Impacts Of Wastewater Irrigation On Agricultural Environment And Its Economic Loss Evaluation In Hebei Province

The paper evaluates the impacts of wastewater irrigation on agro-environmental quality in Hebei province and predicts its future trend. After qualification of environmental pollution, we use environmental economy methods to evaluate the environmental cost of wastewater irrigation, i.e. calculating the environmental pollution and resources depletion as economic loss.After sampling and investigation in Luancheng county, Zhao county and Xinhe county of Shijiangzhuang city and Qingyuan county of Baoding city, the following conclusions can be made.Compared with clean water irrigated farmlands, soil heavy metals of typical wastewater irrigated farmlands accumulated and among which Cd pollution are the most serious. Forecast research indicates that heavy metals values will not be higher than national soil environmental quality standards. Wastewater irrigation has impacts on shallow groundwater, and the main contaminants are NO3--N, NO2~-N, COD and volatile phenols. Forecast research indicates that NO3--N will accumulate in the future, and its increasing rate is 111.8%. Heavy metals in wheat and maize in typical wastewater irrigated farmlands accumulate and exceed national standards, and the percentage of exceeding are 42.4% and 33.3% for wheat and maize respectively. Grains contaminated with exceeded heavy metals are 2.5×105 tons. Wastewater irrigation can also increase the incidence of diseases like cancer, hepatomegaly and tummy bug, and the increase percentage are 120.7%, 213.8%, 510.4% and 176.9% respectively. Amount of sufferers increased by sewage irrigation is 23.34% of population in wastewater irrigated areas.The economic loss was calculated as: the total environmental cost from wastewater irrigation was about 737 million RMB in Hebei province in 2000, which accounts for 0.87% of the total agricultural production value. Among which, people's healthiness loss was 95.3% of the total environmental cost. Marginal environmental cost for grain (wheat and corn) production in sewage irrigation areas was 0.43RMB/kg in Hebei province.