INTRODUCTION
Research rationale
Eutrophication is a significant environmental concern that deteriorates water quality and hinders the objectives of the Water Framework Directive (2000/60/EC) in Europe According to the International Lake Environment Committee, eutrophication impacts 54% of Asian lakes, 53% in Europe, 48% in North America, 41% in South America, and 28% in Africa This process, which involves the gradual accumulation of nutrients like nitrogen and phosphorus, can overwhelm a water body's ability to self-purify, leading to structural changes in aquatic ecosystems While natural eutrophication occurs over millennia as lakes age, human activities have accelerated this process through the discharge of chemical nutrients, posing threats to aquatic life, compromising water quality, limiting access to safe drinking water, and endangering public health and recreational opportunities.
Eutrophication leads to algal blooms that block light from penetrating the water, adversely affecting aquatic flora and fauna As algae overgrow, they can deplete oxygen levels, resulting in hypoxic conditions and creating dead zones where organisms cannot survive.
Solar energy is a clean and sustainable resource that generates electricity without contributing to toxic pollution or greenhouse gas emissions Solar power plants do not produce air or water pollution, making them an environmentally friendly option By reducing reliance on more harmful energy sources, solar energy can positively impact the environment However, some critics argue that solar panels are not entirely clean due to the energy and potentially harmful chemicals required for their production Consequently, extensive research and projects are underway to evaluate the environmental effects of solar panel installations.
Taiwan prioritizes environmental stability and sustainability, making the impacts of eutrophication and solar panel installations on its water ecosystems a significant concern for the nation.
Allowing for all aspects and problems that I mentioned above, I suggest research: “Monitoring eutrophication of freshwater”.
Research’s objectives
- The objective of my research was to assess the eutrophication and manage the water quality in local areas (two regions in North and South) of Taiwan.
- In addition, evaluating the possible effects of solar panels on the research water environment where they are installed.
This study used parameters of Water Quality Index and calculated by River Pollution Index equations.
Research question
- How does eutrophication take place at two research sites?
- Is the solar panel having any impact on water quality in two research regions?
Limitations
Due to the limited time of my internship in Taiwan, there are not many observations the fluctuation about the effects of eutrophication and solar panels factors on research regions.
LITERATURE REVIEW
Eutrophication
Eutrophication is the process of nutrient enrichment in water bodies, leading to increased primary productivity influenced by factors such as light, temperature, oxygen, and retention time This phenomenon often manifests as a greenish slim layer that reduces light penetration and limits oxygen availability, adversely affecting the growth of other aquatic species Eutrophication is classified into four trophic states: Oligotrophic, characterized by low nutrient levels and minimal marine life; Mesotrophic, with intermediate nutrient levels and emerging water quality issues; Eutrophic, indicating high nutrient richness and significant productivity; and Hypertrophic, marked by very high nutrient concentrations that lead to severe water quality problems and excessive plant growth.
The above mentioned trophic states category is described in Table 2.1 as adopted from Chapman (1996).
Table 2.1: Nutrient level, biomass and productivity of lakes at each trophic category
Ultra- oligotroph icOligotrop hicMesotroph icEutrophicHypereutr ophic
Eutrophication Index
The Eutrophication Index (E.I) is a key Water Quality Indicator (WQI) used to evaluate aquatic systems (Giordani et al., 2009) Several methods exist for assessing eutrophication quality, including the trophic index TRIX (Vollenweider et al., 1998; Primpas and Karydis, 2011), chl-a biomass classification schemes (Simboura et al., 2005; Pagou et al., 2002), and the Eutrophication Index itself (Primpas et al., 2010).
TRIX was measured according to the equation based on Vollenweider et al
(1998), whereas eutrophication ranges have been modified and applied following to Primpas and Karydis (2011):
TRIX = log 10 [(C PO4 *C DIN *C Chl-a *D%O 2 ) +1.5]/1.2
The E.I was calculated by the following mathematical equation (Primpas et al., 2010): E.I = 0.279*C PO4 + 0.261*C NO3 + 0.296*C NO2 + 0.275*C NH4 + 0.261*C Chl-a Where: C DIN is the concentration of dissolved inorganic nitrogen (= C NO3 +
The concentrations of various nutrients are critical for understanding water quality, including C NO2 (nitrite), C NH4 (ammonium), C NO3 (nitrate), and C PO4 (phosphate), measured in mg*m -3 for TRIX and mmol*m -3 for E.I calculations Additionally, C Chl-a indicates the concentration of phytoplankton chlorophyll-a, also expressed in mg*m -3 The percentage deviation of oxygen concentration from saturation conditions is represented by D%O 2, highlighting the ecological balance within aquatic environments.
