International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Vol-6, Iss-4, Spl. Issue-2 Dec.-2018, http://iraj.in PRELIMINARY WATER QUALITY EVALUATION OF THE RIVER,

1PATILA AMOSA, 2FAAINU LATU, 3TAEMA IMO, 4VAREA VAURASI

1,2,3,4ScienceDepartment, National University of Samoa, Samoa Email: [email protected], [email protected], [email protected], [email protected]

Abstract - This study analysed water samples collected from Vaisigano River on Island, Samoa to evaluate the degree of pollution by nutrients, heavy metals and microorganisms. Samples were collected monthly from December 2016 to April 2017 at 3 sites along the river and analysed for dissolved oxygen (DO), biochemical oxygen demand (BOD),total - phosphorous (TP), nitrate (NO3 ), faecal coliform (FC), Enteroccoci (Ent) and the two heavy metals Cu and Pb. The results were used to calculate a water quality index (WQI) for each station with (WQIw) and without bacteria (WQIwt) to estimate the contribution of microbes to water contamination and to determine the overall health of each site. The WQIw values for the three stations ranged from (37.48 – 41.05)± 1.91 while WQIwt ranged from (41.14– 59.03)± 9.14. All values were below 100 which is the critical value for surface water safety for use for human activities, aquatic life and wildlife survival. Based on the WQI values, water quality at the three sites was generally poor.

Keywords - Water quality index, pollution, microbial contamination, nutrients, Samoa

I. INTRODUCTION temperate and other tropical regions [9]. Fewer studies conducted in the vicinity of Samoa on the The impact of climate change on the quality of water quality of streams [9, 10] have shown only partial resources and associated health implications has seen compliance to established drinking water standards. an influx of research to assess the health of rivers. For example, of 44 streams analysed by [10] in Water quality (WQ) describes the biological and American Samoa, only 16% complied with water physico-chemical characteristics of water in relation quality standards for phosphorous. Analysis of to its intended use(s),standards and criteria[1, 2]. freshwater springs commonly used by communities in These surface waters may be contaminated by various Samoa showed total and faecal coliform levels way human pathogens [3], excess nutrients[4] or heavy above the recommended national and WHO limits metals[5] washed into the waters during heavy [11]. rainfall events from mainly non-point sources.The The Samoan government vision for the 2016 – 2020 outbreak of water-borne diseases is a consequence of Strategy for the Development of Samoa [12]focuses consuming untreated tap water, bathing in and on “accelerating sustainable development and drinking water from sources polluted by various broadening opportunities for all” and stressing the wastewater microbes or eating contaminated need to “improve access to clean water that meet freshwater food [6]. national quality standards and promoting a healthy It is important for information from these Samoa”. In an effort to address part of this vision, a investigations to be presented in a manner that is preliminary assessment was conducted at Vaisigano clearly understood by policy makers for the river, one of the main catchments supplying the development of appropriate mitigation strategies, and reticulated system in the country to determine its also by local communities for awareness and correct physical, chemical and microbiological composition enforcement of measures to protect these resources. A and thereby health status. water quality index (WQI) summarises large amounts of data into a single value indicative of the water II. EXPERIMENTAL health. The main target of these indices is comparison with WQ standards so that the indices will determine 2.1. Study site whether the variable(s) comply with the standards or The Vaisigano Watershed in located on Upolu island, not and the frequency and the extent of exceedance Samoa(Figure 1) and receives an average annual for non-compliance [7]. The advantages of the WQI rainfall of about 4,277 mm, with average amounts of is its ability to integrate the measurements of all 2,923 mm and 1,515 mm respectively falling in the variables for water analysis in a single number, its wet and dry seasons [13]. It is about 3,700 hectares ability to combine different measurements in a large and feeds two treatment plants before diversion variety of different measurement units in a single into the reticulated water supply. Three sites were metric and its effectiveness as a communication selected for sampling to get a representative tool [8]. characterization of water quality. The three sites were The majority of streams in the tropical Pacific have located at Vaoala (V1,13.87°W, 171.75°S), Maagiagi not been scientifically explored for chemical and (V2,13.85°W, 171.75°S) and Malifa (V3,13.84°W, microbiological quality compared to streams in the 171.75°S).

Preliminary Water Quality Evaluation of The Vaisigano River, Samoa

49 International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Vol-6, Iss-4, Spl. Issue-2 Dec.-2018, http://iraj.in

Figure 1. Study sites along the Vaisigano watershed on Upolu Island, Samoa(Source: MNRE Mapping Division].

