Just as there are many Native American groups and tribes, there are many ways in which people across the country recognize, or do not recognize Thanksgiving. For some, Thanksgiving represents a time of thankfulness for one’s good fortunes throughout the year. Some take a more traditional stance and give thanks for the food they are able to eat. But for some Native Americans, Thanksgiving is a time of mourning.

This Thanksgiving will mark the 47th Day of Mourning that is held at Cole’s Hill, Massachusetts. Cole’s Hill overlooks Plymouth Rock where the first of the English Separatists formed the first permanent colony on North American soil.

The leaders of the Day of Mourning explain that some Native Americans choose not to celebrate Thanksgiving as it is a reminder of the arrival of the Pilgrims and other European settlers. The settlers not only brought new diseases to the new world, but also violence that would result in the genocide of millions of Native Americans, the loss of Native lands and the assault on traditional Native values and culture.

Many people seem to have a only vague idea of what Native Americans in this country have been put through. For example, they can give you a rough outline of the Trail of Tears in which Andrew Jackson forced Native peoples from their lands on a forced march that saw the death of many of the Natives.

But if you ask them about boarding schools for Native Americans, the forced sterilization of Native women, the relocation movement that broke families apart and tore them from reservations, many people will have no idea that these things happened. And relatively recently.

Violent acts of colonialism are not some abstract actions that happened hundreds of years ago, they are manifest actions that still occur to this day. Per the Indian Health Service, Native Americans are at a higher risk of alcoholism, diabetes, domestic violence and depression among other ailments. These negative health outcomes have been linked to forced cultural change and other aspects of colonialism (see LaDuke, Winona. “Recovering the Sacred: The Power of Naming and Claiming.”)

One particular act of colonialism is on my mind as this current Thanksgiving approaches, and that is environmental racism.

Environmental racism is discrimination in which a minority group is subjected to environmental dangers such as pollution or hazardous materials by being forced to exist near such materials. The case it brings to mind is the fight against the Dakota Access Pipeline at the Standing Rock Reservation.

The original path of the pipeline would cross the Missouri River North of Bismarck, North Dakota according to Catherine Thorbecke of ABCNews. The Bismarck Tribune reports that “one reason that route was rejected was its potential threat to Bismarck’s water supply, documents show.” The pipeline was then moved south of Bismarck and upstream from the Standing Rock Reservation.

My question is, why is the pipeline too dangerous for the people of Bismarck, but not too dangerous for the Native population at the Standing Rock Reservation? It may be a conversation worth having over your Thanksgiving dinner.