利用植物监测、评价广州市大气中二氧化硫的污染程度

1981年我们利用植物对广州市的大气环境作了监测、评价。在市区，设18个点，另以南湖为对照点。每个点均选定木麻黄(Casuarina equisetifolia)、大叶榕(Ficus lacor)，石栗(Aleurites moluccana)及羊蹄甲(Bauhinia purpurea)为采样植物。全年分春，夏、秋，冬四次采样。采用燃烧法，对叶片或技条进行含硫量的测定。分析结果,利用下列公式：IPC=Cm/Ck计算出各点的含硫量指数。根据这些指数，对各监测点的空气中二氧化硫的污染程度进行分级： Ⅰ．清洁(<1.0)，Ⅱ．轻污染(1.1—1.5)，Ⅲ.中污染(1.6—2.0)，Ⅳ．重污染(>2.1)。用曲线图比较，70个含硫指数中，有69个的含硫量高于对照点，占99%。四种植物中，有三种植物含硫量的最高值出现在荔湾区。按污染级数比较，70个含硫指数中，Ⅳ．重污染的有12个，占含硫指数的17%。在荔湾区14个含硫指数中，Ⅳ．重污染的有7个，占50%，说明荔湾区是二氧化硫污染的高值区，与大气采样结果是相似的。Ⅲ．中污染的有24个含硫指数，占34%，Ⅱ．轻污染的有33个，占47%，Ⅰ．清洁的有1个点，占1.4％。采用相关系数比较，把四种植物的年平均值作为自变量(x)，大气采样的年平均值为因变量(y)，通过公式：求出相关系数r:木麻黄、大叶榕、石栗、羊蹄甲分别为0.27，0.49、0.55，0.48，表明y随着x的增加而增加，为正相关。由此可见，植物受SO2的污染之后，分析的结果与大气采样的结果，有一定的相关性。因此，认为以上述四种植物来评价大气中SO2的污染程度，与大气采样互相补充，全面了解环境质量是可行的。此方法可节省人力物力，不要求高精仪器，本地区绿化植物的品种多，取材容易，因此有一定的实际意义。

Using Plants to Monitor and Evaluate the Level of Sulphur Dioxide Pollution in the Atmosphere of Guangzhou City

Plants were used to monitor and evaluate the atmospheric environment of Guangzhou city in 1981. 18 sites were chosen within the city for monitoring and one site of Nan Hu at the outskirts of Guangzhou was chosen for control. On each site, we sampled four plants species for measuring the sulphur content in their leaves. Sampling were made four times in a year: spring, summer, autumn and winter, inflammation method was adopted. The sulphur content index was calculated by the following formula: IPC=Cm/CkAccording to this index, four classes of pollution can be distinguished: Ⅰ.clean (<1.0); Ⅱ. light (1.1–1.5); Ⅲ. medium (1.6–2.0); Ⅳ- heavy (>2.1). Evalution: 1. Comparing by graphic curves, it comes into notice that there were 69 sites among 70 sulphur content index (99%) with higher sulphur content than that of the control. Among the 4 plant species studied, three were found in Li Wan District with maximum amounts of sulphur. 2. According to classes of pollution 12 (17%) out of the 70 indices belong to heavy. Among 14 indices in Li Wan District, 7 belong to heavy (50%), which means that Li Wall District is one of the serious polluted area by SO2. 3. Comparing by correlation coefficients, we used the annual mean value of the four plant species as independent variables (x), and that of the atmospheric sample as dependent variables (y). The formula: was used to evaluate the correlation coefficients of these four species. The values obtained were 0.27, 0.49, 0.55 and 0.48 respectively. It shows clearly that the x and y are positively correlated.