Samples of water containing concentrations of total organic carbon at levels greater than 20 mg/l when preserved with 40 mg/l of mercuric chloride did not provide a complete inhibition of microbiological growth. A complete inhibition was noted at a preservation level of 400 mg/l of mercuric chloride. A study was conducted on chemical changes of forms of nitrogen and phosphorus in wastewater effluents preserved with 400 mg/l of mercuric chloride. A variety of wastewater treatment plant effluent samples was combined into one composite. The composite was then divided into ten equal samples. Each sample was analyzed separately for Kjeldahl nitrogen, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, orthophosphate phosphorus and total phosphate phosphorus after 10, 30, 60, 80 and 100 days. Due to a logistical handling problem, the samples were usually processed in order in batches. An analysis for total organic carbon, total inorganic carbon and dissolved inorganic mercury was conducted after 100 days.