Sugarloaf Reservoir Catchment

Yarra River, upstream of Sugarloaf Reservoir, contaminated with pesticides (Jan 28 2011)

First study looking at pesticides in the upper Yarra in 30 years 'Effects of pesticides monitored with three sampling methods in 24 sites on macroinvertebrates and microorganisms' published in Environmental Science and Technology (January 2011)

Surface Water

4,4-DDD 0.022ug/L, 4,4-DDE 0.024ug/L, 4,4-DDT 0.046ug/L, Atrazine 0.31ug/L, Azoxystrobin 0.02ug/L, Boscalid 0.02ug/L, Carbaryl 0.039ug/L, Chlorpyrifos 0.04ug/L, Cyproconazole 0.39ug/L, Cyprodinil 0.02ug/L, DEA 1.3ug/L, DIA 1.3ug/L, Dieldrin 0.022ug/L, Diflenoconazole 0.15ug/L, Dimethoate 0.094ug/L, Dimethomorph 0.01ug/L, Endosulfane 0.012ug/L, Fenarimol 0.2ug/L, Fenoxycarb 0.034ug/L, Fipronil 0.22ug/L, Hexazinone 0.96ug/L, Imidacloprid 0.59ug/L, Indoxacarb 0.33ug/L, Iprodione 3ug/L, Linuron 0.6ug/L, Metalaxyl 0.012ug/L, Methiocarb 1.2ug/L, Myclobutanil 2.9ug/L, Oxadixyl 0.39ug/L, Penconazole 0.05ug/L, Pendimethalin 0.04ug/L, Pirimicarb 1.4ug/L, Prochloraz 0.06ug/L, Procymidone 0.91ug/L, Prometryn 21ug/L, Propargite 0.15ug/L, Propiconazole 0.021ug/L, Pyraclostrobin 0.1ug/L, Pyrimethanil 70ug/L, Simazine 15ug/L, Spinosad 0.03ug/L, Tebuconazole 0.04ug/L, Tebufenozide 0.045ug/L, Terbutryne, Tetraconazole 0.059ug/L, Triadimefon 0.012ug/L, Triadimenol 0.02ug/L, Trichlorfon 0.006ug/L, Trifloxystrobin 0.73ug/L.

Sediment

4,4-DDD 29ug/kg, 4.4-DDE 32ug/kg, 4,4-DDT 13ug/kg, Atrazine 2ug/kg, Azoxystrobin 3ug/kg, Bifenthrin 30ug/kg, Boscalid 48ug/kg, Carbaryl 0.039ug/kg, Chlorothalonil 460ug/kg, Chlorpyrifos 42ug/kg, Cyprodinil 2ug/kg, Diazinon 17ug/kg, Dieldrin 20ug/kg, Fipronil 5ug/kg, Hexachlorobenzene 4ug/kg, Hexazinone 123ug/kg, Imidacloprid 10ug/kg, Indoxacarb 9ug/kg, Iprodione 170ug/kg, Linuron 18ug/kg, Metalaxyl 1ug/kg, Myclobutanil 120ug/kg, Oxadixyl 2ug/kg, Permethrin 80ug/kg, Pirimicarb 26ug/kg, Prochloraz 3ug/kg, Prometryn 374ug/kg, Propyzamide 180ug/kg, Pyraclostrobin 1ug/kg, Pyrimethanil 272ug/kg, Simazine 260ug/kg, Spinosad 100ug/kg, Tebufenozide 2ug/kg, Trifloxystrobin 793ug/kg.

New (April 2010) Golf Course for Eastern Golf Club proposed 1 km upstream of Melbourne Water Supply Offtake at Yering Gorge.

Also see Yarra Page

New Yarra River Water Supply Maps Here and Here

New Goulburn River Page here

Olinda Creek (this page) polluted by US multinational

More Polluted Run Off in Olinda Creek Catchment http://www.greenstink.com.au/

Also see Woori Yallock catchment and surrounds

Questions over plans to pump water from Yarra.

Water is pumped directly from the Yarra River at Yering Gorge. What is the likelihood of pesticides being pumped into Sugarloaf from the Yarra River due to agricultural activities upstream?

