Results
Food quality, as regards the fresh vegetables picked from the market, would largely be determined through both the chemical and physic al analysis. The question is whether such analyses would appropriately define the food quality as far as the heavy metals are put into consideration. While the research aimed at collecting five samples for chemical analysis, it ended up managing on three samples collected for spinach, parsley and rocket, which is entirely cultivated in the United Kingdom. Three concentration tests were conducted on each sample for every heavy metal, which included copper, iron and Zinc with different concentrations determined in the process.
| Anova: Single Factor | ||||||
| SUMMARY | ||||||
| Groups | Count | Sum | Average | Variance | ||
| org spinach | 3 | 95.75673267 | 31.91891089 | 4.2755091 | ||
| spinach | 3 | 92.97356436 | 30.99118812 | 1.47429235 | ||
| org parsley | 3 | 84.78 | 28.26 | 0.1831 | ||
| parsley | 3 | 92.75 | 30.91666667 | 5.27503333 | ||
| org rocket | 3 | 89.74 | 29.91333333 | 1.83563333 | ||
| rocket | 3 | 80.58 | 26.86 | 0.2223 | ||
| ANOVA | ||||||
| Source of Variation | SS | df | MS | F | P-value | F crit |
| Between Groups | 54.54929822 | 5 | 10.90985964 | 4.93440439 | 0.01099965 | 3.105875 |
| Within Groups | 26.53173624 | 12 | 2.21097802 | |||
| Total | 81.08103445 | 17 |
For the copper concentrations, three tests were conducted with ANOVA results showing the following outcomes as show below.
Table 1: The Anova Single Factor Results on the concentration of copper in organic and non-organic vegetables
A quick check on the behavior of the concentrations in the three subsequent tests for each type of the vegetable is also shown below.
| 1 | 2 | 3 | |||
| Conc. of | org spinach | 32.43 | 29.64 | 33.68 | |
| Conc. of | spinach | 29.64 | 32.00 | 31.33 | |
| Conc. of | org parsley | 28.75 | 28.07 | 27.96 | |
| Conc. of | parsley | 31.42 | 28.41 | 32.92 | |
| Conc. of | org rocket | 28.41 | 31.04 | 30.29 | |
| Conc. of | rocket | 27.4 | 26.65 | 26.53 | |
Table 2: Concentration of copper in each test
Based on the observation, it is evident that there are slight differences in terms of the copper concentrations in organic and non-organic vegetables. The average copper concentration in organic spinach is roughly 31.92 mg/kg, which is slightly higher than the one in conventional or non-organic spinach, which settles at 30.99 mg/kg. The trend could not be extended to parsley which recorded copper concentration of 28.26 mg/kg in organic parsley, which is relatively lower compared to the copper concentrations in the non-organic parsley which registered 30.92 mg/kg. Organic rocket had higher concentration of 29.91 mg/kg compared to the concentration of 26.86 mg/kg in the non-organic rocket. Despite having the averages determined for copper concentrations, the tests equally displayed varying figures. A graph portraying the trend is as shown below.
Graph 1: A linear relationship between concentration of copper in mg/L and Absorption
The research equally conducted a test on the iron concentrations in vegetables. The Anova results are as shown below.
| Anova: Single Factor | ||||||
| SUMMARY | ||||||
| Groups | Count | Sum | Average | Variance | ||
| organic spinach | 3 | 1106.977 | 368.9924 | 998.87952 | ||
| spinach | 3 | 1106.977 | 368.9924 | 998.87952 | ||
| organic parsley | 3 | 464.1552 | 154.7184 | 1687.4126 | ||
| parsley | 3 | 984.1917 | 328.0639 | 1072.5863 | ||
| org rocket | 3 | 649.3557 | 216.4519 | 19.736603 | ||
| rocket | 3 | 244.7023 | 81.56743 | 270.35355 | ||
| ANOVA | ||||||
| Source of Variation | SS | df | MS | F | P-value | F crit |
| Between Groups | 218781.4 | 5 | 43756.28 | 52.009826 | 1.02E-07 | 3.105875 |
| Within Groups | 10095.7 | 12 | 841.308 | |||
| Total | 228877.1 | 17 |
Table 3: Average iron concentrations in the organic and non-organic vegetables
Based on the results, it is evident that spinach would have no difference in terms of the iron concentration regardless of whether it is organic or non-organic. Organic parsley would have a lower iron concentration compared to its non-organic counterpart which records almost double the figure. On the other hand, organic rocket would have an extremely high concentration of iron compared to the non-organic rocket counterpart. With this, it is difficult for one to establish a trend of whether the non-organic vegetable has a high or low concentration compared to the organic counterpart. A summary of the performance of each is as shown below.
