2. WATER QUALITY

Monitoring Requirements

2.1 Water quality monitoring was conducted at five monitoring stations. Appendix B shows the established Action and Limit Levels (AL Levels) for water quality parameters.

Monitoring Equipment

2.2 Water samples were collected at three depths at all sampling locations: (1) 1m below the water surface, (2) mid depth, and (3) 1m above the bottom of the lake. The parameters of water depth, dissolved oxygen (as % saturation), turbidity, temperature, and pH were measured in-situ. Water samples were collected for analysis by a HOKLAS accredited laboratory. The water quality monitoring equipment deployed is described in Table 2.1.

Table 2.1 Water Quality Monitoring Equipment

Equipment	Model and Make
Dissolved Oxygen Measuring Meter	YSI 85D
Turbidmeter	HACH 2100P
pH Meter	Hanna HI9023
Water Sampler	Wildco Alpha Water Bottle (Vertical)
Differential Global Positioning System (DGPS)	MLR FX412
Water depth echo sounder	Cuda 168

Monitoring Parameters, Frequency and Duration

2.3 Table 2.2 summarised the monitoring parameters, frequencies and duration of the water quality monitoring.

Table 2.2 Water Quality Monitoring Parameters, Period and Frequency

Monitoring Station	Parameters, unit	Frequency	No. of Depths
WM1-WM5	^1Dissolved Oxygen Saturation, % ^1Water depth, m ^1pH value ^1Temperature, °C ^1Turbidity, NTU Dissolved Oxygen, mg/L Conductivity, mS/cm Salinity, g/L Copper (Cu), mg/L Chromium (Cr), mg/L Lead (Pb), mg/L Zinc (Zn), mg/L Tributyl Tin (TBT), ng Sn/L Suspended Solids, mg/L Total Nitrogen, mg/L Total Phosphorous, mg/L Total Silica, mg/L 5-day BOD, mg/L COD, mg/L Ammonia, mg/L Chlorophyll a, mg/L E. Coli, cfu/100mL	Once per week	3 (Surface, Mid-Depth, Bottom)

Note:

1. Parameters to be measured in-situ.

Monitoring Locations

2.4 Five stations were designated for water quality monitoring. The locations of these monitoring stations are summarized in Table 2.3 and depicted in Figure 2.1.

Table 2.3 Water Quality Monitoring Locations

Location	HK Metric Grid E	HK Metric Grid N
WM1	821 821.66	820 493.99
WM2	822 034.44	820 369.10
WM3	821 839.52	820 377.60
WM4	821 932.82	820 278.32
WM5	821 915.76	820 184.51

Monitoring Methodology

2.5 Dissolved Oxygen saturation, water depth, pH value, temperature and turbidity were measured in-situ at the designated water quality monitoring stations. General observation, weather conditions, with the sampling time, date and location were marked on a field record sheet.

2.6 Water samples were taken from each monitoring station with a water sampler for laboratory analysis. The sample was then poured into a pre-labelled bottle. The label contained the sample identification number, sample location, date, time, project name and analyses required.

2.7 The samples were placed in a cooler with ice (to 4ºC without being frozen) and kept away from sunlight. Samples were submitted to a Hong Kong Accreditation Scheme (HOKLAS) laboratory for analysis within 24 hours of sampling.

Operating/Analytical Procedures

2.8 A Differential Global Positioning System (DGPS) was used to ensure that the correct location was selected prior to sample collection.

2.9 A portable, battery-operated echo sounder was used for the determination of water depth at each designated monitoring station.

2.10 All in-situ measurements and samples for analysis were taken at three water depths, namely 1m below water surface, mid-depth and 1m above lake bottom.

2.11 At each measurement/sampling depth, two consecutive measurements for each in-situ parameters were taken. Where the difference in the value between the first and second readings of each set was more than 25% of the value of the first reading, the reading was discarded and further readings were taken.

2.12 Water samples were collected using the water sampler and the samples were stored in pre-labelled bottles. Water samples collected were well-mixed in the water sampler prior to transferring to sample bottles. The sample bottles were then packed in cool-boxes (cooled at 4^°C without being frozen), and delivered to ALS Technichem (HK) Pty Ltd. for the laboratory analysis.

Maintenance and Calibration

2.13 The dissolved oxygen meter, which also measures temperature, was calibrated by the wet bulb method before each monitoring day. Before the routine calibration, the sensor for dissolved oxygen was thermally equilibrated in water-saturated air. The calibration cup served as a calibration chamber and it was loosened from airtight condition before it was used for the calibration. Calibration was also carried out in a water sample with a known concentration of dissolved oxygen at 3-month intervals. The sensor was immersed in the water and after thermal equilibration, the known mg/L value was keyed in and the calibration was carried out automatically.