The following quote can be dated back to 1983. 26 years later nothing has changed (except the pesticides being used).

"A recent pilot survey conducted by the EPA on several agricultural catchments on the Upper Yarra and upstream of the offtake for the Winneke Reservoir concluded that "the pesticide levels detected represent a potential problem for the protection of stream biota in streams draining areas of intense agriculture. Interim Threshold Estimates for the protection of acquatic ecosystems were exceeded up to a factor of 80. Generally the levels of pesticides detected were below the recommended limits for the protection of potable water supplies. However levels of 2,4,5-T detected in one creek approached potable water limits." Administration Management Strategies for Non-Point Sources of Water Pollution in Victoria. EPA June 1983 Publication 170.

In a 1982 study 'Pilot survey of Pesticide Levels in Water and Sediments of Streams in Agricultural Catchments. Publication No:142 March 1982 Water Quality Branch EPA Victoria'; pesticides were sampled in surface waters and sediments in seven locations in the upper Yarra River catchment. Site 7 was located downstream of Yering Gorge (downstream of the current location of the Sugarloaf Reservoir pumping station at Yering Gorge which had not been constructed when the above survey was being undertaken).

In relation to Site 7 the report says p12 "DDE was detected in the three sediment samples collected from the Yarra River. Dieldrin was detected in samples collected on 23/12/80 and 15/5/80. Concentrations of both DDE and dieldrin were low at this site"...p14 "The detection of dieldrin in sediments collected from the Yarra River, site 7, also indicates that dieldrin is being transported significant distances"...p16 "Pesticides were detected in seven of the 25 water samples collected from the Yarra River. DDE, DDT and lindane were detected on four occasions, but at concentrations close to detection limits. Dieldrin (0.02ug/l) was detected on two occasions, malathion (2.6ug/l) detected in one sample and 2,4-D (1.1ug/l) was also detected in a single water sample."

Sugarloaf August 2007

Did you know that drinking water from Sugarloaf Reservoir in eastern Melbourne is pumped directly from the Yarra River at Yering Gorge? Meaning that any pollutants upstream can be washed into the Yarra and possibly then pumped into Sugarloaf Reservoir.

December 2007: December cropping and vegetable growing, 7km upstream from Sugarloaf Offtake - Stringybark Creek catchment.

Do you also know that approximately 7 million litres of treated sewage a day are pumped into Olinda Creek downstream of Lilydale? (see Herald Sun article 25/9/06) This amount can be as high as 13.5 million litres. Olinda Creek then discharges into the Yarra River approximately 2km upstream from where the pumps are positioned to supply Sugarloaf.

Also see New York Times article Drugs are in the Water. Does it Matter?

November 2004: Flooding of Yarra Valley floodplain above Yering Gorge.

July 2007: Maroondah Aqueduct near Yarra Glen which connects Maroondah Reservoir with Sugarloaf Reservoir. Several portions of the aqueduct flow through open farmland, but most of the aqueduct is underground.

Vineyards within 20 metres of the Yarra River just south west of Yarra Glen and only 3km upstream from Yering Gorge offtake. Vineyards can leach toxic pesticides including Simazine which chemically castrates amphibians at 0.1 parts per billion.

July 2007: Stringybark Creek catchment - Orchards and Vineyards.

July 2007: New Vineyards means increased pesticide regimes and more demand on water resources.

Dec 2007: Vineyards in close proximity to Stringybark Creek. More pesticides are registered for Vineyards in Victoria than any other agricultural crop. In times of rain these pesticides can leach into waterways. This vineyard is only 8km upstream from the offtake for Melbourne's drinking water supply.

Dec 2007: Cattle in tributary of Stringbark Creek, 8km upstream from the Sugarloaf offtake.

Dec 07: Apple Orchard in close proximity to Stringybark Creek trib.

July 2007: Headwaters of Stringybark Creek east of Silvan dam.

August 2007: Headwaters of Stringybark Creek - Melbourne's water supply covered in berri farms.

July 2007: High potential for agricultural runoff from this berri farm in the Stringybark catchment.

