Dubey Brajesh, Townsend Timothy
Department of Environmental Engineering Sciences, University of Florida, Gainesville, Florida 32611-6450, USA.
Environ Sci Technol. 2004 Oct 15;38(20):5400-4. doi: 10.1021/es0493392.
The toxicity characteristic leaching procedure (TCLP) and the synthetic precipitation leaching procedure (SPLP) were performed on commercially purchased samples of the waste-derived soil amendment marketed as Ironite. Ten samples of the 1-0-0 grade (the most widely available in Florida) were tested. Two samples of the 12-10-10 grade and three samples of the 6-2-1 grade (a liquid version) were tested as well. TCLP leachate concentrations from the 1-0-0 grade samples ranged from 5.0 to 8.0 mg L(-1) for lead and 2.2 to 4.8 mg L(-1) for arsenic. SPLP concentrations from the 1-0-0 samples ranged from 0.62 to 3.1 mg L(-1) for lead and 1.9 to 8.2 mg L(-1) for arsenic. All of the 1-0-0 grade samples exceeded the U.S. hazardous waste toxicity characteristic (TC) limit for lead (5 mg L(-1)), while five of the 10 SPLP samples exceeded the TC limit for arsenic (5 mg L(-1)). The greater arsenic leachability in the SPLP relative to the TCLP was determined to be a result of lower pH conditions in the SPLP. A composite sample of the 1-0-0 grade was found to leach much greater concentrations of both arsenic and lead using California's waste extraction test (WET). Lead leachate concentrations were much lower in the two 12-10-10 samples (0.03 mg L(-1) or less); arsenic concentrations in these leachates (both TCLP and SPLP) exceeded 5 mg L(-1). None of the 6-2-1 samples contained lead or arsenic above TC limits. An experiment performed on the 1-0-0 grade which examined leachability as a function of pH found that at pH values in the range of what is encountered in the human digestive system (pH 4.0 to 1.5) lead leached 2-36% of its initial content, and arsenic leached 1-6% of its initial content. A simple gastric acid leaching experiment found 83 and 37% of the lead and arsenic present to leach, respectively.
对市售的名为Ironite的废衍生土壤改良剂样品进行了毒性特性浸出程序（TCLP）和合成沉淀浸出程序（SPLP）。测试了10个1-0-0等级的样品（在佛罗里达州最常见）。还测试了2个12-10-10等级的样品和3个6-2-1等级的样品（液体版本）。1-0-0等级样品的TCLP浸出液中铅的浓度范围为5.0至8.0mg/L，砷的浓度范围为2.2至4.8mg/L。1-0-0样品的SPLP浓度中铅的范围为0.62至3.1mg/L，砷的范围为1.9至8.2mg/L。所有1-0-0等级的样品都超过了美国危险废物毒性特性（TC）铅限值（5mg/L），而10个SPLP样品中有5个超过了砷的TC限值（5mg/L）。相对于TCLP，SPLP中砷的浸出性更高，这被确定是由于SPLP中较低的pH条件所致。使用加利福尼亚州的废物提取试验（WET）发现，1-0-0等级的复合样品浸出的砷和铅浓度要高得多。两个12-10-10样品中的铅浸出液浓度要低得多（0.03mg/L或更低）；这些浸出液（TCLP和SPLP）中的砷浓度超过了5mg/L。6-2-1样品中没有一个的铅或砷含量超过TC限值。对1-0-0等级进行的一项实验研究了浸出性与pH的函数关系，发现在人体消化系统中遇到的pH值范围内（pH 4.0至1.5），铅浸出了其初始含量的2-36%，砷浸出了其初始含量的1-6%。一项简单的胃酸浸出实验发现，分别有83%和37%的铅和砷被浸出。