2.2. Materials and Procedures The FC and Entcontent of all water samples was Water samples were collected monthly at the three determined using the membrane filtration (MF) sites from December 2016 to April 2017.Five method following the protocols of [15]. This samples were collected at each site in sterilised250 ml procedure shows discrete bacterial colonies that can Schott bottles at a depth of about 10 cm below the be visually counted. Highly contaminated water water surface [14]. This sampling strategy reduced requires several sample dilutions in order to obtain the possibility of contamination from debris and filter plates with an appropriate range of colonies to bacteria deposited by wind on the surface water. validate enumeration. Preliminary measurements Samples were processed within 5 hours of sampling showed dense bacterial growth of raw samples hence for FC, Ent, BOD, nitrate, total phosphorous, copper all samples for the study period were serially diluted and lead.pH and DO were measured on site with a to 10-2 to obtain viable counts of bacterial colonies. handheld MP-103 pH/ORP/Temperature meter microprocessor-based waterproof DO/O2/Temp tester 2.3. WQI Calculations respectively. The health of the three sites was evaluated by calculating a WQI value based on the Canadian BOD was measured using a modified Winkler Water Quality Guidelines for the Protection of method [15, 16]and expressed as BOD5,the difference Aquatic Life [18] and using the median of replicate between the initial DO and the 5-day dissolved monthly measurements. This method requires a oxygen content after incubation of samples in the description of the water body and the number of sites dark at 20°C. TP was measured by means of the to be studied, measurement duration, variables which Ascorbic Acid Method (AAM) and using UV Vis should be at least four and research objectives. Spectroscopy. The concentration of nitrate, Cu and Although a minimum of one year is the recommended Pb were determined by spectrophotometric analysis duration, the method can still be applied to shorter using a Hach spectrophotometer and following the durations as with five months for this study. Cadmium Reduction Method (CRM), the The WQI is derived from the algorithm: Bicinchoninate Method 8506 and the PAR Method 10216 respectively [17]. ₁₂₃ WQI = 100 – ( where .

Preliminary Water Quality Evaluation of The Vaisigano River, Samoa

50 International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Vol-6, Iss-4, Spl. Issue-2 Dec.-2018, http://iraj.in F1 represents the scope or proportion of variables that excursioni = 1 do not meet standards, F2 denotes the frequency of non-compliant to the standards and F3 represents When the test value must not be less than the theamplitude or the amount by which the objective, measurements do not meet the standards. excursioni = 1 The categorisation of water quality as shown in Table F = x 100 1 1 is based on the calculated WQI values and on the F = x 100 ranking of [18]. To estimate the contribution of 2 microbial contamination on water quality, WQI F = 3 .. values were calculated with (WQIw) and without nse (normalized number of excursions) (WQIwt) the microbial data.

∑ = 2.4 Data Processing and Analysis All statistical analyses were conducted using the statistics computer software package MINITAB 17 Excursion is the number of times a variable level is while WQI calculations were performed using greater or less than the standard. When the test value EXCEL 2016. must not exceed the standard,

Table 1.Water quality ranking. WQI Category Excellent: Water quality is protected with a virtual absence of threat or impairment; 95 – 100 conditions very close to natural or pristine levels Good: water quality is protected with only a minor degree of threat or impairment; 80 – 94 conditions rarely depart from natural or desirable levels Fair: water quality is usually protected but occasionally threatened or impaired; 65 – 79 conditions sometimes depart from natural or desirable levels Marginal: water quality is frequently threatened or impaired; conditionsoften depart 45 – 64 from natural or desirable levels Poor: water quality is almost always threatened or impaired; conditions usually depart 0 - 44 from natural or desirable levels

III. RESULTS AND DISCUSSION

3.1. Physicochemical characteristics The pH and concentration of the nine parameters investigated are summarised in Table 2. The mean pH of water was alkaline above 8.0 and within the accepted standard for drinking water. Nitrate and phosphorous in addition to atmospheric CO2 and acid rain contribute to the acidity of the rivers. With low levels of these compounds in water, the pH was expected to remain above neutral.

Table 2.Statistical characteristics of physico-chemical and microbial composition of river water.

Min=minimum; Max=maximum; AM=arithmetic mean; Med=median; Sd=Standard deviation; pH=no unit; Bacterial concentration in x103 cfu/100mL; units for all other parameters in mg/L.

