I started a new topic because this sounds important. I'm not an expert and would like to know the exact answer from anyone who know this more.

施有biosolids的土壤生产的粮食, 蔬菜, 吃了这种土壤种植的饲料的鸡是不是也被称为organic呢? If so, shall we go for, or avoid organic foods?

Here is the link to "biosolids", http://ehp.niehs.nih.gov/qa/105-1focus/focusbeauty.html , if you haven't heard of this word. It's just another name for processed "sewage sludge".

Here is a link from U.S. Environmental Protection Agency: http://www.epa.gov/owm/mtb/biosolids/useofmid/ If you just google "biosolids" or search from EPA website, you'll find lots of debate about the bad effect of biosolids application.

And, land with biosolids can be used to produce crops and vegetables that might be consumed by human beings. The following paragraphs are from this link http://www.ext.vt.edu/pubs/compost/452-303/452-303.html

"Agricultural Land Application of Biosolids in Virginia: Managing Biosolids for Agricultural Use

High N-use crops such as corn, soybean, small grains, and forages will minimize the amount of land needed for biosolid application and will benefit from the N supplying capability of bisolids. Crops grown for their flowering parts, such as cotton, can produce undesirable amounts of vegetative growth if they continue to accumulate N late in the season. Thus, slow release N sources such as biosolids and manures may impair the quality of such crops; however, biosolids can be used efficiently on other crops in rotation with cotton.

Biosolids can be applied to vegetable crops, but green leafy vegetables tend to accumulate higher concentrations of metals than the grain of agronomic crops. Some scientists have cautioned against using biosolids on vegetable crops because they provide a direct conduit of potentially harmful trace elements from the soil to humans. Therefore, grain and forage crops are better choices for biosolids application than vegetables. Tobacco accumulates heavy metals such as Cd in high concentrations, and the use of biosolids on tobacco land is not recommended. "