Examples of observational studies:

The authors reported that these results support the hypothesis that prolonged (i.e., more than 30 years) exposure to chlorinated drinking-water from surface water sources is associated with an increased risk of bladder cancer.

There are two types of clinical studies.

There are two common types of observational studies: cohort and case‐control studies.

Types of epidemiological studiesa I.

Association of similar losses in mutagenic activity by removing the analogous chlorine from an open-ring structure compound, 3-(dichloromethyl)-4,4-dichloro-2-chlorobutenoic acid, strongly supported this hypothesis.

In studies of children, observational techniques are highly developed

Thus, the TA98 mutations are consistent with the hypothesis that the chemicals responsible for mutagenic effects of ozonated water are distinct from those induced by chlorination by-products.


Case Studies are a type of observational research that involve ..

4.1.2.3 Neurotoxicity Neurotoxicological findings for the brominated THMs are limited to various observations of anaesthesia associated with acute high-dose exposures and results from a behavioural study conducted by Balster & Borzelleca (1982).

of the hypothesis that have not yet been ..

Clinical observations of animals dosed with high levels of BDCM in these studies and others (NTP, 1987) included ataxia, sedation, laboured breathing and anaesthesia (500 mg/kg of body weight), as well as gross evidence of liver and kidney damage.

Design of Observational Studies

A number of recent studies support the hypothesis that chloroform acts to produce cancer in rodents through a non-genotoxic/cytotoxic mode of action, with carcinogenesis resulting from events secondary to chloroform-induced cytolethality and regenerative cell proliferation (Larson et al., 1994a,b, 1996; Pereira, 1994; Templin et al., 1996a,b,c, 1998).

Observational Research - Definition, Methods & Examples

As with other disinfectants, the terminal elimination phases observed for 36Cl from chlorine dioxide seem compatible with the hypothesis that the bulk of the elimination is as chloride ion.

Registration of observational studies ..

At higher levels of biological organization, a limited number of studies have been conducted to document that the genotoxic form of MX reaches the systemic circulation and to measure mutagenic effects in particular cell types in vivo.

Statistics/Methods of Data Collection/Observational Studies

It is clear from the limited data available that it would be inappropriate to try to generalize data from only a few examples to these two larger classes of DBPs.

Registration of observational studies: Is it time

The competing, but not necessarily exclusive, hypothesis is that the clearly hepatocarcinogenic metabolites TCA and DCA are produced in sufficient quantity to account for some or all of the liver cancer that results from chloral hydrate treatment.