PESTICIDE AND HEAVY METAL RESIDUES IN · PDF filerisks from such chemicals including potential...

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AUSTRALASIAN JOURNAL OF ECOTOXICOLOGY VolVolV . 13, pp. 65-79, 2007

Rose and KibriaPesticides and heavy metal residues

P A P E R S

INTRODUCTIONGoulburn-Murray Water (G-MW) is the largest rural water supply authority in Australia, providing water for irrigation, rural domestic and stock drinking and town raw water. G-MW’s region covers 68 000 square kilometres (Figure 1) from the Great Dividing Range in Victoria north to the River Murray and from Corryong down river to Nyah near Swan Hill. The bulk of water is supplied by gravity through 7150 km of irrigation channels to dairy farms, orchards (stone fruit, pome fruit, and olives), vineyards, crops (canola, beans, wheat and rice), forage, tomatoes and aquaculture (fi sh and yabby farming). These agricultural enterprises use a range of pesticides to control pests and weeds. Irrigation water contaminated with pesticides can be unfi t for human consumption, stock drinking, fi sh farming, irrigation and food processing. It is sometimes necessary to outfall small volumes of channel waters into natural waterways. Any pesticide contained in this outfall water could impact on aquatic biota living in these natural waters. It is therefore essential to ascertain the concentrations of chemical contaminants (pesticides and related heavy metals) in G-MW’s supply channels to establish concentrations relative to risk factors and ensure that appropriate measures can be taken to reduce risks from such chemicals including potential impacts on the aquatic environment.

PESTICIDE AND HEAVY METAL RESIDUES IN GOULBURN MURRAY IRRIGATION WATER 2004-2006

Gavin Rose1 and Golam Kibria2*

1Future Farming Systems Research Division, DPS Werribee Centre, 621 Sneydes Rd, Werribee, Victoria 3030, Australia.2Goulburn Murray Rural Water Authority, Planning and Environment Group, 40 Casey Street, Tatura 3616, Victoria, Australia.

Manuscript received, 4/8/2007; accepted, 29/2/2008.

ABSTRACTDuring 2004-05 and 2005-06 irrigation seasons, a pesticide and heavy metals monitoring study was conducted at 15 potential risk sites located within the six Goulburn-Murray Water irrigation areas in northern Victoria using an economical, innovative passive sampling technique. Three of these sites were irrigation channel offtakes from the Murray and Goulburn Rivers and fi ve sites were channel outfalls to natural watercourses or lakes. The monitoring found three agricultural chemicals on a regular basis across the six irrigation areas. The most common were: endosulfan (an organochlorine insecticide) (in passive samples), atrazine (herbicide) and copper (fungicide) (in spot samples). The three other chemicals that were found on a less regular basis were chlorpyrifos, parathion methyl (in passive samples) and azinphos methyl (organophosphorus insecticides) in spot samples only). The sites where the above chemicals were frequently detected were Shepparton, Mooroopna, Ardmona, Kyabram and Nagambie, which comprise intensive orchards and tomato farming. Nagambie was the only offtake site, and Mooroopna the only outfall site. On comparison of average predicted water concentrations with national water quality guidelines (ANZECC and ARMCANZ 2000), endosulfan levels were within the guidelines for protecting slightly to moderately disturbed aquatic ecosystems (99% for endosulfan) but chlorpyrifos levels often exceeded recommended guidelines (95% for chlorpyrifos), as did the spot detections of azinphos methyl (99% level). However, chlorpyrifos was detected in only two sampling periods at outfall sites. The State Environment Protection Policy (Waters of Victoria or SEPP WoV; EPA 2003) exempted artifi cial channels and drains from protection of benefi cial use (including protection of aquatic ecosystems), but because of the requirement for reuse, the risk from the pesticide concentrations are likely to be low at offtake and outfall sites, although short periods of elevated chlorpyrifos, endosulfan and azinphos methyl may have occurred. Water endosulfan and chlorpyrifos concentrations at four sites estimated from passive sampler concentrations would have exceeded the recommended water quality guidelines for the purpose of aquaculture or fi sh farming.

Key words: pesticides; Goulburn Murray Water; endosulfan; copper; atrazine; aquatic ecosystems.

*Author for correspondence: email: [email protected]

A preliminary pesticide use survey conducted in 2001 by G-MW (Krake et al. 2001) found that more than 75 pesticides (36 herbicides, 23 insecticides, 17 fungicides) were used in different farming sectors across the six Irrigation Areas (Central Goulburn, Shepparton, Murray Valley, Rochester-Campaspe, Torrumbarry, and Pyramid-Boort; Figure 1). Commonwealth Scientifi c & Industrial Research Organisation (CSIRO) (Kookana et al. 2003) undertook a first tier assessment of the risks associated with these pesticides to water quality, as well as to humans, stock, food industries, pastures, aquaculture and aquatic fl ora, fauna and aquatic ecosystems. The risk assessment using the Pesticide Impact Rating Index methodology of Kookana et al. (2004) identifi ed 10 of the 75 pesticides assessed that presented the highest risks to these activities. Kookana et al. (2003) recommended monitoring of these high-risk and some additional moderate-risk pesticides in the G-MW irrigation supply channels using reliable sampling techniques such as passive sampling methodologies. These included organophosphorus pesticides (azinphos methyl, parathion methyl, omethoate, phorate, chlorpyrifos), organochlorines (α-endosulfan, β-endosulfan, endosulfan sulfate), carbamates (methomyl, thiodicarb), synthetic pyrethroids (bifenthrin, esfenvalerate and tau-fl uvalinate), herbicides (atrazine, molinate, pendimethalin, trifl uralin), fungicide (chlorothalonil) and some heavy metals (copper, cadmium, lead and zinc).

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AUSTRALASIAN JOURNAL OF ECOTOXICOLOGY

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Routine spot water sampling can monitor chemical contaminants in the aquatic environment. However if concentrations are low, or vary over time and need to be measured over a long period of time, water sampling can be expensive and require intensive effort. “Passive sampling” provides an alternative in situ technique that can be used for longer periods of time, and can accumulate substances continuously where concentrations are low or variable. Passive samplers work by the laws of diffusion and solubility and provide time-integrated concentrations of contaminants in flowing water. The attributes and benefits of passive sampling applied to water monitoring are identified by Stuer-Lauridsen (2005) and Barceló (2007). For common pesticides, laboratory studies (Leonard et al. 2002) using spiked water solutions have derived concentration factors over time relationships for each device in the linear range. This enables average water concentrations of common pesticides to be determined with reasonable accuracy from passive sampler concentrations over the deployment period (Hyne et al. 2004; Hyne and Aistrope 2008). Field studies (Leonard et al. 2002; Hyne et al. 2004) found a good agreement between pesticide concentrations determined using trimethylpentane-containing passive samplers (TRIMPS) and those calculated from daily river-water extraction. Hence, membrane-based passive samplers are a promising tool for the time–integrated monitoring of hydrophobic contaminants, such as pesticides in aquatic ecosystems (Leonard et al. 2002; Hyne et al. 2004), and they allow time-integrated pesticide water concentrations to be determined and compared with national water quality guideline values. In this study, the TRIMPS passive sampling technique developed by Hyne et al. (2004) and Hyne and Aistrope (2008) for monitoring of pesticides in aquatic environments has been adopted. However, despite the advantages with the TRIMPS passive samplers they are generally limited to hydrophobic substances with high log K

ow values (chemicals with log K

ow values (chemicals with log K

ow values (chemicals with log K >3.5 are considered

hydrophobic).

