575.619.81 - Principles of Toxicology, Risk Assessment & Management

Environmental Engineering and Science
Fall 2023


Risk assessment and risk management have become central tools in continued efforts to improve public safety and the environment within the limited resources available. This course introduces the basic concepts of environmental risk assessment, relative risk analysis, and risk perception, including identifying and quantifying human health impacts and evaluating ecological risk. The course describes legislative and regulatory initiatives that are attempting to base decisions on risk assessment, along with the controversy that surrounds such approaches. It also addresses specific federal requirements for risk analysis by industry. The course discusses the realities of using risk assessments in risk management decisions, including the need to balance costs and benefits of risk reduction, issues of environmental equity, accounting for the uncertainties in risk estimates, effective risk communication, and acceptable risk.


Profile photo of Michael Dellarco.

Michael Dellarco


Course Structure

The course content is divided into modules. Each module addresses a particular aspect of the risk assessment in an aggregating fashion such that by the end of the course the student is expected to be able to evaluate components of a risk assessment and to construct a risk assessment for various kinds of environmental problems. Course Modules can be accessed by clicking Course Content on the left of the course menu. A module will have several sections including the overview, content, readings, discussions, and assignments. Students are encouraged to preview all sections of the module before starting. Most modules run for a period of seven (7) days, exceptions are noted on the Course Outline page. Students should regularly check the Calendar and Announcements for assignment due dates.

Course Topics

Course Goals

The goal of this course is to identify and describe the characteristics of a risk assessment and to understand the role of the risk assessment and risk management process in environmental decision-making.


Course Learning Outcomes (CLOs)


Not required

Other Materials & Online Resources

Instruction will be based on required readings, discussions, and assignments.  Suggested resources and readings will be provided as a means to provide additional background information or to provide more detail about particular topics that may be less familiar to the student. Discussions and assignments are used to describe the subject matter, illustrate concepts, and engage the student in the decision-making process.

Student Coursework Requirements

It is expected that each class will take approximately 6-9 hours per week to complete. Generally assigned reading will take 3-4 hours per week, listening to the audio annotated slide presentations and viewing web sites will take approximately 1–2 hours per week, and completing homework assignments will take approximately 2–3 hours per week. This course will consist of three basic student requirements:

  1. Preparation and Participation (Discussion) (20% of Final Grade Calculation)

Each student is responsible for carefully reading all assigned material and being prepared for discussion. Additional readings may be assigned to supplement discussions. 

Post your initial response to the discussion questions by 12:00 am eastern time of day 3 for that module week. Posting a response to the discussion question is part one of your grade for class participation (i.e., Timeliness).

Part two of your grade for class participation is your interaction (i.e., responding to classmate postings with thoughtful responses) with at least two classmates (i.e., Critical Thinking). Just posting your response to a discussion question is not sufficient; we want you to interact with your classmates. Be detailed in your postings and in your responses to your classmates' postings.  Feel free to agree or disagree with your classmates and cite evidence to support your position to make this a constructive class experience. Please ensure that your postings are civil and constructive.

The instructor will monitor class discussions and will respond to some of the discussions as discussions are posted. In some instances, the instructor will highlight key points of the discussions or summarize the overall discussions and post a summary for the class.

Evaluation of preparation and participation is based on contribution to discussions.

Preparation and participation are evaluated by the following grading elements:

Timeliness (50%)
Critical Thinking (50%) 

Preparation and participation are graded as follows:

100–90 = A—Timeliness [regularly participates; all required postings; early in the discussion; throughout the discussion]; Critical Thinking [rich in content; full of thoughts, insight, and analysis and supported by evidence].

89–80 = B—Timeliness [frequently participates; all required postings; some not in time for others to read and respond]; Critical Thinking [substantial information; thought, insight, and analysis has taken place]. 

79–70 = C—Timeliness [infrequently participates; all required postings; most at the last minute without allowing for response time]; Critical Thinking [generally competent; information is thin and commonplace].

