Saliza Mohd Nazri - PowerPoint Presentation

Slide1

Saliza Mohd Nazri – Doctor of Biotechnology

Analysis of Jacobs SKM’s benchmark study on effluent emissions from shrimp aquaculture and sugarcane farms

1Slide2

Introduction

Jacobs SKM was contracted by QCA

to give independent advice on environmental and technical issues in the investigation on the regulatory reform of aquaculture in Queensland [

1

].

Table

1

. Summary of effluent emissions by Jacobs SKM

[1].

2Slide3

Comparison

Table

1

. Summary of effluent emissions by Jacobs SKM

[

1

].Table 2

. The effluent discharge data from prawn aquaculture farms based on CRC Report 2002 [2] (note: units have been converted to the same unit used by Jacobs SKM for ease of comparison).

3Slide4

Prawn farm effluent data from Jacobs SKM benchmark study

4Slide5

Investigation of the value stated in the benchmark study

F

irst

row of prawn farm

discharges

The original

study was conducted by

Trott

and

Alongi

[

4

]

but was cited in

Burford’s

[

5

]

review.

T

he

prawn farm pollutant loads did not lead to eutrophication due to physical and biological processes associated.

Examples

of the associated processes

:

1)the

fast settlements of the nutrients within the creeks and forests, 2)the efficient flushing and removal process of sediments during high currents and fluxes, 3)the primary production undergo grazing by the zooplankton,4)the consumption of zooplankton by juvenile fish5) the effluent discharges were in an intermittent pattern that permitted the “fallowing” to take place at the estuary [4].

5Slide6

Investigation of the highest N value stated in the benchmark study (prawn farm discharges)

Derived

from a study done by Jackson

[

6

]

which investigated the effluent loads from three intensive shrimp farms in Australia.

In

the study, it was reported that due to the unusual condition of Farm A

, only the discharge values obtained from Farm B and Farm C should be used

as indicator of the pollutant loads released from intensive shrimp farms

[

6

].

This

is because Farm A used double amount of water (1.36 X 10

6

L ha

-1

day

-1

) as the management changed its main shrimp production species from

P.monodon

to

M.japonicus

in the early of the study and faced difficulties from the switch.

6Slide7

Jackson [

6

]

proposed in the conclusion of his research, intensive shrimp farms would typically produce 1 kg ha

-1

day

-1

(365 kg ha

-1

yr

-1

)of

net loads of total

nitrogen.

In conclusion, if a correction was to be made in the benchmark study, the 657 kg ha

-1

yr

-1

value of nitrogen effluent stated would be replaced with 365 kg ha

-1

yr

-1

.

7Slide8

Sugarcane farm effluent data from Jacobs SKM benchmark study

8Slide9

Jacobs SKM referenced a report done by Dr McPhee

[

7

]

in the first row of the benchmark study of the sugarcane farm effluent data.

However

, a further investigation into this report by McPhee revealed that there was also data on the nitrogen emission from sugarcane farms of 300 kg/ha/

yr

reported in 1990s (on page 7 of the report).

Hence

, there is a big area of

improvement needed

on the

conclusiveness

of the data extracted by Jacobs SKM. If this had been reported in the benchmark study, the N emission level would be double than the present data and this would lead to a different

conclusion regarding the relative contributions to effluent

loads in GBR

.

9Slide10

121 - 365

<1 - 300

Recommended potential correction

10Slide11

References

[1]

Erftemeijer

, P.L.A., Benchmark Study : Emissions, Productivity and Employment for Aquaculture and other Types of Land Use in Queensland. 2014, QCA: Jacobs SKM.

[2] ACIL

,

Submission to the Productivity Commission on Industries in the Great Barrier Reef Catchment and Measure To address Declining Water Quality. 2002.

[3] Bartley, R. and W. Speirs, Review and summary of constituent concentration data from Australia for use in catchment water quality models

, in eWater Cooperative Research Centre Technical Report. 2010, CSIRO.[4]

Trott, L.A. and D.M. Alongi, Quantifying and predicting the impact of prawn effluent on the assimilative capacity of coastal waterways and Pond and Effluent management

, in FDRC Project 97/212. 2001: Aquaculture CRC Ltd Project E1.[5]

Burford

, M.A., et al.,

A synthesis of dominant ecological processes in intensive shrimp ponds and adjacent coastal environments in NE Australia.

Mar

Pollut

Bull, 2003.

46

(11): p. 1456-69.

[6] Jackson

, C., N. Preston, and P.J. Thompson,

Intake and discharge nutrient loads at three intensive shrimp farms.

Aquaculture Research, 2004.

35

(11): p. 1053-1061.

[7] McPhee

, D.,

A comparison of anthropogenic discharge quality and quantity into Queensland East Coast catchments.

2001, APFA.11Slide12

Conclusions

T

he

benchmark study done by Jacobs SKM that is used by the

QCA in reporting to the Queensland

Government in their decision to determine the fate of regulatory reform of aquaculture in Queensland warrants further improvements.

The unilateral

approach adopted by Jacobs SKM in evaluating and comparing the environmental impacts of point source pollutants from aquaculture with other diffuse-source effluents from other agricultural activities may not be the best

approach.

As postulated by

Burford

[5],

bioindicators

of ecological processes may potentially be a more accurate and reasonable way of evaluating the water quality affected by prawn farm effluents.

Primary production rates

Phytoplankton responses to nutrients

Community shifts in zooplankton

Nitrogen isotope ratios in plants

12Slide13

Acknowledgements

Prof Ross Barnard

Helen Jenkins

13