Evans C D, Jenkins A
Institute of Hydrology, Wallingford, OX10 8BB, UK.
Environ Pollut. 2000 Jul;109(1):21-34. doi: 10.1016/s0269-7491(99)00242-0.
Data for eight reservoirs in the South Pennines covering the period 1980-98, and for 1988-98 at the River Etherow Acid Waters Monitoring Network site, have been analysed for temporal trends using the Seasonal Kendall test. Rising trends in pH were identified at seven of the eight reservoirs, generally accompanied by declining aluminium levels. Nitrate concentrations have, however, increased sharply at the two reservoirs for which adequate data were available. Data for a wider range of determinands at the Etherow suggest that pH increases in the region can be attributed to declining sulphate concentrations, as a result of reductions in sulphur deposition. Nitrate concentrations have again increased at this site. Results are significant in a national context in that pH recovery, although widely believed to have taken place in the UK since the 1970s, has rarely been shown to have occurred. For the South Pennine region, which has been severely acidified by historically high acid deposition levels, there have clearly been improvements over the last 18 years, although many surface waters remain acidic. Observed trends for nitrate suggest that some of the pH recovery resulting from reduced sulphur deposition may have been offset by nitrogen saturation in the region, due in part to continued high levels of nitrogen deposition.
对南奔宁山脉8个水库1980 - 1998年期间的数据，以及伊瑟罗河酸性水域监测网络站点1988 - 1998年的数据，使用季节性肯德尔检验分析了时间趋势。在8个水库中的7个发现pH值呈上升趋势，通常伴随着铝含量的下降。然而，在有足够数据的两个水库中，硝酸盐浓度急剧增加。伊瑟罗河更广泛的测定指标数据表明，该地区pH值的升高可归因于硫沉降减少导致的硫酸盐浓度下降。该站点的硝酸盐浓度再次上升。这些结果在全国范围内具有重要意义，因为尽管人们普遍认为自上世纪70年代以来英国已出现pH值恢复，但很少有证据表明确实发生了这种情况。对于因历史上高酸沉降水平而严重酸化的南奔宁地区，尽管许多地表水仍呈酸性，但在过去18年里显然已有改善。观察到的硝酸盐趋势表明，硫沉降减少导致的部分pH值恢复可能已被该地区的氮饱和所抵消，部分原因是氮沉降持续处于高水平。
