What Level of Effect Is a No Observed Effect?
نویسندگان
چکیده
The no observed effect concentration (NOEC) is currently a major summary statistic in ecotoxicity testing. Its use is heavily criticized, partly because it is a poor estimator of ‘‘safe’’ chemical concentrations. In this short communication, we review the limited information available on the percentage effect that corresponds with the NOEC, a value designated the ECNOEC, and calculate ECNOEC values for fish growth data. The average ECNOEC for different test protocols was found to vary widely, with values for chronic studies ranging from 10 to 34%. Individual results varied even more widely. This analysis suggests that the NOEC is neither a consistent summary statistic nor an indicator of safe concentrations of toxic chemicals. Keywords—No observed effect concentration Median effective concentration Median lethal concentration Risk assessment
منابع مشابه
Perserviced Service Quality in Razi University and its Effect on Student Satisfaction
Student satisfaction is one of the concerns of the higher education system in the country which has been less studied. This article is based on research that identifies and prioritizes the variables that affect studentschr('39') satisfaction. Data were collected and analyzed using a researcher-made questionnaire with a sample size of 409 members of 11 faculties of Razi University.The study incl...
متن کاملThe Effect of Iranian EFL Learners’ Attitude towards English Language Learning on Their Autonomy
In the process of English learning, each learner has his/her own attitude towards learning. In this path, s/he should feel free to be responsible for what s/he wants and seeks to learn which shows how autonomous the learner is. This study is based on the hypotheses that there is a relationship between what the learner feels towards English language learning and his/her level of autonomy. For th...
متن کاملOn the effectiveness of integrated skills approach in language teaching: a meta-analysis
This meta-analysis was conducted to synthesize the effect of 22 primary studies which have been conducted to test the effect of the integrated skills approach (ISA) on language skills and components. Three questions guide this analyses: What is the overall effect of ISA on language skills and sub-skills? To what extent moderator variables such as learners level of education and proficiency mod...
متن کاملThe Effect of Teaching Consumption of Organic Foods on Nutritional Knowledge and Performance of High School Students
Background & objectives: Today, the world is facing with increase of population and shortage of foods. Organic products are produced without the intervention of any chemicals or artificial methods. In spite of general teaching to increase nutritional knowledge, there still is a deep gap between recommendations and what is seen in nutritional performance, so choosing the right teaching methods i...
متن کاملتاثیر عصارهی الکلی زیرهی سبز بر میزان هورمون تستوسترون و اثرات ضد باروری آن در موشهای صحرایی نر بالغ نژاد ویستار
Background and Objectives: One of the complications arising from the consumption of Cuminum Cyminum is reproductive system disorders in humans and animals. Since there has been no comprehensive research on the effect of this herbal medicine on spermatogenesis and production of testosterone in males, the present study was carried out with the aim of determining the effect of Cuminum Cyminum alco...
متن کاملActivation-Induced Apoptosis in T cells: Effect of Age and Caloric Restriction
We have previously shown that the proliferative response of T cells to antigenic or mitogenic stimulus decreased with age and that caloric resection (CR) attenuated the age-related decline in proliferation and IL-2 expression. Because activation-induced apoptosis is known to regulate cell proliferation and eliminate the high number of activated cells during an immune response, it was of interes...
متن کامل