What problem can arise from using inadequately processed sewage sludge?

Using inadequately processed sewage sludge can lead to toxicity in food crops because sewage sludge often contains harmful pathogens, heavy metals, and other toxic substances that may not be eliminated during improper treatment. When this sludge is applied to agricultural land without adequate processing, these contaminants can leach into the soil and be taken up by food crops, leading to potential health risks for consumers.

Proper treatment of sewage sludge is essential to eliminate or reduce these hazardous contaminants to safe levels, ensuring that crops grown in such soil do not accumulate toxic substances. This process is critical for maintaining food safety and protecting public health. The other options, while they relate to soil conditions, do not address the significant health concerns associated with the toxicity that can arise from improperly managed sewage sludge.