Verification and Evaluation of Arsenic Detection Ability in Drinking Water among CDC Laboratories in China

Objective To evaluate the ability of CDC laboratories at all levels in detecting arsenic in drinking water by proficiency testing based on inter-laboratory comparison.

Methods A total of 158 CDC laboratories of different administration levels were selected from 31 provinces (autonomous regions and centrally administered municipalities) and Xinjiang Production and Construction Corps for proficiency testing in November 2018. A standard sample and a testing sample of arsenic were distributed to each laboratory. The robust statistical iterative algorithm A was used to analyze testing results, and the z value was used to evaluate such results.

Results A total of 151 laboratories reported their testing results, among which 118 laboratories (78.1%) had satisfactory results, 6 laboratories (4.0%) had suspected results, and 27 laboratories (17.9%) had outliers. The CDC laboratories at the provincial, provincial capital, and prefecture levels had a significantly better arsenic detection ability than those at the county and district levels (χ² = 11.5, P < 0.05), and there was no significant difference in arsenic detection ability between the CDC laboratories in eastern, central, and western regions (χ² = 2.84, P >0.05).

Conclusion CDC laboratories in China generally have a good arsenic detection ability, and the detection ability of some laboratories needs to be improved. Training of water quality detection should be strengthened.