SECTION 2 



WATER QUALITY & CHEMISTRY OF POND WATERS 



Introduction 



This section describes the sampling methods and analysis procedures for the major 

 solutes, and the trace elements including molybdenum, arsenic, boron and selenium. Trends in 

 solute and trace element concentrations in the ponds are also described. 



Sampling and Measurement Procedures 



Pond Water Sampling 



Two sites at each pond were sampled using one liter Nalgene polypropylene bottles. 

 Water samples were taken 2-3 meters in from the shoreline of each pond at representative 

 corners. One water sample was immediately analyzed on-site for pH, temperature, DO, Eh, 

 alkalinity', EC, and density (Table 2.1). The second 1-liter sample was brought to the University 

 of California West Side Field Station near Five Points and filtered. The samples were first 

 vacuum filtered through No. 2 Whatman filter paper to eliminate the large particles. Solutions 

 were then pumped through a 6" diameter, 0.45nm membrane filter using a peristaltic pump 

 (Geotech Environmental Equipment Inc). The final filtering was through a Gelman 0.45 (im 

 membrane filter (Millipore filter holder) using a suction fiask. About 400 to 500 mL of the 

 resulting filtrate was acidified with nitric acid to - pH 2.0 for trace element analysis. The 

 remaining unacidified filtered sample was kept cold under ice and reserved for anion and carbon 

 analysis. 



Table 2.1 Pond Water Sample On-Site Measurement Instrumentation 



Parameter Equipment 



O Electrical Conductivity (EC) YSI Model 32 Conductance Meter with YSI 3417 dip- 



type plastic cell and YSI 701 Temperature Probe. 



O pH, temperature (Centigrade) Markson Model 90 pH/temperature meter with Markson 



Duramark or Tefmark II pH electrode, YSI 701 

 temperature probe. 



O Redox potential (Eh) Markson Model 90 pH/Temperature Meter, Markson 



redox combination platinum electrode, YSI 701 

 temperature probe. 



O Dissolved oxygen (DO) YSI Model 5 IB, YSI Oxygen/Temperature probe. 



O Alkalinity Acid titration to pH 4.5 with Markson pH meter and pH 



electrode, YSI 701 temperature probe. 



O Density Fisher Specific Gravity Hydrometer, range 1.000-1.225 



and cylinder. 



Chemical Analysis 



The Applied Research Laboratories (ARL) Model 3510 Inductively Coupled Plasma 

 Spectrophotometer (ICPS) instrument was used for sodium (Na), potassium (K), calcium (Ca), 

 magnesium (Mg), arsenic (As), molybdenum (Mo) and boron (B) determination. For ICPS 

 analysis, the standards (Inorganic Ventures, Toms River, New Jersey), in various concentra- 

 tions, were acidified, and 5 ppm scandium (Sc) and 10 ppm bismuth (Bi) added as internal 

 standards. Internal standards are also added to all acidified samples to be analyzed by ICPS. 

 A standard comparable to the sample concentration was analyzed after every six samples to 

 check for recovery. Intermittently, a dilute sample and a previously analyzed sample were 

 inserted as samples to check reproducibility. 



'Alkalinity is presented in this report in terms of mg/l CaCO^ 



page 2.1 



