A comprehensive study was conducted to explore the concentration and distribution of heavy metals in farm soils and river sediments around a gold mining area in Fiji with particular emphasis on ecological and human health risks. Representative samples were acquired from farm sites in Matanagata Village and the Nasivi river, both situated around the Vatukoula gold mine limited (VGML), the largest operational gold mine in Fiji. Following aqua regia digestion and analysis by AAS, the average soil concentrations for Cu (110.4 mg kg –1 ), Cr (136.2 mg kg –1 ) and Cd (1.7 mg kg –1 ), and sediment concentrations for Pb (69.31 mg kg –1 ), Cd (1.82 mg kg –1 ), Cu (88.95 mg kg –1 ) and Cr (143.12 mg kg –1 ) were found to exceed the recommended guideline values. Based on the geo–accumulation index ( I geo ) and enrichments factor (EF), the farm soils were moderately contaminated with Cd while the and sediments showed moderate to significant contamination with Pb, Ni and Cr. Ecological risk assessment confirmed moderate to considerable ecological risk in the metal–contaminated samples, with Cd and Pb generally presenting greater risk compared to other metals. Multivariate analyses including principal component analysis pointed to gold mining activities as a potential source for heavy metals in the area. Furthermore, human health risk assessment (HRA) indicated that while adults faced no significant carcinogenic or non–carcinogenic risks from metal exposure (HI < 1), children were at more risk from Co, Mn, Cr and Fe exposure, as well as potential carcinogenic risk from Cd (ILCR = 1.46E–04).

Heavy metal concentrations were determined in sediment and bivalve samples from Marovo Lagoon in the Solomon Islands. In the sediments, heavy metal levels ranged from 10 ? 3?47 ? 2 ?g/g Cd, 25 ? 4?351 ? 5 ?g/g Cr, 145 ? 3?418 ? 7 ?g/g Cu and 20 ? 3?371 ? 5 ?g/g Pb. When compared to the baseline values measured in a 1991 study of the same lagoon, a simple relative ratio in the range of 2?43 was noted for all metals in sediments as compared to baseline and confirms significant anthropogenic influence. The heavy metal contamination of bivalves showed level ranges of 2.00 ? 0.01?10 ? 1 ?g/g Cd, 9 ? 3?42 ? 2 ?g/g Cr, 47 ? 3?76 ? 3 ?g/g Cu and 24 ? 11?86 ? 14 ?g/g Pb. The higher levels of metals in the Marovo Lagoon sediments when compared to other Pacific studies are attributed to intense logging activities around the bay and other potential anthropogenic sources such as mining and discharge of waste into the lagoon.

