Eutrophication & Agricultural Water Quality: SSI Chemistry Package (digistem.ie)

Eutrophication & Agricultural Balance Simulator

Investigate the trade-off between crop yields for Irish farmers and aquatic ecosystem health in local rivers under the EU Nitrates Directive.

Environmental & Farm Controls

Fertilizer Rate ($\text{N}$): 140 kg/ha

Irish Teagasc advisory standard: ~100–170 kg/ha for grassland/crops.

Riparian Buffer Strip Width: 6 meters

Vegetated buffer zones trap nitrate and phosphate runoff before reaching water.

Rainfall Event Severity: 35 mm (Heavy)

Heavy Irish weather increases soil leaching and surface run-off dramatically.

Water Temperature: 17 °C (Summer)

Warmer temperatures accelerate algal growth and lower $O_2$ solubility.

Simulated Output Key Data

River Nitrate Concentration ($\text{NO}_3^-$)

18.4 mg/L

Safe (<50 mg/L)

Dissolved Oxygen ($\text{DO}$)

8.2 mg/L

Healthy Aquatic Life

Farm Economic Profitability

€785 / ha

Ecosystem Visualizer (Konva.js Interactive Render)

Hover elements for real-time data

Eutrophication Profile over Time (30-Day Outlook)

Leaving Cert Practical & SSI Worksheet

Student Inquiry: Balancing Farming & River Health

Name: ______________________

Date: ______________________

1 Pre-Lab Inquiry & Predictions

Q1. Why do crops requires nitrogen fertilizers? What chemical form does nitrogen take when dissolved in water?

Write your answer here...

Q2. Predict what will happen to Dissolved Oxygen ($\text{DO}$) levels 10 days after a heavy summer rainstorm washes fertilizer into a calm river.

Write your answer here...

2 Simulation Data Collection Protocol

Run three test trials in the simulator and log your findings in the table below:

Trial	Fertilizer (kg/ha)	Buffer Strip (m)	Rainfall (mm)	Max Nitrate (mg/L)	Min DO (mg/L)	Farm Profit (€/ha)
1 (Control)	100	10	20	--	--	--
2 (High Intensive)	250	2	50	--	--	--
3 (Mitigated)	160	18	50	--	--	--

3 Winkler Titration Stoichiometry Practice

Problem: A $100.0 \text{ cm}^3$ sample of river water required $14.2 \text{ cm}^3$ of $0.0100 \text{ M}$ Sodium Thiosulfate ($\text{Na}_2\text{S}_2\text{O}_3$) solution to reach the starch-iodine endpoint.

Calculate moles of $\text{S}_2\text{O}_3^{2-}$ added.
Using the $1 : 4$ ratio ($\text{O}_2 : \text{S}_2\text{O}_3^{2-}$), determine the moles of Dissolved Oxygen in $100 \text{ cm}^3$.
Convert this to concentration in $\text{g/L}$ and then $\text{mg/L}$ ($\text{ppm}$). ($M_r \text{ of } O_2 = 32.0 \text{ g/mol}$).

Show your step-by-step working...

4 Socio-Scientific Policy Recommendation

As an environmental advisor to the Minister for Agriculture and Food, draft a 3-point compromise policy that allows Irish farmers to remain economically viable while ensuring rivers comply with the $50 \text{ mg/L}$ nitrate limit and support wild Atlantic salmon populations. Justify your points using evidence from the simulator.

Type or write your policy recommendations here...

SSI Chemistry Learning Suite (digistem.ie)

Eutrophication & Agricultural Balance Simulator

Environmental & Farm Controls

Simulated Output Key Data

Ecosystem Visualizer (Konva.js Interactive Render)

Eutrophication Profile over Time (30-Day Outlook)

Teacher Instruction & Lesson Plan (5E Model)

1 ENGAGE: Local Context & Societal Conflict (15 mins)

2 EXPLORE: Interactive Simulation Inquiry (25 mins)

3 EXPLAIN: Chemical Mechanism & Winkler Titration (30 mins)

4 ELABORATE: Socio-Scientific Stakeholder Debate (30 mins)

5 EVALUATE: Assessment Rubric (15 mins)

Student Inquiry: Balancing Farming & River Health

1 Pre-Lab Inquiry & Predictions

2 Simulation Data Collection Protocol

3 Winkler Titration Stoichiometry Practice

4 Socio-Scientific Policy Recommendation