Assessing Water Quality by Statistical Methods
Assessing Water Quality by Statistical Methods
Source: https://www.mdpi.com
Edited by: Alina Barbulescu
Water, indispensable for life, has became scarcer in the last period due to overexploitation and pollution. Deforestation, urbanization, and, generally, agricultural and economic development lead to the water quality decreasing not only of the surface water, but also of the groundwater, endangering the water reserve.
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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.
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.
Developing Quality Control Handbooks for Water and Wastewater Treatment
Introduction
This section provides a step by step discussion regarding the development of a Quality Control Handbook for a water or wastewater treatment plant. A workshop format has been chosen for the development of the handbook in order to channel the multiple knowledge inputs needed for it. For a proper. The workshop format targets participants coming from water or wastewater treatment facilities. These participants are expected to be knowledgeable of the operational activities of the plant and able to share their actual experiences. The successful implementation of this handbook depends on the creation of a setting in which the employees themselves act as both teachers and students. Active participation is a key success factor, and practical demonstrations are necessary to supplement the theoretical aspects. The workshop format can be easily replicated and as such, helps facilitate the development of operating manuals in other water treatment facilities or water companies. Once completed, these manuals may be used to define the required skills of the operating personnel and may also be used for actual on-the-job training. The handbook is to be finalized after successful completion of four group sessions.
Developing Quality Control Handbooks for Water and Wastewater Treatment
Introduction
This section provides a step by step discussion regarding the development of a Quality Control Handbook for a water or wastewater treatment plant. A workshop format has been chosen for the development of the handbook in order to channel the multiple knowledge inputs needed for it. For a proper. The workshop format targets participants coming from water or wastewater treatment facilities. These participants are expected to be knowledgeable of the operational activities of the plant and able to share their actual experiences. The successful implementation of this handbook depends on the creation of a setting in which the employees themselves act as both teachers and students. Active participation is a key success factor, and practical demonstrations are necessary to supplement the theoretical aspects. The workshop format can be easily replicated and as such, helps facilitate the development of operating manuals in other water treatment facilities or water companies. Once completed, these manuals may be used to define the required skills of the operating personnel and may also be used for actual on-the-job training. The handbook is to be finalized after successful completion of four group sessions.
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