Ozone in the troposphere affects humans and ecosystems as a pollutant and as a greenhouse gas. Observing, understanding and modelling this dual role, as well as monitoring effects of international regulations on air quality and climate change, however, challenge measurement systems to operate at opposite ends of the spatio-temporal scale ladder. Aboard the ESA/EU Copernicus Sentinel-5 Precursor (S5P) satellite launched in October 2017, the TROPOspheric Monitoring Instrument (TROPOMI) aspires to take the next leap forward by measuring ozone and its precursors at unprecedented horizontal resolution until at least the mid-2020s. In this work, we assess the quality of TROPOMI's first release (V01.01.05–08) of tropical tropospheric ozone column (TrOC) data. Derived with the convective cloud differential (CCD) method, TROPOMI daily TrOC data represent the 3 d moving mean ozone column between the surface and 270 hPa under clear-sky conditions gridded at 0.5∘ latitude by 1∘ longitude resolution. Comparisons to almost 2 years of co-located SHADOZ ozonesonde and satellite data (Aura OMI and MetOp-B GOME-2) conclude to TROPOMI biases between −0.1 and +2.3 DU (<+13 %) when averaged over the tropical belt. The field of the bias is essentially uniform in space (deviations <1 DU) and stable in time at the 1.5–2.5 DU level. However, the record is still fairly short, and continued monitoring will be key to clarify whether observed patterns and stability persist, alter behaviour or disappear. Biases are partially due to TROPOMI and the reference data records themselves, but they can also be linked to systematic effects of the non-perfect co-locations. Random uncertainty due to co-location mismatch contributes considerably to the 2.6–4.6 DU (∼14 %–23 %) statistical dispersion observed in the difference time series. We circumvent part of this problem by employing the triple co-location analysis technique and infer that TROPOMI single-measurement precision is better than 1.5–2.5 DU (∼8 %–13 %), in line with uncertainty estimates reported in the data files. Hence, the TROPOMI precision is judged to be 20 %–25 % better than for its predecessors OMI and GOME-2B, while sampling at 4 times better spatial resolution and almost 2 times better temporal resolution. Using TROPOMI tropospheric ozone columns at maximal resolution nevertheless requires consideration of correlated errors at small scales of up to 5 DU due to the inevitable interplay of satellite orbit and cloud coverage. Two particular types of sampling error are investigated, and we suggest how these can be identified or remedied. Our study confirms that major known geophysical patterns and signals of the tropical tropospheric ozone field are imprinted in TROPOMI's 2-year data record. These include the permanent zonal wave-one pattern, the pervasive annual and semiannual cycles, the high levels of ozone due to biomass burning around the Atlantic basin, and enhanced convective activity cycles associated with the Madden–Julian Oscillation over the Indo-Pacific warm pool. TROPOMI's combination of higher precision and higher resolution reveals details of these patterns and the processes involved, at considerably smaller spatial and temporal scales and with more complete coverage than contemporary satellite sounders. If the accuracy of future TROPOMI data proves to remain stable with time, these hold great potential to be included in Climate Data Records, as well as serve as a travelling standard to interconnect the upcoming constellation of air quality satellites in geostationary and low Earth orbits.

This paper presents the evaluation of TROPOMI tropical tropospheric ozone columns by comparison with ground based (SHADOZ) and other satellite (OMI and GOME2) data. The subject is suitable for publication in AMT and the results are of interest for the users of these data. The paper is well organised and provides valuable information about TROPOMI O3 data. The analysis of error sources is interesting. It clearly highlights the limitations of the CCD retrieval method for UV sensors based on strong assumptions about the variability of the stratospheric column of O3 and on the deep convective cloud cover. I recommend this paper after the issues listed below are dealt with.

This paper presents a review around seagrass habitat in Tarawa Lagoon, Kiribati and explores the links between seagrass occurrence and the national priority issues of climate change, urban development, human health, nearshore fisheries, threatened species, ocean policy, research capacity and awareness. The contribution of healthy seagrass habitats to many aspects of these national issues is often overlooked and there is need to establish the knowledge gaps and priority actions that can enable mitigation of issues that impact on valuable seagrass resources and their management. Research data on seagrass habitats in Kiribati, and the wider Pacific Island region, is limited and this hinders informed decisions at local, national and regional levels. We present a comprehensive review on seagrass within a national context to aid prioritisation and uptake of information for resource owners, and wider stakeholders, in Kiribati while acknowledging local expertise. The paper highlights data and knowledge gaps that if addressed, will provide information useful to Kiribati nationals, communities and government stakeholders. Recommendations for actions that fill these gaps and build understanding of seagrass resources in Kiribati are provided.

The spectrophotometric kinetic method was validated for the determination of iodine in different food samples. The method is based on the iodide catalysed reduction of Ce4+ to Ce3+ by As3+. The absorbance of the kinetic indicator reaction was measured at 370 nm for exactly 1 min at 37 degrees C. The change in absorbance per min, as a measure of initial rate, was plotted against the different iodine concentrations to achieve a linear calibration equation with the R-2 value of 0.9998 which showed excellent reproducibility. The limit of detection (LOD) was 1.54 ng/mL and the limit of quantification (LOQ) was 4.90 ng/mL. The incineration of the food organic matter was achieved by ashing the food samples at 600 degrees C using KOH and ZnSO4 in steps for 3 h. Trace levels of iodine (ng) were determined successfully using the validated spectrophotometric kinetic method for the 9 food samples (36 sub-samples). The Fiji seaweeds, lumiwawa (brown seaweed) showed the highest iodine content being 6373.30 +/- 0.39 ng/g followed by sea grapes (green seaweed) 1162.81 +/- 0.61 ng/g, lettuce 114.81 +/- 0.08 ng/g, English cabbage 108.40 +/- 0.06 ng/g, Chinese cabbage 104.01 +/- 0.06 ng/g, pumpkin 101.24 +/- 0.08 ng/g, long bean 97.61 +/- 0.10 ng/g, banana 76.18 +/- 0.10 ng/g and tomato 40.32 +/- 0.04 ng/g. The coefficient of variation for the sample analysis was < 5.31% with a mean and standard deviation of 2.55 +/- 0.17% for the food samples analysed. The recovery analysis of iodine from standard samples ranged from 99.84 +/- 0.91% to 100.24 +/- 5.92% with an excellent average recovery of 100.06 +/- 3.16%. The analytical coefficient of variation was calculated to be 0.34% for the food samples analysed. This shows exceptional system analytical stability of the method used in this study.

