Urban gardening and community gardens have taken root in Tallinn, but hobby gardeners are often concerned about pollution caused by traffic. Piret Vacht, associate professor of environmental management at Tallinn University's School of Natural Sciences and Health, set out with her colleagues to determine whether food grown near busy thoroughfares is safe to eat.

"The Tallinn Environment and Public Utilities Department has been keeping an eye on this for years to ensure we can confidently promote community gardening," Vacht explained on the radio program Huvitaja. The study included six gardens, two of which were educational gardens at kindergartens. The research team collected both soil and plant samples, analyzing both washed and unwashed produce.

Boxes help manage risks

The researchers focused primarily on heavy metals in the study. Heavy metals are trace elements that accumulate in soil from various sources of pollution and can pose health risks over time if allowed to build up. However, the analysis brought good news. "The results for heavy metals in the soil were actually quite good," Piret Vacht confirmed. Slightly elevated levels were found in only a few samples.

One of the main reasons for these positive results lies in changing gardening practices. Most community gardens have moved to using raised beds. "Since many have switched to garden boxes, the issue of historical soil contamination is not particularly relevant in community gardens," Vacht said.

The soil used in urban gardens has also raised concerns, but according to the researcher, these fears are unfounded. "It's made from cemetery and landscaping waste. It's tested periodically and the levels are completely acceptable. Most community gardens use this soil," the associate professor added. No abnormal concentrations of heavy metals were found in it.

Air pollution inescapable

Although the soil is clean, urban gardeners still need to take air pollution into account. Cities have many sources of pollution. In addition to vehicle emissions, one must now also consider things like tire particles and dust from road surfaces. "In most cases, everything is just fine. But the effects of air pollution are noticeable — it's highly recommended to thoroughly rinse plants before eating them," said Piret Vacht.

Longer-growing crops are particularly susceptible. "Certain individual plants, like mint, for example, absorbed significantly more pollutants than other herbs or vegetables," Vacht noted.

Fruit can also pose a problem. In some areas, such as Lasnamäe, researchers observed that fruits in particular tend to collect more surface pollution. But the solution is simple.

"We haven't studied all of Tallinn's apples, but we did take samples primarily from Lasnamäe, from the Vormsi green space, which includes a food forest. There it was very clear that the air pollution load was quite high. But once the fruit was washed, all levels were completely normal," Vacht added. The same washing rule should always be followed for lettuce, herbs and tea plants grown in the city center.

What to plant and where?

Although the food is safe, it's worth being more selective about what to grow in more polluted areas. "Where air pollution is a concern, it's better to grow fewer leafy vegetables and opt instead for crops like carrots, tomatoes and other root vegetables," Piret Vacht advised. In areas where soil contamination is known to be a greater issue, it's wiser to grow fast-maturing leafy greens.

In areas with cleaner air, there's more freedom of choice. "In places where the air is a bit cleaner, you can confidently grow herbs," the associate professor said.

Overall, food grown in the city is comparable to store-bought produce. "Even in agricultural settings, there are always questions — what kinds of pesticides were used or whether the field was located next to a major road. Those risks are just as present in much of what's sold to us in stores," Vacht noted.

--

Follow ERR News on Facebook and X and never miss an update!