Monitoring total suspended solids by using nephelometry

Correlation curves were developed relating nephelometric turbidity units (NTU) with total suspended solids (TSS) for diked upland dredged material placement site effluents of three US Army Corps of Engineers (COE) maintenance dredging projects in the Chesapeake Bay, Maryland. The procedure was developed in an effort to ensure compliance with Maryland's 400 milligrams per liter (mg/l) TSS standard for COE dredging projects. Samples of the sediments to be dredged were collected and analyzed, correlating turbidity readings with TSS determined by standard gravimetric techniques. The correlation curves were provided to the COE inspectors to measure the effluent with a turbidity meter and to extract a TSS concentration from the correlation curve. Samples collected and analyzed after initiation of the dredging indicated that the correlation curves were an overestimate of the actual TSS concentrations of the effluent discharges. The procedure, endorsed by the State of Maryland, provided immediate on-site TSS analysis eliminating the previously encountered delays in obtaining gravimetric analysis of effluent discharges and potential contract management problems.     

对改良硫酸钡比浊法测定水中硫酸根方法的改进

通过条件试验，对改良比浊法测定水中硫酸根方法进行了改进。检测限为０．１６ｍｇ／Ｌ，对地面水，地下水，降水和废水的测定，相对标准差小于１．２％，加标回收率在９５．９％－１０３．８％之间。