| organic spinach | spinach | organic parsley | parsley | org rocket | rocket | |
| 1 | 352.41 | 352.41 | 116.11 | 315.47 | 217.79 | 81.37 |
| 2 | 405.44 | 405.44 | 197.89 | 303.48 | 211.49 | 65.23 |
| 3 | 349.13 | 349.13 | 150.16 | 365.24 | 220.07 | 98.11 |
Table 4: The performance of each vegetable in terms of the iron concentrations in the 3 tests
It is also evident that when tests are conducted on the spinach samples, the figure for the iron concentration remains the same for the organic and non-organic test. The highest iron concentration in spinach settled at 405.44 mg/kg. Parsley shows varying but consistent figures which shows higher iron concentration in non-organic parsley compared to the organic parsley. The highest figure for the iron concentration in the non-organic parsley settled at 365.24 mg/kg while the lowest iron concentration in the organic parsley settled at 116.11 mg/kg. Organic rocket showed high iron concentrations with the highest figure landing at 220.07 mg/kg compared to the non-organic counterpart which recorded as low iron concentration as 65.23 mg/kg. Based on the average concentrations and the concentrations for the individual test, it is evident that there is no clear trend and iron concentrations in vegetable may largely depend on other factors that are separate from whether the vegetable is organic, or non-organic. Despite lack of a clear trend, a graph of iron concentration against absorption still remains linear as shown below.
Graph 2: Iron concentration against absorption
Lastly, the research focused on testing the zinc concentration in both organic and non-organic vegetables. The ANOVA single factor test results are as shown below.
| Anova: Single Factor | ||||||
| SUMMARY | ||||||
| Groups | Count | Sum | Average | Variance | ||
| organic spinach | 3 | 100.296 | 33.43201 | 6.088767 | ||
| spinach | 3 | 66.54342 | 22.18114 | 14.9377 | ||
| org parsle | 3 | 359.5849 | 119.8616 | 434.8387 | ||
| parsley | 3 | 92.44216 | 30.81405 | 71.80296 | ||
| Org rocket | 3 | 259.5598 | 86.51994 | 8.87803 | ||
| rocket | 3 | 142.7339 | 47.57797 | 3.202452 | ||
| ANOVA | ||||||
| Source of Variation | SS | df | MS | F | P-value | F crit |
| Between Groups | 22094.58 | 5 | 4418.917 | 49.12195 | 1.41E-07 | 3.105875 |
| Within Groups | 1079.497 | 12 | 89.95809 | |||
| Total | 23174.08 | 17 | ||||
Table 5: The average zinc concentrations in organic and non-organic vegetables sampled in United Kingdom
It is evident that organic spinach has a higher zinc concentration of 33.43 mg/kg compared to the one in the non-organic spinach which recorded an average zinc concentration of 22.18 mg/kg. The trend still appears in organic parsley which recorded an average zinc concentration of 119.86 mg/kg, which is higher than the one in non-organic parsley that settled on an average of 30.81 mg/kg. The trend would still be extended to rocket in which organic rocket registered an average zinc concentration of 86.52 mg/kg, which was higher than the one in non-organic rocket, which settled at 47.58 mg/kg. Therefore, it can be noted that zinc concentrations are generally high in the organic vegetables compared to the non-organic counterparts as noticed in the tests across parsley, rocket and spinach. The same trend would be made clear in the individual tests as shown in the summary table indicated below.
| organic spinach | spinach | org parsley | parsley | Org rocket | rocket | |
| 1 | 35.56 | 26.62 | 143.94 | 30.73 | 85.06 | 49.00 |
| 2 | 30.72 | 20.37 | 107.46 | 39.33 | 84.55 | 48.17 |
| 3 | 34.02 | 19.55 | 108.19 | 22.38 | 89.95 | 45.57 |
Table 6: A summary of the individual tests on zinc concentration available in both organic and non-organic vegetables, which include rocket, parsley and spinach
Zinc concentration, same to copper and iron concentrations, exhibit almost the same trend of absorption. The linear relationship shows that when the concentration of zinc is high in the soil, the absorption rate is equally high as shown in the graph below.