August 2007: O'Shannessy-Silvan Aquaduct (Silvan) connects up the two reservoirs. Much of the aquaduct runs through farmland.

Olinda Creek - One source of Melbourne's drinking water

April 07: Lilydale Lake which most likely captures much of the runoff from the Northern Dandenongs including Mount Evelyn. Water is then allowed to settle in this artificial lake constructed in the 1990's, probably as a way to better control runoff flowing down the creek and into the Yarra.

April 2007: Houses just upstream of Lilydale Lake. New housing developments are also occurring.

Olinda Creek Downstream of Lilydale Lake

April 2007: Olinda Creek from Beresford Road, downstream of Lilydale Lake, flows through Lilydale including a large industrial estate which was once home to an ASEA Electric Factory. Where do the stormwater drains flow into?

Google Earth image of Lilydale Industrial Estate dissected by Olinda Creek.

April 2007: ABB group in the Lilydale Industrial Park.

April 2007: Olinda Creek from Nelson Road at the northern end of the Lilydale Industrial park. Water not looking very tasty.

April 2007: Olinda Creek near Nelson Road.

April 2007: Stormwater pipe draining from Industrial Park near Nelson Road. One wonders what toxicants can be disposed off in an Industrial Park, down stormwater drains.

April 2007: Big bus depot in close vicinity to Melbourne's drinking water.

April 2007: Lilydale Sewage Treatment Plant. Yarra Valley Water pumps on average about 7 million litres of treated sewage into Olinda Creek each day. Melbournians are drinking treated sewage.

Google Earth image showing Lilydale Sewage Treatment facility (top of image) and quarry both located in the Olinda Creek catchment. Interesting to note that numerous pharmaceuticals and hormones can end up in sewage treatment facilities. 3 'official' sewage treatment plants operate in the Yarra catchment above Sugarloaf Reservoir. There are also a large number of sewage discharge points associated with residential areas.

Some pharmaceuticals detected in Australian wastewater include; Amoxycilin (antibiotic), Bacitracin (antibiotic), Carbamazepine (antiepileptic), Cefaclor (antibiotic), Cephalexin (antibiotic), Chlortetracycline (antibiotic), Ciprofloxacin (antibiotic), Clindamycin (antibiotic), Cloxacillin (antibiotic), Doxycycline (antibiotic), Enrofloxacin (antibiotic), Gemfibrozil (lipid regulator), Ibuprofen (analgesic/anti-inflammatory), Lincomycin (antibiotic), Monensin (antibiotic), Naladixic Acid (antibiotic), Naproxen (anti-inflammatory), Norfloxacin (antibiotic), Oleandomycin (antibiotic), Oxytetracycline (antiobiotic), Penicillin G (antibiotic), Penicillin V (antibiotic), Roxithromycin (antiobiotic), Salicyclic Acid (analgesic), Salinomycin (antibiotic), Sulfamethoxazole (antibiotic), Sulfasalazine (antibiotic), Sulfathiazole (antibiotic), Tetracycline (antibiotic), Trimethoprim (antibiotic), Tylosin (antibiotic).

Google Earth image of another quarry (Boral) located in the catchment.

Australian Native Landscapes are located on Boral land in the green wedge at Coldstream. This property is emitting large quantities of pollution in the form of run off into the catchment area for the Olinda creek as well as air borne contaminants.

See here for further details; http://www.greenstink.com.au/

Because the run off is a concentrated solution of residue from a composting process utilising materials gathered from private and commercial gardens all over Melbourne it contains a varying and horrendous mix of all the chemicals that are sprayed on gardens by householders. There has never been any testing done for pesticide residue both in the leachate pond on the property and on the surrounding surface area and groundwater. This facility needs to be placed in an area which is not a catchment area for drinking water supplies.

April 2007: Olinda Creek near Coldstream West Road, about 3 kms downstream from the Lilydale Sewage Treatment Plant.

April 2007: A massive 132 ha, 27 hole golf course, with 16ha Olive Grove (7,000-8,000 trees!) is currently being constructed by Croydon Golf Club (Croydon Developments Pty Ltd) on a property known as Coowerp. The new development is located only one kilometre from where Olinda Creek meets the Yarra River, which in turn is only 2 km upstream from the offtake for the Sugarloaf Reservoir. This is a very large development in Melbourne's water supply. Much of the site has already copped two herbicide spraying events in 2006 to kill off unwanted pasture.

