August update - Mannering Park, Lake Macquarie, fish kill

Investigations of the recent fish kill at Mannering Park, Lake Macquarie, show it was likely a natural event.

EPA officers, Central Coast Council and NSW Fisheries attended the site and collected fish and water samples for laboratory analysis. Through extensive water sampling, toxicity testing and analysis there are no significant findings of pesticides, metals or toxicity.

The NSW Department of Planning and Environment labs tested for a full suite of metals and pesticides and found levels below the Australian and New Zealand Environment Conservation Council (ANZECC) marine water quality guidelines (where guideline limits are specified). Levels of pH and electrical conductivity were within normal ranges for a saline lake.

The sampling results for Total nitrogen and Total phosphorus were above the guideline values, which may indicate that disruption of sediment has occurred.

These results, along with analysis of weather conditions at the time, indicate the most likely cause of the deaths was from a combination of factors.

The bay at Mannering Park has elevated temperatures compared to the rest of Lake Macquarie due to the cooling water discharges from Vales Point power station.

A range of fish, including tropical fish, are attracted to the bay due to these higher temperatures.

The fish kill was preceded by cool nights in the first week of August and a shift to northerly winds, with the strongest winds on August 4.

This may have caused cold lake water to enter the bay and resulted in a turnover of the water column.

If this was rapid enough it would have caused a disturbance of the sediments, which explains the high ammonium concentrations observed on August 5, and potentially the release of sulfides.

Our results suggest the combination of the temperature and sulfide stress likely overwhelmed fish, acclimatized to higher temperatures.

We know the important role Lake Macquarie and the bay plays in the community and the region’s wider environment and have deployed a ‘smart buoy’ at Wyee Point to allow ongoing monitoring in the coastal lake.

The EPA has worked closely with the Department of Planning and Environment – Science, Biosecurity, Food and Fisheries and Central Coast Council on the investigation that produced these findings. The dead fish have also been removed by Council.

Sampling map

Aerial view of Mannering Park, Lake Macquarie showing sampling sites

Fish autopsy results received 30/08/2022

Pesticides Units GI Tract – Fish 3 Gills – Fish 3 Liver – Fish 3 Gills – Fish 1 GI Tract – Eagle Ray Gills – Eagle Ray Liver – Eagle Ray

Aldrin

µg/kg

<50

<190

<180

<290

<50

<50

<50

Allethrin

µg/kg

<50

<190

<180

<290

<50

<50

<50

Alpha-Chlordane

µg/kg

<50

<190

<180

<290

<50

<50

<50

alpha-HCH

µg/kg

<50

<190

<180

<290

<50

<50

<50

Ametryn

µg/kg

<50

<190

<180

<290

<50

<50

<50

Atraton

µg/kg

<50

<190

<180

<290

<50

<50

<50

Atrazine

µg/kg

<50

<190

<180

<290

<50

<50

<50

beta-HCH

µg/kg

<50

<190

<180

<290

<50

<50

<50

Bifenthrin

µg/kg

<50

<190

<180

<290

<50

<50

<50

Bioresmethrin

µg/kg

<50

<190

<180

<290

<50

<50

<50

Carbophenothion

µg/kg

<50

<190

<180

<290

<50

<50

<50

Chlorpyrifos

µg/kg

<50

<190

<180

<290

<50

<50

<50

Cis-permethrin

µg/kg

<50

<190

<180

<290

<50

<50

<50

Crotoxyphos

µg/kg

<50

<190

<180

<290

<50

<50

<50

Cyfluthrin

µg/kg

<50

<190

<180

<290

<50

<50

<50

Cypermethrin

µg/kg

<50

<190

<180

<290

<50

<50

<50

DDD-p,p'

µg/kg

<50

<190

<180

<290

<50

<50

<50

DDE-p,p'

µg/kg

<50

<190

<180

<290

<50

<50

<50

DDT-p,p'

