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.
Clearing the Waters A focus on water quality solutions
Reproduction
This publication may be reproduced in whole or in part and in any form for educational or nonprofit purposes without special permission from the copyright holders, provided acknowledgement of the source is made. UNEP would appreciate receiving a copy of any publication that uses this publication as a source. No use of this publication may be made for resale or for any other commercial purpose whatsoever without prior permission in writing from the United Nations Environment Programme.
Clearing the Waters A focus on water quality solutions
Reproduction
This publication may be reproduced in whole or in part and in any form for educational or nonprofit purposes without special permission from the copyright holders, provided acknowledgement of the source is made. UNEP would appreciate receiving a copy of any publication that uses this publication as a source. No use of this publication may be made for resale or for any other commercial purpose whatsoever without prior permission in writing from the United Nations Environment Programme.
Boiler Water Quality Requirements and Associated Steam Quality for Industrial/Commercial and Institutional Boilers
Introduction:
The purpose of this publication is to acquaint engineers, purchasers and operators of industrial, commercial and institutional (ICI) boilers with ABMA's judgment as to the relationship between boiler water quality and boiler performance. This document is published for general guidance as a supplement to detailed operating manuals supplied by the equipment manufacturers. It should also be noted that the information presented is directed to steel boiler designs, as opposed to cast iron sectional or copper finned tube boilers. Furthermore Utility Boilers and Combined Cycle Boilers, which require extremely close control of water quality and steam purity, are not the topic of this document. This new document combines two previous ABMA Guideline documents, namely “Boiler Water Requirements and Associated Steam Purity for Commercial Boilers” (1998), and “Boiler Water Limits and Achievable Steam Purity for Water tube Boilers”, (1995). The document discusses the effect of various feed water and condensate systems on the boiler operation. It also provides information on boiler water and steam testing as well as system care and maintenance. It is recognized that specific boiler usage and water treatment will vary and may require values different from these recommendations. Boiler users therefore, need to define limits, equipment and operating parameters for their particular application. These recommendations are for information only. Everyone is free to accept or reject the conclusions of these suggestions as their own judgment warrants in all aspects of the conduct of their business. The ABMA does not represent or warrant that any level of steam purity depicted will be achieved by any particular boiler or boilers.
Boiler Water Quality Requirements and Associated Steam Quality for Industrial/Commercial and Institutional Boilers
Introduction:
The purpose of this publication is to acquaint engineers, purchasers and operators of industrial, commercial and institutional (ICI) boilers with ABMA's judgment as to the relationship between boiler water quality and boiler performance. This document is published for general guidance as a supplement to detailed operating manuals supplied by the equipment manufacturers. It should also be noted that the information presented is directed to steel boiler designs, as opposed to cast iron sectional or copper finned tube boilers. Furthermore Utility Boilers and Combined Cycle Boilers, which require extremely close control of water quality and steam purity, are not the topic of this document. This new document combines two previous ABMA Guideline documents, namely “Boiler Water Requirements and Associated Steam Purity for Commercial Boilers” (1998), and “Boiler Water Limits and Achievable Steam Purity for Water tube Boilers”, (1995). The document discusses the effect of various feed water and condensate systems on the boiler operation. It also provides information on boiler water and steam testing as well as system care and maintenance. It is recognized that specific boiler usage and water treatment will vary and may require values different from these recommendations. Boiler users therefore, need to define limits, equipment and operating parameters for their particular application. These recommendations are for information only. Everyone is free to accept or reject the conclusions of these suggestions as their own judgment warrants in all aspects of the conduct of their business. The ABMA does not represent or warrant that any level of steam purity depicted will be achieved by any particular boiler or boilers.
Basic Laboratory Study Guide
Preface:
The Laboratory Study Guide is an important resource for preparing for the certification exam and is arranged by chapters and sections. Each section consists of key knowledges with important informational concepts you need to know for the certification exam. This study guide also serves as a wastewater treatment plant operations primer that can be used as a reference on the subject. In preparing for the exams:
- Study the material! Read every key knowledge until the concept is fully understood and knownto memory.
- Learn with others! Take classes in this type of wastewater operations to improve your understanding and knowledge of the subject.
- Learn even more! For an even greater understanding and knowledge of the subjects, read and review the references listed at the end of the study guide.
Basic Laboratory Study Guide
Preface:
The Laboratory Study Guide is an important resource for preparing for the certification exam and is arranged by chapters and sections. Each section consists of key knowledges with important informational concepts you need to know for the certification exam. This study guide also serves as a wastewater treatment plant operations primer that can be used as a reference on the subject. In preparing for the exams:
- Study the material! Read every key knowledge until the concept is fully understood and knownto memory.
- Learn with others! Take classes in this type of wastewater operations to improve your understanding and knowledge of the subject.
- Learn even more! For an even greater understanding and knowledge of the subjects, read and review the references listed at the end of the study guide.