River; stated in regards to Wandin Yallock Creek that “pesticides appear to be the most likely toxic influence at this site. TDE, DDE, DDT and Dieldrin have been detected in the sediments at a site 2km downstream of a major market gardening and horticultural area, and DDT and Dieldrin have been found in the sediments of a site in the middle of the market gardening area…TDE, DDE, DDT and Dieldrin have been detected in sediment samples 8km downstream of areas of intensive market gardening and potato growing…” (Environmental Studies Program Ministry for Conservation. The Benthic Macroinvertebrates of the Yarra River and its Tributaries. By Ian C Campbell, Luisa A. Macmillan, A Jenny Smith, Maryanne E McKaige 1982. Environmental Studies Series Publication No 362)
Another study (31) published in 1983 looked at pesticide transport in three sub catchments of the Upper Yarra Catchment. The pesticides Diedrin, DDT, DDE, Linuron and 2,4,5-T were detected. Pesticides at one location were most frequently detected in flows during vegetable washing operations. Pesticide concentrations were also generally higher in storm flow samples. Pesticide loads transported from catchments were generally between 1.3 and 9.3 mg/ha and between 134 and 228mg/ha in relation to vegetable washing plants. The authors wrote; “The concentrations of Dieldrin and DDT do not appear to present problems for drinking water supply in the Yarra River itself although, on occasions the concentrations detected in flows from cultivated land during storms and operation of vegetable washing plants exceeded health criteria”. (Pesticide Transport from Intensive Agricultural Catchments. C.R. Fitzpatrick and P.D.Sutherland. Hydrology and Water Resources Symposium, 1983, Hobart, 8-10 November. Institution of Engineers Australia 1983).