A Spearman's pH-nitrate and pH-TP correlation there was a small positive correlation between pH and (df=16) was run to assess the relationship between pH nitrate at V1 and V2 and a small negative correlation and these nutrients in all the study sites to determine between these parameters at V3. For pH-TP, a if these were major contributors to pH.For nitrate, negative correlation existed in all sites. From the p-

Preliminary Water Quality Evaluation of The Vaisigano River, Samoa

51 International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Vol-6, Iss-4, Spl. Issue-2 Dec.-2018, http://iraj.in values in Table 3, none of the Spearman’s correlation principal source of nitrate and phosphorous in coefficient was statistically significant (p> 0.05). groundwater is synthetic fertilizers, manure, slurries, sewage sludge and crop residue from nearby farms Table 3.Spearman correlation between pH and nitrate and [4]. Both nutrients promote algal growth in water total phoshorous. bodies subsequently leading to eutrophication and Site pH-nitrate pH-TP degraded aesthetic characteristics of water. r p r p The concentration of Cu at all sites fell below the V1 0.280 0.494 -0.021 0.946 limit published in the SNDWS while the V2 0.248 0.413 -0.208 0.496 concentration of Pb exceeded the threshold of 0.01 V3 -0.197 0.518 -0.658 0.015 mg/L. Low levels of Cu have been measured in rivers with high heavy metal contamination [22]. Pb may The level of DO was quite low and indicative of high enter the rivers through industrial and agricultural bacterial contamination in the waters which use up activities[23]. Used batteries that are not properly oxygen for respiration. The nitrate in the two rivers disposed of may also add to Pb in soil sediments and was well below the thresholds established in the rivers as well as paint thinners [24]. Dispersal of Pb Samoa National Drinking Water Standards (SNDWS) in water also transfers Pb from any contaminated [19]as well the guidelines for the Pacific region upstream sites to lower sites [25]. [20]while the Total-P concentration exceeded these The FC and Enterococci bacteria were detected in all guideline values. the sites. The mean concentration of FC bacteria was way above the threshold established in the Samoa The low nitrate levels could mean more utilization by National Drinking Water Standards [19] which microbes or reduced loading from surrounding land. currently does not include a standard for Enterococci. The detection of total phosphorus at concentrations above the maximum permitted by law suggests that 3.2. Health analysis there is strong pollution in the river waters coming The data for WQI calculations are given in Table 4. from domestic and industrial sewage, animal excreta, Based on the grouping in Table 1, the WQIw ranged and fertilizer use without proper treatment [21]. The from 37.48 – 41.05 indicating poor health of all the concentration of these parameters is directly related study sites.The WQIwt values were slightly higher to those of bacteria as these organisms use inorganic than the WQIw levels and ranged from 41.14 – 59.03. nutrients for their physiological processes. Aerial However, excluding the microbes does not change the observations and the Watershed Management Plans health status of V1 and V2 from poor. for Vaisiganoriver [13], indicate less intensive agricultural systems near the sampling sites. The

Table 4.WQI data for the three sampling sites.

Sites Month pH DO BOD TP Nitrate Cu Pb FC Ent WQIw WQIwt Dec 8.4 1.35 0.86 0.060 1.770 0.000 0.054 0.000 1.500 Jan 8.3 1.32 0.54 0.049 1.770 0.020 0.024 0.100 0.078 V1 Feb 8.3 0.04 0.23 0.064 1.990 0.030 0.036 0.200 0.057 41.05 46.83 Mar 8.4 0.91 0.18 0.070 2.215 0.060 0.088 0.000 0.062 Apr 8.4 0.72 0.72 0.075 2.210 0.060 0.079 9.300 0.121 Dec 8.4 1.96 0.77 0.070 0.440 0.000 0.047 0.000 2.300 Jan 8.4 0.99 0.59 0.045 2.875 0.020 0.052 0.100 0.031 V2 Feb 8.4 0.03 0.40 0.049 2.655 0.020 0.016 0.100 0.040 37.48 41.14 Mar 8.5 0.73 0.37 0.078 1.095 0.070 0.024 0.000 0.009 Apr 8.6 0.75 0.75 0.062 1.545 0.070 0.051 4.200 0.000 Dec 8.4 1.35 0.77 0.060 1.330 0.000 0.047 0.000 2.300 Jan 8.3 1.20 0.59 0.049 2.875 0.020 0.029 0.200 0.031 V3 Feb 8.3 0.03 0.40 0.054 2.655 0.020 0.016 0.200 0.047 40.47 59.03 Mar 8.4 0.91 0.32 0.078 1.330 0.060 0.050 0.000 1.400 Apr 8.4 0.75 0.72 0.064 2.210 0.060 0.079 6.500 0.047 Standards 6.5 - 8.56#4*0.01 - 0.10#5010.0100 #SPREP[20]; *EPA[26]; all other standards from the SNDWS [19]. All units are as given in Table 2.