The objectives of this current research were as follows:1. To monitor time-integrated accumulation of hydrophobic,

risk pesticides in passive samplers constructed from low density polyethylene tubing (LDPE) containing the solvent 2,2,4-trimethylpentane (TRIMPS) and the solvent mixture 1-dodecanol : 2,2,4–trimethylpentane (Samples chemicals in the range 2.5< log kow <3.5).

2. To monitor the range and quantity of pesticides and heavy metals in spot samples with respect to different monitoring sites for quality assurance of results obtained with passive sampling technique.

3. To compare pesticide and heavy metals monitoring results with ANZECC and ARMCANZ (2000) guideline trigger values for the protection of aquatic ecosystems and agricultural and aquacultural (fi sh and yabby) use.

4. To provide information on pesticide usage in the study area and enhance Victorian Department of Primary Industries’ (DPI) ability to sustain irrigated agricultural industries.

The State Environment Protection Policy (Waters of Victoria or SEPP WoV; EPA 2003) exempted artifi cial channels and drains from protection of benefi cial use (including protection

of aquatic ecosystems). However, The ANZECC and ARMCANZ (2000) guideline trigger values for the protection of aquatic ecosystems have been included in this paper for comparison. Moreover, chemicals detected in this study are results of customers’ usage of chemicals in the six irrigation regions for which G-MW does not have any control.

MATERIALS AND METHODSThe pesticide and heavy metals monitoring was conducted for two years (2004-05 and 2005-06) at 15 potential risk sites (14 in season 2004-05), identifi ed in G-MW’s six Irrigation Areas. These sites were Torgannah, Burramine, Katamatite (Murray Valley), Shepparton (Shepparton), Mooroopna, Ardmona, Tatura and Kyabram (Central Goulburn), Nagambie (Goulburn weir), Corop (Rochester-Campaspe), West Boort and Appin (Pyramid-Boort) and Kerang town, Kangaroo Lake and Torrumbarry weir (Torrumbarry) (Figure 1). The sites selected were based on surveys conducted in the six irrigation areas, the intensity of farming in each irrigation area, and the proximity of farms in relation to irrigation channels. Retrieval and deployment of passive samplers took place at the same time (i.e. 28 days’ interval) during which time 2-L spot water samples were also collected from each site.

Of the 15 sites monitored, eight sites were identifi ed as sites linked to natural waterways called ‘natural sites’.

Three of these natural sites were Murray and Goulburn River offtakes or ‘reference sites’ as follows:• Burramine (Murray River-Yarrawonga main channel - site 2), • Torrumbarry Weir (Murray River-National Channel - site 15) and • Nagambie (Goulburn Weir; Goulburn River-Stuart Murray canal - site 9).

Five of the natural sites were outfalls to natural waterways or lakes as follows:• Torgannah (outfall to Torgannah Lagoon - site 1),• Katamatite (outfall to Broken Creek - site 3), • Mooroopna (outfall to Goulburn River - site 5), • Appin (outfall to Lake Meran and Loddon River - site 12), and• Kangaroo Lake (RAMSAR lake - site 14).

The other seven sites were artifi cial channels as follows:• Shepparton (intensive orchards - pome and stone fruit - site 4),• Ardmona (intensive orchards - pome and stone fruit - site 6),• Kyabram (intensive tomatoes - site 7),• Tatura (town supply - site 8),• Corop/Rochester (tomatoes and vineyards, town supply and stock and domestic supply - site 10),• West Boort (olives, stock and domestic supply, town supply - site 11),• Kerang (mixed farming, town supply - site 13).

The 2004-05 and 2005-06 monitoring targeted 18 pesticides and four heavy metals (listed above) that were identifi ed as highest to moderate risk to different receptors (Krake et al. 2001; Kookana et al. 2003).

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Passive sampler preparationPassive samplers were prepared at the Ecowise - WSL, Richmond Laboratory, Victoria, Australia, following procedures of Leonard et al. (2002). Two types of passive samplers were used, one with the solvent 2,2,4-trimethylpentane (TRIMPS) and the other with a solvent mixture of 1-dodecanol:2,2,4-trimethylpentane (3:2).

Deployment and retrieval of passive samplersNolan-ITU fi eld staff (now Hyder Consulting Pty Ltd, based in Melbourne) was engaged to perform deployment and retrieval of passive samplers and spot samples.

Passive samplers were constructed using prefabricated low-density polyethylene (LDPE) membrane bags (Scubs Brand, Schur Inventure A/S, Niels Finsensvej Denmark). Passive sampler bags (approx. 3 x 10 cm and with a mean wall thickness of 40 µm) were pre-rinsed/soaked overnight (24 hours) in 2,2,4-trimethylpentane in the fume cupboard to leach out any contaminants absorbed on the bags. A glass organic-solvent dispenser was used to measure 10 mL of solvent/solvent mixture directly into a passive sampler bag. Air was extruded from the bag by compressing the solvent to the top of the bag. Each passive sampler bag was then sealed with plastic dialysis clips (Sigma Aldrich, Sydney), and secured with a 4-cm spring paper clip. Each sampler was then placed in a small wire-mesh cage (97 x 14 cm) for protection. Solvent fi lled passive sampler bags were submerged in deionised water in an Esky during transport to the fi eld. In the fi eld, each passive sampler bag was placed in a rock-fi lled autoclave basket (17.8 x 16.8 x 15.6 cm; (mesh 10 mm) (Interpath Services, Heidelberg, Melbourne) and then deployed in sites in the six irrigation areas channels.

After 28 days, the passive samplers were retrieved, and the solvent from the deployed bags was collected in a glass vial (23x46 mm) with 0.3 g anhydrous sodium sulfate. The vials with solvent were then placed into a small foam box wrapped with ice bricks and dispatched via fast courier to DPI, Werribee Chemistry Laboratory for analysis. Each sampling involved the deployment of triplicate membrane devices, which were analysed separately.