Graph 3: The relationship between zinc concentrations in mg/L against absorption rates
Discussion
Base on the research process, and the rest of the supporting studies, it remains evident that vegetables would be regarded as part of the edible parts of the plants. Therefore, vegetables still appear in the wide range of the protective foods and equally remain beneficial in terms of helping the biological system to prevent diseases and keep a healthy body. Vegetables are known for supplying a good range of the elements which include zinc, iron and copper. The three elements are essentially engaged in the functions of a good range of the enzymes known for keeping the body system healthy. The micronutrients are also said to be important in terms helping the plants to develop. Some of the studies have gone ahead noting that plants which are grow in the copper and zinc contaminated soils may end up accumulating a significant portion of the metals. However, copper is both vital as well as toxic when used above the optimal levels (Amos-Tautua and Onigbinde 2014). The research process above considered a significant check on the concentration of heavy metals in organic and inorganic vegetables. The vegetables that were considered in the experiment included the spinach leaves, rockets and parsley. The key question is whether the non-organic vegetables have good scores on the concentration of heavy metals as compared to their organic counterparts. Based on the observations made from the research, it is clear enough organic vegetables have a higher zinc concentration compared to their non-organic counterparts.
Organic parsley, for instance, show relatively high zinc concentrations, followed with organic rocket and organic spinach. The non-organic range of the vegetables has relatively low concentrations and the trend cut across the sampled vegetables. In general, the organic vegetables show high zinc concentrations on the basis of the research process. The question is whether the performance of organic vegetables on zinc concentration is of any importance or not. Based on a range of the observations, organic vegetables do not exhibit the same performance when it comes to zinc concentrations (Bagdatlioglu et al. 2010). Parsley has the highest concentration with the figure settling at 143.94 mg/kg. Organic rocket records its highest figure at 89.95 mg/kg and spinach has its highest figure settling at 35.56 mg/kg. As much as organic vegetables show a good performance in terms of the zinc concentrations, the critical concern is whether the figure is within the safety range. FAO and WHO recommend that the highest zinc concentration should stand at 99.4 mg/kg. This means that organic parsley is already within the toxic range with organic rocket lying within the optimal range based the standards set by WHO and FAO. Most of the studies have already indicated that zinc concentrations within the optimal range remain beneficial as far as the organic vegetables are put into consideration.
Zinc is counted as one of the many trace elements that would be found in high concentrations within the red blood cells. Zinc concentrations equally remain vital to such enzymes like carbonic anhydrase, which is also known for the promotion of a good range of the reactions associated to the carbon dioxide metabolism. Zinc is also fundamentally known to support the normal growth as well as development of the pregnancy. A daily intake of zinc is expected to maintain a more stead rate due to the fact that the body of a human being does not have a specialized zinc storage system. Under normal circumstances, zinc would naturally occur in soil with concentrations in rocks approximated to be 70 mg/kg. However, it has also been observed that zinc concentrations are likely to go higher as a result of the anthropogenic additions. Amos-Tautua and Onigbinde (2014) equally noted that high concentrations of zinc that can be traced in vegetables would sometimes posit the health dangers which may not be limited to the reproduction challenges, the depressed immune function and impairment in terms of growth among other issues.
Apart from the zinc concentration, another focus is placed on the iron concentrations. In a study, iron has largely been regarded as one of the significant constituents of chlorophyll and therefore remains significant in the plant photosynthesis. Perhaps, a traceable iron deficit would be regarded as an urgent problem that needs immediate attention. High concentration of iron in vegetables would only increase or boost the nutritional health of individuals living in an area. This may not imply that extreme levels of iron concentration may not have any impact. Some of the studies have indicated that certain iron concentrations may increase the risks of the colon cancer. This must be the reason as to why the World Health Organization and FAO recommended a safety limit of 425 mg/kg for the iron concentration. The question is whether the organic or the non-organic vegetables have any impact on this concentration or not. Based on the results, the iron concentrations in the organic spinach are just the same when compared to the iron concentrations in the non-organic spinach. The highest value for the iron concentrations in spinach stood at 405.44 mg/kg, which is relatively lower compared to the safety limit set by FAO and WHO. On the other hand, the non-organic parsley show relatively high iron concentrations compared to the organic parsley.