Table 2.2 outlines various methods for estimating eutrophication, detailing the indices used for each tool, the classifications of eutrophication status, and the corresponding ranges Nutrient levels, dissolved oxygen (DO), and chlorophyll-a (chl-a) were assessed using standardized methods and quality assurance protocols in line with ISO 17025 certification procedures, as referenced by Mullin and Riley (1955), Murphy and Riley (1962), Holm-Hansen et al (1965), Carpenter (1965), Koroleff (1970), Strickland and Parsons (1977), and Welschmeyer (1994).
Table 2.2: The methodological tools, indicators, and ranges are used for Greek coastal areas in the eutrophication assessment.
E.I e a Vollenweider et al (1998). b Primpas and Karydis (2011). c Simpoura et al (2005).
7 d Pagou et al (2002). e Primpas et al (2010).
Eutrophication assessment in Taiwan
The E.P.A evaluates river quality using the "River Pollution Index," a comprehensive measure that assesses pollution levels by analyzing the concentration of four key water quality parameters.
- Dissolved Oxygen (DO): The amount of gaseous oxygen dissolved in water.
- Biochemical Oxygen Demand (BOD 5 ): The amount of dissolved oxygen that is consumed by aerobic microorganisms when they decompose organic matter in water.
- Suspended Solids (SS): Small solids particles which remain in suspension in water.
- Ammonia Nitrogen (NH 3 -N): Concentration of all of the nitrogen in the form of ammonia and ammonium combined.
For assessment of eutrophication levels of the water reservoirs, the E.P.A uses
“Carlson’s Trophic State Index” (CTSI) which is calculated based on the concentration of three independent water quality variables:
- Transparency (SD): The depth of light penetration into the water.
- Chlorophyll-a (Chl-a): Liable for the absorption of light that supplies energy for photosynthesis.
- Total Phosphorus (TP): The sum of all phosphorous compounds that occur in various forms.
MATERIALS AND METHODS
Water sampling and analysis
Water samples were taken from different locations of the two regions in the North and South of Taiwan.
Table 3.1: Location of water sample
Figure 3.1: Flood detention pond in North of Taiwan
Water quality assessment
Principle: Chlorophyll is extracted in 90% alcohol and the absorbances are read at 665 and 750 nm in a spectrophotometer Using the absorption coefficients, the amount of chlorophyll is calculated (Arnon, 1949).
Figure 3.2: Steps to estimate chlorophyll-α index
Figure 3.3: Alcohol 90% and a DR 6000 spectrophotometer using in Chl-α estimation
Calculation: Calculate the amount of chlorophyll present in the extract in àg using the following equations:
- V e : the concentration of C 2 H 5 OH (mL)
Suspended solids are determined by filtering a thoroughly mixed sample through a 0.45 µm glass fiber filter The residue collected on the filter is then dried to a constant weight at a temperature range of 103-105 °C (Joe Ferry 2004).
Figure 3.4: Procedure of Suspended Solids measurement
Figure 3.5: Glass fiber filter, furnace and electronic balance using in SS measurement
- :The original weight of the filter paper (mg)
- : The weight of the filter paper after filtration through the water sample (mg)
3.2.3 Analyze the Chemical Oxygen Demand (COD) index
The Chemical Oxygen Demand (COD) is measured in mg/L, indicating the milligrams of O2 consumed per liter of sample during the testing procedure This involves heating the sample with sulfuric acid and potassium dichromate, a strong oxidizing agent, for two hours During this process, oxidizable organic compounds reduce the dichromate ion (Cr2O72) to the green chromic ion (Cr3+) Depending on the colorimetric method used, either the remaining Cr6+ or the produced Cr3+ is quantified The COD reagent also includes silver ions, which act as a catalyst, and mercury ions to mitigate chloride interferences Results are analyzed at a wavelength of 420 nm.
