How are we contaminating our own drinking water?

BY NORA AND MAILAN
SCIENCE PROJECT, WEEK 11-14

The theme we chose was agriculture and nursery.  Even though we have agriculture and nursery we decided to focus more on the nursery. We have two big nurseries’ here at Nesodden, with the biggest one being Schrader nursery. Schrader nursery is one of the biggest in Norway and nursery and they supposedly sell great flowers with low environmental footprint. The other nursery we chose is called Strand nursery.

We started off by creating 9 questions to ask both nurseries. We wanted to ask both nurseries the same questions so we could see the difference.

1. Where do you access the water you use? And do you often have any challenges when it comes to accessing water?
2. Do you have any alternatives to watering when it´s drying in the summer?
3. How much water do you use approximately during a day?
4. Do you have any water treatment plants?
5. Do you use pesticides in your plants?
6. How does fertilization, spraying and other agricultural activities affect groundwater, freshwater and the fjord?
7. What do you think is going to help to contaminate groundwater, freshwater, and our fjord?
8. If so, what are you doing to prevent this?

So, when we called Strand nursery, they were not into answering our questions, so they gave us very minimal answers. We tried to ask them to elaborate themselves but on a lot of the questions their answer was “I don’t want to comment on that”. Since they gave us so minimal answers, we decided to focus more on Schrader, the bigger company. It might have been that Strand had a very busy day the day that we called, but I don’t think nurseries are that busy in these corona-times. During the lack of information, we decided not to put the answers in our article.

QUESTION AND ANSWERS FROM SCHRADER NURSERY

1. Where do you access the water you use?

We collect rainwater from the roofs of the greenhouses. The rainwater is collected into three ponds. Inside the greenhouses we have many large pools that collect irrigation water for reuse and to prevent runoff to the environment.

2. Do you often have any challenges when it comes to accessing water?

It’s rare. In extreme summer of drought, we need to use some water from a borehole, but since there’s a little too much lime in it, we need to adjust it to get the right PH-value.

3. Do you have alternatives to watering when there is a drought in the summer?

The water we collect doesn’t run out fast. Even a small downpour provides a lot of water. 10 mm of rain of 20,000 sqm provides a lot of water. So, it’s rare we need extra water.

4. How much water do you use approximately in a day?

I don’t know that number by heart, but it varies a lot from day to day depending on photosynthesis, solar radiation, temperature, humidity, etc. With a lot of sunlight, there is a high photosynthesis with increased use of co2 and water.

5. Do you have any treatment plant for your water?

Yes, the water we collected and store in the pool under the greenhouses goes through a sand filter before it is reused.

6. Do you use pesticide in your plants?

Essentially, we use utility animals to fight pests. There are organisms we buy on mail order that live off the pests that can get on the plants. Here you can see some of the useful animals we use: http://www.biobestgroup.com/en/biobest/products/biological-pest-control-4463/#productGroup_4479

If the utility animals do not help, then we may need to spray with approved pesticides. To control the growth of plants, some plants are treated with something called straw shortens. It is also used on, for example, corn fields so that the grain does not become too high and crack in wind and rain.

7. How does fertilizing, spraying and other activities in agriculture affect groundwater, fresh water and the fjord?

We grow flowers in a closed environment with the recycling of irrigation water, so there are little emissions from our business. When you say agriculture, it’s a proven term. The vast majority of productions in Norway use little pesticides, because we have a cold climate there are fewer pests than in warmer countries. Runoff from fertilization of fields, both organic and conventional fertilizer provides a runoff of phosphorus and nitrogen that are nutrients in the fertilizer. Especially with heavy rainfall.

8. Do you think what you’re doing could help pollute groundwater, fresh water and our fjord?

The supply of too much nitrogen and phosphorus, both from agriculture and sewage (sewage from houses, runoff from horse dung, manhole dung and fertilizer on the fields provides the same pollution of nitrogen and phosphorus). Flower production companies release very little irrigation water as we collect the irrigation water in pools and reuse it until it is empty, so that the plants take up all the nutrients in the water.

9. If so, do you do anything to prevent this?

We collect almost all irrigation water; the plants take in about 30% of the water when we water. The rest we collect reuse.

Those who are producing in the fields, such as grains and vegetables, have their own methods for reducing runoff to waterways and water. That can variate between not to plow the field, plant fang crops, plant a belt of vegetation along streams that suck up the nutrients before they enter the water, etc. All farms are required to have a plan for how they handle runoff. What it may be good to be aware of is that vegetables use nitrogen/nitrate to grow so that, for example, a salad leaf contains a lot of nitrate. It is not a poison for us humans, but if there is a lot of it in streams and in the fjord then it can provide algae growth that uses up the oxygen in the water and causes damage to aquatic organisms.

CONCLUSION

The conclusion is that both horticultures take measures to avoid contamination of groundwater, and the fjord.  Schrader collects all the irrigation water and uses the water the plants do not take in for recycling. This also makes Strand horticulture, and they have done so for the past 25 years. So, both horticultures do a lot to try their best not to pollute, but the little thing that still pollutes is not easy to avoid. One of the big differences between the two nurseries was that Schrader were much more open about how they treat their water which made it more fun to learn about it.

Schrader nursery

Strand nursery