Racism as a public health crisis: how wastewater epidemiology fits in

10 minute read


Today is the Strike for Black Lives and a day to #ShutDownSTEM. For white people like me, today is about recognizing and reflecting on the anti-Black racism in our society, and committing to specific actions toward ending white supremacy. One of my actions for today is to publicly reflect on how our work at Biobot Analytics contributes to addressing – and potentially perpetuating – racism in public health.

I’ll be going through this excellent Washington Post opinion piece by Dr. Michelle Williams (Dean of the faculty at the Harvard School of Public Health) and Jeffrey Sánchez (former MA State Rep and fellow at HSPH):

Racism is killing black people. It’s sickening them, too.

I read this the other day and saw that wastewater epidemiology has a role to play in essentially every issue brought up in the piece. I’ve been thinking about many of these issues for a while now, but haven’t ever written them down. Hopefully in doing so, I can plant the seed for new ideas or encourage existing ones to grow, sparking conversations within my own company and the broader wastewater epidemiology community.

Social determinants of health (AKA racism)

Across the country, black Americans suffer from higher rates of diabetes, hypertension, asthma and heart disease than white Americans. They are more likely to be obese and get insufficient sleep, which can contribute to such health issues. The role of racism in these underlying conditions cannot be denied.

A growing body of literature shows that social determinants — otherwise known as the conditions in which we’re born and in which we live, work and play — are key drivers of health inequities. For generations, communities of color have faced vast disparities in job opportunities, income and inherited family wealth. They are less likely to have housing security and access to quality schools, healthy food and green spaces. All these factors undoubtedly undermine mental and physical well-being.

One of the most impactful aspects of looking to sewage as a source of health information is that everybody pees. Regardless of access to healthcare, economic opportunity, education level, or anything else – everybody pees. And if you’re like one of the majority of Americans who is connected to sewage infrastructure, then the health information you flush down the toilet is accessible through city sewers. That means that we can use sewage to monitor the health of people who might not have access to healthcare for any variety of reasons, and who therefore aren’t traditionally captured in clinical statistics.

Many crucial social determinants of health are difficult to quantify and therefore study. One of the other things that I find so exciting about wastewater epidemiology is that you could use it to measure these factors and open up new avenues of research and evidence-based policy making. For example, using wastewater to monitor community-level nutritional intake could change the way we identify and study food deserts, and directly quantify the impact of fresh food programs on the local communities who are intended beneficiaries.

Racism-associated stress and its biological consequences

In addition to the consequences of structural racism, it is well-documented that racism itself is hard on a person’s health. Chronic stress caused by discrimination can trigger a cascade of adverse health outcomes, from high blood pressure and heart disease to immunodeficiency and accelerated aging. Evidence even suggests that the racism endured by black mothers contributes to the alarmingly high maternal and infant mortality rate.

As a bioengineer, it’s wild that my training never covered the biological effects of racism-induced stress compounded over a lifetime. There is certainly a large body of research on health issues linked to racism-related stress, but a disproportionate amount of biomedical science is focused on finding genetic markers to explain different rates of disease in sub-populations like racial groups. That had always annoyed me as a scientist uninterested in human genetics, but even more so when I realized that there was this whole other body of research that our field could have been prioritizing instead. And when you zoom in on how these stressors affect health outcomes for Black mothers in this country, the tragedy really crystallizes.

What if we measured biological markers of stress at a community-level through sewage? We could use wastewater epidemiology to show the extent of the biological impact of racism, for example by comparing stress markers in heavily policed communities vs. those with community-led neighborhood watches. Maybe sewage could open up a whole new field of research, directly measuring the biological effects of our racist and unjust society, and paving the way for improvements that rectify and reverse these negative impacts.

Essential workers and unequal access to economic opportunity and public health prevention

Black and brown Americans make up a disproportionate number of essential workers who have stayed on the job through lockdowns, and thus are at higher risk of contracting the disease. And when they do fall ill, they are more likely to receive worse care than white Americans do. That’s true even when controlling for socioeconomic factors such as income and education.

