Severalstudies have concluded that specific level of OP-induced AChE redundance and lethalityin estuarine fish species. Sheep head minnows (Cyprinodon variegatus) wereexposed to selected OP insecticides at normal and high level of fatal rate(40–60% mortality) concentrations.
Theblockage and barrier of brain AChE was always greater that caused mortality ithgreat concentrations. The suppression of brain was much in number about 80% thanwas expected in the fish that survived median lethal exposures. The authorsalso concluded that diversity observed in AChE levels in control fish, themechanism must be lowered by 13% to indicate exposure to OP insecticides. Theseresults conclude that levels of brain suppression brain was 20 to 70% in livefish could be diagnostic of OP insecticide exposure. AChE used asan indicator to detect any possible fluctuation of OP in marine invertebratesbut it is not well defined as expected to be in fish and mollusks. Because of thelack of a well-defined organ system data (such as brains in fish), researchers dependedon a chain of multiple choices of techniques to estimate the results.
Various investigators have used hemolymph, nerveganglion, tissue of muscles, and whole body tissues of invertebrates to estimatethe results of OPs on AChE levels. Blue crabs, Callinectes sapidus, wereexposed to DEF(S, S, S,-tri-n-butyl phosphorotrithioate) at concentrations of1.0 to 10.0 mg/L for 96 h and then assayed for AChE activity.
In control crabs,high activity was found in the ventral ganglion as well as the brain withnegligible activity in claw musculature. Exposed crabs showed a 90% reduction inventral ganglion AChE activity and a greater than 80% reduction in brain AChEactivity AChE activity levels were predominantly higher in the ganglion andbrain after this period.Impact on Marine Mammals and Human PopulationIn recent decades the load of pollutants haveincreased and reduced water quality of many rivers, lakes, and coastal oceans. Environmentaldegradation of these important water re- sources can be estimated by theevaluation of natural water system, species and its environmental componentsand viability on the environment, and the amenities that they provide (U.S. EPA1996, Postel and Carpenter 1997).The indigenous population of Greenland and NorthernCanada can reduce their pollutant intake and risk of health problems bydecreasing their intake of improper food to maintain the health of internal organs,adipose tissue, and preferential consumption of lower trophic species.
The consumptionof young animals will result in decrease level of Cd and Hg and in some casesOHC exposure. For OHCs adult females will be less polluted than that of adultmales. At the same time, these foods are main sources of nutrients and healthrisk can be reduced by changing in diet pattern.Marine mammal distribution is of major importance inplanning contaminant studies and for evaluation the pollution done by municipalsewage because of their larger size, these are primarily and prominently beseen and recorded. In some regions contaminant samples and samples for investigationof effect parameters can only be obtained during tagging operations.