HEAVY METALS (Cr, Pb, Cd, Cu) IN SEDIMENT AND BIVALVES AND NUTRIENTS (PHOSPHATE AND NITRATE) IN MAROVO LAGOON, WESTERN PROVINCE, SOLOMON ISLANDS By Dickson Michael Boboria A thesis submitted in partial fulfillment of the requirement of the degree of the Master of Science Copy right © 2014 by Dickson Michael Boboria Faculty of Science, Technology and Environment The University of the South Pacific August, 2014 Abstract Poor waste management and degradation of natural forests are a great concern in the South Pacific countries as these could lead to the coastal deterioration of the marine and lagoon environments. An investigation of the water quality of the Marovo Lagoon was carried out in early January, 2014 at a total of fifteen sites including ten stations for both sediments and water samples and five different sites for the bivalve samples. The collected sediment, bivalves and - water samples were used to determine heavy metal (Cr, Pb, Cd, and Cu) and nutrient (NO3, 3- PO4 ) pollution in the area. The physical and chemical parameters for water (pH, DO, salinity, turbidity) were also tested on site and showed the following ranges: pH (5.12 –7.86), salinity 0 0 (32.1 – 36.6 /00), DO (4.37 –7.89 mg /L), temperature (21.2 – 25.3 C) and turbidity (140 – 1500 NTU). The dissolved oxygen is at normal levels but an increased turbidity level may represent high sedimentation and microbial activities in the lagoon, while the salinity may indicate less evaporation and fresh water influences in the lagoon. The concentrations of the metals in the analyzed sediment reference material (PACS-1) agreed generally quite well with the certified values and reasonable metal recoveries were practically achieved for all the tested metals. The total metals in the sediment samples appeared in the following order: Cu > Pb > Cr > Cd with the respective ranges of Pb (74.8 – 371 µg/g), Cu (144 – 358 µg/g), Cr (75–351 µg/g) and Cd (24.7 – 47.1 µg/g). This general pattern was also evident for the total metals in the bivalve tissues with the order of: Cd < Cr < Cu < Pb and the relative observed ranges: Cd (1.70 – 10.2 µg/g), Pb (24.0 – 85.5 µg/g), Cr (9.34 – 41.8 µg/g) and Cu (47.0 – 76.0 µg/g). However, the nutrient analyses showed the respective ranges of 1.23 – 136 3- - µg/mL and 0.211– 30.9 µg/mL for PO4 and NO3 but were generally low for all sites except for South Sege and Ngai Passage. The relationship between the sediment metals, the soft tissues metals and the nutrient levels can be explained by the poor hydrodynamic system of the lagoon. The data for the metals in both sediments and bivalves showed values greatly exceedingly or comparable to the ERL and TEL of the Sediment Quality Guidelines of NOAA and the sediment data of Naidu et al. (1991) for the same sites. As for nutrients, they were above the standards the ANZECC, (2000) guidelines for inshore marine waters and Naidu et al. (1991). However, they i were still lower than the Australia and New Zealand standard guidelines and comparable to other Pacific studies indicating a potential ecological impact in the studied area in the future. The calculated Igeo generally showed values of less than 1, reflecting non-polluted environments. The calculated values for dermal contact with sediments (DCCS) and bivalve (DCCB) and ingestion of sediment (IS) and bivalves (IB) also showed values less than 1 mg/kg for all the studied metals, indicating less potential health risk in the lagoon. In general the DCCS, DCCB, IS and IB values showed less Pb risk for both children and adults for the entire study with values comparable to the background level of Pb of 0.46 mg/kg/day. The Wilcoxon test showed a significant result for the sediment data reflecting the increased levels of metals in sediments in the Marovo Lagoon over the years in relation to the Naidu et al. (1991) data for the same sites. The major identified human sources of contaminants in the lagoon include mining, domestic waste, commercial products (paints, Pb batteries, sewage dumping and medical waste), volcano eruptions and waste from logging machinery, applications of fertilizers in the oil palm plantation, small scale agricultural activities and advanced weathering of soil, sewage waste and run off from forest floor and urban sites. In general, the complex reef system and the narrow passages of the lagoon restrict the exchange of contaminants with the open sea categorizing Marovo as a wind mixing lagoon. ii Acknowledgement Firstly I would particularly like to thank Dr Maata Matakite for his supervision, patience and unfailing willingness to assist and helpful input throughout the study. My special thanks go to Dr Katy Soapi for her advice in the thesis write up. I would like to thank Dr Simon Albert (University of Queensland) for