The diagram below shows nitrogen sources and concentration levels in the groundwater of a coastal city.
Sample Response
The diagram displays where it is obtained from as well as its concentration quantities in the groundwater of a town near the coast. Overall, it is immediately apparent that nitrogenous substances are obtained from several places, including coastal vegetation, waste disposal, domestic market garden and coastal vegetation.
To begin with, nitrogen is sourced from several places. The first one is from waste disposal such as landfills, whiles another source is from industrial activities such as leaks from storage tanks and wastewater ponds. Domestic and market gardens like fertilizers and household liquid waste are also sources of nitrogen, and finally, coastal vegetation is all important sources. So, when it rains, all of this drain down the water table into the groundwater. Also, during rainfall, nitrogen is oxidized by lightening and fixation of nitrogen by vegetation takes place as well.
Moreover, under the water table, all these sources accumulate into the water, eventually flowing in one direction to join the ocean. The different types of waste include nitrate uptake by soil particles, ammonia digesting and identification, all of which flow to join the ocean water at a zone known as the groundwater discharge zone.
IELTS Writing Correction
- 1. Name the subject Original: where it is obtained from Suggested revision: the sources of nitrogen Why it matters: The pronoun has no clear antecedent and nitrogen is shown as entering groundwater from sources.
- 2. Use chart term Original: quantities Suggested revision: levels Why it matters: 'Concentration levels' is the precise term used for the variable shown.
- 3. Use precise subject Original: nitrogenous substances Suggested revision: nitrogen Why it matters: The diagram specifically tracks nitrogen rather than an unspecified group of substances.
- 4. Coordinate source areas Original: domestic market garden Suggested revision: domestic and market gardens Why it matters: The diagram labels domestic and market gardens as a coordinated source area.
- 5. Wrong conjunction Original: whiles Suggested revision: while Why it matters: 'While' is the correct conjunction for contrasting the two sources.
- 6. Fix agreement Original: is all important sources Suggested revision: is also an important source Why it matters: The singular subject requires a singular complement and 'also' is the intended adverb.
- 7. Fix number agreement Original: all of this drain Suggested revision: all of these substances drain Why it matters: A plural referent and plural verb are needed for the multiple inputs described.
- 8. Correct movement Original: down the water table Suggested revision: through the soil to the water table Why it matters: The diagram shows nitrogen moving downward through the ground before reaching groundwater.
- 9. Correct word Original: lightening Suggested revision: lightning Why it matters: 'Lightning' is the weather phenomenon shown in the diagram.
- 10. Use standard term Original: fixation of nitrogen Suggested revision: nitrogen fixation Why it matters: The standard scientific collocation is 'nitrogen fixation'.
- 11. Use precise preposition Original: under Suggested revision: below Why it matters: 'Below' more precisely describes the location of groundwater processes.
- 12. Clarify what enters Original: accumulate into the water Suggested revision: release nitrogen into the groundwater Why it matters: The sources themselves do not accumulate in the water; nitrogen from them enters it.
Suggested Rewrites
- where it is obtained from the sources of nitrogen
- quantities levels
- nitrogenous substances nitrogen
- domestic market garden domestic and market gardens
- whiles while
- is all important sources is also an important source
Why this response received Band 5.5
The response has a workable source-to-ocean structure and identifies most major nitrogen sources shown in the diagram. However, it does not explain the concentration pattern and seriously misnames key groundwater processes, while frequent grammatical and lexical errors weaken clarity. The highest priority is to organise the report around sources, concentration zones, groundwater movement, and accurately labelled processes, using the diagram’s terminology exactly.
IELTS Writing Criteria Scores
Task Achievement
Most surface sources and the general flow toward the ocean are identified, but concentration levels are omitted and several underground processes are inaccurately described.
Explain where nitrogen is most concentrated and accurately distinguish nitrate uptake, ammonium degassing, and denitrification from the pollutant sources.
Coherence and Cohesion
The report progresses broadly from sources to groundwater movement, although repetition and unclear referencing sometimes weaken the connections.
Group the description into surface inputs, concentration and flow, and transformations, with explicit references to each stage.
Lexical Resource
There is some relevant environmental vocabulary, but frequent imprecise or incorrect expressions undermine technical accuracy.
Use the diagram’s exact labels and correct terms such as ‘lightning’, ‘ammonium degassing’, and ‘denitrification’.
Grammatical Range and Accuracy
Simple and complex structures are attempted, but agreement, article, plural, and clause errors occur frequently despite generally recoverable meaning.
Prioritise subject–verb agreement and complete noun phrases when describing multiple sources and processes.
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IELTS Academic Writing Task 1
The diagram below shows nitrogen sources and concentration levels in the groundwater of a coastal city.
Your response
Write the task yourself, then compare your choices with the annotated response.