Figure 3.6: Hach COD test kit and a DR 6000 spectrophotometer using in COD analysis
3.2.4 Measurement of the Dissolved Oxygen (DO) and Biochemical Oxygen
Figure 3.7: The measurement device using in measuring DO index
To prepare a water sample for measurement, take 10 mL of the sample and transfer it into a container Fill the container with deionized water and securely close the lid Store the sealed sample at a temperature of 20°C After a period of 5 days, proceed to measure the results.
Figure 3.8: Low temperature incubator using in keeping water sample
3.2.5 Measure pH and ORP values
Figure 3.9: The device using in measuring pH and ORP values 3.2.6 Measure Transparency
The Secchi disk, a 20 cm diameter black and white disk, is used to measure water transparency It is lowered into the water until it is no longer visible, with the maximum depth indicating the water's clarity, referred to as the Secchi Depth.
Figure 3.10: Secchi disk using in measuring the transparency
The Mineral Stabilizer effectively complexes hardness in the sample, while the Polyvinyl Alcohol Dispersing Agent enhances the color formation during the reaction between Nessler Reagent and ammonia, as well as certain amines The intensity of the yellow color produced is directly proportional to the concentration of ammonia, measured at a specific wavelength.
Figure 3.11: Ammonia Nitrogen test procedure
Figure 3.12: Hach NH 3 -N reagent set
2.3.8 Analyze the Total Phosphorous (TP) index:
To analyze phosphates in both organic and condensed inorganic forms, it is essential to convert them into reactive orthophosphate This transformation is achieved through sample pretreatment involving acid and heat, which facilitates the hydrolysis of condensed inorganic phosphates Organic phosphates are also converted to orthophosphates by heating with acid and persulfate In an acidic medium, orthophosphate reacts with molybdate to form a mixed phosphate/molybdate complex The addition of ascorbic acid reduces this complex, resulting in a distinctive intense molybdenum blue color, which is measured at a wavelength of 880 nm.
Figure 3.13: Hach Total Phosphorous Test Kit using in TP analysis
Calculation RPI and CTSI
After analyzing the results for DO, BOD5, SS, and NH3-N parameters, the RPI was calculated using Table 3.3.1 The total score was divided by the number of parameters to assess water quality, and this value was then compared to the Pollution Index Integral Value.
Table 3.2: The calculation and comparison baselines for RPI (Environmental
Protection Administration Executive Yuan, R.O.C, Taiwan)
Point scores Pollution Index Integral Value
For calculation the Carlson’s Trophic State Index, using equation hereunder:
After calculation the CTSI, using Table 3.3.2 to comprise and determine the eutrophication level of reservoir
Table 3.3: The comparison baselines for CTSI (Environmental Protection
RESULTS AND DISCUSSION
Water Quality Assessment
Table 4.1: Water quality index results in site A
The table shows about results of water quality assessment through parameters.
The chlorophyll-α concentration reached a maximum of 296.2 µg/L, with the lowest value being below detection limits, indicating no significant algal bloom and no adverse effects on water transparency The water body exhibited a maximum transparency of 56.7 cm and a minimum of 28.6 cm, reflecting good water quality that supports aquatic life Additionally, suspended solids ranged from 10 mg/L to 30.5 mg/L, with fluctuations that did not significantly impact the transparency index Overall, the data suggests stable water conditions conducive to healthy aquatic ecosystems.
The ammonia nitrogen detection values ranged from a maximum of 1.15 mg/L to a minimum of 0.13 mg/L, with 7 out of 8 samples below 0.8 mg/L, indicating low levels The maximum COD was 32 mg/L and the minimum was 1 mg/L, with concentrations peaking mid-sampling period before declining and then rising again Dissolved oxygen (DO) levels varied from a maximum of 7.3 mg/L to a minimum of 3.7 mg/L, showing a slight increase after initially low concentrations (≤ 5 mg/L) in the first half of the survey The BOD values ranged from 0.5 mg/L to 4 mg/L, with an average below 3 mg/L, suggesting low levels of biodegradable organic matter and minimal impact on water quality Total phosphorus detection peaked at 10,730 µg/L (approximately 10 mg/L) in the first sample, but no significant increases were observed in subsequent measurements The pH values ranged from a maximum of 8.73 to a minimum of 7.14, with an average of 7.8 to 7.9, indicating stable conditions with little effect on water quality Similarly, the oxidation-reduction potential (ORP) values ranged from a maximum of 429 mV to a minimum of 72 mV, averaging between 210 and 229 mV, which is conducive to biological growth.
