环洪泽湖地区耕地养殖污染负荷估算及其风险评价

根据2013年环洪泽湖地区统计年鉴中畜禽养殖量数据,采用排泄系数法估算环湖地区各区(县)内畜禽养殖粪尿产生量及其中污染物含量、流失量和耕地畜禽粪便污染负荷量,并运用耕地畜禽粪便承载预警值对该地区畜禽养殖进行环境风险评价。结果表明:环洪泽湖地区畜禽养殖产生的粪尿共626.63万t,以生猪产生量最高,占总量的56.9%; 其次分别为家禽和牛,分别占总量的19.4%和17.8%。畜禽粪便中化学需氧量(COD)和总氮(TN)的流失量较高,分别占流失总量的65.7%和21.5%。各区(县)污染物的流失状况差异较大。环湖地区耕地畜禽粪便负荷量平均为12.21 t/hm²,污染风险指数平均为0.41,总体预警级别为Ⅱ级,表明现阶段禽畜粪便的排放已对该区整体环境产生了影响,其中以淮阴区、洪泽县和宿城区畜禽粪便负荷量对生态环境的污染威胁相对较大,应作为环洪泽湖地区养殖废弃物排放监管和治理的重点。

Estimation of livestock pollution loading and the risk assessment for farmland in Hung-tse Lake regions

According to the statistical data of livestock and poultry in the region of the Hung-tse Lake in 2013, the manure production of livestock and poultry, pollutant quantity and losses were estimated by using the excretion coefficient method. The warning value of pollution loading for arable land was used to assess the environmental risk of livestock and poultry manure discharge. The results indicated that the total amount of livestock and poultry manure in the lake regions was 6.266 3 million ton, in which the waste from pigs was the highest, accounting for 56.9% of the total manure, followed by poultries and cattle, accounting for 19.4% and 17.8%, respectively. The losses of COD and TN from livestock and poultry manure were higher than other pollutants, accounting for 65.7% and 21.5% of the total loss, respectively. And the losses of pollutants differed among different districts or counties. The average pollution loading for farmland was 12.21 t/hm², and the risk index of contamination was 0.41 corresponding to an alarm level was Ⅱ. This showed that the manure discharge from livestock and poultry had a slight negative impact on the overall environment around Hung-tse Lake regions, among which Huaiyin District, Hongze County and Sucheng District should be given more attention for the manure losses management from livestock and poultry.