The diagram below shows nitrogen sources and concentration levels in the groundwater of a coastal city.
Sample Response
The diagram displays the sources of nitrogenwhere it is obtained from as well as its concentration levelsquantities in the groundwater of a town near the coast. Overall, it is immediately apparent that nitrogennitrogenous substances are obtained from several places, including coastal vegetation, waste disposal, domestic and market gardensdomestic market garden and coastal vegetation.
To begin with, nitrogen is sourced from several places. The first one is from waste disposal such as landfills, whilewhiles 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 also an important sourceis all important sources. So, when it rains, all of these substances drainall of this drain through the soil to the water tabledown the water table into the groundwater. Also, during rainfall, nitrogen is oxidized by lightninglightening and nitrogen fixationfixation of nitrogen by vegetation takes place as well.
Moreover, belowunder the water table, all these sources release nitrogen into the groundwateraccumulate into the water, eventually flowing in one direction to join the ocean. The underground processesdifferent types of waste include nitrate uptake by soil particles, ammonia degassingdigesting and denitrificationidentification, all of which occur before the groundwater flows into the oceanall of which flow to join the ocean water at a zone known as the groundwater discharge zone.
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
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