1994: Great Forester River (Tasmania). Pesticide: Simazine

The two sites on the Great Forester River which were also sampled under the MRHI program (Great Forester off Tasman Highway and Great Forester at Prosperity Rd.) have shown slight to moderate impairment on a number of occasions (Table 3). However OESIGNAL scores again suggest that the impairment is due to other factors other than water quality. However it is worth noting that the herbicide simazine  was detected in the water at both of these sites in spring 1994. The concentration was 1µg/l at Prosperity Rd. and 0.7µg/l at Tasman Highway. Davies et al. (1994) reported that the aquatic fauna of Tasmanian streams may suffer minor short term disturbances if frequently exposed to triazine herbicides such as simazine. They found that concentrations between 1 and 20µg/l had no major impact on the aquatic fauna even when exposed for several weeks, but that concentrations above 100µg/l were regarded as having short term lethal effects. The concentrations found at the two sites were unlikely to cause any adverse impact on the aquatic fauna. However, because the sites were sampled only once, it is impossible to determine when or where the impact occurred, nor the peak concentration of simazine in the water

Aquatic Ecology Of Rivers In the Great Forester Catchment
A Report Forming Part of The Requirements for State of Rivers Reporting

Tom Krasnicki River Health Officer Land and Water Assessment Branch DPIWE.
Report Series WRA 99/07 June 1999.