Risk Management For Laboratories
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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.
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.
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.
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