Health implications of air pollution vary dependent upon pollutant sources. This work determines the value, in terms of reduced mortality, of reducing ambient particulate matter (PM2.5: effective aerodynamic diameter 2.5μm or less) concentration due to different emission sources. Suva, a Pacific Island city with substantial input from combustion sources, is used as a case-study. Elemental concentration was determined, by ion beam analysis, for PM2.5 samples from Suva, spanning one year. Sources of PM2.5 have been quantified by positive matrix factorisation. A review of recent literature has been carried out to delineate the mortality risk associated with these sources. Risk factors have then been applied for Suva, to calculate the possible mortality reduction that may be achieved through reduction in pollutant levels. Higher risk ratios for black carbon and sulphur resulted in mortality predictions for PM2.5 from fossil fuel combustion, road vehicle emissions and waste burning that surpass predictions for these sources based on health risk of PM2.5 mass alone. Predicted mortality for Suva from fossil fuel smoke exceeds the national toll from road accidents in Fiji. The greatest benefit for Suva, in terms of reduced mortality, is likely to be accomplished by reducing emissions from fossil fuel combustion (diesel), vehicles and waste burning.

Increased CO2 emissions into the atmosphere lead to increased concentrations of dissolved CO2 in the ocean. A chemical reaction between the dissolved CO2 and seawater produces HCO3 −, CO3 2− and H+ ions. These H+ ions increase the acidity of seawater and decrease the pH. Increased acidity and decreased availability of CO3 2− ion affect calcite and aragonite production by marine calcifiers in the ocean. To assess potential responses of the larger benthic foraminifer Marginopora vertebralis to ocean acidification, we performed growth experiments at three pH levels [7.5, 7.8, 8.1 (ambient seawater)] for 11 weeks. Specimens were stained with the fluorescent compound Calcein ( ̴40 µmole/l) prior to treatment, allowing identification of calcite added during the treatment period. At pH 8.1, specimens increased their test weight by 8.4%, at pH 7.8 growth was 4.2%, and at pH 7.5, growth was only 3.2%. These differences represent a significant relationship between ocean pH and test growth (i.e., calcification). In addition, several specimens in the pH 8.1 treatment underwent asexual reproduction during the experiment, while no reproduction was observed in the pH 7.8 or 7.5 treatments. These results indicate that ocean acidification predicted to occur by the end of the 21st century will cause a decline in population densities of Marginopora vertebralis in their natural environment, as consequences of both reduced growth rates and rates of reproduction. And because the tests of these foraminifers are important components of carbonate sediments on coral cays and tropical beaches, a decline in their rates of sediment production will exacerbate the consequences of rising sea level.

The researchers from the University of the South Pacific developed the in-house capacity to measure CH4 and N2O using GC-FID and GC-ECD respectively. A series of clean air samples were collected from a coastal site near Suva, Fiji (18°08’S, 178°26’E). The precision for CH4 measurements is 4 ppbv and for N2O measurements is approximately 2 ppbv. The seasonal cycles of both greenhouse gases observed are similar with a seasonal amplitude of approximately 30 ppbv. However some variability is observed during the summer months in the methane dataset which demands further investigation. Unfortunately the N20 data set is very recent and does not extend back to the previous summer months. The datasets obtained at this site will be compared to other sites such as South Pole and Samoa. The dataset looks very appreciable although it needs to be verified through inter-laboratory comparisons. This site is quite interesting due to complex tropical meteorology in the region affecting transport of methane from the Northern into Southern Hemisphere.