2.14 The turbidimeter has already been calibrated at 3-month intervals. Before the measurement, a zero check in distilled water was performed with the turbidimeter. The turbidimeter was calibrated with a solution of known NTU.

2.15 The pH meter was calibrated at 3-month intervals. Before the measurement, a zero check in distilled water was performed with the meter. The probe was calibrated with a solution of known salinity. A similar procedure was carried out for pH value calibration.

2.16 Calibration records are presented in Appendix C.

Laboratory Analysis

2.17 All laboratory work was carried out by ALS Technichem Pty. Ltd. The determination work started within 24 hours after collection of the water samples. The analyses followed the standard methods according to Table 2.4 and as described in APHA Standard Methods for the Examination of Water and Wastewater.

Table 2.4 Analytical Methods to be applied to Water Quality Samples

Determinant, unit	Reference Method Used^1 (APHA 20^th ed)	Reporting Limits
Dissolved Oxygen, mg/L	4500O: G	0.1 mg/L
Conductivity, mS/cm	2510B	1 mS/cm
Salinity, g/L	2520B	0.1 g/L
Copper, mg/L	3125 / ICPMS	1 mg/L
Chromium, mg/L		1 mg/L
Lead, mg/L		1 mg/L
Zinc, mg/L		10 mg/L
Tributyl Tin, ng Sn/L	UNEP/ICO/IAEA	5 ng Sn/L
Suspended Solids, mg/L	2540D	2 mg/L
Total Nitrogen, mg/L	4500Norg: B 4500NO3: F	0.1 mg/L
Total Phosphorus, mg/L	4500P: B4, F	0.1 mg/L
Total Silica, mg/L	4500Si: F	0.01 mg/L
5-day BOD, mg/L	5210B	2 mg/L
COD, mg/L	5220B	2 mg/L
Ammonia Nitrogen, mg/L	4500NH3: G	0.01 mg/L
Chlorophyll-a, mg/L	10200H2	5 mg/L
E. Coli. cfu/100mL	DoE Section 7.9.4.2 & 4	1 cfu/100mL

Note:

1. All testing conducted by the laboratory are In-House methods based on the method stated in the “Standard Methods for the Testing of Water and Wastewater, 19^th & 20^th ed” (APHA) or the USEPA SW846.

QA/QC Procedure

2.18 ALS Technichem has comprehensive quality assurance and quality control programmes. The QA/QC procedures for each analytical batch:

· At least 1 reagent blank solution was prepared and analyzed;

· At least 1 duplicate sample analysis was performed in every 10 samples;

· At least 1 in every 10 samples was spiked with a known concentration of the analyte to determine the matrix effect of the sample.

Results and Observations

2.19 Monitoring of water quality was carried out at the 5 designated monitoring stations on 4 occasions during the reporting period (21 November 2005, 2 December 2005, 8 December 2005, and 14 December 2005). The monitoring schedule is presented in Appendix D. All monitoring data and graphical presentation of the monitoring results are provided in Appendix E and summarised in Table 2.5.