The burden of COVID-19 is not evenly distributed, and neither is the ability to implement preventative measures like staying home from work. That’s resulted in extremely disparate impacts, with Black people and other communities of color bearing a much greater share of COVID-19 deaths than their distribution in the population.

Here again, wastewater epidemiology could provide a quantitative and direct way to measure and monitor these disparities. By moving measurements upstream and into city manholes, we could identify new surges of COVID-19 on a community-by-community basis, mobilize testing centers to the areas where they are most needed, and make sure that even if certain communities aren’t being tested, they are being counted and served.

And it’s not just COVID-19 where this line of reasoning applies: with opioids, we’ve also realized that wastewater monitoring could be leveraged to identify communities who are experiencing high levels of opioid use and even overdoses (determined by measuring Narcan, the overdose reversal treatment) but who aren’t calling first responders and therefore have very low overdose numbers captured in official statistics. Thinking about quantifying these sorts of “treatment gaps” through wastewater could provide public health and city officials with yet another tool to address disparities within their local communities.

Environmental racism

Environmental racism is another topic that I’m baffled was never covered in any of my scientific training. Across the country, low-income communities of color are more likely to have factories and other sources of pollution built near them, further exacerbating health disparities. The disproportionate exposures to pollution faced by low-income communities of color are not passive mistakes, but rather the result of a systemically racist society.

This is another area where I’m excited by the potential of wastewater epidemiology to contribute to how these issues are studied, monitored, and improved. For example, measuring biomarkers of exposures to pollutants could complement associative studies linking toxic exposures to long-term health outcomes in individuals living in or from communities most affected by environmental racism. Imagine if the EPA’s metrics controlling what factories are and aren’t allowed to dump in the water weren’t about how much the factories were dumping, but rather about the direct health effects they were having on nearby populations.

Wastewater epidemiology as a potential tool of oppression

I’m excited about the prospect of sewage-based monitoring as a tool for quantifying health inequities by directly measuring the biological impacts of racist systems on individuals and communities. But I recognize that as with all other emerging technologies, this one is not without risks.

Yes, we could use wastewater epidemiology to shine a brighter light on social determinants of health and establish direct links between socioeconomic conditions and health outcomes. But we could also use wastewater epidemiology to entrench stigma and justify inequitable policies. For example, you could imagine insurance companies using sewage-based indicators as “objective” measures of community health, and varying premiums based on which neighborhood you live in. I could absolutely see an argument being made that such sewage-derived metrics are “objective” measures free from bias and therefore legitimate to act on. But it is clear that such measures would just be thinly veiled proxies for existing inequities.

Yes, wastewater epidemiology could be used to highlight the shockingly high rates of COVID-19 in communities with many low-income, non-white essential workers. And it could be used as an early warning for reemergence of COVID-19 cases on college campuses, thus providing administrators with finer and more responsive control over when to implement control measures. Or it could be used to justify unsafe return-to-campus or return-to-work policies, wherein the absence of COVID-19 in the sewers would justify the “safety” of forcing workers back to work even if they do not feel safe doing so.

And finally, even though sewage-based monitoring has the potential to revolutionize how we monitor the health of the majority of Americans, there’s still a non-negligible portion of the population that is not serviced by sewers. As we advocate for additional federal funding to integrate wastewater-based monitoring into standard public health practice, we must recognize which populations will be excluded. Even in the US, sanitation is not a solved issue. Those without access to sewer systems may also be those with the least access to public health services. Whether our work serves to increase these inequities or decrease them is up to us.

Making change goes beyond sewage

Which brings me to my last point. At the end of the day, wastewater epidemiology isn’t going to solve any of these societal issues. Sewage isn’t going to tell us anything we don’t know: we don’t need wastewater epidemiology to know that racism is bad and that it contributes to health disparities. At its best, wastewater epidemiology will provide additional concrete evidence to motivate change and actionable metrics to quantify improvements. At worst, it will be deployed thoughtlessly and in ways that further entrench existing disparities. It’s up to us, the technology leaders and entrepreneurs working to integrate wastewater epidemiology into standard public health practice, to make sure that doesn’t happen.