Spot samplingSpot sampling was done once every four weeks to coincide with passive sampler retrieval and deployment. At each site, a grab sampler was used to collect 2 L of water, which was placed into a gamma-sterilised PET bottle. The 2-L sample is used as 1L is required for dichloromethane (DCM) extraction, 10 mL for Solid Phase Extraction (SPE) and 20 mL for heavy metals. Stephens and Müller (2007) indicate 1L is suffi cient for spot sampling validation. Spot water samples were kept over ice during courier transport to DPI, Werribee for analysis.

Water temperature During the 2005-06 irrigation season, the surface water temperature of each site was recorded using a fractional degree thermometer (405 mm blue LO-tox™ fi lled) during each deployment and retrieval period. The water temperature

was monitored to ensure that passive samplers were not exposed to cool water temperatures, as dodecanol/TRIMPS mixture-containing bags solidify at 4°C (note the dodecanol/TRIMPS is the solvent that will solidify below 10°C). The lowest temperatures in August were between 8 and 12°C at all sites, and all exceeded 15°C between October and March.

Analytical techniques TRIMPS samplesThe trimethylpentane (TRIMPS) samples were diluted and then injected to a gas chromatograph with a pulsed fl ame photometric detector (GC-PFPD) for organophosphorus insecticides. Endosulfan and synthetic pyrethroids were detected by injection onto a GC with electron capture detection (GC-ECD). Fungicides, herbicides and carbamates were determined by injection on GC with a nitrogen-phosphorus detector (GC-NPD). In each case the sample injection was simultaneously screened on two capillary columns of different stationary phase polarity, usually 5% phenyl on dimethylpolysiloxane and 50% phenyl on dimethylpolysiloxane. Quantitation was by external standards injected with each sample batch and repeated after fi ve sample injections. The concentration of the calibration standards was made to suit the range expected for passive sampler solvents with the lowest level standard at a concentration selected at twice the GC LOD (limit of detection). Calculated concentrations from the screening column and confi rmatory column are required to be within 20% of the mean value reported.

Dodecanol/TRIMPS samplesDodecanol/TRIMPS samples (3 parts dodecanol to 2 parts TRIMPS) were diluted 1/5 with hexane and injected on GC-ECD for endosulfan and synthetic pyrethroids. Phorate, parathion methyl and chlorpyrifos were determined on GC-PFPD, and trifl uralin, chlorothalonil and pendimethalin were determined on GC-NPD on the same dilutions. Gas chromatography quantitation was as described for TRIMPS above. Omethoate, methomyl, atrazine, molinate, thiodicarb and azinphos methyl were determined by direct injection onto a liquid chromatography-triple quadrupole mass spectrometer (LC-MSMS) in full scan mode. Pesticides were determined using positive ion mode with electrospray interface. The mass spectrometer was set up in multiple reaction monitoring mode with selected ion fragmentation for each precursor ion with monitoring of two product ions with the most sensitive ion selected for quantitation with secondary ion confi rmation within 20% of the fi rst value. A 2.1 mm id by 150 mm length Waters Xterra C18 reverse phase column was used with a 10 μL injection. The mobile phase was a linear gradient starting with 20% methanol in 5mM ammonium acetate buffer (pH = 7) with a fi nal mixture of 90% methanol in acetate buffer.

The analytical results were converted into time weighted average water concentrations using the concentration factors from Leonard et al. (2002); and Hyne and Aistrope (2008) for the pesticides detected in passive samplers. The conversion was made only for those pesticides where a published experimental relationship was available.

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Spot samples A 1.0 L sub-sample of water was extracted with 100 mL of dichloromethane (DCM), and then re-extracted twice with 50 mL of DCM. The DCM extracts were combined and dried through a sodium sulfate column. The extract was reduced and inverted into hexane which was then reduced to 1 mL.

In 2004-05, the fi nal extract was analysed with GC-PFPD (pulsed fl ame photometric detector) for OPs and GC-NPD (nitrogen phosphorus detector), for carbamates and molinate, trifl uralin, pendimethalin, atrazine and chlorothalonil. In 2005-06, chlorpyrifos, parathion methyl and phorate were determined by injection to a gas chromatograph with a pulsed fl ame photometric detector (GC-PFPD). In 2005-06 trifl uralin, pendimethalin and chlorothalonil were determined on GC-NPD.

In 2005-06, solid phase extraction with Bond Elute PPL and C18 was separately applied to water samples, with eluants combined and inverted into methanol followed by LC-MSMS determination as above for omethoate, methomyl, thiodicarb, atrazine, and molinate and azinphos methyl. The method changes were implemented to enhance the detection limits of these pesticides.

Organochlorines and synthetic pyrethroids were analysed by GC-ECD (electron capture detector) after purifi cation on florisil SPE. Tau-fluvalinate was extracted with dichloromethane as above, after sample acidifi cation, and determined on GC-ECD.

Each analytical batch included a spiked tapwater recovery of each target pesticide in the range normally detected. The recoveries were required to be within 70-120% for stated LORs (limits of reporting). As this recovery range is within the normal method uncertainty the results were not corrected for recovery.

Metals were determined following representative sub-sampling and acidification with high purity nitric acid. The fi nal nitric acid concentration in samples was 1% w/v to match the concentration in the multi-element external calibration standards. A multi-element internal correction standard solution was added to each sample. Each batch of samples included a multi-element certifi ed standard from a different supplier than the instrument calibration standards and also included a duplicate sample and two process blanks. Samples were then analysed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The ICP-MS was tuned for optimum LODs across a multi-element screen. Each metal determination was calculated using indium as the default internal correction standard. Samples were reported only after quality control acceptance criteria for blanks, duplicates and check standard were satisfi ed.

Quality assuranceFor each batch of passive sampler solvent analysed, a blank TRIMPS and blank solution were also analysed. In addition a blank of each sampler solvent was retained immediately before the subsequent deployment to confi rm the pesticide-free status of the samplers. Two of each of the three replicate solvent samples were randomly tested to determine pesticide concentrations. The third sample was

retained as a confi rmatory and alternative quality assurance sample. Normally two solvent samples tested and showing residues <LOR would deem analysis of the triplicate sample as unnecessary. Quality assurance conformed to that listed by Bergquist and Zaliauskiene (2007), i.e. that two measures are required: replicate quality control and sampling device control or blanks to confi rm any contamination during the deployment period.

RESULTS AND DISCUSSION

Passive samplersEndosulfan in TRIMPSThe following regression equations were used to estimate the water endosulfan concentrations in TRIMPS solvent samplers following Leonard et al. (2002): • α-endosulfan: y = 1.01x+1.70• β-endosulfan: y = 1.01x+1.61• endosulfan sulfate: y = 1.11x+1.67

Where y = log10

(Concentration Factor) and x = log10

(number of deployment days) and where the Concentration Factor (CF) is the ratio of the pesticide concentration in the TRIMPS to the concentration in the water once the equilibrium has been reached, shown as occurring from 10 to 42 days in Leonard et al. (2002).