supplying me with some images of logging and oil palm plantation from the lagoon; the local boys at Chea villages, especially Scoti, Uncle Bill and others, for their assistance during the sampling trip; and Dr Nathan Wales for showing me how to plot sampling sites on the google map. I would not have been able to complete my thesis without the information supplied by Solomon Island Meteorological Service; Solomon Island Water Authority for the preservation of samples in Honiara; Dr Luke Mani for his advice during the sampling period; USP Laucala campus and Honiara local campus; Charly Bradford and the family for providing accommodation during the sampling period; the local people around the studied sites for providing some useful information about the lagoon; Naidu et al. (1991) for use of their data as the background study of the recent study. Thanks go to the Geography Department (Marine campus) in lending me the GPS equipment during my sampling trip and the Earth Science Department for lending me micro- sieves to prepare my sediment samples. Thanks also to the School of Biological and Chemical Sciences for further preservation of samples at the Laucala Campus and Mr Steven Sutcliffe, the Chief Technician (SBCS) for assisting with the order of chemicals that are required for my bench work. The funding provided by the FSTE Reseach Office to carry out the project was very much appreciated. I would like to thank my family, especially my dad (Boboria) and mum (Roselyn Boboria) for their encouragement and advice all through out my study time. Finally, I am gratefully acknowledging the scholarship by the SIG that enabled me to do my postgraduate studies at the University of the South Pacific. My special thanks go to the Lord Almighty in giving me strength, knowledge and understanding to complete this thesis on time. iii Table of Contents Abstract……………………………………………………………………………………….i–ii Acknowledgment………………………………………………………………………………iii Table of content………………………………………………………………………….iv–xxiii List of Tables……………………………………………………………………………..xiii–xv List of figures .…………………………………………………………………………...xvi–xvii List of plates xviii Acronyms………………………………………………………………………………..xix–xxiii Chapter One: General Introduction………………………………...1 1.1 Background………………………………………………………………………………1–2 1.2 Water quality testing………………………………………………………………………..2 1.3 Sources of pollution and their definitions………………………………………………..2–3 1.3.1 Brief definitions of Urban pollution, Agriculture and Atmospheric pollution…………….3 1.3.2 Types of pollution: Organic pollution……………………………………………………….3–4 1.3.3 Pesticides and herbicides: chemical pollution…………………………………………...4 1.3.4 Sediment pollution: Storm runoff and salt water intrusion……………………………….4–5 1.4 Nutrient cycling in oceans………………………………………………..........................5–6 1.4.1 The Nitrogen cycle……………………………………………………………….……..……..6–7 1.5 Bioindicators of metals in sediment.……………………………………………………..7–8 1.6 Biochemical alteration…………………………………………………………………...8–9 1.7 Environmental legislation: Fiji and Solomon Islands………………………………......9–12 iv 1.8 General information on the Solomon Islands…………………………………………...…12 1.8.1 Climate change……………………………………………………………………………...13-14 1.8.2 Typical wastes generated in Solomon Islands…………………………………...…..….14-16 1.8.3 Other contaminants used in Solomon Islands…………………………………..…………..17 1.8.4 Attitudes of people in Solomon Islands towards waste……………………………………..18 1.8.5 Barriers to rubbish collection in Solomon Islands………………………….......................18 1.8.6 Barriers to waste management practices in PICTs and Solomon Islands………....…….18 1.9 Project objectives……………………………………………………...…………………..19 1.10 Structure of thesis………………………………………………………………..….........20 Chapter Two: Metals in sediment……………………………………21 2.1 Introduction………………………………………………………………………………..21 2.2 Heavy metals pollution of aquatic environment……………………………………….21-23 2.3 Pacific Island region…………………………………………………………………...23-25 2.3.1 Waste management in the Pacific Island countries……………………………………...….26 2.3.2 Waste disposal in PICTs countries………………………………….…….…………...….27-29 2.3.3 Threats to the Pacific region……………………………………………………...…..……….30 2.3.4 Actions taken by some PICTs towards the marine environmental threat……………...…31 2.3.5 Research challenges in PICTs………………………………………………...…...................31 2.4 Background on the studied metals………………………………….…………………..…32 2.4.1 Lead……………………………………………………………………………….………………33 2.4.2 Chromium………………………………………………………………….………………….…34 v 2.4.3 Cadmium……………………………………………………...………………..........................35 2.4.4 Copper…………………………………………………………………………..……….........…36 2.5 Chemical analytical techniques in pollution monitoring………………………………….36 2.6 Metals in sediment…………………………………………………………………...……37 2.6.1 Properties influencing sorption of heavy metal