Google Earth image of Construction of Croydon Golf Course, September 8 2007

December 2007: Olives being planted by Croydon Golf Course

April 2007: A massive new dam has been constructed by the Golf Course in close vicinity to Muddy Creek which flows into Olinda Creek. The site is also located in a Green Wedge and will see removal of land from productive agricultural use. The development has been controversial with VCAT hearings occurring.

April 2007: Muddy Creek appears to also be dammed in this photo, with a smaller dam. Is this how the larger dam is replenished with water as well as getting water rights to pump from the Yarra River?

Google Earth image of site selected for new Croydon Golf Course. This image is looking south. The red marks indicate approximate property boundaries. About 70% of the site lies in LSIO - Land Subject to Inundation Overlay - Yarra Ranges Shire Planning Scheme. This means that it lies within the 100 year flooding zone.

April 2007: The offending new Croydon Golf Club dam as seen from Macintyre Lane.

April 2007: Large construction taking place for the Croydon Golf Club.

April 2007: Large golf course construction has taken place in very close vicinity to Muddy Creek inside the LSIO.

ditto. One hopes there's not a large flood or large amounts of construction sediment could wash into the Yarra River. This lies within the LSIO.

April 2007: Croydon Golf Course in proximity to Olinda Creek. Note the sediment precautions.

December 2007: New buildings for Croydon Golf Course in Melbourne's drinking water supply. Corhanwarrabul (Mt Observatory) in background.

April 2007: Olinda Creek - Melbourne's water supply, just downstream from the new Croydon Golf Course development. Instead of pumping treated sewage water into the Yarra River, perhaps this water could be pumped onto the new golf course instead?

August 2007: Logging in McCrae creek catchment - private land.

Vineyards Slaty Creek catchment

Irrigated Pasture 3km's from Melbourne's drinking water supply offtake. Many pesticides are also registered for use in Irrigated Pastures.

Pilot Survey of Pesticide Levels in Water and Sediments of Streams in Agricultural Catchments. EPA March 1982 Water Quality Branch Publication 142.

P2 2.1 Upper Yarra Catchment

A total of 174 water samples were analysed and pesticides were detected in 58 of these samples. Organochlorine compounds were most frequently detected with dieldrin being detected in 30 samples, DDT or its metabolites in 18 samples and lindane in 15 samples. (In some instances DDT, dieldrin and lindane were all detected in a single water sample). Chlorophenoxy compounds (2,4-D and 2,4,5-T) were detected in seven samples and organophosphorus insecticides were positively identified once although they were suspected to occur on a total of eight occasions.

While the concentration of these compounds are generally low, less than 0.05 ug/l, they exceeded the Interim Threshold Estimates for the protection of aquatic ecosystems by up to a factor of 80. Furthermore on a number of occasions several pesticides were detected in single samples. In these cases toxic effects from each pesticide may be addictive or synergistic. Thus it is concluded that the pesticide levels detected represent a potential problem for the protection of stream biota in streams draining areas of intensive agriculture, particularly in the Wandin Yallock, Stringybark and Woori Yallock Creeks.

Generally the levels of pesticides detected were well below the recommended limits for the protection of potable water supplies. However levels of 2,4,5-T detected in Wandin Yallock Creek did approach potable limits on one occasion.

Residues of DDT (maximum 80 mg/Kg) and metabolites and dieldrin (maximum 80 mg/kg) were detected in sediments from all sites sampled in the Yarra system. Dieldrin levels in sediment increased over the sampling period suggesting that dieldrin levels in streams may be the result of ongoing inputs to streams rather than the result of ongoing inputs to streams rather than the result of past practices.

Highest pesticide concentrations were detected in Wandin Yallock and Stringybark Creek. This is consistent with the intensive agricultural land use in these catchments. Moderate levels of dieldrin were detected in Woori Yallock creek even though likely sources of dieldrin contamination were at least eight km upstream of the sampling site indicating that significant transport of dieldrin had occurred.

