Pollution on Mytilus edulis — SCHAFER 
249 
Hydrolysates of specimens from LA. 7, L A. 
39, and L.B. 23 contained those amino adds 
reported above for the Tomales Bay specimens, 
plus tyrosine and cysteine. The spot indicative 
of valine assumed a shape which suggests that 
phenylalanine may also be present. In the case 
of L.A. 7 three unidentified amino adds were 
present also; in the case of L.B. 23, two. 
DISCUSSION 
An analysis of the free amino acids present 
in specimens from the three types of situation 
indicated above shows that 1 1 of these occurred 
in all forms. Those specimens taken from pol- 
luted water contained proline, cystine, and 
methionine as well. Those from nonpolluted 
water contained the proline and methionine but 
lacked the cystine. The chromatograms of those 
specimens which had been transferred from 
clean to polluted waters lacked all three of these 
free amino acids, proline, methionine, and cys- 
tine. Taurine/asparagine, not found in any of 
the others, either from dean or polluted water, 
is dearly discernible on the chromatograms of 
the transferred specimens. 
The nature of the pollutants involved in con- 
tributing to these differences has not been spe- 
cifically determined. The data compiled by the 
Los Angeles Bureau of Sanitation (1957), cover- 
ing the periods August 1956 to February 1957, 
show oxygen depletion and increased coliform 
bacterial counts for the areas covered in this 
study. Reish (I960) summarizing characteristics 
of the areas classifies L.A. 7 and L.B. 23 as 
"healthy bottom” areas and lists a dissolved oxy- 
gen at 6.0 ppm for the median at the surface. 
He classifies L.A. 39 as "very polluted bottom” 
with a dissolved oxygen of 1.6 ppm. In describ- 
ing the nature of the substrate he indicated the 
presence of black sulfide mud in each instance. 
A visually obvious pollutant at all three stations 
is an oily substance. The concentration of this 
at L.A. 39' is such that all submerged structures 
appear to have a tarlike coating. Water circu- 
lation at this point seems to be limited to that 
produced by tidal fluctuation. 
Whatever the composition of the pollutants, 
they seem to contain factors which have in- 
fluenced the metabolism of the sulfur-containing 
amino acids, cystine and methionine. It is known 
that methionine can be converted to cystine, and 
that cystine and methionine, via cysteine, in 
mammals can act as a precursor of taurine. Cys- 
tine is present as a free amino acid only in those 
specimens from polluted water. It is protein- 
bound in M. edulis from both clean and polluted 
water. Methionine occurs in free form in all but 
the transferred specimens. It is also found as 
part of the proteins from M. edulis of both dean 
and polluted water. Cysteine appears only in the 
protein-bound form in those animals analyzed 
from polluted water. 
If the spot that appeared in the position of 
taurine/asparagine on the chromatogram, is as- 
sumed to be, at least in part, taurine, then this 
amino add appears in the free form in only 
those specimens transferred. 
If the specimens taken from dean water can 
be considered as those with a normal metabolic 
pattern, then It can be safely postulated that 
the metabolism of methionine has not been al- 
tered in any except the transferred specimens, 
where it does not appear in free form. The 
presence of cystine as a free amino add in indi- 
viduals from polluted water suggests that some 
environmental factor has freed a portion of it 
from proteins or that an amount in excess of 
that utilized in protein formation has been 
synthesized. The possible appearance of free 
taurine in the transferred specimens and the 
total absence of free methionine suggests that 
some factor in the change of environment may 
have brought about the conversion of the latter 
to taurine. 
The disappearance of proline In those speci- 
mens of M. edulis transferred from a dean to 
a polluted environment is unexplainable at 
present. 
SUMMARY 
In an attempt to determine the effects of 
water pollutants upon the wharf mussel, Mytilus 
edulis, the following analyses were made. 
1. Specimens were collected from polluted 
waters. From these the free amino acid content 
of muscle tissue was analyzed by means of two- 
dimensional paper chromatography. These were 
found to contain 14 identifiable free amino 
adds plus some (two in one instance, three in 
