Reviews of Environmental Contamination and Toxicology

Significant volumes of wastewaters, with organic and inorganic contaminants such as suspended solids, dyes, pesticides, toxicants, and heavy metals, are discharged from various industries. These wastewaters create a serious environmental problem and pose a threat to water quality when discharged into rivers and lakes. Thus, such contaminants must be effectively removed to meet increasingly stringent environmental quality standards. It is becoming increasingly recognized that the nontoxic and biodegradable biopolymer chitosan can be used in wastewater treatment (Peniston and Johnson 1970).

The organophosphorus (OP) insecticides were developed before and during World War II. The history of their development has been reviewed (Holmstedt 1963; Karczmar 1970; Ursdin 1970; Koelle 1981). In 1936, Schrader synthesized paraoxon, parathion, and octamethylpyrophosphoramide (OMPA, schradan) in a search for an effective cockroach control agent (Ursdin 1970). Parathion use in agriculture began after World War II. In 1949, a mixer loader was killed by parathion in Lake Placid, FL (Griffiths et al. 1951). Monitoring red blood cell acetyl-cholinesterase (RBC AChE) of exposed workers was begun in 1950 in the Florida citrus industry (Griffiths et al. 1951), perhaps the first use of human blood esterase monitoring in agriculture.

The adverse effects of cyanobacterial toxins were first reported as stock deaths at Lake Alexandrina, South Australia, in 1878. Since then, cyanobacterial poisonings in animals and humans have been widely reported around the world (Codd and Poon 1988). In fact, cattle and wildlife mortality from cyanobacterial poisonings is relatively common in many countries (Carmichael 1981). Animals that have been killed in large numbers include cattle, sheep, pigs, birds, and fish; small numbers of deaths of horses, dogs, rodents, amphibians, and invertebrates have also been recorded (Codd and Poon 1988). According to the compilations of Carmichael (1992a), approximately 85 animal poisoning incidents related to cyanobacterial blooms have been recorded around the world from 1878 to 1991.