Seasonal variations in pesticide levels in steams in the Upper Yarra catchment were examined. Results of water analyses indicated that chlorophenoxy herbicides were detected in the period that they were expected to be used. However, the detections of the more persistent organochlorine compound, DDT, was greatest in winter when streamflows were high, with relatively few detections being made in the summer when DDT is normally used. It would appear that streamflow is an important factor in the mobilization and transport of DDT. Further work would be required to establish whether levels of DDT in streams are the result of current practice or are primarily due to residues from past spraying activity.

November 2004: Flooding of Yarra Valley floodplain above Yering Gorge. Melbourne's drinking water catchment

4. Description of Study Areas

4.1 Upper Yarra Catchments

The Upper Yarra is situated between the Dandenong Ranges and the Great Dividing Range to the north east of Melbourne. The study area corresponds to the Yarra River catchment above Yering Gorge and extends as far east as Mt Gregory, covering a total area of 2136 km2.

Good annual rains up to 1600mm, and moderate winter temperatures mean that a wide variety or agricultural enterprises can be undertaken.

Agricultural activities are restricted to the western half of the Upper Yarra Catchment by the mountainous terrain to the east. Consequently, most of this eastern region supports native bushland although small areas of river flats are used for grazing.

Land in the west of the study area is more suitable for agriculture and its fertile soils and close proximity to Melbourne have resulted in most land being cleared for use in a wide variety of agricultural pursuits.

Intensive agricultural activities are carried out in areas where the basaltic or alluvial soils are fertile and easily worked. The area to the east of Silvan Dam is intensively farmed and produces a variety of fruit and vegetables, notably cherries, apples, berries, potatoes, carrots and cutflowers.

The Coldstream District is an important cabbage and brussel sprout growing area while Toolangi in the north and more importantly Gembrook in the south produce large potato crops annually.

Grazing, mainly of beef cattle, is carried out where soil fertility is low or ground conditions preclude cultivation.

Yarra catchment above Yering Gorge.

6. Results and Discussion

The main compounds detected throughout the survey period were organochlorines. However it should be noted that the detection limit in water for most organophosphates and chlorophenoxy herbicides was 0.2 ugL-1, over an order of magnitude higher than detection limits for organochlorines. Furthermore, this detection limit is considerably higher than threshold levels for protection of aquatic ecosystems (see Table 6). On seven occasions chromotograms revealed prominent peaks when using phosphorus and sulphur filters. Retention times did not correspond to those available organophosphorus standards however these compounds were quite possibly metabolites.

November 2004: Flooding of Yarra Valley floodplain above Yering Gorge. Looking towards Yarra Glen which is situated several kilometres upstream from the Sugarloaf/Yarra offtake.

6.1 Upper Yarra Catchment

6.1.1 Sediments

Sediments were collected from the Upper Yarra sampling sites on three occasions:

30/7/1980 before the main pesticide spray season

22/12/1980 at the peak of the spray season

15/5/81 after the spray season

DDT and/or its metabolites TDE and DDE were detected in all sediments collected except for the sample collected on the 30/7/80 at Wandin Yallock Creek, site 4. Dieldrin was the only other pesticide detected and it was found on at least one occasion at all sites. Both DDT and dieldrin are persistent pesticides which are strongly absorbed to sediments.

(i) Site Results:

Results of analysis of sediment samples from each site are briefly discussed below.

Site 1 - Myers Creek: Pesticides were detected in the three sediment samples collected from Myers Creek. DDE was present in low to moderate concentrations in each sample. TDE and DDT were detected at low concentrations in sediments collected on 23/12/1980, whilst dieldrin was detected in the sample collected on 15/5/81.

Site 2 - Woori Yallock Creek: TDE, DDE, DDT and dieldrin were detected in all sediment samples collected from Woori Yallock Creek. Maximum concentrations of TDE (0.02 mg/Kg), DDE (0.05 mg/Kg), DDT (0.04 mg/Kg) and dieldrin (0.08 mg/g) were detected in sediments collected on 15/5/1981.

