Summer Pollution Study {One Year Pond Study}

As summer slowly draws to a close, I find myself glancing ahead to the Autumnal Equinox, which falls on Sunday 22nd September this year, and with it, the official start of autumn. Before the seasons shift, I like to pause and take stock of the studies we still want to complete. Looking back through our one year pond study, I realised there were three summer investigations we hadn’t yet finished: a summer night-time pond visit, a summer water study and a summer pollution study.

Find out more! If you’d like to know more about why we decided to do a year long pond study, this is the post for you!

This week (week 24), we focused on our summer pollution study, intentionally replicating the work we carried out in spring so that our observations and results could be easily compared. Seasonal comparisons are one of the most valuable aspects of long-term nature study, and this investigation did not disappoint.

Read about our very own pond ecosystem as well as our examination of the pond water

Pond pollution is one thing that would affect the number and variety of plants and trees in our UK pond. Read about it here and see what we found.

Observing Seasonal Changes in the Pond

The very first thing the children noticed was just how much the water level had dropped since spring.

In our spring visit, the pond was noticeably full and lively. Returning in late summer, the difference was dramatic. The waterline had dropped by well over a foot, something the children were quick to demonstrate by walking along areas that had previously been submerged.

Even familiar landmarks told the story. The post where we regularly spot a heron now stood high and dry, and when a Canada Goose obligingly wandered over and stood beside the sign, the scale of the water loss became undeniable.

This observation led naturally into a discussion about summer pollution, evaporation, rainfall patterns, and how lower water levels can concentrate pollutants.

I have written a post about Moorhen chicks and have included a follow up to show their growth from eggs to chick to fledgling teen-agers!

Collecting and Comparing Pond Water Samples

To continue mirroring our spring study, the children collected two water samples:

• One from the deeper end of the pond
• One from the muddy, shallow edge

We used simple, labelled jam jars and left the samples to settle for 15 minutes, just as we had done earlier in the year.

Fancy doing some pond art? Read here for our bark rubbings and leave hammering

What We Noticed

In spring, the water samples were surprisingly clear, with visible bubbles and movement. This time, even after settling, both jars were significantly murkier. Spring water is directly below:

This lined up perfectly with what we had already observed at the pond itself. With lower water levels, sediment is disturbed more easily, and pond pollution becomes far more visible.

This was a great opportunity to talk about how pollution isn’t always newly introduced—sometimes it’s simply more concentrated or more noticeable due to environmental changes.

Click here to read about the animals and plants we have found around our pond

Testing Pond pH Levels

We tested the pH of both water samples using universal indicator paper, repeating the same method we used in spring.

• Spring pH: 8
• Summer pH: 8

The pond remained slightly alkaline but well within the range needed to support life.

We discussed why this stability matters. Even small shifts in pH can make a pond uninhabitable for plants and animals, so the fact that our pond continues to support abundant life was reassuring, and fascinating for the children to observe.

We’ve done a whole study on the heron which you can read here!

Summer Pond Pollution: A Visible Increase

During our spring visit, there was very little visible pollution around the pond. In contrast, our summer walk revealed rubbish scattered throughout the area, particularly where falling water levels had exposed the shoreline.

This sparked some thoughtful conversations about:

• Increased human activity during summer
• How rubbish travels and collects as water recedes
• The difference between natural debris and human-made waste

Seeing pond pollution first-hand had a much bigger impact than any textbook discussion could have.

Take a peek at our Ash Tree Study which we began right at the start of our pond study and its extension Ash Tree and Lichen

Summer Pollution Study: Air Quality and Lichen Observations

One of our favourite ongoing observations has been the lichen growing on a nearby ash tree.

While lichen can indicate an unhealthy tree, it is also a powerful sign of good air quality. We first recorded it in spring, and we were pleased to see that it is still thriving now.

This continuity offered a useful contrast: while summer pollution has clearly affected the pond environment, the surrounding air quality remains clean.

Read More! We learnt all about the variety of pond birds in the UK and the summer pond fauna

The Value of Long-Term Nature Study

As we prepare to complete our remaining summer pond studies, a water-focused investigation and a night-time visit, I’m struck by how rewarding this one year pond study has been.

There is something deeply satisfying about returning to the same place week after week, season after season, and noticing both dramatic changes and reassuring constants. It has encouraged patience, attention to detail, and genuine scientific thinking in my children and, if I’m honest, in me too.

Reflection Questions about the Summer Pollution Study

Use these questions to encourage deeper thinking and discussion:

1. What differences did you notice between the pond in spring and summer?
2. Why do you think pollution was easier to see in summer?
3. How might lower water levels affect pond animals and plants?
4. Why is it important that the pond’s pH stayed the same?
5. How does human behaviour change in summer, and how might that affect natural spaces?

Hands-On Activities to Extend the Lesson

• Pond Clean-Up Walk: With gloves and bags, collect rubbish around the pond and sort it into recyclable and non-recyclable items.
• Seasonal Comparison Chart: Create a chart comparing spring and summer observations (water level, clarity, pollution, wildlife).
• Build a Mini Pond Model: Use a tray, soil, water, and small stones to demonstrate how pollution becomes concentrated as water evaporates.
• Nature Journaling: Sketch the pond in summer and label changes compared to earlier seasons.
• Research Project: Look up local water conservation efforts and discuss how communities can reduce summer pollution.