Thus for a TRIMPS α-endosulfan concentration of 2.3 µg/L the predicted water concentration for the 28 days’ deployment is calculated as follows:

log10

CF α-endo

= 1.01 (log10

28) + 1.70

log10

CFα-endo

= 1.01*1.447+1.70 = 3.161

so CFα-endo

= 1958, which predicts a 28-day concentration average of 2.3/1958 µg/L= 0.0012 µg/L in water.

In TRIMPS the limit of reporting (LOR) was 1 µg/L for α- and β-endosulfan and 4 µg/L for endosulfan sulfate. Using the prediction regression equations, the water LORs for the 28 days were 0.0005 µg/L, 0.0006 µg/L and 0.003 µg/L respectively.

In the 2004-05 and 2005-06 irrigation seasons, endosulfan was detected at eight sites on a regular basis. Endosulfan was detected at elevated concentrations (higher than the ANZECC aquaculture guidelines of 0.003 μg/L) only at fi ve sites (Shepparton, Mooroopna - an outfall site to the Goulburn River, Ardmona, Kyabram and Nagambie, a river offtake site) (see Figures 2, 3, 4, 5 and 6). The fi gures show that the estimated endosulfan concentration at each of these fi ve sites exceeded the ANZECC water quality guideline trigger value for aquaculture/fi sh farming (0.003 µg/L). However, the appropriate ANZECC guideline trigger value for aquatic ecosystems protection (99%; 0.03 µg/L) was not exceeded (the fi gure at Ardmona in September 2005 was just below 0.03 µg/L, and Mooroopna in October 2004 was just above 0.025 µg/L).

These fi ve sites where higher endosulfan concentrations were detected are in proximity to intensive horticultural (orchards and tomato) industries. Endosulfan is registered for insect control on a number of crops including pome fruit, stone fruit

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and vegetables. The higher concentrations of endosulfan were most commonly found in passive samplers during the early part of the irrigation season (September-January), except at Kyabram in 2004-05.

Endosulfan was not detected at Nagambie (which is a Goulburn River channel offtake) in 2004-05. However, it was detected in passive samplers on three occasions during 2005-06 (Figure 6). The detection of endosulfan in 2005-06 may be related to the growing of tomato crops in the vicinity of Goulburn River in that season.

Endosulfan was detected using TRIMPS in 2005-06 (≤ 0.0015 µg/L) at Murray River offtakes at Burramine on four occasions and at Torrumbarry on three occasions (Table 1). Endosulfan was detected at each of the three other outfall sites: Katamatite (once only September 2005), Appin (fi ve samples in 2004-05 and six samples in 2005-06) and Kangaroo Lake (seven samples in each season) in addition to detections at Mooroopna. The levels at Torgannah, Katamatite, Appin and Kangaroo Lake were well below 0.03 µg/L, the 99%

Figure 2. Shepparton (site 4). Four-week average endosulfan (±SE) water concentration for each deployment period for TRIMPS. The horizontal (solid) line represents the ANZECC/ARMCANZ (2000) guideline trigger values for protection of aquatic ecosystems (0.03 µg/L for 99% protection) and horizontal (broken) line for freshwater aquaculture (<0.003 µg/L). No detections in 2004-05.

Figure 3. Mooroopna (site 5). Four-week average endosulfan (±SE) water concentration for each deployment period for TRIMPS. The horizontal (solid) line represents the ANZECC/ARMCANZ (2000) guideline trigger values for protection of aquatic ecosystems (0.03 µg/L for 99% protection) and horizontal (broken) line for freshwater aquaculture (<0.003 µg/L).

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Figure 4. Ardmona (site 6). Four-week average endosulfan (±SE) water concentration for each deployment period for TRIMPS. The horizontal (solid) line represents the ANZECC/ARMCANZ (2000) guideline trigger values for protection of aquatic ecosystems (0.03 µg/L for 99% protection) and horizontal (broken) line for freshwater aquaculture (<0.003 µg/L).

Figure 5. Kyabram (site 7). Four-week average endosulfan (±SE) water concentration for each deployment period for TRIMPS. The horizontal (solid) line represents the ANZECC/ARMCANZ (2000) guideline trigger values for protection of aquatic ecosystems (0.03 µg/L for 99% protection) and horizontal (broken) line for freshwater aquaculture (<0.003 µg/L).

aquatic protection trigger value (Table 1). Thus, endosulfan concentrations at all the sites linked to natural waterways were below this 99% aquatic ecosystem protection level. Rainfall contribution to channel fl ow within the G-MW areas is minimal due to the channels being elevated from the receiving farms, which do not operate as catchments.

Endosulfan in Dodecanol/TRIMPSEndosulfan was not detected in dodecanol/TRIMPS samplers in either year.

Chlorpyrifos in TRIMPS The following regression equation was used to estimate the water chlorpyrifos concentrations in TRIMPS solvent samplers following Leonard et al. 2002:

• Chlorpyrifos: y = 0.95x+1.88

Where y and x have been defi ned in the endosulfan equations above. Thus the concentration factor for chlorpyrifos = 1799. In TRIMPS the LOR was 10 µg/L for chlorpyrifos. Using the prediction regression equation the corresponding water LOR of 0.01 µg/L for the 28 days is 0.0055 µg/L.

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72



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nd

nd

12. A

ppin

(P-

B)

20

04-0

5 20

05-0

6 ns

nd

ns

0.

0015

0.

0015

nd

0.

0015

0.

0015

0.

0015

0.

0015

0.

0015

0.

0015

nd

nd

0.

0015

0.

0007

nd

0.

0013

14. K

anga

roo

Lak

e (T

)

2004

-05

2005

-06

ns

nd

ns

0.00

15

0.00

15

0.00

15

0.00

20

0.00

15

0.00

26

0.00

15

0.00

15

0.00

15

0.00

15

0.00

15

0.00

15

0.00

15

0.00

15

nd

15. T

orru

mba

rry

wei

r (T

)

2004

-05

2005

-06

ns

nd

ns

0.00

15

ns

0.00

15

ns

0.00

15

ns

nd

ns

nd

ns

nd

ns

nd

ns

nd

End

osul

fan

TV

for

99%

aqu

atic

eco

syst

em p

rote

ctio

n –

0.03

µg/

L;

End

osul

fan

TV

for

aqu

acul

ture

0.0

03 µ

g/L

; ns

= n

ot s

ampl

ed;

nd =

not

det

ecte

d. M

V =

Mur

ray

Val

ley

Irri

gatio

n A

rea;

CG

=

Cen

tral

Gou

lbur

n Ir

riga

tion

Are

a; G

W =

Gou

lbur

n W

eir;

P-B

= P

yram

id H

ill -

Boo

rt I

rrig

atio

n A

rea;

T =

Tor

rum

barr

y Ir

riga

tion

Are

a.

