求翻译：地下水污染的主要原因有:过度开采地下水，引起地下水位下降，沿海地区海水倒灌；农业生产中大量使用化肥、农药以及污水灌溉等，污染物渗入地下水中；受污染的地面水体或废水渠、废水池、废水渗井等连续渗漏。地下水一经污染后，总矿化度、总硬度升高，硝酸盐、氯化物含量升高，有毒物质增加，溶解氧下降，有时还会出现病原体。地下水污染不易发现，难以治理和恢复，影响供水水质，加剧水资源短缺，应限制开发，合理使用，从而保护地下水资源。是什么意思？

The major causes of groundwater pollution: overexploitation of groundwater, causing water table decline, seawater flooding in coastal areas; heavy use in agricultural production, such as chemical fertilizers, pesticides and sewage irrigation and infiltration of pollutants in underground water; conta

Pollution of groundwater overexploitation of groundwater, mainly due to falling water tables, coastal seas caused; agriculture used in production as well as fertilizers, pesticides, pollutants such as sewage for irrigation in infiltration to groundwater; contaminated surface water or waste water pip

The major causes of groundwa