The highest iron concentration for the non-organic parsley is 365.24 mg/kg while the highest value for the organic parsley stands at 197.89 mg/kg. While both the non-organic and the organic parsley show safety levels of iron concentrations, the non-organic counterpart maybe preferable in case where there is iron deficiency. On the other hand, organic rocket recorded higher iron concentrations compared to the non-organic counterpart. The highest value of the iron concentration for the organic rocket stood at 220.07 mg/kg while the highest value for the non-organic counterpart stood at 98.11 mg/kg. Based on the observations made on the iron concentrations, rocket and parsley show an opposite relationship as spinach retains values for iron concentration in non-organic and organic vegetables. Based on this observation, it is evident that choosing either the non-organic or organic vegetables may not necessarily determine the level of the iron concentrations. This means that iron concentrations are likely to entirely depend on the type of the vegetable that one would choose (Wuana & Okieimen 2011). Some of the vegetables have high iron concentrations both in the organic and non-organic forms, others would show significant levels of iron concentrations in their non-organic forms as compared to their organic forms, and the rest would indicate high iron concentrations in their organic forms as compared to their non-organic forms. Other researches have also indicated that levels of iron concentrations in the vegetables would sometimes be determined by the type of the soil under investigation (Johansson et al. 2014). However, this may not highly be mentioned in the context due to the fact that the research was conducted within United Kingdom, which presumably bears the same soil profile and other characteristics of the soil that would posit similar outcomes across the chemical analyses.
Unlike the tests performed on iron and zinc, the tests performed on copper concentrations almost showed insignificant differences in terms of the concentrations in organic and non-organic vegetables (Głodowska and Krawczyk 2017). Copper has largely been thought to play the most integral role in terms of acting as a key ligand to most of the enzymes and proteins found in the body. In certain incidents, copper would play the role of a ligand to the ferroxidase II known for oxidizing iron. This process is said to give room for mobilization as well as transportation of iron from the hepatic stores to the necessary bone marrows. This means that the availability of copper in vegetables is deemed necessary for the diet that would be consumed by people in the United Kingdom (Domagała-Świątkiewicz and Gąstoł 2012). However, high copper concentrations are thought to be toxic due to episodes of dermatitis, nausea, gastro-intestinal disorders, dwarfism, anemia and the electrolyte-imbalance, which have been witnessed in a range of the studies. This is the reason as to why FAO and WHO introduced a limit to the copper concentrations, which stand at a safety limit of 73.30 mg/kg. Based on the findings established in the prior section, the copper concentration in the organic spinach stood at 31.92 mg/kg, which is not far from the non-organic counterpart that registered a concentration of 30.99 mg/kg. On the other hand, organic parsley registered copper concentration of 28.26 mg/kg while the non-organic counterpart registered a slightly higher figure that settled at 30.92 mg/kg.
Organic rocket noted a copper concentration of 29.91 mg/kg while the non-organic counterpart recorded a concentration of 26.86 mg/kg. With these figures in place, a number of observations can be made. First, there is no type of vegetables that recorded a figure that seemed close to the safety limit. This means that all the vegetables were within the safe range as far as copper concentrations are put into consideration. Secondly, there is a no clear trend for copper concentrations between the non-organic and organic vegetables due to the almost insignificant differences. This means that choosing either organic or non-organic vegetable would not significantly influence the levels of the copper concentrations in vegetables (Dotse, 2010). Finally, there is minimal range of the copper concentrations that would be determined or observed in a range of the types of vegetables. This means that most of the vegetables would almost have the same absorption rates as noted with rockets, spinach and parsley samples in the experiment conducted in the research process.
