Effect Of Reclaimrd Water Irrigation For Crops, Soils And Health Risk Assessment

Wastewater reuse for agriculture is one of efficient paths to meet the shortage of water resource. However, there are little studies about it's effects on crops, soil environments and human health was found, largely limits its safe applications for reclaimed water. This study was is mainly focusing on (i) the influence of irrigating with reclaimed water treated into different extends for crops(cucumber, celery cabbage, maize) and soil; (ii) the primary assessments for health risk of irrigation with reclaimed water.The quality of crops was slightly affected when irrigating with tertiary effluent or second effluent. In comparison, irrigation with sewage led to a little increase of proteins and sugar in crops. The contents of non-metallic inorganic matters in crops after irrigation with different water followed the order: tap water < tertiary effluent < secondary effluent < sewage. When sewage was directly used for irrigation, the content of NO3-and NO2- in celery cabbage was 554.4mg/kg and 5.213mg/kg, respectively, which both overran the standard levels. So sewage was not considered to be suitable enough for irrigation. Irrigating with tertiary effluent did not have great influence for the heavy metal content compare with rinsing irrigation; irrigation with second effluent resulted in slight increase of heavy metals and sewage could lead to apparent accumulation of heavy metals. Due to the short period irrigation, there was not big change for the content of heavy metals in soils when diffluent water sources were used.Risk assessments of applying reclaimed water in agriculture suggested that when using tertiary effluent, secondary effluent and sewage, the total risk of personal cancer annually caused by heavy metals was 4.31×10-7/a, 5.69×10-7/a, 3.33×10-6/a, respectively, which were lower than maximum acceptable level of 5.0×10-5/a, recommended by International Commission on Radiological Protection (ICRP). Lifelong risk to humanbody health caused by chemical hazard matters reached 5.36×10-10/a, 8.23×10-10/a and 4.61×10-9/a, without excess of the maximum acceptable risk level(7×10-5/a). The health risk of reclaimed water...