73


Rose and KibriaPesticides and heavy metal residuesTa

ble

2. A

traz

ine

(µg/

L)

in s

pot w

ater

sam

ples

in G

-MW

site

s (s

hade

d si

tes

are

linke

d to

nat

ural

wat

erw

ays)

.

Atr

azin

e T

V fo

r 95%

pro

tect

ion

- 13

µg/L

; ns

= n

ot s

ampl

ed; n

d =

not

det

ecte

d. M

V =

Mur

ray

Val

ley

Irri

gatio

n A

rea;

S =

She

ppar

ton;

CG

= C

entr

al G

oulb

urn

Irri

gatio

n A

rea;

GW

= G

oulb

urn

Wei

r;

R-C

= R

oche

ster

-Cam

pasp

e Ir

riga

tion

Are

a; P

-B =

Pyr

amid

Hill

- B

oort

Irr

igat

ion

Are

a; T

= T

orru

mba

rry

Irri

gatio

n A

rea.

Tab

le 2

. Atr

azin

e (µ

g/L

) in

spo

t wat

er s

ampl

es in

G-M

W s

ites

(sha

ded

site

s ar

e lin

ked

to n

atur

al w

ater

way

s).

Site

Se

ason

A

ugus

t Se

ptem

ber

Oct

ober

N

ovem

ber

Dec

embe

r Ja

nuar

y F

ebru

ary

Mar

ch

Apr

il

1.T

orga

nnah

(M

V)

2004

-05

2005

-06

ns

trac

e ns

tr

ace

nd

trac

e nd

0.

033

nd

0.04

9 nd

0.

048

nd

0.04

8 nd

0.

024

nd

0.02

2

2. B

urra

min

e M

V)

2004

-05

2005

-06

ns

trac

e ns

0.

014

nd

0.03

4 nd

0.

039

nd

0.06

2 nd

0.

038

nd

0.04

8 nd

0.

027

nd

trac

e

3. K

atam

atite

(M

V)

2004

-05

2005

-06

ns

trac

e ns

0.

017

nd

0.03

1 nd

0.

030

nd

0.05

6 nd

0.

038

nd

0.04

5 nd

0.

030

nd

trac

e

4. S

hepp

arto

n (S

)

2004

-05

2005

-06

ns

trac

e ns

tr

ace

nd

trac

e nd

tr

ace

nd

0.02

7 0.

01

0.02

4 nd

0.

041

0.02

0.

035

0.02

0.

036

5. M

ooro

opna

(C

G)

20

04-0

5 20

05-0

6 ns

tr

ace

ns

0.03

1 nd

tr

ace

nd

nd

0.01

0.

021

0.01

0.

034

nd

0.04

7 0.

017

0.03

4 tr

ace

0.03

5

6. A

rdm

ona

(CG

)

2004

-05

2005

-06

ns

trac

e ns

nd

nd

tr

ace

nd

trac

e nd

0.

026

0.01

0.

021

nd

0.03

8 0.

014

0.03

0 0.

020

0.03

6

7. K

yabr

am (

CG

) 20

04-0

5 20

05-0

6 ns

tr

ace

ns

0.02

1 nd

tr

ace

nd

trac

e nd

nd

nd

tr

ace

0.01

0.

021

nd

0.03

2 0.

01

0.04

0

8. T

atur

a (C

G)

2004

-05

2005

-06

ns

trac

e ns

nd

nd

tr

ace

nd

trac

e nd

0.

025

0.01

0.

040

nd

0.04

1 nd

0.

040

0.02

0.

042

9. N

agam

bie

(GW

) 20

04-0

5 20

05-0

6 ns

tr

ace

ns

nd

nd

trac

e nd

tr

ace

nd

0.04

2 0.

02

0.03

3 0.

01

0.04

4 0.

019

0.04

8 0.

02

0.03

9

10. C

orop

(R

-C)

2004

-05

2005

-06

ns

trac

e ns

0.

017

nd

0.02

4 nd

tr

ace

nd

nd

nd

trac

e nd

0.

020

0.01

1 0.

039

trac

e 0.

036

11. W

est B

oort

(P

-B)

2004

-05

2005

-06

ns

trac

e ns

0.

016

0.01

0.

022

0.01

tr

ace

0.01

tr

ace

nd

trac

e 0.

01

Tra

ce

0.01

8 0.

032

0.01

0.

033

12. A

ppin

(P-

B)

2004

-05

2005

-06

ns

trac

e ns

0.

020

0.02

0.

020

nd

trac

e nd

nd

nd

nd

0.

01

Tra

ce

0.01

2 0.

032

0.02

0.

030

13. K

eran

g to

wn

(T)

2004

-05

2005

-06

ns

trac

e ns

0.

035

nd

trac

e nd

0.

022

0.01

tr

ace

nd

0.03

8 nd

0.

031

nd

0.05

0 nd

0.

028

14. K

anga

roo

Lak

e (T

) 20

04-0

5 20

05-0

6 nd

tr

ace

nd

0.01

2 nd

tr

ace

nd

nd

nd

nd

nd

0.02

0 nd

T

race

nd

0.

029

nd

0.02

2

15. T

orru

mba

rry

wei

r (T

) 20

04-0

5 20

05-0

6 ns

0.

01

ns

0.01

6 ns

0.

022

ns

0.03

2 ns

0.

045

ns

0.03

8 ns

0.

030

ns

0.03

0 ns

0.

020

74


Chlorpyrifos was detected in the 2005-06 season using passive samplers at four sites. Chlorpyrifos was detected once only at the outfall sites of Katamatite (0.089 µg/L) and Mooroopna (0.01 µg/L), but was detected in channels at elevated levels in six periods at Shepparton and in four periods at Ardmona (Figures 7 and 8). The predicted level of 0.089 µg/L chlorpyrifos at Katamatite in January 2006 was well above the ANZECC 95% aquatic ecosystem protection guideline value of 0.01 µg/L, as were fi ve of the detections at Shepparton and three at Ardmona. In the 2004-05 season, chlorpyrifos was detected on two occasions at Shepparton, 0.033 µg/L in March 2005, with 0.02 µg/L predicted for April. These detections are later than normal application times for stone and pome fruit and are more likely to be related to pasture and forage applications.

Chlorpyrifos in dodecanol/TRIMPSThere were no detections for chlorpyrifos in Dodecanol/TRIMPS samplers in 2004-05. In 2005-06 chlorpyrifos was detected in dodecanol/TRIMPS at Shepparton once (September) and three times at Ardmona (September, October and December). These detections were at levels approximately double the values in TRIMPS, except for a low level (0.006 µg/L) for December where there was no TRIMPS detection.