Conclusion
The research aimed establishing a significant analysis of the metal contents that would be found in the organically and non-organically grown vegetables, either washed or unwashed. The literature review noted that human beings largely depend on a range of food sources that are known for containing fiber, vitamins and minerals among other significant elements. One of the food sources includes a range of the vegetable said to contain a varying range of the copper, zinc and iron concentrations. During the experiment, it was found necessary to extract the samples of parsley, rocket and spinach grown within United Kingdom. The procedure required division of the samples into two significant groups, prepare the standard solutions for every sample and introducing the mixes into the available digester that carries with it the hot plate. On the basis of the tests conducted on the samples, it could be established that the organic vegetables exhibited high zinc concentrations compared to their non-organic counterparts. While high levels of zinc concentrations would be needed, most of the organic vegetables could retain an optimal range. The second observation that was made from the experiment included the fact that iron concentrations would largely depend on the type of the vegetable rather than whether the vegetable is organic or non-organic. Lastly, copper concentrations showed insignificant changes or differences between the organic and the non-organic vegetables that were included in the experiment.
Appendix
Copper Statistics
| Concentration /mg/L | Abs | Average | Standard deviation | ||
| 0 | 0.001 | 0.002189 | -0.0006 | 0.000864157 | 0.001397538 |
| 2 | 0.1565 | 0.164787 | 0.153068 | 0.158118224 | 0.006024525 |
| 4 | 0.2881 | 0.293323 | 0.281406 | 0.287609634 | 0.005973937 |
| 6 | 0.4139 | 0.417383 | 0.412216 | 0.414499448 | 0.002635185 |
| 8 | 0.5158 | 0.516321 | 0.508882 | 0.513667843 | 0.004152782 |
| 10 | 0.6113 | 0.614352 | 0.604539 | 0.610063625 | 0.005022257 |
| Samples | |||||
| org spinach | 0.048596 | 0.043596 | 0.050596 | 0.047596 | |
| org spinach 2 | 0.046964 | 0.041964 | 0.048964 | 0.045964 | |
| org spinach 3 | 0.049412 | 0.044412 | 0.051412 | 0.048412 | |
| spinach | 0.046964 | 0.041964 | 0.048964 | 0.045964 | |
| spinach 2 | 0.048392 | 0.043392 | 0.050392 | 0.047392 | |
| spinach 3 | 0.047984 | 0.042984 | 0.049984 | 0.046984 | |
| org parsley | 0.04642 | 0.04142 | 0.04842 | 0.04542 | |
| org parsley 2 | 0.046012 | 0.041012 | 0.048012 | 0.045012 | |
| org parsley 3 | 0.045944 | 0.040944 | 0.047944 | 0.044944 | |
| parsley | 0.046372 | 0.048372 | 0.046372 | 0.047038667 | |
| parsley 2 | 0.044548 | 0.046548 | 0.044548 | 0.045214667 | |
| parsley 3 | 0.047284 | 0.049284 | 0.047284 | 0.047950667 | |
| org rocket | 0.044548 | 0.046548 | 0.044548 | 0.045214667 | |
| org rocket 2 | 0.046144 | 0.048144 | 0.046144 | 0.046810667 | |
| org rocket 3 | 0.045688 | 0.047688 | 0.045688 | 0.046354667 | |
| rocket | 0.04394 | 0.04594 | 0.04394 | 0.044606667 | |
| rocket 2 | 0.043484 | 0.045484 | 0.043484 | 0.044150667 | |
| rocket 3 | 0.043408 | 0.045408 | 0.043408 | 0.044074667 | |
