This article states that land use impacts the chemical and nutrient properties of the Palmiet River.
The river, particularly in areas near informal settlements, was found to be unsanitary; pollution from land use was the largest contributing factor found in this study. The introduction of this article describes the topography of the areas the Palmiet flows through as well as the types of development (i.e. CBD, industry, residential) and the types of rainfall the Pinetown basin receives in both summer and winter.
The water’s pH was tested in the summer, and the highest pH was 10, 93 – a very alkaline reading. In winter, this same site had a pH 8.11, a drastic decline from the previous season. The high pH at this particular site was explained by the industrial discharge into the river from the Pinetown CBD. It is stated that the Palmiet flows through 6km of a nature reserve, although the article mentions that this natural vegetation displays only a “limited purifying capacity with regard to certain physicochemical parameters… As the effect of human activities negatively impacts the sanitary quality” (Moodley et.al, 2016)
The method of study was like the one that will be conducted by the matric students of 2018. 6 sampling sites were selected before and after the major land use areas along the length of the Palmiet, as well as testing before and after the Palmiet-Mgeni confluence to ascertain what effect the Palmiet has on the Mgeni.
This article concludes that “anthropogenic activities and processes have caused a general deterioration of… water quality across all land use types” (Moodley et.al, 2016), meaning that human activity of all types has had a detrimental effect on the quality of the water.
This source is very reliable as it is published by a credible scientific journal (IJSEAS, published January 2016). It is conducted by multiple members – several with doctorates in environmental sciences and at least one with an MSc – on the Palmiet River. Many details are given about the methodology and testing, describing the processes used and the way in which the sources were analysed. The samples taken from the sites were all analysed at either the UKZN chemistry laboratories or at Talbot and Talbot Laboratories (Pty) Ltd. The source also includes a comprehensive reference list and author profiles.
This is a very useful source, as its analysis of the impact of types of land use on the river is appropriate to the stated hypothesis.
The source contains very few limitations, which include the tests that will be conducted by the Thomas More College grade 12 students, as they differ in that not all the experiments that this study did will be performed in the matric students’ analysis. (e.g. E. coli, total coliforms (bacteria), ammonia levels, conductivity, etc.). The pH testing will be performed by the students; thus, this article will allow for useful comparison between the results obtained in personal studies and those seen in this article. Regardless, it is a very appropriate and useful academic article.
The article states in the abstract “pollution in the catchment is…the determining agent.” (De Villiers et.al, 1985) This is the general conclusion of the article which studied the effects of urbanization on the water quality of South African rivers. The article utilized the Palmiet River as the focus of the research, which makes the research relevant, even though it is an older article.
Nine sampling sites were selected with a focus on the areas surrounding the main channel and its tributaries. Samples were taken during the summer rainfall seasons, the season where the article states that the “runoff is relatively high” (De Villiers et.al, 1985). The high sulphate content at station 3, in the midst of the Pinetown industrial area, (seen on page 38 of the original article) is found to be the result of at least two industrial spills. One manufactures detergents using sulphuric acid and the seepage of this acid into the river is a major contributing factor to the quality of the water further downstream, however another factory’s runoff consisted of a highly alkaline discharge. pH tests were conducted on the river, with an average pH measurement of 7.3 – a relatively neutral reading. The increase in SO4 concentrations at stations 7 and 8 was attributed to the extensive road construction that was occurring in the area. It was noted that a sewerage site regularly overflows into the river, and that many residencies are situated close to the river banks. The conclusion of the article is that although the runoff and urban effluent are highly polluted, the quality of the river is still relatively acceptable.
This article is relevant to the stated hypothesis as it observes the effect of residential and urban land use on the Palmiet, as well as the other rivers that impact it.
Although it is slightly dated, the research is useful as a means of comparison against the matric student’s results. One may be able to see how the quality has altered over time. The article is particularly useful as it performs a similar test to the one that will be conducted by the students (i.e. pH) on the same river.
This source is reliable as it has numerous sources that are correctly referenced, and the authors are both from the University of Durban-Westville. De Villiers is based in the department of geography and Malan is based in the chemistry department, however the information is dated. This is further discussed in the limitations. The article is also published in a South African scientific journal, Water SA – making it both a very valid and reliable article.
The limitations of this article are its dated content, as much has been altered in the years since 1985; technology has developed and been enhanced, and residencies have been built up. This makes the information slightly less reliable, but the article remains relevant and valid. Many of the tests conducted will not be done by the matric students, meaning that a lot of the information gleaned from this article loses some of its usefulness. Regardless, this article is very useful and informative.
This doctoral thesis found that “the most significant human impacts on the hydrological system are due to land use change”. The aim of the research was to explain how the quality of surface water varies as the types of development on the land changes, as well as to provide guidelines to minimise pollution that occurs because of the nearby land development, with a focus on the Kuils-Eerste river catchment in the western cape.
In the catchment, land use was found to be largely agricultural, with 35% of the surveyed area being occupied by vineyards. Experiments were carried out to find out whether various types of land use differ in their contributions to the deuteriation of water quality. This is very similar to the stated hypothesis. All surveyed sites were found to fall into the same category of sandy soil, with the top layer of the soil in the fynbos areas being loamy sand. This undoubtedly affected results and the grade 12 experiments will be conducted on different soil types. This is further discussed in the analysis.
High chloride concentrations were found on golf courses or recreational grass, leading to more polluted runoff from these areas. Areas of disturbed soil contributed highly to the amount of soil particles in runoff, and these areas are particularly common where intensive small-scale farming occurs on small holdings.