Table 2.5 Summary of Water Quality Monitoring Results

Parameters	Monitoring Data (Depth Averaged Data)
	WM1	WM2	WM3	WM4	WM5
Temperature, ^OC	16.8 – 24.6 (16.9 – 24.6)	16.6 – 25.0 (16.8 – 25.0)	16.8 – 25.2 (17.0 – 25.2)	16.7 – 26.1 (16.9 – 26.0)	17.0 – 25.4 (17.0 – 25.4)
Daily Temperature Difference^1, ^OC	0.2 – 1.4
Turbidity, NTU	1.0 – 1.3	0.9 – 1.3	1.0 – 1.3	1.0 – 1.4	0.8 – 1.4
pH	7.4 – 7.8 (7.4 – 7.8)	7.4 – 7.8 (7.4 – 7.8)	7.2 – 7.9 (7.4 – 7.8)	7.5 – 7.8 (7.5 – 7.8)	7.4 – 7.7 (7.5 – 7.7)
Dissolved Oxygen, mg/L	4.5 – 9.0 (5.8 – 7.2)	4.8 – 8.4 (5.8 – 7.6)	4.3 – 8.8 (4.9 – 7.6)	3.5 – 8.0 (4.4 – 7.5)	4.1 – 7.4 (4.4 – 6.9)
Conductivity, mS/cm	77 – 87	80 – 108	79 – 83	76 – 82	78 – 84
Salinity, g/L	all <0.1	all <0.1	all <0.1	all <0.1	all <0.1
Copper, mg/L	all <1	all <1	all <1	all <1	all <1
Chromium, mg/L	all <1	all <1	all <1	all <1	all <1
Lead, mg/L	all <1	all <1	all <1	all <1	all <1
Zinc, mg/L	all <10	all <10	all <10	all <10	all <10
Tributyl Tin, ng Sn/L	all <5	all <5	all <5	all <5	all <5
Suspended Solids ^2, mg/L	<2 – 3	all <2	all <2	all <2	all <2
Total Nitrogen, mg/L	0.2 – 0.5 (0.3 – 0.5)	0.2 – 0.5 (0.3 – 0.4)	0.2 – 0.5 (0.3 – 0.5)	0.3 – 0.5 (0.4 – 0.5)	0.2 – 0.5 (0.2 – 0.5)
Total Phosphorous^1, mg/L	all <0.02	all <0.02	all <0.02	all <0.02	all <0.02
Silicate, mg/L	8.55 – 10.10 (8.79 – 10.10)	8.60 – 10.10 (8.64 – 10.06)	8.50 – 10.30 (8.26 – 9.51)	7.93 – 9.10 (8.09 – 8.89)	7.84 – 9.27 (7.85 – 9.18)
Ammonia Nitrogen, mg/L	all <0.01	all <0.01	all <0.01	<0.01 – 0.02	<0.01 – 0.02
Unionised Ammonia^3, mg/L	<0.00047 – <0.00054	<0.00027 – <0.00030	<0.00022 – <0.00024	<0.00020 – <0.00022	<0.00017 – <0.00018
BOD5, mg/L	<2 – 5	all <2	all <2	all <2	all <2
COD, mg/L	<2 – 6	<2 – 4	<2 – 4	<2 – 5	<2 – 4
Chlorophyll-a, mg/L	0.9 – 1.3	1.0 – 1.6	0.9 – 1.4	0.9 – 1.4	1.2 – 1.5
E. Coli^4, cfu/100mL	all <1	all <1	all <1	all <1	all <1

Note: 1. Present as depth average 2. Present as annual median

3. Present as annual median 4. Present as geometric mean for last 5 measurements

2.20 The QA/QC results for laboratory testing in the reporting period were acceptable. The QA/QC results are summarised in Appendix F.

2.21 All recorded levels during the reporting period were below the AL Levels. Table 2.6 summarises water quality exceedances in the reporting period.

Table 2.6 Summary of Water Quality Exceedances

Parameters	WM1		WM2		WM3		WM4		WM5		Total
	Action	Limit	Action	Limit	Action	Limit	Action	Limit	Action	Limit	Action	Limit
Dissolved Oxygen	0	0	0	0	0	0	0	0	0	0	0	0
pH	0	0	0	0	0	0	0	0	0	0	0	0
Temperature	-	0	-	0	-	0	-	0	-	0	-	0
Suspended Solids	0	0	0	0	0	0	0	0	0	0	0	0
Ammonia Nitrogen	0	0	0	0	0	0	0	0	0	0	0	0
E. Coli	0	0	0	0	0	0	0	0	0	0	0	0
BOD5	0	0	0	0	0	0	0	0	0	0	0	0
COD	0	0	0	0	0	0	0	0	0	0	0	0

Note: Assessment criteria applied to depth averaged results at each location.

2.22 Water temperatures measured ranged from 16.8 – 26.0 ^OC. The maximum daily variation between each station was 1.4 ^OC on 2 December 2005. The variation was within the AL Levels. Salinity measurements at all stations were below detection limit, indicating no intrusion of saline water was present in WRC. DO level at all station was above the Theme Park EIA proposed standard of 4.2 mg/L.

2.23 BOD₅ levels ranged from <2 – 5 mg/L., while COD levels measured from <2 – 7 mg/L. Depth averaged results of both parameters complied with the standards proposed in the Theme Park EIA (5 and 30 mg/L respectively). The medians of SS measurements during the same period also observed the proposed standards (25 mg/L). Low levels of SS measurements (annual median all below 2 mg/L) correlate with the low in-situ turbidity measurements (0.8 – 1.4 NTU).

2.24 The unionised ammonia levels, derived from Ammonia Nitrogen, temperature, pH and salinity levels, were substantially lower than the proposed standard of 0.021 mg/L. Together with other measurements in terms of Total Nitrogen and Total Phosphorus, nutrient levels within the WRC were relatively low.

2.25 For heavy metals (Cu, Cr, Pb, Zn), majority of the readings were below the detection limit. All TBT readings were below the detection limit and AL Levels.

2.26 All E.Coli measurements were below the detection limit of 1 cfu/100mL. The geometric mean of last five readings at all monitoring locations were below the AL Levels.