µg/kg

<50

<190

<180

<290

<50

<50

<50

delta-HCH

µg/kg

<50

<190

<180

<290

<50

<50

<50

Deltamethrin

µg/kg

<50

<190

<180

<290

<50

<50

<50

Diazinon

µg/kg

<50

<190

<180

<290

<50

<50

<50

Dichlorvos

µg/kg

<50

<190

<180

<290

<50

<50

<50

Dieldrin

µg/kg

<50

<190

<180

<290

<50

<50

71

Dimethoate

µg/kg

<50

<190

<180

<290

<50

<50

<50

Endosulfan II

µg/kg

<100

<380

<350

<570

<100

<100

<100

Endosulfan I

µg/kg

<100

<380

<350

<570

<100

<100

<100

Endosulfan Sulfate

µg/kg

<50

<190

<180

<290

<100

<100

<100

Endrin Ketone

µg/kg

<50

<190

<180

<290

<50

<50

<50

Endrin

µg/kg

<50

<190

<180

<290

<50

<50

<50

Enthion

µg/kg

<50

<190

<180

<290

<50

<50

<50

Fenamiphos

µg/kg

<50

<190

<180

<290

<50

<50

<50

Fenitrothion

µg/kg

<50

<190

<180

<290

<50

<50

<50

Fenthion

µg/kg

<50

<190

<180

<290

<50

<50

<50

Fenvalerate

µg/kg

<50

<190

<180

<290

<50

<50

<50

Gamma-Chlordane

µg/kg

<50

<190

<180

<290

<50

<50

<50

gamma-HCH

µg/kg

<50

<190

<180

<290

<50

<50

<50

Heptachlor Epoxide

µg/kg

<50

<190

<180

<290

<50

<50

<50

Heptachlor

µg/kg

<50

<190

<180

<290

<50

<50

<50

Hexachlorobenzene

µg/kg

<50

<190

<180

<290

<50

<50

<50

Hexazinone

µg/kg

<50

<190

<180

<290

<50

<50

<50

L-cyhalothrin

µg/kg

<50

<190

<180

<290

<50

<50

<50

Malathion

µg/kg

<50

<190

<180

<290

<50

<50

<50

Methidathion

µg/kg

<50

<190

<180

<290

<50

<50

<50

Methoxychlor,p,p'