69-63 = D—Timeliness [infrequently participates; some required postings missing; most at the last minute without allowing for response time]; Critical Thinking [rudimentary; information is thin and commonplace]

  1. Assignments (30% of Final Grade Calculation)

Assignments will include a mix of qualitative assignments (e.g. readings, literature reviews, critiques, evaluations and case study analysis). Include a cover sheet with your name and assignment identifier. Also include your name and a page number indicator (i.e., page x of y) on each page of your submissions. Each assignment should have the problem statement, assumptions, computations, and conclusions/discussion delineated in a professional manner. All Figures and Tables should be captioned and labeled appropriately. Completeness and neatness counts. 

All assignments are due according to the dates in the Calendar. 

Late submissions will be reduced by one letter grade for each week late (no exceptions without prior consultation and written acceptance by the instructor).

Qualitative assignments are evaluated by the following grading elements:

Each part of the question is answered (20%)

Writing quality and technical accuracy (30%) (Writing is expected to meet or exceed accepted graduate-level English and scholarship standards. That is, all assignments will be graded on grammar and style as well as content.)

Rationale for answer is provided (20%)

Examples are included to illustrate rationale (15%) (If a student does not have direct experience related to a particular question, then the student is to provide analogies versus examples.)

Outside references are included (15%)

Qualitative assignments are graded as follows:

100–90 = A—All parts of the question are addressed; Writing Quality/ Rationale/ Examples/ Outside References [rich in content; full of thought, insight, and analysis].

89–80 = B—All parts of the question are addressed; Writing Quality/ Rationale/ Examples/ Outside References [substantial information; thought, insight, and analysis has taken place].

79–70 = C—Majority of the parts of the question are addressed; Writing Quality/ Rationale/ Examples/ Outside References [generally competent; information is thin and commonplace].

69-63 = D—Some parts of the question are addressed; Writing Quality/ Rationale/ Examples/ Outside References [rudimentary and superficial; little analysis or insight displayed].

  1. Final Project (50% of Final Grade Calculation)

A final project will be assigned in Module 10. The project is designed to test the concepts and procedures taught in the previous modules and the ability of the student to make decisions to develop and assess the significance of their risk assessment. Each student must work independently to design and develop a complete risk assessment using the background information provided and other technical resources available.

The term paper is evaluated by the following grading elements:

Student preparation and presentation of the selected topic in a concise and cogent manner – more is not necessarily better and suggested length is 8 -20 pages (40%)

Student technical understanding of the selected topic in the context of the course material (40%)

Student assessment of the topic including a summary or conclusion where appropriate (20%)

The Final Project is graded as follows:

100–90 = A—Student preparation and presentation of the material is well defined and clearly stated [rich in content, full of thought, insight, and analysis exhibited].

89–80 = B—Student preparation and presentation of the material is well defined and clearly stated [substantial information, thought, insight, and analysis exhibited].

79–70 = C— Student preparation and presentation of the material is well defined and clearly stated [generally competent but information is thin and commonplace, and analysis is limited] 

69-63 = D— Student preparation and presentation of the material is not well defined or clearly stated [rudimentary and superficial treatment with little analysis or insight displayed].


Grading Policy

Student assignments are due according to the dates in the Calendar and Assignments items in the corresponding modules. Generally, grades will be posted one week after assignments due dates. 

Format, organization and content must be correct and professional. Egregious violations of the rules of the English language will be noted without comment. Consistently poor performance in spelling or grammar is taken as an indication of poor written communication ability that may detract from a student’s grade.

A grade of A indicates achievement of consistent excellence and distinction throughout the course—that is, conspicuous excellence in all aspects of assignments and discussion in every week.

A grade of B indicates work that meets all course requirements on a level appropriate for graduate academic work. These criteria apply to both undergraduates and graduate students taking the course.