Several studies have been done on methane (CH4) emissions from the agricultural sector from Asia, the United States and Australia however data from tropical South Pacific is scarce. This presentation looks at the evaluation of CH4 emissions from the agricultural sector in Fiji particularly from rice cultivation and enteric fermentation. A passive observational study using the static chamber method was done on two rice (Oryza sativa L.) varieties (Star and Totoka) to determine the seasonally integrated methane fluxes which were found to be 247.26 mg m-2day-1 and 134.27 gm-2day-1 for Star and Totoka respectively. Since there were statistically no significant differences (p-value > 0.05) between the means of the flux from the two varieties, an average flux value was used to determine the total CH4 emitted from the irrigated rice farms in Fiji. This equated to 0.06 Gg year-1 for the year 2014. The flux values obtained over the season showed a weak positive correlation with light intensity levels, atmospheric and chamber temperatures for both varieties. The other aspect of this presentation is the estimation of the total annual CH4 flux from enteric fermentation. These were determined to be 2.64 Gg yr-1, 2.46 Gg yr-1, 0.19 Gg yr-1, 0.08 Gg yr-1 and 0.03 Gg yr-1 for beef, dairy cows, goat, sheep and pig respectively based on the livestock population in 2014 using the Intergovernmental Panel on Climate Change (IPCC) models and guidelines. On a global scale, methane emissions from enteric fermentation is increasing however in Fiji there is a slow rise compared to other developed and developing countries. The total methane emissions from the agricultural sector in 2014 that includes emissions from enteric fermentation and two rice ecosystems (irrigated and rainfed) was 154179.93 tonnes of CO2 equivalent. The emission factor determined in this project will validate national greenhouse gas inventory and be instrumental in projecting future emissions from the agricultural sector.

The Southern Hemisphere ADditional OZonesonde (SHADOZ) network was assembled to validate a new generation of ozone‐monitoring satellites and to better characterize the vertical structure of tropical ozone in the troposphere and stratosphere. Beginning with nine stations in 1998, more than 7,000 ozone and P‐T‐U profiles are available from 14 SHADOZ sites that have operated continuously for at least a decade. We analyze ozone profiles from the recently reprocessed SHADOZ data set that is based on adjustments for inconsistencies caused by varying ozonesonde instruments and operating techniques. First, sonde‐derived total ozone column amounts are compared to the overpasses from the Earth Probe/Total Ozone Mapping Spectrometer, Ozone Monitoring Instrument, and Ozone Mapping and Profiler Suite satellites that cover 1998–2016. Second, characteristics of the stratospheric and tropospheric columns are examined along with ozone structure in the tropical tropopause layer (TTL). We find that (1) relative to our earlier evaluations of SHADOZ data, in 2003, 2007, and 2012, sonde‐satellite total ozone column offsets at 12 stations are 2% or less, a significant improvement; (2) as in prior studies, the 10 tropical SHADOZ stations, defined as within ±19° latitude, display statistically uniform stratospheric column ozone, 229 ± 3.9 DU (Dobson units), and a tropospheric zonal wave‐one pattern with a 14 DU mean amplitude; (3) the TTL ozone column, which is also zonally uniform, masks complex vertical structure, and this argues against using satellites for lower stratospheric ozone trends; and (4) reprocessing has led to more uniform stratospheric column amounts across sites and reduced bias in stratospheric profiles. As a consequence, the uncertainty in total column ozone now averages 5%.