µg/kg

<50

<190

<180

<290

<50

<50

<50

Methyl Chlorpyrifos

µg/kg

<50

<190

<180

<290

<50

<50

<50

Methyl Parathion

µg/kg

<50

<190

<180

<290

<50

<50

<50

Mevinphos

µg/kg

<50

<190

<180

<290

<50

<50

<50

Oxyfluorfen

µg/kg

<50

<190

<180

<290

<50

<50

<50

Parathion

µg/kg

<50

<190

<180

<290

<50

<50

<50

Phorate

µg/kg

<50

<190

<180

<290

<50

<50

<50

Profenofos

µg/kg

<50

<190

<180

<290

<50

<50

<50

Prometon

µg/kg

<50

<190

<180

<290

<50

<50

<50

Prometryn

µg/kg

<50

<190

<180

<290

<50

<50

<50

Propargite

µg/kg

<50

<190

<180

<290

<50

<50

<50

Propazine

µg/kg

<50

<190

<180

<290

<50

<50

<50

Propetamphos

µg/kg

<50

<190

<180

<290

<50

<50

<50

Simazine

µg/kg

<50

<190

<180

<290

<50

<50

<50

Simetryn

µg/kg

<50

<190

<180

<290

<50

<50

<50

Tebuconazole

µg/kg

<50

<190

<180

<290

<50

<50

<50

Terbuthylazine

µg/kg

<50

<190

<180

<290

<50

<50

<50

Terbutryn

µg/kg

<50

<190

<180

<290

<50

<50

<50

Tetrachlorvinphos

µg/kg

<50

<190

<180

<290

<50

<50

<50

Trans-permethrin

µg/kg

<100

<380

<350

<570

<100

<100

<100

Metals* and Inorganics

Aluminium

mg/kg

72

33

33

510

26

5

<4

Antimony

mg/kg

<2

<2

<5

<3

<2

<2

<2

Arsenic

mg/kg

<3

<3

<7

<5

<3

<3

11

Barium

mg/kg

<1

3

<2

9

<1

<1

<1

Beryllium

mg/kg

<1

<1

<2

<2

<1

<1

<1

Boron

mg/kg

<10

<10

<23

<15

<10

<10

<10

Cadmium

mg/kg

<1

<1

5

<2

1

<1

2

Calcium

mg/kg

230

26000

150

47000

1400

200

34

Chromium

mg/kg

<1

<1

<2

<2

<1

<1

<1

Cobalt

mg/kg

<1

<1

<2

<2

<1

<1

<1

Copper

mg/kg

10

<3

140

<5

<3

<3

<3

Iron

mg/kg

330

100

740

710

92

57

130

Lead

mg/kg

<2

4

<5

<3

<2

<2

<2

Lithium

mg/kg

<1

<1

<2

<2

<1

<1

<1

Magnesium

mg/kg

320

770

260

1700

300

230

59

Manganese

mg/kg

11

18

<5

33

8

<2

<2

Mercury

µg/kg

N/A

N/A

N/A

N/A

11

31

15

Molybdenum

mg/kg

<1

<1

<2

<2

<1

<1

<1

Nickel

mg/kg

<2

<2

<5

<3

<2

<2

<2

Phosphorus

mg/kg

2800

14000

3600

23000

2000

1800

1000

Potassium

mg/kg

3100

1600

3700

510

1400

2100

1100

Selenium

mg/kg

<4

<4

14

<6

<4

<4

<4

Silicon

mg/kg

75

28

<14

310

25

<6

<6

Silver

mg/kg

<0.6

<0.6

<1.4

<0.9

<0.6

<0.6

<0.6

Sodium

mg/kg

1500

3900

1700

5200

3100

3800

660

Strontium

mg/kg

<3

180

<7

310

7

<3

<3

Sulfur

mg/kg

2800

1700

3500

1700

2300

2000

1000

Thallium

mg/kg

<2

<2

<5

<3

<2

<2

<2

Tin

mg/kg

<2

<2

<5

<3

<2

<2

<2

Titanium

mg/kg

<1

<1

<2

11

<1

<1

<1

Vanadium

mg/kg

<1

1

3

2

<1

<1

<1

Zinc

mg/kg

36

31

83

50

16

12

9

 

*For guidance on safe metal limits for human consumption in fish including mercury see NSW Department of Primary Industries advice

Pesticides results received 22/08/2022

Pesticides Units ANZECC marine WQG
(95% species protection)
Kevin
St
Vales
Pt
Wyee
Marina
Vales Pt
Discharge
Point 22
Aldrin µg/L No guideline
value
<0.3 <0.3 <0.3 <0.3
Allethrin µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Alpha-Chlordane µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
alpha-HCH µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
Ametryn µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Atraton µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Atrazine µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
beta-HCH µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Bifenthrin µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Bioresmethrin µg/L No guideline
value
<0.3 <0.3 <0.3 <0.3
Carbophenothion µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Chlorpyrifos µg/L 0.009 <0.4 <0.4 <0.4 <0.4
Cis-permethrin µg/L No guideline
value
<0.3 <0.3 <0.3 <0.3
Crotoxyphos µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Cyfluthrin µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Cypermethrin µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
DDD-p,p' µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
DDE-p,p' µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
DDT-p,p' µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
delta-HCH µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Deltamethrin µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Diazinon µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Dichlorvos µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
Dieldrin µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Dimethoate µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Endosulfan II µg/L No guideline
value
<1.0 <1.0 <1.0 <1.0
Endosulfan I µg/L 0.01 <0.9 <0.9 <0.9 <0.9
Endosulfan Sulfate µg/L No guideline
value
<1.0 <1.0 <1.0 <1.0
Endrin Aldehyde µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Endrin Ketone µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Endrin µg/L 0.008 <0.5 <0.5 <0.5 <0.5
Ethion µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Fenamiphos µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Fenitrothion µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Fenthion µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
Fenvalerate µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Gamma-Chlordane µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
gamma-HCH µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
Heptachlor Epoxide µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Heptachlor µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
Hexachlorobenzene µg/L No guideline
value
<0.3 <0.3 <0.3 <0.3
Hexazinone µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
L-cyhalothrin µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Malathion µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Methidathion µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Methoxychlor,p,p' µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Methyl Azinphos µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
Methyl Chlorpyrifos µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
Methyl Parathion µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Mevinphos µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
Oxyfluorfen µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Parathion µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Phorate µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
Profenofos µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Prometon µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Prometryn µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Propargite µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Propazine µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Propetamphos µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Simazine µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Simetryn µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Sulprofos µg/L No guideline
value
<0.4 <0.4 <0.4 <0.4
Tebuconazole µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Tebuthiuron µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Terbuthylazine µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Terbutryn µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Tetrachlorvinphos µg/L No guideline
value
<0.5 <0.5 <0.5 <0.5
Trans-permethrin µg/L No guideline
value
<0.7 <0.7 <0.7 <0.7