Preliminary Water Quality Evaluation of The Vaisigano River, Samoa

52 International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Vol-6, Iss-4, Spl. Issue-2 Dec.-2018, http://iraj.in The Land use map of the Vaisiganowatershed in Enterococci bacteria in soil particles which then Figure 2 shows predominantly forested areas and transport the microbes into the water. The survival of agricultural activities including livestock as well as entere ic bacteria in sediment laden waters was found swamp areas and community dwellings. Dense to be much longer compared to those without [30]. livestock in the vicinity of V1 could also contribute to There was also evidence of organic and inorganics contamination of the watershed through runoff of rubbish disposal along parts of the river although the waste into the rivers. government has established legislations for to prevent disposals in or around the watersheds. Towards the Storm water inflows have been found to result in a end of the sampling period, ddigging activities took high influx of faecal bacteria into surface waters place along the banks of Vaisiiganoriver between V2 [27]and could be one of the major sources of and V3 thereby causing the water at V3 to become contamination at V2 and V3 which are located very turbid at times due to run-off into the rivers. close to the public roads. It is also common for many families to have their pigsties along the river banks CONCLUSIONS of[28],as well as free-roaming domestic animals coming in contact with the water bodies. Poorly This research investigated the concentration of controlled discharge of faecal waste coupled with various chemicals and bacteria in three sites along the droppings from wildlife may contaminate surface Vaisiganoriver to determine the level of waters[29]. In a study on the impact of soil sediments contamination, if any, from human activities or on indicator faecal organisms, high levels of bacteria natural events. The measurements showed that: were found in surface sediments along the river bank 1. All parameters investigated were detected in the near the edge of the water [27]. In addition to animal study sites. waste directly entering the water shed, contaminated 2. The mean pH of all samples was within the range soils can also add to water pollution through soil stipulated in SNDWS while water temperature was erosion. stable around 27.0 ± 0.01 °C. 3. The concentration of FC well exceeded the The Vaisigano watershed has a population of over threshold stipulated in the SNDWS for open waters 20,000[13]. Leakage of untreated wastewater from and the concentration of Enterococci surpassed the septic tanks and leaching into the groundwater single sample standards[31]forr recreational waters. 4. The mean level of dissolved oxygen ranged from 0.83 – 1.16 mg/L while BOD ranged from 0.59 – 0.88 mg/L. 5. Nitrate and copper concentrations all complied with the standards in the SNDWS with maximum mean values of 0.88 and 0.03mg/Lrespectively. 6. With any standard for Total-P missing from the SNDWS, the measurements in this study exceeded the guidelines for rivers in the Water Quality Protection Criteria for surface waters in the South Pacific [20]. 7. From a survey of the study sites and analysis of Land Use Maps for the two watersheds, the potential sources of bacteria and chemicals in water include faecal wastes from humans, livestock and birds, decomposition of organic matter in the rivers, weathering and soil runoff into rivers as well as leaching of untreated wastewater.

The WQI is a useful tool to determine the overall Figure 2.Land usemap of the Vaisigano catchment [13]. health of a water body. However, it is important to select carefully the parameters to be used in the system feeding the rivers is a potential source of calculations. As evident from WQIw and WQIwt, the bacterial contamination. It can also be assumed that values can change depending on the number of water the higher the number of people that contribute to quality parameters chosen. The health of all the study sewage or faecal contamination, the more likely the sites falls into the poor category thus requires urgent presence of a range of microbes in water. The action to confirm the causes of contamination and decompoosition of dense vegetation around the two develop strategies to address this issue, especially watersheds adds organic matter to the soil which when the communities along the catchment use the could also promote the growth of faecal coliform and river for recreational and some domestic activities.

Preliminary Water Quality Evaluation of The Vaisigano River, Samoa

53 International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Vol-6, Iss-4, Spl. Issue-2 Dec.-2018, http://iraj.in Additionally, more replicate measurements need to be [15] APHA, Standard Methods for Examination of Water and undertaken in at least a 12-month period and more Wastewater - Part 900: Microbial Examination. 1999, Washington D.C, : American Public Health Association, sites to be selected along the river to confirm the American Water Works Association and Water overall health of the river. A yearly duration also Environment Federation. determines whether seasonal variation has any effect [16] Delzer, G.C. and S.W. McKenzie Five-day biochemical on river water quality while multiple sites enable oxygen demand: U.S. Geological Survey Techniques of Water-Resources Investigations, book 9, chap. A7, section comparison of any spatial disparities. 7.0, November. 2003. 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