State of the Bay Report 2010-Final - Anchor Environmental

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Anchor Environmental Until recently the Langebaan WWTW did not discharge any effluent into the sea as all of it was used it to irrigate the local golf course. However, increasing volumes of effluent received by this plant is yielding more water than is required for irrigation and some of this is now discharged into the Bay. There are nine sewage pump stations in Saldanha Bay and two conservancy tanks, all of which are situated on the western border of Small Bay. The conservancy tanks are positioned adjacent to the Yacht Club. There are eighteen sewage pump stations in Langebaan situated throughout the town, many of which are near the edge of the lagoon, and three conservancy tanks spread around the edge of the lagoon at Oosterwal, Stofbergsfontein and Oudepos (Figure 4.17). Sewage effluent can enter the Saldanha/Langebaan marine environment via three routes, namely; Discharge of treated sewage effluent in the Bok River which drains into Small Bay Overflow of sewage pump stations as a result of pump malfunction of power failures Seepage or overflow from septic or conservancy tanks Historically a number of these pump stations used to overflow from time to time directly into the Bay when the pumps malfunctioned. This has now a rare event, however, as much of the associated infrastructure has been upgraded recently and is now regularly maintained. The Saldanha WWTW operates under an exemption issued by the Department of Water Affairs (DWAF) in terms of the Water Act of 1956 which authorises the release of a total volume of 958 000 m 3 per year. Table 4 shows the general standards as specified under the Water Act 54 (1956), and the revised general limits specified under the National Water Act 36 of 1998 for various other parameters and substances contained in the released waters of the WWTW of Saldanha and Langebaan. 4.3.6.1 Water quality parameters associated with the Saldanha WWTW Trends over time for water quality parameters associated with effluent from the Saldanha WWTW are shown in Figure 4.18-Figure 4.19. Before 2005, the daily volume discharged never exceeded 2000 m 3 , but volumes of effluent released have subsequently been increasing steadily over time and are now approaching the maximum annual limit allowed in terms of the exemption issued by DWAF. Numbers of faecal coliforms in the effluent from the WWTW exceeded allowable limits specified on 14 occasions since 2003 (15% of the time) (Figure 4.18). Allowable limits for Total Suspended Solids were exceeded on 12% of the occasions on which measurements were made, and measurements for Chemical Oxygen Demand (COD) exceeded allowable limits 28% of the time (Figure 4.18). Chemical Oxygen Demand is commonly used to indirectly measure the amount of organic compounds in water. A worrying sign is the levels of Ammonia Nitrogen discharged which are consistently above the allowable margin of 3 mg/l; allowable limits being exceeded 94% of the time. Nitrate Nitrogen limits were exceeded on 19% of the occasions (Figure 4.19). Table 4.5. General standards as specified under the Water Act 54 (1956) and revised general limits specified under the National Water Act 36 of 1998. SUBSTANCE/PARAMETER GENERAL STANDARDS UNDER THE WATER ACT GENERAL LIMIT FOR GENERAL AUTHORISATION State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 70
Anchor Environmental (1956) UNDER THE NATIONAL WATER ACT (1998) Temperature 35oC - Electrical Conductivity measured in milliSiemens per meter (mS/m) 75 70 above intake to a maximum of 150 pH 5.5-9.5 5.5-9.5 Chemical Oxygen Demand (mg/l) 75 75 (after removal of algae) Suspended Solids (mg/l) 25 25 Soap, oil or grease (mg/l) 2.5 2.5 Ortho-Phosphate as P (mg/l) - 10 Nitrate/Nitrite as Nitrogen (mg/l) - 15 Ammonia (ionised and un-ionised) as N (mg/l) 10 3 Fluoride (mg/l) 1 1 Chlorine as Free Chlorine (mg/l) 0.1 0,25 Dissolved Cyanide (mg/l) 0.5 0.02 Dissolved Arsenic (mg/l) 0.5 0.02 Dissolved Cadmium(mg/l) 0.05 0.005 Dissolved Chromium (VI) (mg/l) 0.05 0.05 Dissolved Copper (mg/l) 1 0.01 Dissolved Iron (mg/l) - 0.3 Dissolved Lead (mg/l) 0.1 0.01 Dissolved Manganese (mg/l) 0.4 0.1 Mercury and its compounds (mg/l) 0.02 0.005 Dissolved Selenium (mg/l) 0.05 0.02 Dissolved Zinc (mg/l) 5.0 0.1 Boron (mg/l) 1 1 Phenolic compounds as phenol (mg/l) 0.1 - Faecal Coliforms (per 100 ml) 100 1000 State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 71
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State of the Bay 2010: Saldanha Bay
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TABLE OF CONTENTS Anchor Environmen
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11 BIRDS 234 Anchor Environmental 1
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LIST OF FIGURES Anchor Environmenta