 

Ecotoxicology results received 22/08/2022

Bacterial luminescence
inhibition (V.fisheri)
Light emitted at
15-min
Light emitted
at 30-min
Result
Kevin St >80% >80% Not toxic
Vales Pt >80% >80% Not toxic
Wyee Marine >80% >80% Not toxic
Vales Pt Discharge Point 22 >80% >80% Not toxic

* Fish results to come

 

Nutrients testing results received 19/08/2022

Organics Units 2018 ANZECC marine WQG (95% species protection) Kevin St Vales Pt Wyee Marina Vales Pt Discharge Point 22
Total Nitrogen as N mg/L 0.3 0.6 0.6 0.7 0.6
Ammonia as N mg/L 0.11 0.07 0.06 0.07
Nitrite + Nitrate as N mg/L 0.02 0.01 <0.01 0.01
Total Kjeldahl Nitrogen as N mg/L 0.6 0.6 0.7 0.6
Reactive Phosphorus as P mg/L
<0.01
<0.01
<0.01
<0.01
Total Phosphorus as P mg/L 0.03 0.06 0.08 0.05 0.08
Biochemical Oxygen Demand mg/L 2 4 2 4

 

Direct toxicity test results received 19/08/2022

72-h amphipod Mellita immobilisation test Immobilisation at 72 hours (%) Result
Kevin St 0 Not toxic
Vales Pt 0 Not toxic
Wyee Marina 0 Not toxic
Vales Pt Discharge Point 22 0 Not toxic

*Pesticides and fish results to come.

pH and conductivity data

Sample Location Kevin St Vales Pt Vales Pt Discharge Point 22 Wyee Marina

pH

pH unit

8.1

8.1

8

8.1

Conductivity

µS/cm

44000

43000

44000

43000

 

Water sample metals data

Dissolved metals 2018 ANZECC marine WQG (95% species protection) Kevin St Vales Pt Vales Pt Discharge Point 22 Wyee Marina

Aluminium

mg/L

No guideline value

<0.04

<0.04

<0.04

<0.04

Boron

mg/L

No guideline value

3.6

3.7

3.7

3.7

Calcium

mg/L

No guideline value

300

300

300

300

Chromium mg/L 0.027  <0.001 <0.001 <0.001  <0.001 

Iron

mg/L

No guideline value

<0.1

<0.1

<0.1

<0.1

Lithium

mg/L

No guideline value

0.19

0.15

0.16

0.15

Magnesium

mg/L

No guideline value

1000

1000

1000

1000

Potassium

mg/L

No guideline value

320

330

320

320

Sodium

mg/L

No guideline value

8100

8200

8000

8000

Strontium

mg/L

No guideline value

6.1

6.2

6.2

6.1

Sulfur

mg/L

No guideline value

680

680

660

660

Titanium

mg/L

No guideline value

<0.01

<0.01

<0.01

<0.01

Antimony

mg/L

No guideline value

<0.001

<0.001

<0.001

<0.001

Arsenic

mg/L

No guideline value

<0.003

<0.003

<0.003

<0.003

Barium

mg/L

No guideline value

0.0097

0.0095

0.0094

0.01

Beryllium

mg/L

No guideline value

<0.0002

<0.0002

<0.0002

<0.0002

Cadmium

mg/L

0.0055

<0.0003

<0.0003

<0.0003

<0.0003

Cobalt

mg/L

0.001

<0.001

<0.001

<0.001

<0.001

Copper

mg/L

0.0013

<0.002

<0.002

<0.002

<0.002

Lead

mg/L

0.0044

<0.001

<0.001

<0.001

<0.001

Manganese

mg/L

No guideline value

<0.003

<0.003

<0.003

<0.003

Molybdenum

mg/L

No guideline value

0.011

0.011

0.011

0.011

Nickel

mg/L

0.07

<0.001

<0.001

<0.001

<0.001

Selenium

mg/L

No guideline value

<0.005

<0.005

<0.005

<0.005

Silver

mg/L

0.0014

<0.0001

<0.0001

<0.0001

<0.0001

Thallium

mg/L

No guideline value

<0.0005

<0.0005

<0.0005

<0.0005

Tin

mg/L

No guideline value

<0.001

<0.001

<0.001

<0.001

Vanadium

mg/L

0.1

0.0025

0.0025

0.0022

0.0021

Zinc

mg/L

0.008

<0.005

<0.005

<0.005

<0.005