Site 3 - (Lower) Wandin Yallock Creek: TDE, DDE, DDT and dieldrin were detected in sediments. Maximum DDT concentrations (0.04 mg/Kg) were detected in sediments collected on 30/7/1980 whilst maximum dieldrin concentrations 0.05 mg/Kg) were detected in sediments collected on 15/5/1981.

Site 4 - (Upper) Wandin Yallock Creek: No pesticide residues were detected in sediment samples on 30/7/1980. The maximum DDT concentration (0.04 mg/Kg) was detected in sediments collected on 23/12/1981 while the maximum dieldrin concentration (0.02 mg/Kg) was detected in sediments sampled on 15/5/1981.

Site 5 - Stringybark Creek: The maximum concentrations of TDE (0.07 mg/Kg), DDE (0.05 mg/Kg), and DDT (0.08 mg/Kg) detected in sediments in the Upper Yarra catchment were in samples collected from Stringybark Creek on 20/7/1980. Analysis of sediments collected on 15/5/1980. Analysis of sediments collected on 15/5/80 indicated that DDT levels had declined to 0.04 mg/Kg. However, dieldrin levels had increased to 0.04 mg/Kg.

Site 6 - Olinda Creek: DDT and/or its metabolites were detected in all sediment samples collected at site 6, although levels were generally low. Dieldrin was detected in sediments collected on 15/5/1980.

Site 7 - Yarra River: DDE was detected in the three sediment samples collected from the Yarra River. Dieldrin was detected in samples collected on 23/12/1980 and 15/5/1980. Concentrations of both DDE and dieldrin were low at this site.

(ii) Sediment Results in relation to Landuse:

Sediment results are presented graphically in Figure 1. Generally pesticide levels were highest at sampling sites receiving runoff from intensive agricultural areas, including sites 3 and 4 on Wandin Yallock Creek, site 5 on Stringybark Creek and site 2 on Woori Yallock Creek.

Highest DDT residues were evidently associated with market gardening and horticultural landuse east of Silvan, while highest dieldrin levels were detected in Woori Yallock Creek which drains the potato growing area of Gembrook.

(iii) Seasonal Trends in Sediment Result:

It can be seen from Figure 1 that there are no clear seasonal trends in DDT levels. However, from the raw data it is evident that the total number of detections of TDE, DDE and DDT combined were greatest in the summer (19 detections), followed by winter (14 detections), and autumn (11 detections). This suggests that DDT detections increase during the spray season but are also influenced by other factors.

In the Namoi Environment Study the State Pollution Control Commission (1980) found that DDT residues in sediments in the Namoi River were highest during the spray season but were also increased by floods. They concluded that during floods DDT residues were flushed from drains and creeks to the Namoi River and carried downstream.

It is possible that similar factors were influencing levels of DDT in sediments collected from the Upper Yarra catchment. This would explain the maximum number of DDT, TDE and DDE detections during the spray season in summer and also why there were a large number of detections in the winter, when stream flows were high. However further data over several years would be required to confirm this phenomenon.

Dieldrin was detected in 14 of the 21 sediment samples analysed. From Figure 2 it can be seen that dieldrin levels at all sites reach a maximum in sediments collected on 12/5/1981. In fact, dieldrin was detected at only two sites in samples collected on 20/7/1980, at five sites in samples collected on 23/12/1980 and at all sites in samples collected on 12/5/1981. The low levels of dieldrin detected in sediments sampled on 20/7/1980 may have been the result of flood flows, which occurred between 29/6/1980 and 7/7/1980, flushing contaminated sediments and transporting them downstream. Dieldrin is primarily used by potato growers who apply it to crops between September and the end of November. The observed increase in sediment dieldrin levels in samples collected on 23/12/1980 and 15/5/1981 could be a result of losses of dieldrin from crops during runoff events and their subsequent accumulation in stream sediments due to low summer and autumn stream flows. However, further data over several years is required to confirm these trends.

March 05: Part of Melbourne's drinking water catchment in distance - Lilydale/Coldstream area.

