DNA can Identify Individuals

I have asked this question in the biology stackexchange. Below the law part:

I know that there are some efforts from scientists working with bladder cancer to perform liquid biopsy from urine for detection and monitoring of the cancer such as this one. I've been searching online - but the "wastewater" search term gives me tons of hits about "microbiome" and several types of pathogens. However, I am really interested in sequencing the sewage to find and analyze human DNA. I have been wondering about liquid biopsies to get an estimate of the cancer status of a population.

I can immediately think of several problems:

Laws and Ethics

  1. Is it legal in the US or European Union?
    • It could be difficult to get informed consent of all people who are connected to a certain sewage system. You may get informed consent from all residents but what about visitors?
    • It could be difficult to opt out of such study the wastewater without a) moving to a different place b) using a septic tank.
    • I only found this elaborating other privacy issues: its just about Cov-19 and drug testing; both of which are not able to identify individuals at a genomic level.

An additional question:

  1. Could a sewage provider offer service to people only if they consent that their DNA present in the sewage will be monitored? Such as airline and other companies will only offer their service to people who consent to their terms of service.

The biologists have referred me to the law stack exchange for the first part of the question.

  1. Given the laws in a) US or b) EU would I even be required to get informed consent?

I am NOT looking for answers regarding drug testing or microbiome data!

Thanks for sharing your references and expertise with me.

  • 3
    My first thought is that the bodily fluids have been abandoned so consent may not be an issue, especially as the is no way (that I know of) to link random sewer deposits with an identifiable person without having their DNA on file in the first place. But the Human Tissue Act 2004 may be relevant
    – user35069
    Commented Jul 1, 2021 at 11:46
  • 1
    @RockApe OK neither English nor "law jargon" are my first languages... Given the HTA and the DNA section here is it legal?
    – ilam engl
    Commented Jul 1, 2021 at 12:09
  • The s45 cross-reference to Schedule 4 is a prime example of "law jargon" and will take time (that I don't have at the moment) to decipher.
    – user35069
    Commented Jul 1, 2021 at 12:19
  • I'm not sure it's technically possible to sequence an individual from a collection of cells from hundreds/thousands of people.
    – Dale M
    Commented Jul 1, 2021 at 12:29
  • 1
    @DaleM see last answer to the orignial question in the biology stack exchange
    – ilam engl
    Commented Jul 1, 2021 at 12:44

1 Answer 1


I assume US as the jurisdiction, and don't purport to have checked all 50 states for laws deviating from federal law. The question is not clear as to what exactly is being done (something that has a reasonable relation to "consent"), so to be concrete, I assume the proposal is to take samples from waste water and analyze cells for the presence of a specific genetic property. I also adopt the convenient fiction that from that cell, one can extract information that allows an absolute match between the sample and an individual (or set of individuals in the case of identical twins), if you have a sample from the individual.

Consent would be required to draw a blood sample or take a saliva or skin sample from the individual. Otherwise, collecting the sample is assault. No consent is required to pick up a cup that a person has used and discarded (it would be assault to grab the cup from them). "Informed" consent is special kind of consent applicable to medical care, and reduces to the requirement that the medical care provider explain the risks and benefits, so that the individual will agree to undertake some action (let them cut into you, prod you, give you drugs). None of those considerations exists in the proposed experiment.

HIPAA imposes a requirement of maintaining privacy w.r.t. health information, mainly via the Privacy Rule. A clear application of the rule is that if a patient is diagnosed with cancer, the health care provider cannot publicly disclose the patient's name and diagnosis. If the record is anonymized, the diagnosis can be disclosed. (The full information can also be "shared" between parties with a statutorily-defined interest in the record, e.g. the insurance company). An important limit on HIPAA is that it does not apply to everybody, it only applies to "covered entities", and is limited to healthcare providers, healthcare clearinghouses, and health plans. Genetic researchers are not healthcare providers, so they are not covered entities, so they are not subject to HIPAA.

There is also what is known as "The Common Rule", which is a restriction on what you can do in research if you receive federal funds. Let us assume that the research is federally funded. §46.102 defines a "human subject" in subsection (e), which is very long. The core of the definition is that the researcher

(i) Obtains information or biospecimens through intervention or interaction with the individual, and uses, studies, or analyzes the information or biospecimens; or

(ii) Obtains, uses, studies, analyzes, or generates identifiable private information or identifiable biospecimens

(i) is not applicable: the question is whether the cell is "identifiable private information or identifiable biospecimens"

We move on down the definition to learn that

Identifiable private information is private information for which the identity of the subject is or may readily be ascertained by the investigator or associated with the information.

and that

An identifiable biospecimen is a biospecimen for which the identity of the subject is or may readily be ascertained by the investigator or associated with the biospecimen.

An individual is not, in the general case, readily identifiable from their DNA, even if theoretically you could identify an individual by taking DNA samples from everybody and matching to the water sample. This research is not human subjects research, so the rule is irrelevant.

The regulation doesn't say what "readily identifiable" means, so of course technol9ogy or circumstances could change and this planned research could become human subject's research. In the universe in which that happens, it simply complicates the process. Then the researcher must submit the proposal to their IRB, which will check that the protocol protects the anonymity of the "subject". That would probably preclude publishing the specific information plus the full whole genome sequence. Here, we would have to engage in wild speculation as to how having an anonymous DNA sample makes identification "readily available".

Of course if Congress rewrites the law to include "imaginably identifiable", that changes everything.

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