Decades of Toxic Dumping off Our Coast

By Christian Paullin, Environmental Reporter

If you have ever visited the coastline on the Palos Verdes Peninsula, San Pedro, or Long Beach, you have likely come across a warning sign deterring anyone from catching and eating White Croaker, Barred Sea Bass, Black Croaker, Topsmelt, Barracuda, and shellfish. These signs stand to protect you from the danger of eating toxic fish—a reminder of an environmental disaster that has continued since the 1940s, right in your own front yard. 

The illegal (and legal) dumping of Dichlorodiphenyltrichloroethane (DDT) off the Palos Verdes Peninsula has been the source of recent national news. So what happened, and how can we work to contain a massive environmental disaster, decades in the making? Read on to discover what these deadly chemicals are and how we can protect our coastlines from further harm. 

DDT has long been used as a pesticide globally. It was initially used by the military in World War II to kill mosquitoes and fleas, to control diseases such as malaria, typhus, and bubonic plague; however, it would later used for commercial farming throughout the world in the 1950s to 1980s. It is relatively inexpensive to produce, and does not break down easily. The fact that it did not require constant reapplication made it popular with farmers. Ironically, this same feature makes this chemical so harmful to our environment (3).

For nearly 30 years, the Montrose Chemical Company, located in Torrance, legally dumped DDT via sewer systems that led topipes off White Point (1). There was no explicit law at the time restricting the company from pouring chemicals straight into the sewer system (2).  The former site of Montrose Chemical is now the Montrose Chemical Superfund site.  Brown pelicans nearly became extinct, and other fish-eating birds like bald eagles also became scarce.   Fortunately, Montrose Chemical was forbidden to dump DDT in the sewer in 1971.  The area along the Palos Verdes Peninsula, extending out to about 1.5 miles, is now the Palos Verdes Shelf Superfund Site.  The amount of DDT in ocean sediments near San Pedro has decreased, and brown pelicans have recovered. But this was only a small fraction of the amount Montrose was truly dumping into our local waters.

For decades there were rumors of additional large scale illegal barrel dump sites which were finally confirmed by UCSB researcher, David Valentine. Valentine was studying methane seepage, rather than chemical dumps in waters between Catalina and Palos Verdes. In 2011, he decided to investigate the rumors of the barrels using his sonar equipped deep-water robot. He quickly found many unknown waste barrels in a small area. Further testing would later show the barrels contained DDT. A group of scientists, led by NOAA-Scripps Institute of Oceanography, began mapping the underwater dump site first located by Valentine and exposed a massive dump site in a report released in 2020. Their findings were eloquently reported on by Rosanna Xia of the LA Times in October 2020, making headline news across the country.

The dump site was so large that the group had a difficult time finding an end to the site. Everywhere they looked, they would encounter more barrels and the designated site was continually expanded. The group employed data algorithms to estimate the number of barrels because there were too many data points to count (9). 

Initially the reported amount of DDT dumped was around 110 tons (4), however, the newly discovered dump sites led investigative journalists to look into Montrose’s history logs, which showed nearly 2000 barrels of DDT were dumped per month between 1947-1961, amounting to an additional 767 tons of chemicals of our local coasts (5). 

The danger of DDT was first brought into the public eye in the 1960s via Rachel Carson and her book,  Silent Spring, which detailed the effects of pesticides, specifically DDT, on animals. Her research found pesticides to be carcinogenic, promote tumor growth, affect reproductive health of animals, specifically birds, and other harmful consequences on wildlife (7). Consequently DDT directly affects humans as well. Women heavily exposed to DDT during childhood have a 5-fold greater likelihood of developing breast cancer. Pregnant mother’s exposure to DDT is also directly linked to an increased chance of breast cancer for their daughter (8). Beyond those effects, there are likely long-term effects unknown to us. 

Though dropping DDT levels allowed birds to partially recover, some conflicting reports have shown animals such as deceased dolphins washed up on local beaches to have heightened levels of DDT in recent years (5).

As of April of 2021, Sen. Dianne Feinstein and the NOAA-Scripps team worked together to report their findings in a US congressional briefing. Multiple state and federal agencies are following the findings closely. The EPA has initiated a multi-year, clean-up feasibility study to determine if there is a better option than a natural recovery approach, which is the expected course of action. (5).