100–98 = A+

97–94 = A

93–90 = A−

89–87 = B+

86–83 = B

82–80 = B−

79–77 = C+

76-73 = C

72-70 = C-

69–67 = D+

66-63 = D

<63 = F

Final grades will be determined by the following weighting:


% of Grade

Preparation and Participation (Class Discussions)




Final Project


Course Policies

Students are encouraged to contract the instructor with any questions about any relevant topic, but especially when encountering difficulty with one or more topics covered in the course or meeting the course schedule.

Academic Policies

Deadlines for Adding, Dropping and Withdrawing from Courses

Students may add a course up to one week after the start of the term for that particular course. Students may drop courses according to the drop deadlines outlined in the EP academic calendar (https://ep.jhu.edu/student-services/academic-calendar/). Between the 6th week of the class and prior to the final withdrawal deadline, a student may withdraw from a course with a W on their academic record. A record of the course will remain on the academic record with a W appearing in the grade column to indicate that the student registered and withdrew from the course.

Academic Misconduct Policy

All students are required to read, know, and comply with the Johns Hopkins University Krieger School of Arts and Sciences (KSAS) / Whiting School of Engineering (WSE) Procedures for Handling Allegations of Misconduct by Full-Time and Part-Time Graduate Students.

This policy prohibits academic misconduct, including but not limited to the following: cheating or facilitating cheating; plagiarism; reuse of assignments; unauthorized collaboration; alteration of graded assignments; and unfair competition. Course materials (old assignments, texts, or examinations, etc.) should not be shared unless authorized by the course instructor. Any questions related to this policy should be directed to EP’s academic integrity officer at ep-academic-integrity@jhu.edu.

Students with Disabilities - Accommodations and Accessibility

Johns Hopkins University values diversity and inclusion. We are committed to providing welcoming, equitable, and accessible educational experiences for all students. Students with disabilities (including those with psychological conditions, medical conditions and temporary disabilities) can request accommodations for this course by providing an Accommodation Letter issued by Student Disability Services (SDS). Please request accommodations for this course as early as possible to provide time for effective communication and arrangements.

For further information or to start the process of requesting accommodations, please contact Student Disability Services at Engineering for Professionals, ep-disability-svcs@jhu.edu.

Student Conduct Code

The fundamental purpose of the JHU regulation of student conduct is to promote and to protect the health, safety, welfare, property, and rights of all members of the University community as well as to promote the orderly operation of the University and to safeguard its property and facilities. As members of the University community, students accept certain responsibilities which support the educational mission and create an environment in which all students are afforded the same opportunity to succeed academically. 

For a full description of the code please visit the following website: https://studentaffairs.jhu.edu/policies-guidelines/student-code/

Classroom Climate

JHU is committed to creating a classroom environment that values the diversity of experiences and perspectives that all students bring. Everyone has the right to be treated with dignity and respect. Fostering an inclusive climate is important. Research and experience show that students who interact with peers who are different from themselves learn new things and experience tangible educational outcomes. At no time in this learning process should someone be singled out or treated unequally on the basis of any seen or unseen part of their identity. 
If you have concerns in this course about harassment, discrimination, or any unequal treatment, or if you seek accommodations or resources, please reach out to the course instructor directly. Reporting will never impact your course grade. You may also share concerns with your program chair, the Assistant Dean for Diversity and Inclusion, or the Office of Institutional Equity. In handling reports, people will protect your privacy as much as possible, but faculty and staff are required to officially report information for some cases (e.g. sexual harassment).

Course Auditing

When a student enrolls in an EP course with “audit” status, the student must reach an understanding with the instructor as to what is required to earn the “audit.” If the student does not meet those expectations, the instructor must notify the EP Registration Team [EP-Registration@exchange.johnshopkins.edu] in order for the student to be retroactively dropped or withdrawn from the course (depending on when the "audit" was requested and in accordance with EP registration deadlines). All lecture content will remain accessible to auditing students, but access to all other course material is left to the discretion of the instructor.