Biological Consulting Services of North Central Florida, Inc.

Helminths and protozoan parasites are very resistant to environmental conditions and to disinfection methods used in conventional water treatment; therefore, these organisms may be present in drinking water and water used for recreational purposes. Cryptosporidium and Giardia are enteric protozoan parasites that are of particular concern when present in drinking water due to their resistance to commonly used disinfectants, such as chlorine. The presence of even a small number of Cryptosporidium or Giardia cysts poses a definite risk to human health as the dose required to cause infection is very low.

These parasites have been linked to numerous waterborne disease outbreaks and, in 1993, Cryptosporidium was responsible for the largest documented waterborne outbreak in the U.S. when over 400,000 people became ill in Milwaukee, WI due to inadequately treated drinking water. Ingestion of these parasites can cause acute gastrointestinal illness, and Cryptosporidium in particular has shown increased health effects in sensitive populations (e.g., infants, AIDS patients, the elderly), including death.

Our laboratory provides helminth and parasite detection services using standard EPA methodologies and novel published procedures for the most sensitive and reliable results. Our team of research scientists also provide enumeration and viability testing for inactivation and filtration testing.

Long Term Enhanced Surface Water Treatment Rule (LT2)

Existing drinking water regulations require public water systems that use surface water sources to remove at least 99% (2-logs) of Cryptosporidium by filtration. New data on Cryptosporidium infectivity, occurrence, and treatment indicate that, while current treatment requirements are adequate for most water treatment facilities, there is a subset of systems that utilize source waters with high levels of Cryptosporidium oocysts and also systems that do not provide filtration. It is these systems that are of particular concern for water quality managers and public health officials.

As a result, the Environmental Protection Agency (EPA) has proposed a long term enhanced surface water treatment rule (LT2), which will increase monitoring requirements for all treatment facilities that use surface water or ground water under the direct influence of surface water.

Cryptosporidium Infectivity and Viability Testing

In addition to detection of Cryptosporidium and Giardia by Method 1623, BCS has a full scale cell culture laboratory, which enables viability testing of Cryptosporidium oocysts. Viability is assessed and the number of infectious oocysts can be estimated using methods outlined in published literature (Slifko et al., 1999).