(iv) Transport of Pesticide Residues in Sediments:

It is thought that the pesticide inputs to Woori Yallock Creek occur in the intensive agricultural areas east of Silvan Reservoir, approximately 8 km upstream of site 2, and the potato growing areas of Gembrook, approximately 16 km upstream of site 2. Consequently the occurrence of DDT and dieldrin in sediments collected at site 2, on the Woori Yallock Creek indicates that these pesticides are being transported away from intensive agricultural areas. Little or no pesticides would be expected to be used in the grazing land between the intensive agricultural areas of Silvan and Gembrook and the sampling site on Woori Yallock Creek.

The detection of dieldrin in sediments collected from the Yarra River, site 7, also indicates that dieldrin is being transported significant distances.

6.1.2. Waters

A total of 174 water samples were collected from the Upper Yarra catchment. Pesticides and their metabolites were detected in 58 of these samples. Pesticide levels exceeded water quality criteria for the protection of aquatic ecosystems on 43 instances in 39 water samples.

Organochlorine compounds, DDT and its metabolites DDE and TDE dieldrin and lindane, were detected in 49 samples. Chlorophenoxy compounds, 2,4-D and 2,4,5-T were detected in seven samples and Malathion, an organophosphorus insecticide, was detected once. On a further seven occasions organophosphorus compounds were suspected to be present but could not be positively identified.

(i) Site Results:

Results of analysis of water samples from each site are briefly discussed below:

Site 1 - Myers Creek: Pesticides were detected in six of the 26 water samples collected from Myers Creek. Dieldrin was detected in three samples, DDE in four samples, DDT in two samples and lindane was detected in one sample. The maximum concentration of DDT detected was 0.03 ug/l.

Site 2 - Woori Yallock Creek: Dieldrin and 2,4,5-T were detected in water samples from this site. Dieldrin was detected in moderate concentrations (0.01 to 0.03 ug/l) in eight of 26 water samples collected. 2,4,5-T (0.05 ug/l) was detected in water samples despite the fact that TDE, DDE and DDT were detected at moderate concentrations in sediments from this site.

Site 3 - (Lower) Woori Yallock Creek: Organochlorine and chlorophenoxy pesticides were detected at this site and chromatograms indicated that organophosphorus pesticides or their metabolites may have also been present.

Pesticides were detected in 14 of the 26 samples analysed and a total of 24 detections were made. DDT (0.01 ug/l) was detected in one water sample. Dieldrin in five samples (0.01 to 0.03 ug/l). Lindane in six samples (0.008 - 0.04 ug/l), 2,4-D in one sample (0.7 ug/l) and 2,4,5-T in two samples (0.32 and 1.1. ug/l).

Site 4 - (Upper) Wandin Yallock Creek: Pesticides were detected in nine of the 23 water samples collected from site 4 and a total of 17 detections of pesticides or their metabolites were made. DDT and/or TDE and DDE were detected in three water samples at moderate concentrations (maximum 0.03 ug/l DDT). Dieldrin (0.03 ug/l) was detected in four samples while lindane was detected at moderate concentrations (0.02 to 0.08 ug/l) in six water samples. 2,4,5-T (1.3 ug/l) was detected in one sample.

Site 5 - Stringybark Creek: Pesticides were detected in seven out of the 22 water samples analysed and a total of 14 detections were made. DDT and its metabolites and dieldrin were the only pesticides detected.

DDT was detected at moderately high levels (0.02 to 0.08 ug/l) in four samples while dieldrin was detected at moderate levels in four samples (0.01 - 0.02 ug/l). No pesticides were detected in water samples from Site 5 collected after 23/12/1980.

Site 6 - Olinda Creek: Pesticides were detected in six water samples and a total of seven detections were made. Dieldrin was detected on two occasions, DDE and 2,4,5-T on one occasion each on two occasions chromotograms revealed peaks suspected of being organophosphorus compounds. The concentrations of these pesticides detected were, with the exception pf 2,4,5-T (0.5ug/l), low.

Site 7 - Yarra River: Pesticides were detected in seven of the 25 water samples collected from the Yarra River. DDE, DDT and lindane were detected on four occasions, but at concentrations close to the detection limits. Dieldrin (0.02 ug/l) was detected on two occasions, malathion (2.6 ug/l) detected in a single water sample.