| blank | 0.003435 | 0.002628 | 0.005375 | 0.003812691 | |
| blank | 0.001093 | 0.004804 | 0.001961 | 0.002619015 | |
| blank | 0.002161 | 0.004229 | 0.004251 | 0.003547113 | |
| blank | 0.00565 | 0.002594 | 0.002009 | 0.00341767 | |
| blank | 0.006627 | 0.002099 | 0.002293 | 0.00367317 | |
| blank | 0.001045 | 0.000749 | 0.003838 | 0.001877466 | |
| blank | 0.000271 | 0.005807 | 0.006631 | 0.004236445 | |
| blank | 0.005422 | 0.000161 | 0.004349 | 0.003310572 | |
| blank | 0.006264 | 0.00247 | 0.006664 | 0.00513233 |
Iron Statistics
| standards Concentration mg/mL | Abs | Average | ||
| 0 | 0.0918 | 0.098121 | 0.09057 | 0.093496941 |
| 2 | 0.1718 | 0.176704 | 0.170939 | 0.173147714 |
| 4 | 0.2435 | 0.245536 | 0.236776 | 0.241937362 |
| 6 | 0.3114 | 0.316132 | 0.306932 | 0.311487828 |
| 8 | 0.3791 | 0.387208 | 0.371513 | 0.379273484 |
| 10 | 0.405 | 0.412794 | 0.398262 | 0.405352028 |
| Samples | ||||
| org spinach 1 | 0.2244 | 0.204744 | 0.238452 | 0.222531989 |
| org spinach 2 | 0.2308 | 0.195168 | 0.263915 | 0.229961082 |
| org spinach 3 | 0.2224 | 0.183574 | 0.233431 | 0.213135282 |
| spinach 1 | 0.2276 | 0.204102 | 0.22837 | 0.220023864 |
| spinach 2 | 0.24 | 0.228615 | 0.242521 | 0.237045467 |
| spinach 3 | 0.2236 | 0.209575 | 0.223736 | 0.218970388 |
| org parsley 1 | 0.1472 | 0.119578 | 0.165738 | 0.144171769 |
| org parsley 2 | 0.1736 | 0.140722 | 0.196943 | 0.170421695 |
| org parsley 3 | 0.1592 | 0.131483 | 0.174618 | 0.155100355 |
| parsley 1 | 0.1988 | 0.197566 | 0.228129 | 0.208165086 |
| parsley 2 | 0.214 | 0.180973 | 0.21798 | 0.204317686 |
| parsley 3 | 0.214 | 0.206686 | 0.251742 | 0.224142761 |
Zinc Statistics
| Absorbance (replicates) | |||
| Standard Concentration (mg/L) | 1 | 2 | 3 |
| 0 | 0.011 | 0.0089 | 0.008 |
| 0.25 | 0.095 | 0.11 | 0.102 |
| 0.5 | 0.194 | 0.197 | 0.188 |
| 1 | 0.329 | 0.333 | 0.337 |
| 1.5 | 0.415 | 0.421 | 0..421 |
| 2 | 0.529 | 0.522 | 0.525 |
| Samples | |||
| org spinach 1 | 0.135742 | 0.133142 | 0.128142 |
| org spinach 2 | 0.12355 | 0.12095 | 0.11595 |
| org spinach 3 | 0.131856 | 0.129256 | 0.124256 |
| spinach 1 | 0.113187 | 0.110587 | 0.105587 |
| spinach 2 | 0.097413 | 0.094813 | 0.089813 |
| spinach 3 | 0.095356 | 0.092756 | 0.087756 |
| org parsley 1 | 0.404229 | 0.411229 | 0.402229 |
| org parsley 2 | 0.312154 | 0.319154 | 0.310154 |
| org parsley 3 | 0.314009 | 0.321009 | 0.312009 |
| parsley 1 | 0.118505 | 0.125505 | 0.116505 |
| parsley 2 | 0.140196 | 0.147196 | 0.138196 |
| parsley 3 | 0.097423 | 0.104423 | 0.095423 |
| org rocket 1 | 0.252718 | 0.255018 | 0.264118 |
| org rocket 2 | 0.251448 | 0.253748 | 0.262848 |
| org rocket 3 | 0.265063 | 0.267363 | 0.276463 |
| rocket 1 | 0.16171 | 0.16401 | 0.17311 |
| rocket 2 | 0.159602 | 0.161902 | 0.171002 |
| rocket 3 | 0.153049 | 0.155349 | 0.164449 |
| blank | 0.006435 | 0.005628 | 0.008375 |
| blank | 0.001907 | 0.007804 | 0.004961 |
| blank | 0.000839 | 0.007229 | 0.007251 |
| blank | 0.00865 | 0.000406 | 0.005009 |
| blank | 0.002934 | 0.005099 | 0.000707 |
| blank | 0.004045 | 0.003749 | 0.006838 |
| blank | 0.003271 | 0.008807 | 0.009631 |
| blank | 0.008422 | 0.002839 | 0.007349 |
| blank | 0.009264 | 0.002753 | 0.009664 |
