Kolpin and his associates acknowledge that they underestimated antibiotic occurrence because they measured concentrations only in water ; antibiotics tend to build up in mud and other sediments 柯尔品等人承认，由于他们只测定了水中的物质含量，而抗生素常堆积在淤泥及其他的沉淀物中，因此可能低估了抗生素的量。