Concentrations of particulate air pollution in Suva, Fiji, have been largely unknown and consequently, current strategies to reduce health risk from air pollution in Suva are not targeted effectively. This lack of air quality data is common across the Pacific Island Countries. A monitoring study, during 2014 and 2015, has characterised the fine particulate air quality in Suva, representing the most detailed study to date of fine aerosol air pollutants for the Pacific Islands; with sampling at City, Residential (Kinoya) and Background (Suva Point) sites. Meteorology for Suva, as it relates to pollutant dispersion for this period of time, has also been analysed. The study design enables the contribution of maritime air and the anthropogenic emissions to be carefully distinguished from each other and separately characterised. Back trajectory calculations show that a packet of air sampled at the Suva City site has typically travelled 724 km in the 24-h prior to sampling, mainly over open ocean waters; inferring that pollutants would also be rapidly transported away from Suva. For fine particulates, Suva City reported a mid-week PM2.5 of 8.6 +/- 0.4 mu g/m(3), averaged over 13-months of gravimetric sampling. Continuous monitoring (Osiris laser photometer) suggests that some areas of Suva may experience levels exceeding the WHO PM2.5 guideline of 10 mu g/m(3), however, compared to other countries, Fiji's PM2.5 is low. Peak aerosol particulate levels, at all sites, were experienced at night-time, when atmospheric conditions were least favourable to dispersion of air pollutants. Suva's average ambient concentrations of black carbon in PM2.5, 2.2 +/- 0.1 mu g/m(3), are, however, similar to those measured in much larger cities. With any given parcel of air spending only seven minutes, on average, over the land area of Suva Peninsula, these black carbon concentrations are indicative that significant combustion emissions occur within Suva. Many other communities in the Pacific Islands, as well as in Africa, Asia and South America share similar climate and similar burning practices and as such are likely to experience similar aerosol black carbon loadings. These black carbon levels indicate the need for combustion emissions, particularly those from open burning and diesel usage, to be addressed in air policy. (C) 2016 Elsevier Ltd. All rights reserved.

The Naboro landfill in Suva, the capital city of Fiji Islands, is a sanitary engineered landfill, consisting of a compacted clay protective liner and leachate collection system. The waste is selectively placed, compacted and then covered with soil. The landfill was commisioned in 2005 and is currently receiving an average of 70,000 tonnes of waste annually. The municipal solid waste deposited in the landfill undergoes anaerobic decomposition and the methane gas generated escapes into the atmosphere, adding to the national greenhouse gas inventory. Currently there are no methane recovery and biogas utilisation technology in place or methane flaring at the Naboro landfill site. A feasibility study was carried out recently and based on the model output and field experiments, it was noted that methane recovery and utilisation could be a viable option although there could be some challenges associated with it. According to the waste chaacterization data supplied by the landfill operator it was noted that 83% is house hold waste, 11% is garden waste and 5% is food waste and 1% construction and demolition waste. Based on the type of waste deposited and the tropical weather condition it was calculated using the model that approximately 800 m3/h of methane is generated in 2016. Figure below shows the landfill gas generated at the Naboro landfill from stage 1 to stage 4. Due to tropical humid weather condition and waste rich is organic waste that decomposes rapidly results in the yearly average emission of 74% of total methane generated despite methane recovery via vertical wells installed at the end of each stage. The emission equates to 47,000 tons of CO2 equivalent per year despite methane recovery. The emission can be reduced if the methane generated could be extracted using vertical recovery wells half way through each stage rather than at the end of each stage and as a consequence a slight decrease in yearly average emissions of 41,000 tons of CO2 equivalent were noted. Another approach is to lay horizontal wells as the waste is compacted in the active cell and this could increase the efficiency of landfill gas extraction. The model result indicate that the use of horizontal wells reduces the yearly average emission to 55% of total methane generated. This highlights the fact that approximately 45 % of the methane generated could be harnessed and could be utilized to generate energy using gas engines. However a large fraction of the methane generated is still lost as emission to the atmopshere and this can be further reduced by enhancing the oxdising capacity of the soil cover. The methane oxidation in cover soil was measured to be 10.3% by measuring the CH4-CO2 ratios in the static chamber measurements. The experimental value is close to the IPCC default value of 10%. The paper will discuss other challenges associated with methane recovery at Naboro landfill particularly with landfill gas management.