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Anchor Environmental Figure 4.27. O
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Anchor Environmental Figure 7.3. Ch
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Anchor Environmental Figure 9.10. C
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Anchor Environmental Figure 12.1. N
Page 19 and 20: Anchor Environmental samples were c
Page 21 and 22: EXECUTIVE SUMMARY Anchor Environmen
Page 23 and 24: Anchor Environmental matter in the
Page 25 and 26: Anchor Environmental considered mos
Page 27 and 28: Anchor Environmental again in 2004,
Page 29 and 30: Anchor Environmental Populations of
Page 31 and 32: GLOSSARY Alien species An introduce
Page 33 and 34: 1 INTRODUCTION Anchor Environmental
Page 35 and 36: 2 STRUCTURE OF THIS REPORT Anchor E
Page 37 and 38: Anchor Environmental complicates ma
Page 39 and 40: Anchor Environmental observed deter
Page 41 and 42: Anchor Environmental 4 ACTIVITIES A
Page 43 and 44: Fish factories Small craft harbour
Page 45 and 46: Anchor Environmental Aerial photogr
Page 47 and 48: Anchor Environmental interferes wit
Page 49 and 50: Anchor Environmental Figure 4.7. Nu
Page 51 and 52: o Decrease in oxygen concentrations
Page 53 and 54: Anchor Environmental Upgrades to th
Page 55 and 56: Anchor Environmental Figure 4.9. A)
Page 57 and 58: Anchor Environmental (possibly link
Page 59 and 60: Anchor Environmental Prestedge Reti
Page 61 and 62: Anchor Environmental the constructi
Page 63 and 64: Number and types of vessels enterin
Page 65 and 66: Anchor Environmental is contained b
Page 67 and 68: Anchor Environmental include the be
Page 69: o 33 3’S o 33 10’S Saldanha Bay
Page 73 and 74: Free ACtive Chlorine (mg/l) Amonia
Page 75 and 76: Faecal coliforms (org/100 ml) Chemi
Page 77 and 78: 4.3.7 Storm water Anchor Environmen
Page 79 and 80: Anchor Environmental sites (concent
Page 81 and 82: Anchor Environmental Discharges fro
Page 83 and 84: Anchor Environmental Table 4.9. Det
Page 85 and 86: 5 WATER QUALITY Anchor Environmenta
Page 87 and 88: Anchor Environmental Stander (1977)
Page 89 and 90: Anchor Environmental coast, result
Page 91 and 92: Anchor Environmental likely as a re
Page 93 and 94: Anchor Environmental Construction o
Page 95 and 96: Anchor Environmental Table 5.2. Per
Page 103 and 104: Counts per 100ml of sample Counts p
Page 105 and 106: Counts per 100ml of sample 10000 10
Page 107 and 108: 5.6 Trace Metal Contaminants in the
Page 109 and 110: State of the Bay 2010: Saldanha Bay
Page 111 and 112: Lead(mg/kg) Mercury (mg/kg) Cadmium
Page 113 and 114: 6 SEDIMENTS 6.1 Sediment particle s
Page 115 and 116: 6.1.2 Sediment Particle size result
Page 117 and 118: State of the Bay 2010: Saldanha Bay
Page 119 and 120: 100% 90% 80% 70% 60% 50% 40% 30% 20
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% POC 18 16 14 12 10 8 6 4 2 0 % PO
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Percentage Percentage 1.8 1.6 1.4 1
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o 33 3’S o 33 10’S Yacht Club B
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Figure 6.12. Variation in the conce
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The concentrations of metals in sed
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concentrations are 56 and 29 times
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threshold of 1.2 mg/kg established
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Cadmium (mg/kg) 8 7 6 5 4 3 2 1 0 C
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Copper (mg/kg) 45 40 35 30 25 20 15
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16000 14000 12000 10000 8000 6000 4
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In summary, elevated trace metal co
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6.5 Summary of sediment health stat
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7.1 Long term changes in seagrass i
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7.2 Long term changes in Saltmarshe
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Figure 8.1. Benthic macrofauna samp
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Table 8.1. Depth at each of the sit
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these species usually provide the l
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(clustering of similar groups) (Meg
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The Big Bay samples BB 25 and BB29
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2007/08 dredging. Other signs of th
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Wet mass per m² Wet mass per m² 4
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Big Bay Crustaceans and polychaetes
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Average number of individuals per m
