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Analysis of Wastewater for Use in Agriculture – A Laboratory Manual of Parasitological and Bacteriological Techniques
Introduction:
The use of wastewater for crop irrigation is becoming increasingly common, especially in arid and semi-arid areas. Crop yields are higher as the wastewater contains not only water for crop growth, but also plant nutrients (mainly nitrogen and phosphorus). However, there is the risk that wastewater irrigation may facilitate the transmission of excreta-related diseases. In the late 1980s, the World Health Organization, the World Bank and the International Reference Centre for Waste Disposal sponsored a series of studies and meetings of experts to examine these health risks (International Reference Centre for Waste Disposal, 1985; Shuval et al., 1986; Prost, 1988; World Health Organization, 1989). From an appraisal of the available epidemiological evidence, it was established that the major risks were: the transmission of intestinal nematode infections both to those working in the waste-water irrigated fields and to those consuming vegetables grown in the fields; these infections are due to Ascaris lumbricoides (the human roundworm), Trichuris trichiura (the human whipworm), and Ancylostoma duodenale and Necator americanus (the human hookworms); and- the transmission of faecal bacterial diseases - bacterial diarrhoea and dysentery, typhoid and cholera - to the crop consumers.
Analysis of Wastewater for Use in Agriculture – A Laboratory Manual of Parasitological and Bacteriological Techniques
Introduction:
The use of wastewater for crop irrigation is becoming increasingly common, especially in arid and semi-arid areas. Crop yields are higher as the wastewater contains not only water for crop growth, but also plant nutrients (mainly nitrogen and phosphorus). However, there is the risk that wastewater irrigation may facilitate the transmission of excreta-related diseases. In the late 1980s, the World Health Organization, the World Bank and the International Reference Centre for Waste Disposal sponsored a series of studies and meetings of experts to examine these health risks (International Reference Centre for Waste Disposal, 1985; Shuval et al., 1986; Prost, 1988; World Health Organization, 1989). From an appraisal of the available epidemiological evidence, it was established that the major risks were: the transmission of intestinal nematode infections both to those working in the waste-water irrigated fields and to those consuming vegetables grown in the fields; these infections are due to Ascaris lumbricoides (the human roundworm), Trichuris trichiura (the human whipworm), and Ancylostoma duodenale and Necator americanus (the human hookworms); and- the transmission of faecal bacterial diseases - bacterial diarrhoea and dysentery, typhoid and cholera - to the crop consumers.
Effects of Heavy Metals on Cell Density, Size, Specific Growth Rate and Chlorophyll a of Tetraselmis Tetrathele Under Controlled Laboratory Conditions
Abstract
The effects of the varying levels of mercury (Hg) and cadmium (Cd) (0, 0.1, 0.3, 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 mg L⁻¹) to the cellular density of the green microalgae Tetraselmis tetrathele were evaluated every 24 h for 120 h. Specific growth rate, cell sizes and chlorophyll a were also monitored in the 5.0 mg L⁻¹ Hg and Cd and were compared to the unexposed at 0, 12, 24, 36, 48 and 120h. Results showed that the algal density of T. tetrathele exposed to various levels of Hg were similar with the control up to 48 h. Variations on different concentrations at different times were observed but the results suggest that T. tetrathele was not affected by Hg even at concentrations up to 5.0 mg L⁻¹ for 48 h but started to show toxicity from 3.0 to 5.0 mg L⁻¹ after 72 h and longer. Cd on the other hand also showed toxicity at 3.0, 4.0 and 5.0 mg L⁻¹ beyond 24 h exposure. The specific growth rate of T. tetrathele exposed to both 5.0 mg L⁻¹ Hg and Cd was statistically similar with those of the unexposed from 0 to 12 h and negative growth rates then followed up to 36 h. The chlorophyll a was significantly lower in the metal -exposed algae than did those unexposed. Chlorophyll a also decreased in T. tetrathele exposed to both heavy metals but algal cell sizes were not affected with the presence of Hg or Cd in the culture system.
Effects of Heavy Metals on Cell Density, Size, Specific Growth Rate and Chlorophyll a of Tetraselmis Tetrathele Under Controlled Laboratory Conditions
Abstract
The effects of the varying levels of mercury (Hg) and cadmium (Cd) (0, 0.1, 0.3, 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 mg L⁻¹) to the cellular density of the green microalgae Tetraselmis tetrathele were evaluated every 24 h for 120 h. Specific growth rate, cell sizes and chlorophyll a were also monitored in the 5.0 mg L⁻¹ Hg and Cd and were compared to the unexposed at 0, 12, 24, 36, 48 and 120h. Results showed that the algal density of T. tetrathele exposed to various levels of Hg were similar with the control up to 48 h. Variations on different concentrations at different times were observed but the results suggest that T. tetrathele was not affected by Hg even at concentrations up to 5.0 mg L⁻¹ for 48 h but started to show toxicity from 3.0 to 5.0 mg L⁻¹ after 72 h and longer. Cd on the other hand also showed toxicity at 3.0, 4.0 and 5.0 mg L⁻¹ beyond 24 h exposure. The specific growth rate of T. tetrathele exposed to both 5.0 mg L⁻¹ Hg and Cd was statistically similar with those of the unexposed from 0 to 12 h and negative growth rates then followed up to 36 h. The chlorophyll a was significantly lower in the metal -exposed algae than did those unexposed. Chlorophyll a also decreased in T. tetrathele exposed to both heavy metals but algal cell sizes were not affected with the presence of Hg or Cd in the culture system.
