ADJ. massive, serious, widespread | cross- Chopping boards can be a source of cross-contamination. | environmental, food | bacterial, radioactive
QUANT. level There is already a high level of environmental contamination.
VERB + CONTAMINATION avoid, prevent | reduce
PREP. ~ by Always keep food covered to prevent contamination by flies. | ~ from There is a danger of serious contamination from radioactive waste. | ~ with Wash everything thoroughly to avoid contamination with bacteria.
PHRASES a source of contamination