Parathion methyl, atrazine and molinate in dodecanol/TRIMPSThe following regression equation was used to estimate the average water concentrations from parathion methyl concentrations in TRIMPS following Hyne and Aistrope (2008):

• Parathion methyl: y = 7.905x

Where y and x have been defi ned in the endosulfan equations above.

In 2004-05 none of these pesticides was detected at or above the limit of reporting in dodecanol/TRIMPS passive samplers. Parathion methyl was detected in channel sites in September and October 2005; at Shepparton (predicted at 0.84 µg/L and 0.54 µg/L) and Ardmona (predicted at 0.92 µg/L and 0.23 µg/L) (Figures 9 and 10), and predicted at 0.34 µg/L in September 2005 at Torgannah.

Parathion methyl and chlorpyrifos are registered for use on a range of horticultural crops (fruits and vegetables). Chlorpyrifos is also registered for control of pasture and forage pests. The reporting of chlorpyrifos and parathion methyl at Ardmona and Shepparton sampling sites is expected to be associated with organophosphorus insecticide usage in stone fruit orchards or maybe chlorpyrifos was used to control insect pests in pasture and forage crops. Historically, DPI residue surveys (DPI 2006) reveal parathion methyl and chlorpyrifos applications in local stone fruit orchards. Parathion methyl has not been listed in the ANZECC and ARMCANZ (2000) aquatic protection guidelines. Parathion ethyl is a related pesticide and has a 99% trigger value of 0.07 µg/L but it is more toxic than parathion methyl (Tomlin 2000).

The herbicides atrazine and molinate were detected on one occasion each in dodecanol/TRIMPS. Atrazine, molinate and parathion methyl have log K

owand parathion methyl have log K

owand parathion methyl have log K values in the range below 3.5 and are expected to be concentrated preferentially in dodecanol/TRIMPS samplers with higher polarity solvent, compared to TRIMPS (Hyne and Aistrope 2008).

Spot Water Samples Endosulfan in Spot Samples Endosulfan was not detected in any of the spot water samples where it was reported in passive samplers. There were only two detections of endosulfan in water samples, at trace levels (50% of the LOR), at Shepparton and Nagambie, both in October 2004. Predicted endosulfan water

Figure 6. Nagambie (site 9). Four-week average endosulfan (±SE) water concentration for each deployment period for TRIMPS. The horizontal (solid) line represents the ANZECC/ARMCANZ (2000) guideline trigger values for protection of aquatic ecosystems (0.03 µg/L for 99% protection) and horizontal (broken) line for freshwater aquaculture (<0.003 µg/L). No detections in 2004-05.

VolVolV . 13, pp. 65-79, 2007


75


concentrations from TRIMPS exceeded spot sample LORs on fi ve occasions; Mooroopna (October 2004), Ardmona (September 2005), Kyabram (December 2004 and February 2005) and Nagambie (November 2005). This suggests that the endosulfan concentrations detected in TRIMPS were the result of transient spike concentrations of endosulfan rather than the 28-day time averaged concentration; see Hyne et al. (2004) and Alvarez et al. (2007). In estimating the likely transient exposures at each of these sites the TRIMPS levels show signifi cant levels of the α- and β-endosulfan, relative to the endosulfan sulfate breakdown product. The fact that the two isomers were present at similar ratios to that of the formulation mix suggests that endosulfan was from direct transfer from spraying operations in channel proximity; see Peterson and Batley (1993).

Figure 7. Shepparton (site 4). Four-week average chlorpyrifos (±SE) water concentration for each deployment period for TRIMPS. The horizontal (solid) line represents the ANZECC/ARMCANZ (2000) guideline trigger values for protection of aquatic ecosystems (0.01 µg/L for 95% protection) and horizontal (broken) line for freshwater aquaculture(<0.001 µg/L).

Figure 8. Ardmona (site 6). Four-week average chlorpyrifos (±SE) water concentration for each deployment period for TRIMPS. The horizontal (solid) line represents the ANZECC/ARMCANZ (2000) guideline trigger values for protection of aquatic ecosystems (0.01 µg/L for 95% protection) and horizontal (broken) line for freshwater aquaculture(<0.001 µg/L). No detections in 2004-05.

Chlorpyrifos in Spot Samples Chlorpyrifos was not detected at the LOR of 0.01 µg/L in spot samples in seven of the matching eight TRIMPS detections at Shepparton, however one sample in October 2005 reported 0.056 µg/L compared to a TRIMPS predicted value of 0.014 µg/L. At Ardmona, none of the water samples was positive for chlorpyrifos at sites where TRIMPS samples showed detections.

In November 2005, a trace level of chlorpyrifos was detected at Ardmona, in comparison with a TRIMPS predicted level of 0.033 µg/L. There was one water sample detection, at Ardmona (0.33 µg/L) in January 2006 which was not matched by any sampler detection. Thus the general pattern of spot samples not detecting the chemical when it was detected in passive samplers is repeated for chlorpyrifos as for endosulfan. This supports the deduction that residues are transferred as transient spikes which would be expected to create peak concentrations several times higher than the averaged TRIMPS predicted level for the 28-day deployment.

VolVolV . 13, pp. 65-79, 2007


76


Azinphos methyl in spot samplesAzinphos methyl is registered for control of insect pests in stone and pome fruit. It was detected in four spot water samples. Three of these detections were at 0.02 µg/L (Mooroopna, Ardmona and Shepparton) but one, in Shepparton channel in November 2005, was elevated at 0.97 µg/L. This value is well above the 99% protection level (0.01 µg/L) for aquatic ecosystems from ANZECC and ARMCANZ (2000) guidelines. This detection was not matched in TRIMPS or dodecanol/TRIMPS. The log K

owmatched in TRIMPS or dodecanol/TRIMPS. The log K

owmatched in TRIMPS or dodecanol/TRIMPS. The log Kof azinphos methyl = 2.96, below the TRIMPS sampling threshold of log K

owthreshold of log K

owthreshold of log K = 3.5.

Atrazine in spot samplesIn the 2004-05 seasons atrazine was found in spot samples on a regular basis at Mooroopna, Nagambie, West Boort and Appin, whereas in 2005-06 it was found on a regular basis at all the sites (see Table 2 for the range of atrazine concentrations detected). The highest level of atrazine detected, 0.062 µg/L, was in the Burramine offtake for the Murray Valley Irrigation Area (MVIA) in December 2005. The other two MVIA sites Torgannah and Katamatite showed concentrations up to 0.049 µg/L and 0.056 µg/L respectively in 2005-06. These levels were less than 5% of the ANZECC 95% aquatic protection guideline value of 13 µg/L. The higher Burramine level at the offtake suggests that the atrazine detected in the MVIA was the result of agricultural activities upstream of Burramine. Nagambie Weir, offtake for Central Goulburn Area, showed a

Figure 9. Shepparton (site 4). Four-week average parathion methyl (±SE) water concentration for each deployment period for TRIMPS. No ANZECC/ARMCANZ (2000) guideline trigger values for protection of aquatic ecosystems or aquaculture. No detections in 2004-05.