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Number Individuals per m² Number I
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8.4.2 Abundance Biomass Indices 8.4
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and percentage organic nitrogen (PO
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Table 8.5. W statistics at all stat
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Figure 8.15: Variation in the diver
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percentage of mud compared to Lange
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Cu (mg/kg) Cd (mg/kg) Ni (mg/kg) Pb
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contaminants. Furthermore dredging
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areas even 5 months after the clear
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Brittle star ( Ophiuroidea spp) Sea
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9.2 Approach and Methodology 9.2.1
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cover data for both mobile and sess
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9.2.3 Data Analysis The similaritie
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40%, co-occurring with sponges espe
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stands of the kelp Ecklonia maxima
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Plocamium spp. Ecklonia maxima Scut
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20 40 A Group 1 B 60 Similarity C G
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Percentage Cover 80 70 60 50 40 30
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Evenness Shannon Wiener 0.9 0.8 0.7
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2005 2008 2009 2010 Dive School Jet
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Table 9.5. Results from the SIMPER
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In general, the inter-annual differ
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The temporal distribution of M. gal
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Consistent with the previous years,
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Saldanha and Langebaan. Results fro
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The average abundance of the four m
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Anchor Environmental Figure 10.5. A
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Anchor Environmental Figure 10.7. A
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Anchor Environmental Within Big Bay
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Anchor Environmental 2008 and 2009
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Anchor Environmental the islands, b
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Anchor Environmental at Saldanha ar
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their main prey species, sardines a
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Anchor Environmental 2009). The eff
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Anchor Environmental attributed to
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Number of breeding pairs 800 700 60
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11.3 Birds of Langebaan Lagoon 11.3
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Anchor Environmental Figure 11.11.
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Anchor Environmental for the gannet
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Taxon Anchor Environmental Occurren
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Taxon Anchor Environmental Occurren
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Anchor Environmental 13 MANAGEMENT
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Anchor Environmental their operatio
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Anchor Environmental concentrations
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Anchor Environmental changes that p
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Anchor Environmental and slight imp
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Birdlife International. 2010. URL w
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Anchor Environmental penguins Sphen
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Anchor Environmental Game, E.T., Gr
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Anchor Environmental Kerwath, S. E.
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Anchor Environmental Moldan, A. 197
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Anchor Environmental Robinson, T.B.
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Anchor Environmental Tunley KL, Att
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State of the Bay Report 2010-Final - Anchor Environmental

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