Surface ozone profiles were studied at Fiji (18.1oS, 178.2oE), Samoa (14.3oS, 170.6oW), Tahiti (18.0oS, 149.0oW), and San Cristobal, Galapagos (0.9oS, 89.6oW) from 1997-2003. Surface ozone levels at these Pacific sites showed a wintertime maximum and a summertime minimum with the lowest mixing ratios occurring at Tahiti and Galapagos, while the highest mixing ratios occurred at Fiji. The seasonal trends at each site were found to be dependent on the varying photochemical sink strength and the changing transport regimes in each season. It was established that the reduced photochemical sink strength in winter was one of the major reasons for the observed increase in surface ozone levels at each site in that season. The presence of the South Pacific Convergence Zone particularly for the Western Pacific (Fiji, Samoa and Tahiti) is the other factor contributing to the observed seasonality and variability in surface ozone levels. The changing frequency of transport from the southern mid-latitude (from high altitudes) is the only transport regime at the boundary layer having the most significant influence on the surface ozone levels at these Pacific sites.

We present a regional and seasonal climatology of SHADOZ ozone profiles in the troposphere and tropical tropopause layer (TTL) based on measurements taken during the first five years of Aura, 2005–2009, when new stations joined the network at Hanoi, Vietnam; Hilo, Hawaii; Alajuela/Heredia, Costa Rica; Cotonou, Benin. In all, 15 stations operated during that period. A west‐to‐east progression of decreasing convective influence and increasing pollution leads to distinct tropospheric ozone profiles in three regions: (1) western Pacific/eastern Indian Ocean; (2) equatorial Americas (San Cristóbal, Alajuela, Paramaribo); (3) Atlantic and Africa. Comparisons in total ozone column from soundings, the Ozone Monitoring Instrument (OMI, on Aura, 2004‐) satellite and ground‐based instrumentation are presented. Most stations show better agreement with OMI than they did for EP/TOMS comparisons (1998–2004; Earth‐Probe/Total Ozone Mapping Spectrometer), partly due to a revised above‐burst ozone climatology. Possible station biases in the stratospheric segment of the ozone measurement noted in the first 7 years of SHADOZ ozone profiles are re‐examined. High stratospheric bias observed during the TOMS period appears to persist at one station. Comparisons of SHADOZ tropospheric ozone and the daily Trajectory‐enhanced Tropospheric Ozone Residual (TTOR) product (based on OMI/MLS) show that the satellite‐derived column amount averages 25% low. Correlations between TTOR and the SHADOZ sondes are quite good (typical r2= 0.5–0.8), however, which may account for why some published residual‐based OMI products capture tropospheric interannual variability fairly realistically. On the other hand, no clear explanations emerge for why TTOR‐sonde discrepancies vary over a wide range at most SHADOZ sites.

In this paper, the use of local seeds to improve the quality of drinking water in Fiji was investigated. Analysis of the heavy metals cadmium, copper, chromium, lead and zinc were performed before and after treatment of water with the local seeds Moringa oleifera, Arachis hypogaea (peanuts), Vigna unguiculata (cowpeas), Vigna mungo (urad) and Zea mays (corn). The results showed that Moringa seeds were capable of absorbing the heavy metals tested compared to other seeds in some water samples. The percentage removal by Moringa seeds were 90 % for copper, 80 % for lead, 60 % for cadmium and 50 % for zinc and chromium.

The drinking water qualities in three countries in the South Pacific Islands, namely Fiji, Tonga and Kiribati, were examined due to the deteriorating water quality. This paper reports the uses of the seeds of the local plant Moringa oleifera and a few other local seeds, such as peanuts (Arachis hypogaea), cowpeas (Vigna unguiculata), urad (Vigna mungo) and corn (Zea mays) for their effectiveness in water clarification as natural coagulants in water treatment in the South Pacific. Moringa oleifera seeds contain proteins that have active coagulation properties and are being used for turbidity removal in many countries. The quality of the treated water was analyzed and experiments were conducted. on different dosages of Moringa oleifera seeds. Determinations of pH, turbidity, hardness as calcium and magnesium, heavy metals and nutrient levels were conducted before and after treatment with Moringa oleifera and other seeds. In this study, Moringa seeds were found to be better than the other seeds in turbidity removal and had greater potential for water purifications than the other seeds tested. The use of the local Moringa seeds for clarification is therefore useful in the purification of drinking water in developing countries, since other chemicals used in water purification are expensive.