(ii) Water Results in relation to Landuse:

Water results are graphically presented in Figure 2. The number of pesticide detections in water samples were greatest at sites 3, 4 and 5 which are located in areas used for intensive agriculture.

TDE, DDE or DDT were detected at all sites, except site 2 where DDT was detected in sediments but not water samples. Highest DDT levels were detected at site 5 which receives runoff from horticultural and market garden areas.

Dieldrin was detected in water samples from all sites but was detected most frequently and at highest levels in Woori Yallock Creek, which drains the potato growing areas of Gembrook and Silvan.

Lindane was primarily detected at sites 3 and 4 on Wandin Yallock Creek, suggesting that it is being used by market gardeners or horticulturalists. Given that lindane is mainly used as a superphosphate-lindane mix for the control of pests in pastures, it is surprising that it was detected at Sites 3 and 4. Possibily it was used in winter sprays in orchards. However, it was not detected at site 5, an orchard growing area.

The chlorophenoxy herbicides 2,4,5-T and 2,4-D were detected at sites 2, 3, 4, 5, 6, and 7. It is thought that the detection of these compounds is associated with the control of noxious weeds, particularly blackberries, along stream banks.

Malathion was the only organophosphorus compound positively identified. It was detected at site 7. The detection of malathion at this site is surprising, particularly as no malathion was detected at sites close to areas of intensive agriculture. It is possible that the contamination of the Yarra River with malathion could have been the result of a spillage or the dumping of old malathion containers in the river.

Dairy located in Melbourne's drinking water supply

(iii) Seasonal Trends in Water Results:

Results of water analyses suggest that there is a marked seasonal variation in the occurrence of pesticides in the Upper Yarra catchment. From Table 5 it can be seen that organochlorine compounds were most frequently detected in water samples collected during winter, chlorophenoxy and organophosphorus compounds were most frequently detected in samples collected during summer, and very few pesticides of any sort were detected in samples collected during autumn.

It is thought that the observed variation in the frequency of pesticide detections is primarily related to:

(i) agricultural practice, this determines when the pesticides are used;

(ii) hydrological factors, these determine the loss of pesticide from fields to streams and subsequent transport; and

(iii) pesticide characteristics, including the persistence of the pesticide and the degree of adsorption to soils.

May 05: View looking north east into Lilydale Quarry.

As noted above, DDT and its metabolites were most frequently detected in the winter. The pattern of DDT detections suggests that stream flow may be the most important factor in determining the mobilisation and transport of this compound. An examination of mean daily streamflows of Woori Yallock Creek near site 2 (State Rivers and Water Supply Commission gauging station number 229215) indicated than mean daily flow was greatest during the winter months suggesting that runoff from the Woori Yallock catchment was greatest in winter. However, it is surprising that no DDT was detectd in samples collected in autumn and that only two DDT detections were made during the summer at the height of the DDT spray season.

Dieldrin was most frequently detected in spring (14 detections) closely followed by winter (10 detections). The detection of dieldrin in spring corresponds with the main period that dieldrin is applied to potato crops. Detections in winter could b due to the loss of dieldrin applied in previous seasons as a result of runoff during winter rains, and its subsequent transport in the high stream flows that occurred in winter.

Lindane, which is more water soluble than either DDT or dieldrin was detected during immediately after, winter, when it was thought to be applied.

March 05: View of Yarra Catchment from south side of Mt Donna Buang.

March 05: View of Yarra Catchment from south side of Mt Donna Buang. Looking into Millgrove logging Block. This area was logged by Amcor Plantations in the mid 1990's. The Millgrove Block reverted to Crown ownership around the year 2000.

March 05: View of Yarra Catchment from south side of Mt Donna Buang.

March 05: View of Yarra Catchment from south side of Mt Donna Buang.

March 05: View of Yarra Catchment from south side of Mt Donna Buang.

March 05: View of Yarra Catchment from Mt Donna Buang looking south.

March 05: View of Yarra Catchment from Mt Donna Buang looking east.

March 05: Cool Temperate rainforest near Warburton.