Figure 10. Ardmona (site 6). Four-week average parathion methyl (±SE) water concentration for each deployment period for TRIMPS. No ANZECC/ARMCANZ (2000) guideline trigger values for protection of aquatic ecosystems or aquaculture. No detections in 2004-05.

VolVolV . 13, pp. 65-79, 2007


77


Rose and KibriaPesticides and heavy metal residuesTa

ble

3. C

oppe

r in

spo

t wat

er s

ampl

es (

µg/L

) at

G-M

W s

ites;

sha

ded

site

s ar

e lin

ked

to n

atur

al w

ater

way

s.

Cu

TV

for

95%

pro

tect

ion

= 1

.4 µ

g/L

, ns

= n

ot s

ampl

ed; n

d =

not

det

ecte

d. M

V =

Mur

ray

Val

ley

Irri

gatio

n A

rea;

S =

She

ppar

ton;

CG

= C

entr

al G

oulb

urn

Irri

gatio

n A

rea;

GW

= G

oulb

urn

Wei

r;

R-C

= R

oche

ster

-Cam

pasp

e Ir

riga

tion

Are

a; P

-B =

Pyr

amid

Hill

- B

oort

Irr

igat

ion

Are

a; T

= T

orru

mba

rry

Irri

gatio

n A

rea.

Tab

le 3

. Cop

per

in s

pot w

ater

sam

ples

(µ

g/L

) at

G-M

W s

ites;

sha

ded

site

s ar

e lin

ked

to n

atur

al w

ater

way

s.

Site

Se

ason

A

ugus

t Se

ptem

ber

Oct

ober

N

ovem

ber

Dec

embe

r Ja

nuar

y F

ebru

ary

Mar

ch

Apr

il

1.T

orga

nnah

(M

V)

2004

-05

2005

-06

ns

3.6

ns

3.6

1.2

2.3

2.6

1.8

1.3

1.4

1.6

1.7

2.2

1.4

1.1

1.1

1.2

1.5

2. B

urra

min

e M

V)

2004

-05

2005

-06

ns

1.8

ns

1.8

nd

1.6

nd

nd

nd

nd

nd

nd

nd

<0.9

nd

<0

.9

nd

<0.9

3. K

atam

atite

(M

V)

2004

-05

2005

-06

ns

2.4

ns

1.9

1.6

2.7

nd

1.0

nd

0.9

nd

1.0

1.0

1.0

nd

<0.9

nd

<0

.9

4. S

hepp

arto

n (S

)

2004

-05

2005

-06

ns

3.6

ns

1.6

nd

1.3

3.6

1.0

1.1

<0.9

1.

1 nd

1.

3 <0

.9

nd

<0.9

nd

<0

.9

5. M

ooro

opna

(C

G)

20

04-0

5 20

05-0

6 ns

4.

3 ns

3.

0 1.

2 3.

0 1.

4 2.

5 1.

4 3.

6 1.

3 1.

7 2.

2 1.

5 1.

0 1.

3 1.

6 1.

1

6. A

rdm

ona

(CG

)

2004

-05

2005

-06

ns

2.5

ns

1.5

nd

2.2

nd

0.9

1.0

<0.9

nd

0.

9 1.

3 <0

.9

nd

<0.9

nd

1.

7

7. K

yabr

am (

CG

) 20

04-0

5 20

05-0

6 ns

2.

6 ns

1.

8 1.

3 2.

4 1.

2 1.

8 1.

6 1.

7 1.

2 2.

2 1.

0 1.

4 1.

2 1.

0 1.

2 1.

4

8. T

atur

a (C

G)

2004

-05

2005

-06

ns

3.5

ns

1.0

nd

2.6

1.2

<0.9

1.

1 <0

.9

1.0

nd

nd

<0.9

nd

<0

.9

nd

nd

9. N

agam

bie

(GW

) 20

04-0

5 20

05-0

6 ns

2.

2 ns

<0

.9

nd

1.3

nd

<0.9

nd

<0

.9

nd

nd

nd

<0.9

nd

<0

.9

nd

nd

10. C

orop

(R

-C)

2004

-05

2005

-06

ns

1.2

ns

1.3

nd

1.2

nd

1.2

nd

1.3

1.4

1.1

1.4

1.0

1.2

2.1

nd

1.2

11. W

est B

oort

(P

-B)

2004

-05

2005

-06

ns

2.2

ns

2.2

1.8

1.7

1.3

2.1

1.4

2.1

1.8

2.2

1.3

2.3

1.5

1.4

1.8

1.5

12. A

ppin

(P-

B)

2004

-05

2005

-06

ns

2.0

ns

2.2

1.9

3.0

1.1

2.4

1.1

2.1

1.9

2.4

1.3

1.9

1.7

1.4

1.7

1.3

13. K

eran

g to

wn

(T)

2004

-05

2005

-06

ns

3.7

ns

3.2

nd

3.6

nd

3.6

nd

4.2

nd

2.7

nd

1.9

nd

2.1

nd

1.7

14. K

anga

roo

Lak

e (T

) 20

04-0

5 20

05-0

6 ns

3.

3 ns

1.

3 1.

9 3.

0 1.

9 nd

2.

4 3.

0 3.

9 3.

7 2.

3 3.

3 2.

4 3.

1 2.

4 3.

4

15. T

orru

mba

rry

wei

r (T

) 20

04-0

5 20

05-0

6 ns

nd

ns

2.

4 ns

1.

2 ns

nd

ns

1.

0 ns

1.

1 ns

<0

.9

ns

<0.9

ns

nd

78


similar pattern with 0.042 µg/L in November 2005 as a spring peak, however levels were elevated, at 0.033-0.048 µg/L, for the remainder of the 2005-06 season, although they were still less than 5% of the 95% aquatic protection guideline value. None of the Central Goulburn sites exceeded the monthly levels at Nagambie, suggesting that the major inputs of atrazine to the Goulburn Valley were agricultural activities upstream of Nagambie. Torrumbarry weir, a Murray River offtake, showed a similar November 2005 maximum, 0.045 µg/L. Corop (Rochester-Campaspe) and the Pyramid-Boort sites of West Boort and Appin, and Torrumbarry sites, Kerang and Kangaroo Lake all showed March-April 2006 maximums for atrazine, indicating irrigated agriculture in these areas contributed to higher than background offtake levels. Atrazine is highly persistent in soil and in the environment. It is likely that the atrazine detected was used to control weeds in forage legumes, broad acre crops and orchards.

