Acid rain, storm period chemistry and their potential impact on stream communities in Hong Kong

Hong Kong experiences acid deposition, however, little is known about the potential impact upon aquatic ecosystems. In a small drainage basin observations reveal that despite acid rain runoff, both baseflow and stormflow, was close to neutral in terms of pH. During storm events chemical analysis reveals that calcium (Ca) concentrations tended to rise. It also appears that the input of acid rain may increase aluminium (Al) levels in the stream. Due to the increased levels of Ca and only slight changes in pH acid deposition may not be generating problems in this stream. The presence of mayflies reported elsewhere may further support the results of the chemical study.