Effect of the Quality of Water Used for Dialysis on the Efficacy of Hemodialysis
Abstract
The quality of the water used for dialysis has been suggested as a factor causing inflammation in patients on hemodialysis (HD). We therefore conducted this study to identify the effect of quality of the water on nutritional state, inflammation and need for human recombinant erythropoietin (EPO) in patients undergoing HD at Agadir, Morocco. This prospective study included patients on HD for at least one year. The water treatment was done according to the standard protocol, which was followed by additional enhancement of ultrafiltration using an additional polysulfone filter (diasafe, Fresenius, Bad Homburg, Germany) before the dialyser. Water was monitored regularly during the study period to ensure acceptable levels of bacterial count as well as endotoxin levels. Various parameters including dry weight, systolic and diastolic blood pressure (PA) before and after an HD session, need for human recombinant EPO, levels of hemoglobin (Hb), albumin, ferritin, C-reactive protein (CRP), and the dose of dialysis delivered (Kt/V) were measured first at the beginning of the study and thereafter, in the third, sixth and 12 th months of the study. The study involved 47 patients, and after 12 months of the study, an improvement in median dry weight (1.2 kg, P = 0017) and a simultaneous median reduction of 20.7 IU/kg/week of EPO, with an in-crease of the median level of Hb, was noted. The results of our study suggest that by improving the biocompatibility of HD with the use of good quality water, patients acquire a better nutritional, inflammatory and hematologic status.
Effect of the Quality of Water Used for Dialysis on the Efficacy of Hemodialysis
Abstract
The quality of the water used for dialysis has been suggested as a factor causing inflammation in patients on hemodialysis (HD). We therefore conducted this study to identify the effect of quality of the water on nutritional state, inflammation and need for human recombinant erythropoietin (EPO) in patients undergoing HD at Agadir, Morocco. This prospective study included patients on HD for at least one year. The water treatment was done according to the standard protocol, which was followed by additional enhancement of ultrafiltration using an additional polysulfone filter (diasafe, Fresenius, Bad Homburg, Germany) before the dialyser. Water was monitored regularly during the study period to ensure acceptable levels of bacterial count as well as endotoxin levels. Various parameters including dry weight, systolic and diastolic blood pressure (PA) before and after an HD session, need for human recombinant EPO, levels of hemoglobin (Hb), albumin, ferritin, C-reactive protein (CRP), and the dose of dialysis delivered (Kt/V) were measured first at the beginning of the study and thereafter, in the third, sixth and 12 th months of the study. The study involved 47 patients, and after 12 months of the study, an improvement in median dry weight (1.2 kg, P = 0017) and a simultaneous median reduction of 20.7 IU/kg/week of EPO, with an in-crease of the median level of Hb, was noted. The results of our study suggest that by improving the biocompatibility of HD with the use of good quality water, patients acquire a better nutritional, inflammatory and hematologic status.
Investigation of The Quality of Water Treated by Magnetic Fields
Abstract
Passing water through a magnetic field has been claimed to improve chemical, physical and bacteriological quality of water in many different applications. Although the treatment process has been used for decades, it still remains in the realms of pseudoscience. If the claims of treating water with magnets are true, the process offers improvements on many of our applications of water in today’s world. A large number of peer reviewed journal articles have reported contradictory claims about the treatment.. Some of the most beneficial claimed water applications from magnetically treated water include improvement in scale reduction in pipes and enhanced crop yields with reduced water usage. Today we are still unsure whether the technology works and those who do believe it works are still trying to understand the mechanisms of how it works. Many research papers are starting to develop similar theories behind the mechanism of the treatment. From previous studies, it has been determined that the most successful MTD’s are those with alternating poles. The majority of the experiments performed during this research were determined to have insufficient controls to produce conclusive results. The conclusions from this research were focused on designing improved experiments to provide more conclusive results. A theory was developed to explain the MTD’s mechanisms of scale reduction. While the experimental results were not conclusive, the results attained backed the theory. Magnetically treated water does not do all that it is claimed it does. However, some of the positive results obtained during this research suggest that the improved experiments developed from this research may provide conclusive results on this controversial topic.
Investigation of The Quality of Water Treated by Magnetic Fields
Abstract
Passing water through a magnetic field has been claimed to improve chemical, physical and bacteriological quality of water in many different applications. Although the treatment process has been used for decades, it still remains in the realms of pseudoscience. If the claims of treating water with magnets are true, the process offers improvements on many of our applications of water in today’s world. A large number of peer reviewed journal articles have reported contradictory claims about the treatment.. Some of the most beneficial claimed water applications from magnetically treated water include improvement in scale reduction in pipes and enhanced crop yields with reduced water usage. Today we are still unsure whether the technology works and those who do believe it works are still trying to understand the mechanisms of how it works. Many research papers are starting to develop similar theories behind the mechanism of the treatment. From previous studies, it has been determined that the most successful MTD’s are those with alternating poles. The majority of the experiments performed during this research were determined to have insufficient controls to produce conclusive results. The conclusions from this research were focused on designing improved experiments to provide more conclusive results. A theory was developed to explain the MTD’s mechanisms of scale reduction. While the experimental results were not conclusive, the results attained backed the theory. Magnetically treated water does not do all that it is claimed it does. However, some of the positive results obtained during this research suggest that the improved experiments developed from this research may provide conclusive results on this controversial topic.
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