The study found that different land cover types contribute differently to the types and amounts of pollutant found in the catchment. W. Chingombe utilized a GIS model to estimate the levels of pollution across various types of land use.
The thesis ends with the note that “the expansion of urban areas and agricultural land has a direct impact on land cover types within the catchment”. This note clearly relates to the stated hypothesis.
The validity of this source is easily assessed as it is a recent publication (2012) done by a doctoral candidate. There are many references included, which appear to all be articles of an academic nature. These increase the validity of the article to a large extent.
The source is reliable and very credible as it was published by the University of the Western Cape. A comprehensive scientific method was followed; therefore, the experiment can be repeated, however the samples were collected during storms in the rainfall season of 2006 and 2007. The content of the source is consistent with other sources from South Africa, improving the reliability of the source.
This source is useful as it creates an awareness that the type of occurrence being studied is not unique to a certain area. It also uses methods that we, as grade 12 students, have used and therefore have a basic understanding of the procedure (i.e. GIS, SASS).
There are limitations to the source, in particular the usefulness of it. This experiment was conducted on an entirely different river, in a province which experiences different developmental growth and weather patterns. Regardless, this source remains very useful as it allows for a broader view of how land use affects water quality. The source is also limited in its reliability, as the samples were taken during the storm season, which would yield results that could possibly be different from results taken from other time periods during the rainy season. It is not specified why it was chosen to use this period to conduct the experiments, a further limitation in terms of understanding the source.
This study was undertaken after a thorough analysis of a previously published article (De Villiers and Malan,1985) found that it could not serve as a very reliable source for future studies, therefore this study was performed two years later. It claims to be more comprehensive than De Villiers previous study, as it surveyed two important tributaries of the Palmiet and sampled the Umgeni “for comparative purposes”.
From the period of 1982 to late 1984, monthly samples were taken of surface water on predetermined days in order to run trace element and macro analyses. There were 11 sample sites selected, which covered the main channel, its tributaries and just below the confluence of the Umgeni and Palmiet.
The article had very similar results as the previous study, in terms of finding that there was a continual deterioration of water quality as the river moves downstream. A new observation in this article is that the geology along the course of the Palmiet river is comprised only of sedimentary rock. Because of this, the authors do not believe that the geological properties of the rock effect the water quality in any significant way. The authors believe that the Palmiet is a very large contributor to the levels of pollutant in the Umgeni river, and believe that the two previously un-surveyed tributaries are heavily polluted, adding to the levels of waste in the water.
Aside from these key points, the research does not differ greatly from that of the previous article by De Villiers and Malan, 1985.
Validity and reliability
The source is scientific in its format; however, it is outdated, thus affecting its validity. The language used is objective, revealing no bias. One of the authors of the original article (De Villiers and Malan,1985), is an author in this article as well. Both authors have excellent credentials and are members of university staff. This also makes the source reliable and trustworthy. The method used is described clearly and logically, adding to the reliability of the source as an academic reference.
Usefulness and Value
The source is valuable and useful because it uses the Palmiet and the Umgeni as the source of its research. The analysis of the confluence of the two rivers is significant because the results allow an understanding of which river carries more pollution and how much of an impact the Palmiet has on the Umgeni river.
The major limitation of the source is its age, as it was conducted over 30 years ago. This makes it useful for comparison, as well as comparison between the previous study it is based on. It is uncertain whether the citations used in this source are still relevant or accurate, another unfortunate limitation of the source.
The article begins with a description of how heavy metals affect the condition of a river. Rivers with heavy metal traces “at concentrations higher than naturally occurring levels are deemed to be potentially harmful and hazardous.” The article also lists common man-made sources of heavy metals, including industry agriculture, households, mining, and urban areas. Heavy metal water contamination is serious as the metals are nondegradable.
The article describes the location of the river catchment and the type of development the river flows through. This can be seen very clearly in Fig. 1 included below. This map depicts the Palmiet catchment with the sample sites and land usage types included. Although the Palmiet river is a relatively small river, the wide variety of activities that take place on its banks subject the water to various sources of potentially harmful pollution.
It is important to note that at the time of its publication, this study was the first to analyse the heavy metal concentrations of the Palmiet catchment. The goal of the research was to control, manage, and rehabilitate polluted river, to minimise the harmful risks the heavy metals pose.
Sites were systematically chosen, with two of the eight sites being before and after the Umgeni confluence. Selenium (Se) was in its highest concentration at site 2, downstream of the industrial area. This is directly as a result of waste put into the water from glass, ceramic, and cement manufacturers. Selenium is used in photosynthetic pathways, which aid in plant growth. The following sites were dense with vegetation and there was an immediate decline in the concentration of selenium at sites 3 and 4. The study included analyses of metal concentrations both in summer and winter. Several types of metals showed seasonal dependency, presumed to be as a result of the varying rainfall. The elements that showed this dependency are all commonly used in the industry areas, in particular Selenium and Strontium. These two metals are not naturally occurring and can carry other effluents into the river through their bonding properties.
This article is extremely useful and appropriate as it looks directly at the Palmiet river and the impact of land use on the river. The source is incredibly useful, not only because of the location of the study, but also because of the specific nature of it. Heavy metals are a common pollutant and are hazardous, yet this study was the first to focus specifically on the contamination of the Palmiet with these toxins.
The source is valid as there is plenty of cross reference to other articles which are known to be reliable. It is a modern study and is very relevant.
The source is credible as all the authors have excellent credentials and the processes that were carried out are explained in great detail, including the depth at distance from shore that the samples were taken. This makes the experiments relatively simple to repeat.
The limitations include the increased development of infrastructure between the time of the study and the matric study, as well as the focus on only one form of pollutant.