Researchers discovered that chemicals used in car tire manufacturing are showing up in fish and shellfish from coastal waters in China. These chemicals, called PPDs and their breakdown products (PPDQs), come from tire wear and industrial pollution. Scientists tested seafood and found these contaminants at varying levels. The good news is that eating seafood with these chemicals at current levels doesn’t appear to cause immediate health problems for teenagers and adults. However, scientists say we should keep watching this issue because these chemicals could potentially cause problems over time, and we need to better understand the long-term effects of eating contaminated seafood.

The Quick Take

  • What they studied: Whether chemicals used in tire manufacturing (called PPDs) and their breakdown products are found in seafood, where they come from, and whether eating them could hurt people’s health.
  • Who participated: Researchers collected fish and shellfish samples from coastal waters near the Pearl River Delta in China. They also calculated how much of these chemicals people might eat based on typical seafood consumption by teenagers and adults.
  • Key finding: Seven different tire chemicals and five related breakdown products were found in all seafood samples tested, with some samples containing much higher levels than others. The most common chemicals were different from what scientists expected to find based on previous studies of polluted water and soil.
  • What it means for you: Based on current levels found in seafood, eating fish and shellfish doesn’t appear to cause immediate health problems. However, scientists recommend continuing to monitor these chemicals because we don’t fully understand their long-term effects, and pollution levels could increase over time.

The Research Details

Scientists collected fish and shellfish samples from coastal areas and tested them in laboratories to measure how much of seven different tire chemicals and five related breakdown products were present. They used advanced testing methods to identify and measure these chemicals at very small levels (measured in picograms, which are trillionths of a gram). The researchers also used statistical models to figure out where these chemicals were coming from—whether from tire wear on roads, industrial factories, or household waste. Finally, they calculated how much of these chemicals people might eat based on typical seafood consumption patterns and compared those amounts to safety standards.

This research approach is important because it’s one of the first times scientists have specifically looked for these tire chemicals in seafood. Previous studies focused on finding them in water and soil, but not in the animals people eat. By testing actual seafood and calculating real-world exposure through diet, scientists can better understand whether these chemicals pose a genuine health risk to people who eat seafood regularly.

The study used advanced laboratory testing methods that can detect very small amounts of chemicals, which is good for accuracy. The researchers used multiple statistical models to identify pollution sources, which helps confirm their findings. However, the study only looked at one coastal region in China, so results may not apply to other parts of the world. The study also didn’t test how these chemicals affect human health directly—it only compared exposure levels to existing safety standards.

What the Results Show

All seafood samples contained the tire chemicals being studied. The total amount of the seven PPD chemicals ranged from very low levels to quite high levels (45.65 to 3168.14 picograms per gram of seafood). The breakdown products (PPDQs) ranged from 14.09 to 1491.29 picograms per gram. Interestingly, the most common chemicals found were different from what scientists expected based on previous studies of polluted water. One specific chemical called 77PD was the most common PPD found, while IPPDQ was the most common breakdown product. When researchers calculated how much of these chemicals people would eat through seafood consumption, teenagers and adults would take in between 0.03 to 3.31 nanograms per kilogram of body weight per day for the PPD chemicals, and 0.01 to 1.56 nanograms per kilogram per day for the breakdown products. These amounts were below the safety thresholds established by health organizations.

The research identified that industrial facilities and household waste were the main sources of these chemicals in the marine environment, rather than just tire wear on roads. Different types of seafood had different patterns of chemical contamination, suggesting that different species accumulate these chemicals in different ways. The breakdown products (PPDQs) were found at lower levels than the original chemicals, indicating that these chemicals may break down over time in the marine environment.

This is one of the first studies to specifically measure these tire chemicals in seafood. Previous research found these chemicals in water, soil, and air, but scientists hadn’t thoroughly studied whether they end up in the fish and shellfish that people eat. The chemical patterns found in seafood were different from patterns found in water and soil samples, suggesting that marine animals may selectively accumulate certain types of these chemicals. This finding is important because it shows that studying pollution in water alone doesn’t tell the whole story about what people actually eat.

The study only looked at seafood from one coastal region in China, so the results may not apply to other parts of the world or to different types of seafood from other areas. The researchers didn’t directly test how these chemicals affect human health—they only compared exposure levels to existing safety standards, which may not account for long-term or combined effects. The study also didn’t measure how these chemical levels might change over time or whether pollution is getting worse. Additionally, the sample size and specific number of seafood samples tested were not clearly reported in the abstract.

The Bottom Line

Based on current evidence, there is no need to avoid eating seafood from this region based on these tire chemicals alone. However, it’s reasonable to eat a varied diet that includes different types of seafood and other protein sources. Health organizations should continue monitoring these chemicals in seafood to catch any increases in pollution levels early. Confidence level: Moderate—the current exposure levels appear safe, but long-term effects are not fully understood.

People who eat large amounts of seafood regularly, especially from coastal areas, should be aware of this research. Families with teenagers and young adults should know about this issue. People living near industrial areas or busy roads where tire wear is high should pay attention to future research. This research is less relevant for people who rarely eat seafood or who live far from coastal areas.

If these chemicals do cause health problems, they would likely develop over many years of exposure, not immediately. Scientists estimate it could take 10-20 years or more of regular exposure before any long-term health effects might appear. However, current exposure levels suggest this is not an immediate concern for most people.

Want to Apply This Research?

  • Track weekly seafood consumption by type (fish, shrimp, clams, etc.) and source (local, imported, farmed, wild-caught) to monitor personal exposure patterns and identify which types of seafood you eat most frequently.
  • Use the app to set a goal of eating varied seafood sources and types throughout the week, rather than relying on one or two types of seafood. This reduces potential exposure to any single contamination source and provides broader nutritional benefits.
  • Set up monthly reminders to review your seafood consumption patterns. If you live in a coastal area, check the app for any updated research or health advisories about local seafood safety. Track any health changes or concerns and discuss them with your doctor if you have questions about your seafood consumption.

This research suggests that current levels of tire-related chemicals in seafood from this coastal region do not pose immediate health risks based on established safety standards. However, this study was conducted in one specific region and may not apply to all areas. Long-term health effects of these chemicals are not fully understood. If you have concerns about seafood safety or your personal health, consult with your healthcare provider or local health department. This information is for educational purposes and should not replace professional medical advice. Pregnant women, nursing mothers, and young children should consult their healthcare provider about seafood consumption choices.