平?jīng)鍪械湫妥魑锓N植區(qū)土壤重金屬污染狀況及其分布特征

朱敏

摘要：土壤重金屬污染已嚴(yán)重危害糧食安全與人類健康。為了解平?jīng)鍪型寥乐亟饘傥廴粳F(xiàn)狀，摸清典型作物生長(zhǎng)、生產(chǎn)環(huán)境，明確土壤重金屬空間分布特征及污染源。選取506個(gè)典型作物種植區(qū)耕層土樣，測(cè)量其重金屬含量，并利用內(nèi)梅羅指數(shù)法和潛在生態(tài)危害指數(shù)法進(jìn)行土壤重金屬污染評(píng)價(jià)。結(jié)果表明，平?jīng)鍪型寥乐亟饘傥廴镜燃?jí)為清潔的樣品占99.41 %、尚清潔占0.59 %；潛在生態(tài)危害等級(jí)輕微的土壤樣品占95.85 %、中等生態(tài)危害占4.15%。506 個(gè)點(diǎn)位樣品中，鉛和砷2種土壤重金屬元素有部分超標(biāo)，超標(biāo)率Pd為0.45%、As為0.90%。從地理區(qū)域來(lái)看，土壤重金屬潛在生態(tài)危害程度在平?jīng)鍪械姆植紴橹胁?> 西部 > 東部；從土壤類型來(lái)看，土壤重金屬污染占比較大的土類主要為山地草甸土、灰褐土、新積土和紅粘土。

關(guān)鍵詞：土壤；重金屬污染；內(nèi)梅羅指數(shù)法；潛在生態(tài)危害指數(shù)法；空間分布

中圖分類號(hào)：X5318.1 ? ? ? ? ?文獻(xiàn)標(biāo)志碼：A ? ? ? ? ?文章編號(hào)：2097-2172（2023）02-0173-05

doi：10.3969/j.issn.2097-2172.2023.02.016

Soil Heavy Metal Pollution Status and Its Spatial Distribution

Characteristics of Typical Crop Planting Areas in Pingliang

ZHU Min

（Pingliang Agricultural Technology Extension Station， Pingliang Gansu 744000， China）

Abstract： Contamination of soil with heavy metals has seriously endangered human health and food security. To understand the current situation of soil heavy metal pollution， to find out the growth and production environment of typical crops， and to clarify the spatial distribution characteristics and pollution sources of heavy metals in Pingliang， 506 farmland topsoils were collected and their heavy metal contents were measured. Results showed that the proportions of tested samples marked as clean grade and still clean grade of soil heavy metal pollution in Pingliang were 99.41% and 0.59%， respectively. The proportions of potential ecological hazard grades of minor and moderate were 95.85 % and 4.15%， respectively. Among samples from 506 points， 2 soil heavy metal elements exceeded the standard and the excess rates were Pd as 0.45% and As as 0.90%. The potential ecological hazard of soil heavy metals by geographic region was Central > West > East. In terms of soil type， the soil types with a large proportion of soil heavy metal pollution were mountain meadow soil， gray-brown soil， new accumulation soil and red clay soil.

Key words： Soil; Heavy metal pollution; Nemero index method; Potential ecological hazard index method; Spatial distribution

土壤重金屬污染問題近年來(lái)引起大眾廣泛關(guān)注。隨著生活水平的提升，人們對(duì)農(nóng)業(yè)綠色食品、產(chǎn)品和糧食安全的要求愈來(lái)愈高，但隨之而來(lái)的農(nóng)田土壤重金屬污染問題卻越來(lái)越凸顯［1 ］。人體內(nèi)重金屬物質(zhì)增加的主要渠道是土壤重金屬經(jīng)過(guò)食物鏈的留轉(zhuǎn)，而土地中重金屬物質(zhì)的高毒性、永久性、難降解特性和在食物鏈中的高蓄積性等，都會(huì)對(duì)人類健康造成危害［2 ］。土地重金屬物質(zhì)中有汞（Hg）、鉛（Pb）、鎘（Cd）、鉻（Cr）和砷（As）等危害性明顯的元素，也包括有一些常見的鋅銅（Cu）、鋅（Zn）、鎳（Ni）等微量元素，這些主要來(lái)自農(nóng)藥、廢水、污泥和大氣沉降等。由于在土……