Figure 4.1: Diagram about some water parameters in site A
Table 4.2: Water quality index results in site B
Due to the limited experimental duration, the parameters show minimal changes, necessitating more time for a precise evaluation All indicators remain normal, and no water quality issues have been detected.
River Pollution Index
Table 4.3: River Pollution Index results in site A
The "Pollution Index Integral Value" measurements indicate that on October 13, 2017, Sample 2 exhibited the highest level of pollution, followed by Sample 3 and Sample 1.
Table 4.4: River Pollution Index results in site B
• The samples taken at site B gave very good results, all of which resulted in
Table 4.5: CTSI results in site A
The results indicate that almost the water samples at the monitoring station are
“Eutrophic” Remarkably, the water samples on 8/12/2017 showed the results of Oligotrophic, Mesotrophic and Oligotrophic respectively.
Table 4.6: CTSI results in site B
The results indicate that the water samples at the monitoring station are
CONCLUSION AND RECOMMENDATION
Conclusion
The installation of solar panels has not significantly impacted water quality, as indicated in part IV, with only minor changes in some parameters that cannot be conclusively linked to solar cells While most water samples from the two sites meet the "non (slightly) polluted" standard according to the RPI, the CTSI indicates that the water samples are at an "eutrophic" level, suggesting an increase in nutrients and potential water issues This is particularly concerning for site B, which serves as a water source for irrigation and could adversely affect crop quality, necessitating an investigation into the causes of these water quality problems.
Water quality indicators at two sites in Taiwan require extended observation, measurement, and analysis to ensure accurate results This prolonged assessment is crucial for timely interventions to address potential eutrophication signs.
Recommendation
In Viet Nam, Water Quality Index is calculated based on parameters: DO, Temperature, BOD 5 , COD, N-NH 4 , P-PO 4 , TSS, Total Coliform, pH and
Transparency After calculating the WQI for each parameter above, WQI calculation applied the following equation:
However, the monitoring and evaluation of water quality indicators in Viet Nam have not yet been widely publicized as well as adequate investment After a brief
30 internship in Taiwan about the water field, I would like to make some recommendation on the assessment of water indicators in our country:
- Firstly, measurement and reporting results should be widely communicated through media or text so that people are more likely to follow up;
- Publish the results and regular update;
- Add the list of equipment, instruments, chemicals on site and analysis in the laboratory;
- To invest in equipment, protective equipment and labor safety for environmental monitoring activities;
- Pay attention to sample preservation;
- Set up many plans for quality assurance and quality control in environmental monitoring.
• A Pavlidou et al (2015) Methods of eutrophication assessment in the context of the water framework directive: Examples from the Eastern Mediterranean coastal areas
• Alexandra P, Nomiki S, Eleni R, Manolis T, Kalliopi P, Paraskevi D, Georgia
A, Harilaos K, Panayotis P (2017) Methods of eutrophication assessment in the context of the water framework directive: Examples from the Eastern Mediterranean coastal areas
• Bhanu Mahajan (14th Dec 2014) Negative environmental impacts of Solar
• Environmental Protection Administration Executive Yuan, R.O.C, Taiwan
• F Esfandi, A.H Mahvi, M Mosaferi, F Armanfar, M.A Hejazi, S Maleki (1 April 2018) Assessment of temporal and spatial eutrophication index in a water dam reservoir
• G Panduranga Murthy, Shivalingaiah, Leelaija, B.C and Shankar P Hosmani
(2017) Trophic State Index in Conservation of lake ecosystems
The article by João G F et al (2015) provides a comprehensive overview of eutrophication indicators essential for evaluating environmental status in accordance with the European Marine Strategy Framework Directive It emphasizes the importance of these indicators in assessing marine ecosystems' health and sustainability, highlighting their role in guiding policy and management decisions to combat eutrophication in European waters.
• John V T (2015) Standard Methods for the Examination of Water and