Heavy metals (copper, cadmium, lead and zinc) in spot samplesLead and zinc were detected (0.22 – 2.4 µg/L and <1.2 – 8.7 µg/L, respectively) on a regular basis at all sites but not at levels of concern except for zinc = 8.7 µg/L at Torrumbarry in September 2005, which exceeded the 95% protection level of 8.0 µg/L. Cadmium was not detected in any samples above the LOR of 0.4 µg/L. Copper was detected on a regular basis at most sites with higher concentrations detected at Torgannah, Mooroopna, West Boort, Appin, Kerang and Kangaroo Lake (see Table 3). These sites are under intensive orchards and vegetable growing. Copper is registered for use as a fungicide on horticultural crops. Channel offtake copper levels were consistently low, or below the LOR of 0.9 µg/L, suggesting that those sites with higher levels were subject to inputs from copper fungicides. The copper levels at the outfall site of Katamatite were generally below the ANZECC 95% aquatic species protection guideline value of 1.4 µg/L in soft water. However, the other three outfall sites of Mooroopna, Appin and Kangaroo Lake were generally above this value (up to 4.3 µg/L), particularly in the 2005-06 season. The origin of the copper is not known but it could be natural or agricultural. Copper toxicity to aquatic species is inversely related to hardness and salinity. Irrigation channel water is generally “soft” in the Goulburn-Murray region with 30-40 mg/L total hardness being normal. Normal salinity ranges between 60 to 160 mg/L total dissolved solids and pH 6.8-7.5. Dissolved organic matter will ameliorate the toxicity of copper.

CONCLUSIONSBecause the pesticide concentrations were measured in a concentrated solvent sample from a semi permeable membrane device, no direct comparison can be made with the national water quality guidelines. However, the endosulfan, chlorpyrifos and parathion methyl concentrations detected were converted into time-weighted average water concentrations using regression equations (Hyne et al. 2002, Hyne and Aistrope 2008). The detected endosulfan and chlorpyrifos concentrations were generally found to be below the ANZECC and ARMCANZ (2000) guideline values for the protection of slightly-moderately disturbed aquatic ecosystems (0.03 µg/L; 99% species protection;

and 0.01µg/L; 95% protection, respectively) at sites where ecosystem protection may have some relevance i.e. offtakes and outfalls. However, water at some channel sites, such as Mooroopna, Shepparton, Ardmona, and Kyabram exceeded the ANZECC and ARMCANZ (2000) guideline values of both endosulfan (<0.003 µg/L) and chlorpyrifos (<0.001 µg/L) for aquaculture or fi sh farming. There are no guideline trigger values for parathion methyl, but due to its higher threshold for toxicity the reported concentrations are expected to be safe for aquatic ecosystems protection and aquaculture.

The levels likely to ascribe higher risk in aquatic systems were present in artifi cial irrigation channels but not in the natural aquatic ecosystems sites at Torgannah, Burramine, Katamatite, Mooroopna, Nagambie, Appin, Kangaroo Lake and Torrumbarry.

The irrigation water tested is delivered to the farmer with no return of excess water to the channel or natural watercourses. It is G-MW policy that delivered water is retained and reused on the property in receipt without return to the delivery channels. For the residues detected, any impact relates to the remaining water supplied to other farmers downstream in the channel. Thus, as the channels tested provide supply by gravity fl ow, it is unlikely that the residues reported are from runoff. Thus the reported pesticides, except for atrazine, are likely to have been transferred by direct spray drift from pesticide application adjacent to the channels. This deduction is supported by the failure to replicate the majority of passive sampler detections and levels in spot water samples indicating transient peaks of pesticide transfer to channels coincident with spray applications close to channels. This study has demonstrated the value of passive sampler technology in monitoring varying concentrations of pesticides from an intensive irrigation area.

ACKNOWLEDGEMENTSThe authors acknowledge the help and cooperation received from the following:

DPI Project “Intergrating Farming Systems into Landscapes” funded the DPI component of the research.

Referees/reviewers: We are grateful to anonymous reviewers whose time, effort, and suggestions greatly helped to improve the paper.

G-MW: Central Goulburn Irrigation Area (Max Cail, Gary Whyte); Murray-Valley (Dave Derby, Rob Williams); Shepparton (Mark Newton); Rochester-Campaspe (David Fehring), Torrumbarry (Ian Hetherington); Pyramid–Boort (David Hellsten); Goulburn Weir (Steve Hall), and EMPA2 Reference Team Members.

DPI Werribee Centre laboratory: Pei Zhang, Davorka Tucman, Simon Phelan, Aaron Elkins, Dr Jun Du, Dr Craige Trenerry, Colin Cook.

Centre for Ecotoxicology, Department of Environment & Climate Change (DECC), NSW: Dr Ross Hyne and Melissa Aistrope.

Others: Nolan-Itu/Hyder Consulting Pty Ltd, Melbourne (Rob Medley, Tara Bassette, Daniel A’vard) and Ecowise-WSL, Melbourne (Andrew Higgins, Hao Zhang).

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REFERENCESAlvarez DA, Huckins JN, Petty JD, Jones-Lepp T, Stuer-Lauridson F, Getting DT, Goddard JP and Gravell A. 2007. Chapter 8, Tool for monitoring hydrophilic contaminants in water: polar organic chemical integrative sampler (POCIS). InComprehensive Analytical Chemistry Vol 48, Passive Sampling Techniques in Environmental Monitoring. Greenwood R, Mills G and Vrana B (Eds), Elsevier, Amsterdam.

ANZECC and ARMCANZ 2000. Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand. Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Volume 1, The Guidelines (Chapters 1-7). Canberra.

Barceló D. 2007. Foreword. In Comprehensive Analytical Chemistry Vol 48, Passive Sampling Techniques in Environmental Monitoring. Greenwood R, Mills G and Vrana B. (Eds), Elsevier, Amsterdam.

Bergquist P-A and Zaliauskiene A. 2007. Chapter 14, Field study considerations in the use of passive sampling devices in water monitoring. In Comprehensive Analytical Chemistry Vol 48. Passive Sampling Techniques in Environmental Monitoring. Greenwood R, Mills G and Vrana B. (Eds), Elsevier, Amsterdam.

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Krake K, Breewel L and Kibria G. 2001. Pesticide and Channel Contamination. Pesticide used in G-MW Irrigation Areas. G-MW Aquatic Plant Services. G-MW Docs Reference 704342. 25 pp.

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Stuer-Lauridsen F. 2005. Review of passive accumulation devices for monitoring organic micropollutants in the aquatic environment. Environmental Pollution 136, 503-524.

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