珠海西部海岸带地下水锰的分布与成因

Distribution and Origin of Manganese in Groundwater in the West Zhuhai Coastal Zone

珠海西部海岸是珠江三角洲地区主要组成部分,环境污染问题严重,通过开展水工环地质调查工作,对地下水水质资料进行分析。结果表明：平原区地下水锰含量普遍较高,为0.155~48.800 mg/L,平均含量为11.359 mg/L;而丘陵区地下水锰含量相对较低,为0.000 3~0.309 mg/L,平均含量为0.0433 mg/L,仅少量锰含量高点位于珠海市香洲区和斗门区的丘陵、台地边缘的地下水系统径流区或排泄区,地下水锰含量分布与所处区域补、径、排条件关系密切。平原区高锰含量的地下水主要为原生环境形成的,后期人类活动影响地下水的锰含量;地下水锰的迁移和富集受多因素控制,包括氧化还原条件、含水层介质与上覆土层性质、咸水区的“盐”效应、酸碱条件、地下水径流条件和环境污染等;该区地下水锰含量与矿化度、COD和氨离子呈显著的正相关关系,而与p H值呈较明显的负相关关系。

The results of groundwater quality in the west Zhuhai coastal zone show that the content of manganese in the plain area is very high, range from 0. 155 to 48. 800 mg/L with an average of 11. 359 mg/L. The content of manganese in the hilly area is relatively low, range from 0. 0003 to 0. 309 mg/L with an average of 0. 0433 mg/L, only few contents of high manganese in groundwater distributed in runoff area or discharge area of groundwater system in the edge hilly area of in Xiangzhou district and Doumen district of Zhuhai city. The distribution of manganese content in groundwater is closely related to conditions of the groundwater recharge, runoff, discharge. The groundwater of high manganese content in the plain area is mainly formed in primary environment, afterwards influenced by human activity. Transport and concentrate of manganese in groundwater is controlled by many factors that are redox environment, aquifer media and characteristics of overlying soils, effect of ＂salt＂, pH condition, runoff conditions, environmental pollution and so on. There exists an obvious positive correlation between the manganese content and salinity, COD, and ammonia ion of groundwater as well as a notable negative correlation between the manganese content and pH value of groundwater in the west Zhuhai coastal zone.